On Feb 7, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 6, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 6, 2016, Jim Wilkins wrote
(in article ):

idwrote in
message ...
On 2016-02-06, Jim wrote:

I often look at all that stuff, and I find extreme ingenuity
with
which people overcame limitations of their current
technologies,
it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone
which
does
everything over two wires without active electronics, only one
very
clever transformer, speaker and carbon mike. I couldn't quickly
find a
circuit description and should return to fixing my fallen TV
antenna
that had me abseiling down the snow-covered roof.
Here is the core circuit of the pre-transistor circuit:

.https://en.wikipedia.org/wiki/Telephone_hybrid

Joe Gwinn

Instead of the phone circuit it shows the Central Office interface
between a two-wire local subscriber line and 4-wire long distance
lines with amplifiers for each direction.

The hybrid combines or separates the mouth and ear signals so
effectively that a little of the user's voice has to be leaked back
into their ear as "sidetone" to keep them from shouting. It "knows"
the difference between the transmit and receive signals in the
single
wire pair. We learned the possibly bad habit of blowing gently and
silently into the microphone to make a sound that only appears in
the
speaker.

Yeah, I was focused on the hybrid, which is used at both ends.

Somewhere I have complete circuit for a POTS phone, but a modern
unit with
touchtone dial (the original, with pot cores and a germanium
transistor). I
recall it came from an old issue of BSTJ.

I have and use a bunch of telephones from that era. After 40 years,
the tone
frequencies had drifted a bit, and I had to retune the touchtone
pads.


Joe Gwinn

I looked at that page for a while, trying to explain intuitively how a
hybrid transformer can separate the overlapping signals passing in
both directions.

The key is to follow both voltages and currents.

One cannot tell direction of propagation from voltage alone, but one can tell
by comparing signed voltages with signed currents.

Joe Gwinn

"Joseph Gwinn" wrote in message
s.com...
On Feb 7, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 6, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 6, 2016, Jim Wilkins wrote
(in article ):

idwrote
in
message
...
On 2016-02-06, Jim wrote:

I often look at all that stuff, and I find extreme
ingenuity
with
which people overcame limitations of their current
technologies,
it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone
which
does
everything over two wires without active electronics, only
one
very
clever transformer, speaker and carbon mike. I couldn't
quickly
find a
circuit description and should return to fixing my fallen
TV
antenna
that had me abseiling down the snow-covered roof.
Here is the core circuit of the pre-transistor circuit:

.https://en.wikipedia.org/wiki/Telephone_hybrid

Joe Gwinn

Instead of the phone circuit it shows the Central Office
interface
between a two-wire local subscriber line and 4-wire long
distance
lines with amplifiers for each direction.

The hybrid combines or separates the mouth and ear signals so
effectively that a little of the user's voice has to be leaked
back
into their ear as "sidetone" to keep them from shouting. It
"knows"
the difference between the transmit and receive signals in the
single
wire pair. We learned the possibly bad habit of blowing gently
and
silently into the microphone to make a sound that only appears
in
the
speaker.

Yeah, I was focused on the hybrid, which is used at both ends.

Somewhere I have complete circuit for a POTS phone, but a modern
unit with
touchtone dial (the original, with pot cores and a germanium
transistor). I
recall it came from an old issue of BSTJ.

I have and use a bunch of telephones from that era. After 40
years,
the tone
frequencies had drifted a bit, and I had to retune the touchtone
pads.


Joe Gwinn

I looked at that page for a while, trying to explain intuitively
how a
hybrid transformer can separate the overlapping signals passing in
both directions.

The key is to follow both voltages and currents.

One cannot tell direction of propagation from voltage alone, but one
can tell
by comparing signed voltages with signed currents.

Joe Gwinn

I just had to explain the insulator at the center of a dipole. If you
want to post about what the little dots on a transformer schematic
mean, please go at it..
--jsw

On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:

"Ed Huntress" wrote in message
.. .
On Sun, 7 Feb 2016 12:11:35 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
...
On Sat, 6 Feb 2016 23:21:08 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in
message
om...
On Sat, 6 Feb 2016 15:38:04 -0500, "Jim Wilkins"
wrote:

"Ignoramus14059" wrote in
message ...
On 2016-02-06, Jim Wilkins wrote:


I often look at all that stuff, and I find extreme ingenuity
with
which people overcame limitations of their current
technologies,
it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone which
does
everything over two wires without active electronics, only one
very
clever transformer, speaker and carbon mike. I couldn't quickly
find
a
circuit description and should return to fixing my fallen TV
antenna
that had me abseiling down the snow-covered roof.

It's a good thing you were strung up.

I hadn't practiced a Dulfersitz in decades.

Abseiling I knew, after having to look it up last year when my
niece
and new nephew went to Gnu Zealand for spelunking and Middle
Earthing.
They had a blast. I had to look up Dulfersitz, and it definitely
does
not look like something I'd try in anything but an emergency. If
you
slipped, you'd likely lose control of the rope and fall.

P.S: Doesn't anyone say "rappelling" any more?

Rappeler is French for recall, as in recalling the doubled rope from
the bottom. Maybe French has lost its cachet of exclusiveness to
German? Have you seen any French competition to Audi, BMW or
Mercedes
recently?

Wednesday the forecast was for 10-20MPH winds, not the howling
gale
that blew the TV antenna down. Thursday I replaced the bent mast
section, then Friday the predicted few inches of light snow clung
to
the guy lines and pulled it down again, and this time it smacked
the
roof HARD right over me.

Time for a new mast system, wot? Better yet, Repent!, and TV no
more.
I'm going on 11 years without it now. Netflix and Redbox give me
the
movie fixes I need, but I haven't suffered through brainless
broadcast
TV or the massively stupid and numerous commercials for over a
decade.
The only commercials I actively seek are those for the Stupor
Bowl,
and even then, at millions a pop, they put some stupid one on.
The
money spent on sports and commercials each year would be enough,
in
one single year, to -feed- and -house- the homeless and hungry
poor
in
America (even those who don't deserve it), and probably a few
dozen
other countries. Too bad so few people have this perspective.
(Sorry, it just slipped out.)

TVs do have an OFF switch, you know, for those of us with the self
control to use it. Mine is mainly my best source of up-to-date local
news and weather. Until I decide how to reengineer the insulators in
a
material with different properties I can use Boston weather
forecasts,
that antenna wasn't damaged.

I used to tell TV haters that they were missing good material on PBS
but it no longer has much that interests me.

There are 5 oak insulator blanks sitting on the milling machine to
be
completed tomorrow. I made one to replace the first fall's damage,
boiled it in wax to drive out the water and seal it, and didn't
lose
any signal strength from it.

Whuffo? Doesn't good cable preclude the need? Or are you
insulating
the mast from something? I don't recall having heard about this.
Or
are you the poor sod who was blessed with an overly lightningized
environment? If so, would oak insulators even help? A million
volt,
million amp spark which jumps thousands of feet of air in an
instant
is pretty hard to protect from, innit? Just sayin...

