I have an odd sort of an antenna installation I have to deal with. At
our camp we have an old Winegard compact amplified UHF VHF/FM antenna,
and an Alliance rotor. This particular Winegard antenna if I'm not
mistaken was available with and without and/or a small built in rotor.
Mine came off a retrofit job many years ago and is amplified and
either we never connected the internal motor or it didn't have one. I
just don't recall. I cannot find any information on this antenna
anywhere. This antenna was admittedly a compromise between signal and
directionality and popular around 1985 or so and was designed for
urban locations close to the transmitters.

Our camp is deep fringe and I would have installed something like an
8200, however I settled for this antenna at the request of the rest of
the family who did not want to see something as large as an 8200 up
there. The small antenna worked OK for several VHF stations which came
in snowy but were watchable, but it did not receive any UHF. None of
us among the three families who use the camp during different parts of
the Summer ever really minded much about this. Our family only spends
two weeks out there. The antenna was small and unobtrusive and as a
bonus we also used it for FM, which worked satisfactorily.

For those familiar with Winegard antennas, (and hopefully someone who
can help me identify this one) the body of this unit is a black
plastic case which looks like an old GA 8780 mast mounted
preamplifier, except it's just a slight bit larger. The case mounted
on top of the mast. Coming out of the black plastic case in sort of a
semi circle arrangement I believe,
( I can't see the antenna right now as the camp is remote, and my
memory isn't that good), are either four or six round radials about .
25inch diameter and 24 inches long.

Now since the digital transition we can get just two stations and
unreliably at that, and so I've finally convinced the other two
families that we need to upgrade to a bigger antenna. So what I plan
to do is remove the small antenna from the top of the mast, install
the High band VHF/UHF HD antenna in it's place and then relocate the
small antenna down the upper mast just above the rotor to preserve our
FM reception. However, In order to do this I will need a section of
mast bent 90 degrees and welded at two points. This small section will
then be clamped or bolted to the main upper mast. See below:

-------------------- New HD antenna
---------------------
l
l
l
l
l

l

l
small amplified antenna l

l
l l
l............... l
l l
clamped to existing l l existing mast
mast, (or bolted) l
l
Rotor
l
l
l lower mast section


New mast section required:

l
l................................
l
l


The horizontal length of the bent section will be about 3 feet. I
figure that I can make this out of a 5 section of pipe, (if nothing
like this is commercially available that is). The small antenna is
very light so I would prefer aluminum tubing if possible. A steel
section would add a considerable amount of unbalanced weight to the
upper mast

So can anyone please help me to identify this antenna? And also if
anyone has any experience in doing something like this, can suggest a
source for materials, or has any comments about it I would really
appreciate hearing from you. Thanks, Lenny

On Jul 14, 6:34*am, klem kedidelhopper
wrote:
I have an odd sort of an antenna installation I have to deal with. At
our camp we have an old Winegard compact amplified UHF VHF/FM antenna,
and an Alliance rotor. This particular Winegard antenna if I'm not
mistaken was available with and without and/or a small built in rotor.
Mine came off a retrofit job many years ago and is amplified and
either we never connected the internal motor or it didn't have one. I
just don't recall. I cannot find any information on this antenna
anywhere. This antenna was admittedly a compromise between signal and
directionality and popular around 1985 or so and was designed for
urban locations close to the transmitters.

Our camp is deep fringe and I would have installed something like an
8200, however I settled for this antenna at the request of the rest of
the family who did not want to see something as large as an 8200 up
there. The small antenna worked OK for several VHF stations which came
in snowy but were watchable, but it did not receive any UHF. None of
us among the three families who use the camp during different parts of
the Summer ever really minded much about this. Our family only spends
two weeks out there. The antenna was small and unobtrusive and as a
bonus we also used it for FM, which worked satisfactorily.