These insulators support the two sections of the dipoles without
letting them short to each other or the metal supporting structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw


I haven't heard of anyone using wood insulators boiled in paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured its
performance but I worked Australia and Norway with 50 W using that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you have
a
lot to choose from. A QRP fanatic/friend I know, who is a plastics
engineer, uses FEP. I don't know where you get it, but it's supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50 MHz.
Immersing wood in 280F molten wax certainly forces a lot of water out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw


There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago. g

--
Ed Huntress

"Ed Huntress" wrote in message
...
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw


I haven't heard of anyone using wood insulators boiled in paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured
its
performance but I worked Australia and Norway with 50 W using that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of water
out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time
is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw


There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago. g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.
https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw

On Feb 7, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 7, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 6, 2016, Jim Wilkins wrote
(in article ):

"Joseph wrote in message
s.com...
On Feb 6, 2016, Jim Wilkins wrote
(in article ):

idwrote
in
message
...
On 2016-02-06, Jim wrote:

I often look at all that stuff, and I find extreme
ingenuity
with
which people overcame limitations of their current
technologies,
it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone
which
does
everything over two wires without active electronics, only
one
very
clever transformer, speaker and carbon mike. I couldn't
quickly
find a
circuit description and should return to fixing my fallen
TV
antenna
that had me abseiling down the snow-covered roof.
Here is the core circuit of the pre-transistor circuit:

.https://en.wikipedia.org/wiki/Telephone_hybrid

Joe Gwinn

Instead of the phone circuit it shows the Central Office
interface
between a two-wire local subscriber line and 4-wire long
distance
lines with amplifiers for each direction.

The hybrid combines or separates the mouth and ear signals so
effectively that a little of the user's voice has to be leaked
back
into their ear as "sidetone" to keep them from shouting. It
"knows"
the difference between the transmit and receive signals in the
single
wire pair. We learned the possibly bad habit of blowing gently
and
silently into the microphone to make a sound that only appears
in
the
speaker.

Yeah, I was focused on the hybrid, which is used at both ends.

Somewhere I have complete circuit for a POTS phone, but a modern unit
with
touchtone dial (the original, with pot cores and a germanium
transistor). I
recall it came from an old issue of BSTJ.

I have and use a bunch of telephones from that era. After 40 years,
the tone frequencies had drifted a bit, and I had to retune the
touchtone
pads.


Joe Gwinn

I looked at that page for a while, trying to explain intuitively how a
hybrid transformer can separate the overlapping signals passing in
both directions.

The key is to follow both voltages and currents.

One cannot tell direction of propagation from voltage alone, but one
can tell by comparing signed voltages with signed currents.

Joe Gwinn

I just had to explain the insulator at the center of a dipole. If you
want to post about what the little dots on a transformer schematic
mean, please go at it.

The dots signify the orientation of the windings with respect to the linking
magnetic flux. If you have a two-winding transformer and drive one winding
with an AC source, the voltage at dotted ends of the windings will be in
phase (the amplitudes will differ according to the ratio of turns).

Joe Gwinn

On Sun, 7 Feb 2016 15:58:29 -0500, "Jim Wilkins"
wrote:

"Ed Huntress" wrote in message
.. .
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw


I haven't heard of anyone using wood insulators boiled in paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured
its
performance but I worked Australia and Norway with 50 W using that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of water
out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time
is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw


There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago. g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.
https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw


Yeah, I guess that reinforces (forgive the pun) the idea that PTFE is
the right material for high frequencies -- low and consistent
dielectric constant, combined with extremely high resistance.

--
Ed Huntress

Nice pictures. So did you just buy it for the copper?

I see you've got a bigger truck now :-).

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 7 Feb 2016 15:58:29 -0500, "Jim Wilkins"
wrote:

"Ed wrote in message
...
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw

I haven't heard of anyone using wood insulators boiled in paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured
its
performance but I worked Australia and Norway with 50 W using that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of water
out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time
is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw

There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago.g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.
https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw

Yeah, I guess that reinforces (forgive the pun) the idea that PTFE is
the right material for high frequencies -- low and consistent
dielectric constant, combined with extremely high resistance.

Low moisture absorption is also essential - water has a high dielectric
constant, and is also quite lossy.

Joe Gwinn

On Sun, 07 Feb 2016 18:13:06 -0500, Joseph Gwinn
wrote:

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 7 Feb 2016 15:58:29 -0500, "Jim Wilkins"
wrote:

"Ed wrote in message
...
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw

I haven't heard of anyone using wood insulators boiled in paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured
its
performance but I worked Australia and Norway with 50 W using that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of water
out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time
is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw

There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago.g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.
https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw

Yeah, I guess that reinforces (forgive the pun) the idea that PTFE is
the right material for high frequencies -- low and consistent
dielectric constant, combined with extremely high resistance.

Low moisture absorption is also essential - water has a high dielectric
constant, and is also quite lossy.

Joe Gwinn

I should know enough to stay out of plastics discussions -- the
chemistry drives me nuts -- but I see that PTFE has extremely low
absorbtion, as does FEP.

I also see that I have been mislead, or I misread something years ago:
Teflon is the name for two products. The common one is PTFE. But there
also is an FEP version, which, I see now, DuPont calls "Teflon FEP."
Finally, the data on dielectric constant is somewhat contradictory for
FEP versus PTFE from different sources. Some say they're the same,
others say that of FEP is twice as high.

Finally, the dielectric *strength* of FEP versus PTFE (which probably
is irrelevant here) is three times higher for FEP.

polymer chemistry torture off

--
Ed Huntress

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 07 Feb 2016 18:13:06 -0500, Joseph Gwinn
wrote:

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 7 Feb 2016 15:58:29 -0500, "Jim Wilkins"
wrote:

"Ed wrote in message
...
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles
without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw

I haven't heard of anyone using wood insulators boiled in
paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured
its
performance but I worked Australia and Norway with 50 W using
that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a
plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and
I
haven't found loss tangent data on thoroughly dried wood above 50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of water
out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors
for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time
is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw

There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago.g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.
https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw

Yeah, I guess that reinforces (forgive the pun) the idea that PTFE is
the right material for high frequencies -- low and consistent
dielectric constant, combined with extremely high resistance.

Low moisture absorption is also essential - water has a high dielectric
constant, and is also quite lossy.

Joe Gwinn

I should know enough to stay out of plastics discussions -- the
chemistry drives me nuts -- but I see that PTFE has extremely low
absorbtion, as does FEP.

I also see that I have been mislead, or I misread something years ago:
Teflon is the name for two products. The common one is PTFE. But there
also is an FEP version, which, I see now, DuPont calls "Teflon FEP."
Finally, the data on dielectric constant is somewhat contradictory for
FEP versus PTFE from different sources. Some say they're the same,
others say that of FEP is twice as high.

According to Wikipedia, both have a dielectric constant of 2.1 at 1 MHz.


Finally, the dielectric *strength* of FEP versus PTFE (which probably
is irrelevant here) is three times higher for FEP.

Yes, dielectric strength is rarely a big issue. Surface leakage is usually
the limiting item.


polymer chemistry torture off

How about some electronic materials torture? Waxy plastics (and paraffin
waxes for that matter) have low dielectric constants because the molecules
are non-polar, and the molecules are large and get in each others way.

Unlike water, where the molecules are polar and will turn to align themselves
to any ambient electric field. Liquid water has a dielectric constant of 80,
but ice is lower, because freezing retards molecular rotation. Test frequency
has a very large effect on the dielectric constant of water, but not so much
on waxy plastics.

Joe Gwinn

Igy

Have you considered a heavy conveyor 'belt' motor ?
A heavy equipment replacement drive motor ?

You know the BIG BIG 'scopes' that dig canals ?

Hate to see it scrapped for the copper and steel.

Martin

On 2/6/2016 1:58 PM, Ignoramus14059 wrote:
On 2016-02-06, Jim Wilkins wrote:

"Ignoramus14059" wrote in
message ...
On 2016-02-05, Jim Wilkins wrote:
"Ignoramus9436" wrote in
message
...
On 2016-02-05, dpb wrote:
On 02/04/2016 7:57 PM, Ignoramus11775 wrote:
It is sitting on my truck:

http://igor.chudov.com/tmp/4500-hp-motor.jpg

It was used to power a big blower at a coal fired electrical
power
station. Then it was rebuilt, then the power station was shut
down
by
the EPA. The power station is 96 years old. They have a 96 years
old
bridge crane that is still operational.

The blower at iFly is 1,600 HP, and this is 4,500 HP, almost 3
times bigger.

http://en-us.fluke.com/community/flu...rs-flying.html


Couldn't find a good picture quickly, unfortunately...reactor
primary
coolant pump motors are around 6,0000 HP (Oconee-class, 850 MWe
output)
to approaching 10,000 HP for later 1100-1200 MWe units. There's
enough
"waste" energy imparted from the impeller work that it's how
initial
temperature is raised from ambient to 560 F at 2250 psia prior to
reactor startup. Oconee flow rate is 131.6E6 lbm/hr total or
roughly
65,000 gpm thru each of the four RCPs...

Power plants do tend to be big machines...

I am taking pictures of their place, as I work there.

They have enormous vertical pumps also, impellers about 12 ft in
diameter. Powered by what clearly looks like antique giant
motors. Much bigger than the motor in the photo that I posted.

i

This is an electrically powered US aircraft carrier supplying
Tacoma,
Washington during the winter of 1929-30, when a drought crippled
their
hydro plant:
http://www.navsource.org/archives/02/020247.jpg
The ship's electric propulsion motors totalled 180,000 HP.
Electricity
was used as an automatic transmission connecting the high-speed
turbo-generators to the much slower propellor shafts, before we
learned to make sufficiently large and reliable reduction gearing.

WW2 submarines used electric drive motors about the size of yours.

-jsw



This is amazing. Most locomotives and large mining trucks are still
electrically driven.

i

This was the first electric drive ship, from the same era as your
motor:
https://en.wikipedia.org/wiki/USS_New_Mexico_(BB-40)
"She ... and was used for the early development of PID controllers.
Invented by the Russian-American engineer Nicolas Minorsky for the
automated steering of ships, the devices have since become widespread
in control engineering."
Talented Russians invented plenty of things -- as refugees in America.

The USS Lexington in the previous photo was originally designed as a
battlecruiser and was thus overpowered as a lighter aircraft carrier.
In trials those electric motors pushed her to 39.81 MPH at 202,973 HP.
The ship's speed increased the load her planes could take off with.
http://www.goodreads.com/book/show/6..._The_Flat_Tops

I often look at all that stuff, and I find extreme ingenuity with
which people overcame limitations of their current technologies, it is
fascinating.

i

On 2016-02-07, Robert Nichols wrote:

[ ... ]

AT&T's original Touch Tone telephones had a clever circuit that
allowed a single transistor to oscillate on two frequencies at
once, with both frequencies closely controlled in both frequency
and relative amplitude. Yes, transistors were relatively
expensive back then.

And -- as a result of that design Tw0 tapped inductors with
associated capacitors), and the mechanical design of the keypad
switches, if you pressed two buttons in a single row or column, you
would get a single tone, shorting out the other tapped inductor, and
thus preventing it oscillating.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2016-02-07, Jim Wilkins wrote:
"Robert Nichols" wrote
in message ...
On 02/06/2016 02:38 PM, Jim Wilkins wrote:
"Ignoramus14059" wrote in
message ...
On 2016-02-06, Jim Wilkins wrote:


I often look at all that stuff, and I find extreme ingenuity with
which people overcame limitations of their current technologies,
it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone which
does
everything over two wires without active electronics, only one very
clever transformer, speaker and carbon mike. I couldn't quickly
find a
circuit description and should return to fixing my fallen TV
antenna
that had me abseiling down the snow-covered roof.

AT&T's original Touch Tone telephones had a clever circuit that
allowed a single transistor to oscillate on two frequencies at
once, with both frequencies closely controlled in both frequency
and relative amplitude. Yes, transistors were relatively
expensive back then.

--
Bob Nichols AT comcast.net I am "RNichols42"

Some Army phones had a 4x4 button pattern:
https://en.wikipedia.org/wiki/Autovon

We were warned not to touch the FO button unless we saw Soviet tanks.

Ah yes -- the "Flash Override" button. You really needed high
rank to use that one. :-) Those, of course, only worked on the "Autovon"
networks -- the typical exchange ignores them -- or drops a trouble card
on receiving them, but likely the person at the dial will never know
about that. :-)

And -- I have seen (and I think that I have, somewhere around
here), a keypad which uses the extra four keys, but labeled differently.

And -- the "card dialer" phones (plastic punched cards, punched
by hand) could generate those tones, too, if you knew what combinations
to punch.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2016-02-07, Martin Eastburn wrote:

Martin

On 2/6/2016 6:24 PM, Lloyd E. Sponenburgh wrote:
"Jim Wilkins" fired this volley in news:n961vj$blk$1
@dont-email.me:

Transistors enabled many improvements but 1950's rotary dial phones
with no active electronics still work on the system.

I have an old WECO model 500 set I use in my shop for nostalgia that works
perfectly!

[ ... ]

They work just fine when the power goes out. I have a princess in the
house and two lineman clip on's in the shop.

At least -- they do if you haven't been talked into "upgrading"
to FIOS by Verizon. (Fiber Optics to the house, and then a powered box
which converts it to analog for the phones in the house. The box has a
rechargeable battery -- which will keep it running for a certain number of
hours of power outage, but not too many of them. :-)

We have digital (key) phones and rotary phones down at the Fraternal Org
I work at.

Of course -- the rotary phones, these days, need electronics at
the exchange to turn the pulses into the control signals which the
touch-tones would get directly. (And -- they *used* to charge extra for
Touch-Tone, which talked directly to the newer exchanges. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Sun, 7 Feb 2016 09:19:52 -0600, Robert Nichols
wrote:

On 02/06/2016 07:41 PM, DoN. Nichols wrote:
On 2016-02-06, Jim Wilkins wrote:
Tbe one that impresses me most is the old analog telephone which does
everything over two wires without active electronics, only one very
clever transformer, speaker and carbon mike. I couldn't quickly find a
circuit description and should return to fixing my fallen TV antenna
that had me abseiling down the snow-covered roof.