For those familiar with Winegard antennas, (and hopefully someone who
can help me identify this one) the body of this unit is a black
plastic case which looks like an old GA 8780 mast mounted
preamplifier, except it's just a slight bit larger. The case mounted
on top of the mast. Coming out of the black plastic case in sort of a
semi circle arrangement I believe,
( I can't see the antenna right now as the camp is remote, and my
memory isn't that good), are either four or six round radials about .
25inch diameter and 24 inches long.

Now since the digital transition we can get just two stations and
unreliably at that, and so I've finally convinced the other two
families that we need to upgrade to a bigger antenna. So what I plan
to do is remove the small antenna from the top of the mast, install
the High band VHF/UHF HD antenna in it's place and then relocate the
small antenna down the upper mast just above the rotor to preserve our
FM reception. *However, In order to do this I will need a section of
mast bent 90 degrees and welded at two points. This small section will
then be clamped or bolted to *the main upper mast. See below:

* *-------------------- New HD antenna
---------------------
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * *l

l

l
small amplified antenna l

l
* * * * * * * * l * * * * * * * * *l
* * * * * * * * l............... * l
* * * * * * * * * * * * * * * *l * l
clamped to existing * l * l *existing mast
mast, (or bolted) * * * * * l
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * *Rotor
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * *l lower mast section

New mast section required:

* * * * * * * *l
* * * * * * * *l................................
* * * * * * * * * * * * * * * * * * * * * * * *l
* * * * * * * * * * * * * * * * * * * * * * * *l

The horizontal length of the bent section will be about 3 feet. I
figure that I can make this out of a 5 section of pipe, (if nothing
like this is commercially available that is). The small antenna is
very light so I would prefer aluminum tubing if possible. A steel
section would add a considerable amount of unbalanced weight to the
upper mast

So can anyone please help me to identify this antenna? And also if
anyone has any experience in doing something like this, can suggest a
source for materials, or has any comments about it I would really
appreciate hearing from you. Thanks, Lenny

My advice is to leave well enough alone. Mount your big antenna where
you planned to remount your compact antenna, rather than going through
all this fabrication. Add a section of mast tubing to raise the rotor
if this spot is too low for good reception.

klem kedidelhopper wrote in message
...
I have an odd sort of an antenna installation I have to deal with. At
our camp we have an old Winegard compact amplified UHF VHF/FM antenna,
and an Alliance rotor. This particular Winegard antenna if I'm not
mistaken was available with and without and/or a small built in rotor.
Mine came off a retrofit job many years ago and is amplified and
either we never connected the internal motor or it didn't have one. I
just don't recall. I cannot find any information on this antenna
anywhere. This antenna was admittedly a compromise between signal and
directionality and popular around 1985 or so and was designed for
urban locations close to the transmitters.

Our camp is deep fringe and I would have installed something like an
8200, however I settled for this antenna at the request of the rest of
the family who did not want to see something as large as an 8200 up
there. The small antenna worked OK for several VHF stations which came
in snowy but were watchable, but it did not receive any UHF. None of
us among the three families who use the camp during different parts of
the Summer ever really minded much about this. Our family only spends
two weeks out there. The antenna was small and unobtrusive and as a
bonus we also used it for FM, which worked satisfactorily.

For those familiar with Winegard antennas, (and hopefully someone who
can help me identify this one) the body of this unit is a black
plastic case which looks like an old GA 8780 mast mounted
preamplifier, except it's just a slight bit larger. The case mounted
on top of the mast. Coming out of the black plastic case in sort of a
semi circle arrangement I believe,
( I can't see the antenna right now as the camp is remote, and my
memory isn't that good), are either four or six round radials about .
25inch diameter and 24 inches long.