I could tell you (in too much detail) how automated connections
were made by at least one set of equipment -- the "Strowger switch",
invented by a somewhat paranoid undertaker who believed that is
competitor's wife (who was a telephone operator) was directing potential
customers to her husband). That was initially picked up by a company
called "Automatic Electric".

AT&T (Ma Bell) used that system for small-down setups later,
calling them "10x10s" in contrast to the crossbar switches used in the
more complex exchanges.

Mechanically, the switch is an amazing bit of engineering, and
relay logic was my first experience with logic circuits (long before the
ICs which continued the principles), with special relays set up to be
slow to pick up, or slow to release along with the normal speed ones.
The connection to the phone came though a two-coil relay, which both
acted to pick up the dialing pulses, and to isolate the audio from the
battery (48 VDC, FWIW) and serve as a balanced line, to be more immune
to induced noise.

It's the Panel Switch that takes the engineering prize. It's been
called a "Telephone office designed by a mechanical engineer." I
visited one of the last panel offices just before it was taken out
of service. Impressive to watch it in action. Glad I didn't have
to maintain it.

https://en.wikipedia.org/wiki/Panel_switch

I remember seeing something very similar to that at the Little Rock,
AR phone company building during a field trip in elementary school
(LRAFB Elementary) in the early Sixties. @~10y/o, we were all awed.

--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
-- Anna Quindlen

On Sun, 7 Feb 2016 12:11:35 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Sat, 6 Feb 2016 23:21:08 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
...
On Sat, 6 Feb 2016 15:38:04 -0500, "Jim Wilkins"
wrote:

"Ignoramus14059" wrote in
message ...
On 2016-02-06, Jim Wilkins wrote:


I often look at all that stuff, and I find extreme ingenuity
with
which people overcame limitations of their current technologies,
it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone which
does
everything over two wires without active electronics, only one
very
clever transformer, speaker and carbon mike. I couldn't quickly
find
a
circuit description and should return to fixing my fallen TV
antenna
that had me abseiling down the snow-covered roof.

It's a good thing you were strung up.

I hadn't practiced a Dulfersitz in decades.

Abseiling I knew, after having to look it up last year when my niece
and new nephew went to Gnu Zealand for spelunking and Middle
Earthing.
They had a blast. I had to look up Dulfersitz, and it definitely
does
not look like something I'd try in anything but an emergency. If
you
slipped, you'd likely lose control of the rope and fall.

P.S: Doesn't anyone say "rappelling" any more?

Rappeler is French for recall, as in recalling the doubled rope from
the bottom. Maybe French has lost its cachet of exclusiveness to
German? Have you seen any French competition to Audi, BMW or Mercedes
recently?

Wednesday the forecast was for 10-20MPH winds, not the howling gale
that blew the TV antenna down. Thursday I replaced the bent mast
section, then Friday the predicted few inches of light snow clung to
the guy lines and pulled it down again, and this time it smacked the
roof HARD right over me.

Time for a new mast system, wot? Better yet, Repent!, and TV no
more.
I'm going on 11 years without it now. Netflix and Redbox give me
the
movie fixes I need, but I haven't suffered through brainless
broadcast
TV or the massively stupid and numerous commercials for over a
decade.
The only commercials I actively seek are those for the Stupor Bowl,
and even then, at millions a pop, they put some stupid one on. The
money spent on sports and commercials each year would be enough, in
one single year, to -feed- and -house- the homeless and hungry poor
in
America (even those who don't deserve it), and probably a few dozen
other countries. Too bad so few people have this perspective.
(Sorry, it just slipped out.)

TVs do have an OFF switch, you know, for those of us with the self
control to use it. Mine is mainly my best source of up-to-date local
news and weather. Until I decide how to reengineer the insulators in a
material with different properties I can use Boston weather forecasts,
that antenna wasn't damaged.

I used to tell TV haters that they were missing good material on PBS
but it no longer has much that interests me.

Yeah, PBS died, SciFi Channel died, History Channel got out of date,
Nature got a new persona which SUCKS BIGTIME. In essence, there are
five hundred channels with nothing but bull**** on them. Reality
programs which have nothing real in them, movies with no actors or
plots, etc. As for news people, they all sound the same (with the
emPHASis on the wrong sylLABBles) and give you their opinions, not the
news. Cronkite is rolling over in his grave. I used to like that rat
******* Peter Jennings until I realized how Liberally skewed his
broadcasts were. Then I saw the TEEVEE bigwigs put him up on stage
fifteen minutes after 9/11. The Bigs forgot to give him -any- news
whatsoever to divulge and he muttered for 45 minutes with the ten
words of news they did give him. It was one of the last straws for me
with TV. I have much better uses for $90/month. (I used to get the
digital music channels, but no longer listen to much music.)


There are 5 oak insulator blanks sitting on the milling machine to
be
completed tomorrow. I made one to replace the first fall's damage,
boiled it in wax to drive out the water and seal it, and didn't lose
any signal strength from it.

Whuffo? Doesn't good cable preclude the need? Or are you
insulating
the mast from something? I don't recall having heard about this.
Or
are you the poor sod who was blessed with an overly lightningized
environment? If so, would oak insulators even help? A million
volt,
million amp spark which jumps thousands of feet of air in an instant
is pretty hard to protect from, innit? Just sayin...

These insulators support the two sections of the dipoles without
letting them short to each other or the metal supporting structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

Oh, OK. Most of us didn't make our own TV antennas. g

OK, two poles, 5 insulators...so, which one sags?

--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
-- Anna Quindlen

"Larry Jaques" wrote in message
...
On Sun, 7 Feb 2016 12:11:35 -0500, "Jim Wilkins"
wrote:
.....

Oh, OK. Most of us didn't make our own TV antennas. g

OK, two poles, 5 insulators...so, which one sags?

The antenna mast consists of fixed and sliding assemblies that
telescope, so I can work on it standing on the ground or the roof and
then raise it to 50' into the good signal above the shadow of a ridge.
The strong permanent portion is a 2x4 attached to the house and
extending about 5' above the roof, with a 5' removeable extension.
Sliding up and down it is the rotator at the bottom of ~37' of steel
mast, made from chain link fence top rail that costs $1 per foot
versus $4 / foot for nearly identical Radio Shack mast.

The guy lines run over pulleys at the top and tie off at the base,
where I can look up to adjust them to straighten the mast, something I
can't do by myself from the outer ends. The weakness of this is that
the pulleys increase the down force tending to buckle the tubing.

When ice, wind or falling branches overwhelm it, the steel tube bends
at the top of the fixed section and costs me about 3 days worth of
cable bill to replace. I bought and predrilled several spare sections.
In three out of four falls the antenna wasn't damaged and it's back
together now with wooden dipole insulators.

We have a week of storms predicted and there's nothing I want to watch
this week on local TV that I can't get from a Boston station so it's
staying down until the weather improves. I have an flat, unobstructed
line of sight to Boston and that antenna is down low. The local
stations retained their VHF channels which require a larger, more
fragile antenna than UHF-only Boston.

The intent is to lower the antenna for bad weather, assuming they
predict it correctly which they didn't. The local joke is that we're
shoveling six inches of "partly cloudy".

The antenna lowers very easily but the guy lines, rotator wires, coax
and the heavy ground wire tangle and make it troublesome to raise
afterwards, and impossible if they are caught in ice. Of course it
may have to come down late at night in a cold, windy rain or sleet
while I can wait for better conditions to haul it back up.

--jsw

On Sun, 07 Feb 2016 19:39:21 -0500, Joseph Gwinn
wrote:

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 07 Feb 2016 18:13:06 -0500, Joseph Gwinn
wrote:

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 7 Feb 2016 15:58:29 -0500, "Jim Wilkins"
wrote:

"Ed wrote in message
...
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles
without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw

I haven't heard of anyone using wood insulators boiled in
paraffin
since I had my first ham radio license, in 1960. You do drag out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding my
first
40m dipole with paraffin-soaked wooden insulators, but that was a
gift
from an old ham who was helping me get started. I never measured
its
performance but I worked Australia and Norway with 50 W using
that
antenna.

Anyway, if you're looking for modern materials that are excellent
insultators, have low dielectric, and stand up to sunlight, you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a
plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz, and
I
haven't found loss tangent data on thoroughly dried wood above 50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of water
out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors
for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle time
is
4 hours per part or if I have to weigh out the quantity of plastic
that will just fill the mold.

-jsw

There are several factors involved, most of which I forgot over 20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time ago.g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.
https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw

Yeah, I guess that reinforces (forgive the pun) the idea that PTFE is
the right material for high frequencies -- low and consistent
dielectric constant, combined with extremely high resistance.

Low moisture absorption is also essential - water has a high dielectric
constant, and is also quite lossy.

Joe Gwinn

I should know enough to stay out of plastics discussions -- the
chemistry drives me nuts -- but I see that PTFE has extremely low
absorbtion, as does FEP.

I also see that I have been mislead, or I misread something years ago:
Teflon is the name for two products. The common one is PTFE. But there
also is an FEP version, which, I see now, DuPont calls "Teflon FEP."
Finally, the data on dielectric constant is somewhat contradictory for
FEP versus PTFE from different sources. Some say they're the same,
others say that of FEP is twice as high.

According to Wikipedia, both have a dielectric constant of 2.1 at 1 MHz.


Finally, the dielectric *strength* of FEP versus PTFE (which probably
is irrelevant here) is three times higher for FEP.

Yes, dielectric strength is rarely a big issue. Surface leakage is usually
the limiting item.


polymer chemistry torture off

How about some electronic materials torture? Waxy plastics (and paraffin
waxes for that matter) have low dielectric constants because the molecules
are non-polar, and the molecules are large and get in each other’s way.

Unprincipled, clumsy oafs.


Unlike water, where the molecules are polar and will turn to align themselves
to any ambient electric field.

Molecular gigolos.

Liquid water has a dielectric constant of 80,
but ice is lower, because freezing retards molecular rotation. Test frequency
has a very large effect on the dielectric constant of water, but not so much
on waxy plastics.

Frigid gigolos.


Joe Gwinn

Thanks for the explanatin, Joe.

--
Ed Huntress

On Feb 8, 2016, Ed Huntress wrote
(in ):

On Sun, 07 Feb 2016 19:39:21 -0500, Joseph Gwinn
wrote:

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 07 Feb 2016 18:13:06 -0500, Joseph Gwinn
wrote:

On Feb 7, 2016, Ed Huntress wrote
(in ):

On Sun, 7 Feb 2016 15:58:29 -0500, "Jim Wilkins"
wrote:

"Ed wrote in message
...
On Sun, 7 Feb 2016 13:14:22 -0500, "Jim Wilkins"
wrote:


These insulators support the two sections of the dipoles
without
letting them short to each other or the metal supporting
structure.
The radio waves picked up from the air appear as a tiny
voltage
between the inner ends.
http://www.hottconsultants.com/pdf_files/dipoles-1.pdf

-jsw

I haven't heard of anyone using wood insulators boiled in
paraffin
since I had my first ham radio license, in 1960. You do drag
out
some
old technology, Jim. g

I'm sure it worked well. In fact, I had a ladder line feeding
my
first
40m dipole with paraffin-soaked wooden insulators, but that
was a
gift
from an old ham who was helping me get started. I never
measured
its
performance but I worked Australia and Norway with 50 W using
that
antenna.

Anyway, if you're looking for modern materials that are
excellent
insultators, have low dielectric, and stand up to sunlight,
you
have
a
lot to choose from. A QRP fanatic/friend I know, who is a
plastics
engineer, uses FEP. I don't know where you get it, but it's
supposed
to be good stuff.

My old end-fed wire (which is now down) has ceramic egg
insulators,
which I've use for most of the past 50 years.

--
Ed Huntress
KC2NZT

The two local station I use that antenna for are near 200 MHz,
and
I
haven't found loss tangent data on thoroughly dried wood above
50
MHz.
Immersing wood in 280F molten wax certainly forces a lot of
water
out
the end grain, and seals the wood to keep it out. I made a
waxed
pulley from scrap casket mahogany that lasted unchanged
outdoors
for
many years until a glue joint failed.

Ned Simmons sent me some cutoff ends of 1" Teflon rod to try. I
couldn't copy the existing insulators while they were 50' up in
the
air, but now I can experiment with either machining the rod or
compressing it into a hot mold. It doesn't matter if the cycle
time
is
4 hours per part or if I have to weigh out the quantity of
plastic
that will just fill the mold.

-jsw

There are several factors involved, most of which I forgot over
20
years ago. The varieties of modified or alloyed FEP (including
Teflon)
are used for all sorts of RF insulation, and terminal insulators
should be easy, but be aware that PTFE has half the dielectric
constant of Teflon. And stay away from PVC. It's dismal for
high-frequency insulation.

Don't ask me why. Remember, I forgot that stuff a long time
ago.g

--
Ed Huntress

I absorbed as much of it as I could as a Mitre lab tech and circuit
board designer. This is what we used for GHz circuit boards.

https://www.rogerscorp.com/acs/produ...Laminates.aspx
--jsw

Yeah, I guess that reinforces (forgive the pun) the idea that PTFE is
the right material for high frequencies -- low and consistent
dielectric constant, combined with extremely high resistance.

Low moisture absorption is also essential - water has a high dielectric
constant, and is also quite lossy.

Joe Gwinn

I should know enough to stay out of plastics discussions -- the
chemistry drives me nuts -- but I see that PTFE has extremely low
absorbtion, as does FEP.

I also see that I have been mislead, or I misread something years ago:
Teflon is the name for two products. The common one is PTFE. But there
also is an FEP version, which, I see now, DuPont calls "Teflon FEP."
Finally, the data on dielectric constant is somewhat contradictory for
FEP versus PTFE from different sources. Some say they're the same,
others say that of FEP is twice as high.

According to Wikipedia, both have a dielectric constant of 2.1 at 1 MHz.


Finally, the dielectric *strength* of FEP versus PTFE (which probably
is irrelevant here) is three times higher for FEP.

Yes, dielectric strength is rarely a big issue. Surface leakage is usually
the limiting item.


polymer chemistry torture off

How about some electronic materials torture? Waxy plastics (and paraffin
waxes for that matter) have low dielectric constants because the molecules
are non-polar, and the molecules are large and get in each others way.