Now since the digital transition we can get just two stations and
unreliably at that, and so I've finally convinced the other two
families that we need to upgrade to a bigger antenna. So what I plan
to do is remove the small antenna from the top of the mast, install
the High band VHF/UHF HD antenna in it's place and then relocate the
small antenna down the upper mast just above the rotor to preserve our
FM reception. However, In order to do this I will need a section of
mast bent 90 degrees and welded at two points. This small section will
then be clamped or bolted to the main upper mast. See below:

-------------------- New HD antenna
---------------------
l
l
l
l
l

l

l
small amplified antenna l

l
l l
l............... l
l l
clamped to existing l l existing mast
mast, (or bolted) l
l
Rotor
l
l
l lower mast section


New mast section required:

l
l................................
l
l


The horizontal length of the bent section will be about 3 feet. I
figure that I can make this out of a 5 section of pipe, (if nothing
like this is commercially available that is). The small antenna is
very light so I would prefer aluminum tubing if possible. A steel
section would add a considerable amount of unbalanced weight to the
upper mast

So can anyone please help me to identify this antenna? And also if
anyone has any experience in doing something like this, can suggest a
source for materials, or has any comments about it I would really
appreciate hearing from you. Thanks, Lenny





Why not a basic satellite receiver ?

On Sat, 14 Jul 2012 06:34:39 -0700 (PDT), klem kedidelhopper
wrote:

Now since the digital transition we can get just two stations and
unreliably at that, and so I've finally convinced the other two
families that we need to upgrade to a bigger antenna.

Before blundering forward, I suggest you do a little research.

1. Go thee unto:
http://www.tvfool.com
Enter your location and have it calculate which stations you can
expect to see at your camp location. Print the results and post them
on the wall as it will save much effort in antenna pointing.

2. Set your TV or converter to rescan for digital channels. They
sometimes move in frequency. With a directional antenna, you may need
to aim it in a probable direction, scan, scribble down the usable
channels, and then do it again with the antenna pointed in another
likely location.

3. If you have a converter, please check for reviews and user
comments. Many of the rush to market converters are little better
than junk.

4. Compare the gain and performance of your proposed antenna at:
http://www.hdtvprimer.com/ANTENNAS/comparing.html
Your existing antenna and amplifier may already be theoretically
sufficient.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Jul 14, 10:33*am, Jeff Liebermann wrote:
On Sat, 14 Jul 2012 06:34:39 -0700 (PDT), klem kedidelhopper

wrote:
Now since the digital transition we can get just two stations and
unreliably at that, and so I've finally convinced the other two
families that we need to upgrade to a bigger antenna.

Before blundering forward, I suggest you do a little research.

1. *Go thee unto:
http://www.tvfool.com
Enter your location and have it calculate which stations you can
expect to see at your camp location. *Print the results and post them
on the wall as it will save much effort in antenna pointing.

2. *Set your TV or converter to rescan for digital channels. *They
sometimes move in frequency. *With a directional antenna, you may need
to aim it in a probable direction, scan, scribble down the usable
channels, and then do it again with the antenna pointed in another
likely location.

3. *If you have a converter, please check for reviews and user
comments. *Many of the rush to market converters are little better
than junk.

4. *Compare the gain and performance of your proposed antenna at:
http://www.hdtvprimer.com/ANTENNAS/comparing.html
Your existing antenna and amplifier may already be theoretically
sufficient.

I know that it isn't sufficient because it now only sometimes gets just two channels. TV fool says that there are more possibilities for that address. Also the neighbor put up an all band POS Radio Shlock antenna with no preamp and he gets a few channels. And he used 300 ohm wire and taped it to the mast!
As for satellite, for just a few weeks out of the year it's not
feasible. Besides we're not looking for that type of TV entertainment
for a Summer camp anyway. During the day we listen to the radio or
swim, hike, etc. Rainy days we might go to a museum or watch a DVD.
Evenings we might watch a show or the news or weather. TV is not a big
thing for us but a few more channels would be nice. I don't want to
lose my FM though and the new HD antenna will not have a low band VHF
section. Lenny

Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

On Sat, 14 Jul 2012 08:00:30 -0700 (PDT), klem kedidelhopper
wrote:

I know that it isn't sufficient because it now only sometimes gets
just two channels. TV fool says that there are more possibilities
for that address. Also the neighbor put up an all band POS Radio
Shlock antenna with no preamp and he gets a few channels. And he
used 300 ohm wire and taped it to the mast!