Unprincipled, clumsy oafs.

Like well-oiled spaghetti.


Unlike water, where the molecules are polar and will turn to align
themselves to any ambient electric field.

Molecular gigolos.

Politicians, too.


Liquid water has a dielectric constant of 80,
but ice is lower, because freezing retards molecular rotation. Test
frequency
has a very large effect on the dielectric constant of water, but not so
much
on waxy plastics.

Frigid gigolos.

These must be the Ice Queens consorts? One would have guessed that her
tastes would run to the warmer side. For balance no doubt.


Joe Gwinn

Thanks for the explanatin, Joe.

We stand ready to help those in polymer distress.

Joe Gwinn

Am Sonntag, 7. Februar 2016 19:14:14 UTC+1 schrieb Jim Wilkins:

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50 MHz.
Immersing wood in 280F molten wax certainly forces a lot of water out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

I salvaged some mahogany from transmission line switchgear which was dismantled in 2010. There was a date on the gear: 1959. The mahogany was externally weathered, but not at all rotten. The weather resistance of mahogany is remarkable.

On Mon, 8 Feb 2016 10:44:31 -0800 (PST), Christopher Tidy
wrote:

Am Sonntag, 7. Februar 2016 19:14:14 UTC+1 schrieb Jim Wilkins:

The two local station I use that antenna for are near 200 MHz, and I
haven't found loss tangent data on thoroughly dried wood above 50 MHz.
Immersing wood in 280F molten wax certainly forces a lot of water out
the end grain, and seals the wood to keep it out. I made a waxed
pulley from scrap casket mahogany that lasted unchanged outdoors for
many years until a glue joint failed.

I salvaged some mahogany from transmission line switchgear which was dismantled in 2010. There was a date on the gear: 1959. The mahogany was externally weathered, but not at all rotten. The weather resistance of mahogany is remarkable.


Being from 1959, it's probably real Honduras mahogany. That's the most
moisture-stable, warp-free wood you can get -- a key reason that
Linhoff and others used it for view-camera frames.

Most of it is pretty soft, but it varies through a wide range of
hardnesses.

I'm down to around 30 board feet of it, harvested in the late '30s.

--
Ed Huntress

Am Montag, 8. Februar 2016 19:53:52 UTC+1 schrieb Ed Huntress:

Being from 1959, it's probably real Honduras mahogany. That's the most
moisture-stable, warp-free wood you can get -- a key reason that
Linhoff and others used it for view-camera frames.

Interesting to know the likely source. Just looked out my pictures and the date is actually 1955. Here's a cross section (I put a little linseed oil on the cut surface to highlight the grain). Looks like this mahogany was laminated somehow:
https://www.dropbox.com/s/zrugo6vnoz...ogany.JPG?dl=0

Most of it is pretty soft, but it varies through a wide range of
hardnesses.

I'm down to around 30 board feet of it, harvested in the late '30s.

Wish I could find some wood like that.

On Mon, 8 Feb 2016 15:08:29 -0800 (PST), Christopher Tidy
wrote:

Am Montag, 8. Februar 2016 19:53:52 UTC+1 schrieb Ed Huntress:

Being from 1959, it's probably real Honduras mahogany. That's the most
moisture-stable, warp-free wood you can get -- a key reason that
Linhoff and others used it for view-camera frames.

Interesting to know the likely source. Just looked out my pictures and the date is actually 1955. Here's a cross section (I put a little linseed oil on the cut surface to highlight the grain). Looks like this mahogany was laminated somehow:
https://www.dropbox.com/s/zrugo6vnoz...ogany.JPG?dl=0

Hmm. Those white lines are characteristic of Honduras mahogany
end-grain, but it does look like it might be at least a couple of
layers laminated.

Honduras mahogany varies wildly. The old-growth stuff, which was
logged out around a century ago, could be dense and moderately hard.
Old corporate boardrooms (like the old one at LeBlond Lathes in
Cincinnati, before they tore it down) were often lined with veneered
panels made from the old-growth stock. Most harvested by the 1950s was
pretty open-grained and soft.

Here are some photos that give you an idea of the range of
appearances:

http://tinyurl.com/julgl82


Most of it is pretty soft, but it varies through a wide range of
hardnesses.

I'm down to around 30 board feet of it, harvested in the late '30s.

Wish I could find some wood like that.

You probably won't. It can be traded only by permit -- it's an
"Appendix II" species. (Swietenia humilis). The few hard and figured
pieces that can be obtained are confined mostly to making musical
instruments. The prices are staggering.

The little bit I have was left over from a boat that was built around
1950.

--
Ed Huntress

Don -

Get a small UPS that is made for laptops. That should power the
phone for hours and days. Maybe the control box into it as well.

I use them on my modem and routers. Lights twinkle in a storm, the
net stays up and no reboot/restart needed on the modem or computer on
their own.
Martin

On 2/7/2016 10:43 PM, DoN. Nichols wrote:
On 2016-02-07, Martin Eastburn wrote:

Martin

On 2/6/2016 6:24 PM, Lloyd E. Sponenburgh wrote:
"Jim Wilkins" fired this volley in news:n961vj$blk$1
@dont-email.me:

Transistors enabled many improvements but 1950's rotary dial phones
with no active electronics still work on the system.

I have an old WECO model 500 set I use in my shop for nostalgia that works
perfectly!

[ ... ]

They work just fine when the power goes out. I have a princess in the
house and two lineman clip on's in the shop.

At least -- they do if you haven't been talked into "upgrading"
to FIOS by Verizon. (Fiber Optics to the house, and then a powered box
which converts it to analog for the phones in the house. The box has a
rechargeable battery -- which will keep it running for a certain number of
hours of power outage, but not too many of them. :-)

We have digital (key) phones and rotary phones down at the Fraternal Org
I work at.

Of course -- the rotary phones, these days, need electronics at
the exchange to turn the pulses into the control signals which the
touch-tones would get directly. (And -- they *used* to charge extra for
Touch-Tone, which talked directly to the newer exchanges. :-)

Enjoy,
DoN.

Look into big transmissions. Drop speed increase HP, drop HP increase
speed.

Martin

On 2/5/2016 4:20 PM, Ignoramus9436 wrote:
On 2016-02-05, Larry Jaques wrote:
On Thu, 04 Feb 2016 19:57:31 -0600, Ignoramus11775
wrote:

It is sitting on my truck:

http://igor.chudov.com/tmp/4500-hp-motor.jpg
Finally, the EPA does something right. If anything in the world could
cause AGWK, coal plants could, though I don't believe in AGWK.
Properly processed pocket nuclear would be good until we get real cold
fusion.

I am also a big fan of nuclear power.


The power station is 96 years old. They have a 96 years old
bridge crane that is still operational.

Is that next on your dismantling list?

This is on my "hope to dismantle" list


The blower at iFly is 1,600 HP, and this is 4,500 HP, almost 3 times bigger.

http://en-us.fluke.com/community/flu...rs-flying.html

Four 400hp motors, but WOW! I'd hate to get their electric bills...


They love their electric bills, I am sure, as they make many times as
much from flying.

1600 hp = 1500 kW bill (I am guessing, considering all losses etc).

1500 kW in an hour at 6 cents per kWh, is 90 dollars per hour.

they make many times as much per hour

i

On Mon, 8 Feb 2016 07:55:05 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Sun, 7 Feb 2016 12:11:35 -0500, "Jim Wilkins"
wrote:
.....

Oh, OK. Most of us didn't make our own TV antennas. g

OK, two poles, 5 insulators...so, which one sags?

The antenna mast consists of fixed and sliding assemblies that
telescope, so I can work on it standing on the ground or the roof and
then raise it to 50' into the good signal above the shadow of a ridge.
The strong permanent portion is a 2x4 attached to the house and
extending about 5' above the roof, with a 5' removeable extension.
Sliding up and down it is the rotator at the bottom of ~37' of steel
mast, made from chain link fence top rail that costs $1 per foot
versus $4 / foot for nearly identical Radio Shack mast.

RatSnack has severely overpriced nearly everything for the past 30
years, before losing most of its stores. I haven't bought anything
there since, so I'm not sure the local store is even operating.
Toprail is standard 1-1/4" galv tubing and RS wasn't selling gold, so
you made the right decision.


The guy lines run over pulleys at the top and tie off at the base,
where I can look up to adjust them to straighten the mast, something I
can't do by myself from the outer ends. The weakness of this is that
the pulleys increase the down force tending to buckle the tubing.

Yeah, it's always a balancing act, isn't it?


When ice, wind or falling branches overwhelm it, the steel tube bends
at the top of the fixed section and costs me about 3 days worth of
cable bill to replace. I bought and predrilled several spare sections.
In three out of four falls the antenna wasn't damaged and it's back
together now with wooden dipole insulators.

Whoa, falling branches? If you have trees close enough to damage an
antenna tower, you have trees -far- too close to the house.


We have a week of storms predicted and there's nothing I want to watch
this week on local TV that I can't get from a Boston station so it's
staying down until the weather improves. I have an flat, unobstructed
line of sight to Boston and that antenna is down low. The local
stations retained their VHF channels which require a larger, more
fragile antenna than UHF-only Boston.

We just finished playing with those storms, so I hope you enjoy them.
What coatings have you tried on the guy wires to prevent icing?


The intent is to lower the antenna for bad weather, assuming they
predict it correctly which they didn't. The local joke is that we're
shoveling six inches of "partly cloudy".

Cute!


The antenna lowers very easily but the guy lines, rotator wires, coax
and the heavy ground wire tangle and make it troublesome to raise
afterwards, and impossible if they are caught in ice. Of course it
may have to come down late at night in a cold, windy rain or sleet
while I can wait for better conditions to haul it back up.

I sure don't miss fiddle****ing around with antennas, I tell ya.

--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
-- Anna Quindlen

On 2016-02-08, Martin Eastburn wrote:
Igy

Have you considered a heavy conveyor 'belt' motor ?
A heavy equipment replacement drive motor ?

You know the BIG BIG 'scopes' that dig canals ?

Hate to see it scrapped for the copper and steel.


I think that someone will eventually buy it, yes.

"Martin Eastburn" wrote in message
...
Don -

Get a small UPS that is made for laptops. That should power the
phone for hours and days. Maybe the control box into it as well.

I use them on my modem and routers. Lights twinkle in a storm, the
net stays up and no reboot/restart needed on the modem or computer
on
their own.
Martin

I have small UPSs around the house because they package 12V batteries
safely for living spaces, and having them where needed avoids tripping
over extension cords in the dark.

The problem to watch for is their own rather high operating current
drain, which limits their On time even with no external load. Their
run time is specified only for the expected high loads, you have to
measure their low-load run time yourself somehow. When I tried an AC
clock for this it ran at double speed on the noisy Modified Sine Wave.
My APC1400 draws 42W from its batteries with nothing plugged in. The
little 100W car inverters can pull half an Amp of no-load current. The
only quiet and efficient one I have doesn't shut off as it's supposed
to at low battery voltage.

They were meant only to run a computer long enough to shut it down
properly and don't adapt too well to other purposes, especially the
tightly cost-engineered small ones with thermal mass cooling matched
to the battery capacity. When I misuse them as backup inverters I
derate them by at least half.

One of the reasons I stayed with copper phone lines instead of FIOS is
that I couldn't find a safe place for a larger backup battery and its
wiring anywhere near where they want to put the modem. I like to be
able to maintain the things I depend on.
--jsw

After a couple of decades using UPSes, I became unconvinced that UPSes
increase reliability and especially uptime. The problem is that UPSes
fail for spurious reasons, and when they fail, they leave devices
unpowered.

i

On Tue, 09 Feb 2016 07:56:35 -0600, Ignoramus4548
wrote:

After a couple of decades using UPSes, I became unconvinced that UPSes
increase reliability and especially uptime. The problem is that UPSes
fail for spurious reasons, and when they fail, they leave devices
unpowered.

i

And when you don't use them ... your devices are left unpowered.

They've saved me more than once.

--
Ed Huntress

"Larry Jaques" wrote in message
...
On Mon, 8 Feb 2016 07:55:05 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
. ..
On Sun, 7 Feb 2016 12:11:35 -0500, "Jim Wilkins"
wrote:
.....

Oh, OK. Most of us didn't make our own TV antennas. g

Most of us didn't make Air Force satellite communications gear either.
https://en.wikipedia.org/wiki/Milstar

When ice, wind or falling branches overwhelm it, the steel tube
bends
at the top of the fixed section and costs me about 3 days worth of
cable bill to replace. I bought and predrilled several spare
sections.
In three out of four falls the antenna wasn't damaged and it's back
together now with wooden dipole insulators.

Whoa, falling branches? If you have trees close enough to damage an
antenna tower, you have trees -far- too close to the house.

Ya think?

The problem was access. When the neighbor on that side decided to have
some trees taken down and finally accepted that it would require a
crane parked on his lawn I joined in to have my risky trees on that
side removed too. Thus the sawmill operation, they were mature oaks
and too good to waste as firewood. They are now a stack of beams for
the permanent shed I can put up in the space they threatened. However
the outer ends of the guy lines necessarily attach to trees which can
drop branches on them.

We have a week of storms predicted and there's nothing I want to
watch
this week on local TV that I can't get from a Boston station so it's
staying down until the weather improves. I have an flat,
unobstructed
line of sight to Boston and that antenna is down low. The local
stations retained their VHF channels which require a larger, more
fragile antenna than UHF-only Boston.

We just finished playing with those storms, so I hope you enjoy
them.
What coatings have you tried on the guy wires to prevent icing?

The guy lines are 80 lb braided Dacron fishing line. When new they
have a smooth slippery finish but it weathers off. Lowering the mast
solves the icing issue IF the forecast is correct. The lower sections
now connect with hitch pins I can remove in the dark wearing gloves.
http://www.linkagepin.com/wire_lock_pin_round_type.html

The intent is to lower the antenna for bad weather, assuming they
predict it correctly which they didn't. The local joke is that we're
shoveling six inches of "partly cloudy".

Cute!


The antenna lowers very easily but the guy lines, rotator wires,
coax
and the heavy ground wire tangle and make it troublesome to raise
afterwards, and impossible if they are caught in ice. Of course it
may have to come down late at night in a cold, windy rain or sleet
while I can wait for better conditions to haul it back up.

I sure don't miss fiddle****ing around with antennas, I tell ya.

The process is as simple as I can get it. I can lower the antennas and
clean my chimney from the ground. The UHF antenna lowers to roof
access height with no tools in 5 seconds. The antennas are attached to
5' mast sections that are easy to disconnect and lay on the roof. The
only significant difference between RS mast and chain link fence top
rail is the looser fit at the joints, which I shimmed with Gorilla
tape. The screws that hold them together prevent rotation and keep the
joints from freezing solid like rusty RS mast.
--jsw

"Ignoramus4548" wrote in message
...
After a couple of decades using UPSes, I became unconvinced that
UPSes
increase reliability and especially uptime. The problem is that
UPSes
fail for spurious reasons, and when they fail, they leave devices
unpowered.

i

The only way I know to check backup battery capacity without lab
equipment is to plug in a laptop with the HWiNFO program logging
battery condition.
http://www.hwinfo.com/download.php
The program gives some idea of how much AC power the laptop consumes
itself, which you can determine more accurately with a Kill-A-Watt on
grid AC, and you can add an external load. I use my 100W crock pot.

When the UPS shuts down the laptop will record the switch to its
internal battery. Even if that runs out too you can see the UPS run
time saved in the log file.

Older business-class laptops running XP are great for this. Last fall
I found a Dell D830 for $5 and a "dead" (easily fixed) D630 for $1.
The D830 will take two more serial ports on a PCMCIA card plus one on
an ExpressCard so I can datalog four serial-output multimeters
simultaneously, using the time stamps to align their separate log
files in Excel. The screen isn't large enough to show a 5th channel on
a USB-connected Radio Shack meter. The meters are all optically
isolated and won't short out the voltages they are connected to, an
excellent reason not to use a multichannel DAQ or Arduino for battery
testing.

This has flaws but its strengths are impressive:
http://www.amazon.com/UNI-T-Multimet.../dp/B007THZMWI
At 9V it matches my nearly unreadable 4-1/2 digit Keithley to +/- 1mV,
easily good enough to use it as a standard to recalibrate $5 HF meters
etc.

--jsw

Ignoramus4548 wrote:
After a couple of decades using UPSes, I became unconvinced that UPSes
increase reliability and especially uptime. The problem is that UPSes
fail for spurious reasons, and when they fail, they leave devices
unpowered.

i

I had a nearly new APC brand fail about 2 weeks after I installed it.. I
bought it to replace a 6 year old APC that took a lightning strike.

The new on failed in a spectacular shower of sparks....


Probably due to the 1/2 bottle of Rolling Rock beer that got dumped
directly into the open control section when the beer fell off the side
of the desk...

There is another APS mounted there now. I have hear it trip on/off quite
a few times and the monitor says it has had both low and high spikes
over the years.

--
Steve W.

On Saturday, February 6, 2016 at 3:37:53 PM UTC-5, Jim Wilkins wrote:
"Ignoramus14059" wrote in
message ...
On 2016-02-06, Jim Wilkins wrote:


I often look at all that stuff, and I find extreme ingenuity with
which people overcame limitations of their current technologies, it
is
fascinating.

i

Tbe one that impresses me most is the old analog telephone which does
everything over two wires without active electronics, only one very
clever transformer, speaker and carbon mike. I couldn't quickly find a
circuit description and should return to fixing my fallen TV antenna
that had me abseiling down the snow-covered roof.

-jsw

The truly amazing thing is that all this stuff is still compatible. You can take your WECO 500 and plug it into your FIOS connected house, and it'll work fine, or you can plug it into your DSL line (with a filter) and it'll work fine. That they have maintained compatibility pretty much since day one is a testament to good engineering, and it's no accident.

I spent a few weeks several years ago working in the lab at Bell Labs. There, in a huge room (taking up several floors) they have pretty much every piece of phone infrastructure ever made. You can hook your device-under-test to hundreds of different phones, dozens of different switches and many, many interface, line balancing and protection devices. I was there qualifying and writing test procedures for interface devices for Lucent DSLAMs.

It's a truly interesting place and what amounts to a "living museum" full of very smart people, most of whom don't have a clue which end of a soldering iron to pick up. But they can jam many megabits per second through copper pairs, and 40 years ago that was deemed "impossible."

I think that someone will eventually buy it, yes.

Isn't it about the right size to make a home-built metal shredder for the rest of your scrap?

Honduras mahogany varies wildly. The old-growth stuff, which was
logged out around a century ago, could be dense and moderately hard.
Old corporate boardrooms (like the old one at LeBlond Lathes in
Cincinnati, before they tore it down) were often lined with veneered
panels made from the old-growth stock. Most harvested by the 1950s was
pretty open-grained and soft.

Interesting. I wonder why the old-growth stock was so much denser? Does it depend on climate, or the state of the soil, or what?

On Tue, 9 Feb 2016 12:52:09 -0800 (PST), Christopher Tidy
wrote:

Honduras mahogany varies wildly. The old-growth stuff, which was
logged out around a century ago, could be dense and moderately hard.
Old corporate boardrooms (like the old one at LeBlond Lathes in
Cincinnati, before they tore it down) were often lined with veneered
panels made from the old-growth stock. Most harvested by the 1950s was
pretty open-grained and soft.

Interesting. I wonder why the old-growth stock was so much denser? Does it depend on climate, or the state of the soil, or what?

I don't know. I'd have to look it up.

With most deciduous woods, slower growth produces harder wood. But
with ring-porous wood (like oak), just the opposite is true. I thought
that Honduras mahogany was ring-porous, but maybe that's wrong.

--
Ed Huntress

"rangerssuck" wrote in message
...

.... very smart people, most of whom don't have a clue which end of a
soldering iron to pick up.

Truth, brother.

But they can jam many megabits per second through copper pairs, and
40 years ago that was deemed "impossible."

I was very impressed by this machine which compressed 4 KHz voice into
2400 bits per second for (...) and transmission through a modem:
http://www.jproc.ca/crypto/hy02.html

We could jam the vocal cord pitch to the low end to sound like Steve
the Stud, or to the high end for Larry the Fairy. When freshly tuned
it sounded pretty good, but it drifted.

https://en.wikipedia.org/wiki/Vocoder

"Christopher Tidy" wrote in message
...
Honduras mahogany varies wildly. The old-growth stuff, which was
logged out around a century ago, could be dense and moderately
hard.
Old corporate boardrooms (like the old one at LeBlond Lathes in
Cincinnati, before they tore it down) were often lined with
veneered
panels made from the old-growth stock. Most harvested by the 1950s
was
pretty open-grained and soft.

Interesting. I wonder why the old-growth stock was so much denser?
Does it depend on climate, or the state of the soil, or what?

Older heartwood vs younger sapwood?

"Ed Huntress" wrote in message
...
--
Ed Huntress

Hey Ed, I held a Christie sign post outside the polling place while
the state rep I was chatting with took a break.
--jsw