Bingo. What I'm trying to get you to do is figure out what a
reasonable receiver and antenna should see at your location. If your
current derangement isn't working up to estimated coverage, it might
easily be a receiver or converter problem. If your neighbor, with his
marginal system, gets good reception, you may have a problem with your
hardware.

I can't tell from your description if you have the preamp mounted on
the antenna, or if it's next to the receiver. It belongs near the
antenna.

As for satellite, for just a few weeks out of the year it's not
feasible.

You could carry a satellite receiver back and forth between your
residence and summer camp. With DirecTV, it is also possible to add a
2nd receiver to your contract for about $10/month plus $50 one time
fee. That might be affordable. Just plug it into a phone line a few
times a year to unload the pay per view data. Dish is more obnoxious,
insisting that all receivers be plugged into the same phone number.

Besides we're not looking for that type of TV entertainment
for a Summer camp anyway. During the day we listen to the radio or
swim, hike, etc. Rainy days we might go to a museum or watch a DVD.
Evenings we might watch a show or the news or weather. TV is not a big
thing for us but a few more channels would be nice. I don't want to
lose my FM though and the new HD antenna will not have a low band VHF
section. Lenny

Then, find a better antenna that covers FM or add a separate FM yagi.
I live in the hills and a big FM yagi is the only antenna that really
works for OTA reception. My former VHF/UHF TV antenna (destroyed in a
storm in Jan 2012) had only about 5dBi gain in the FM band. The 8ft
long FM band yagi (partly mangled in the same storm) has about 10dbi
gain. The difference in reception quality and stability was very
noticeable.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Jul 14, 10:43*am, Jeff Liebermann wrote:
On Sat, 14 Jul 2012 08:00:30 -0700 (PDT), klem kedidelhopper

wrote:
I know that it isn't sufficient because it now only sometimes gets
just two channels. TV fool says that there are more possibilities
for that address. Also the neighbor put up an all band POS Radio
Shlock antenna with no preamp and he gets a few channels. And he
used 300 ohm wire and taped it to the mast!

Bingo. *What I'm trying to get you to do is figure out what a
reasonable receiver and antenna should see at your location. *If your
current derangement isn't working up to estimated coverage, it might
easily be a receiver or converter problem. *If your neighbor, with his
marginal system, gets good reception, you may have a problem with your
hardware.

I can't tell from your description if you have the preamp mounted on
the antenna, or if it's next to the receiver. *It belongs near the
antenna.

As for satellite, for just a few weeks out of the year it's not
feasible.

You could carry a satellite receiver back and forth between your
residence and summer camp. *With DirecTV, it is also possible to add a
2nd receiver to your contract for about $10/month plus $50 one time
fee. *That might be affordable. *Just plug it into a phone line a few
times a year to unload the pay per view data. *Dish is more obnoxious,
insisting that all receivers be plugged into the same phone number.

Besides we're not looking for that type of TV entertainment
for a Summer camp anyway. During the day we listen to the radio or
swim, hike, etc. Rainy days we might go to a museum or watch a DVD.
Evenings we might watch a show or the news or weather. TV is not a big
thing for us but a few more channels would be nice. I don't want to
lose my FM though and the new HD antenna will not have a low band VHF
section. Lenny

Then, find a better antenna that covers FM or add a separate FM yagi.
I live in the hills and a big FM yagi is the only antenna that really
works for OTA reception. *My former VHF/UHF TV antenna (destroyed in a
storm in Jan 2012) had only about 5dBi gain in the FM band. *The 8ft
long FM band yagi (partly mangled in the same storm) has about 10dbi
gain. *The difference in reception quality and stability was very
noticeable.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558begin_of_the_skype_highlighting*FREE*831-336-2558

You don't want to tape 300 ohm twinlead to the mast, it killls the
signal. Use standoffs or coax cable. 300 ohm has lower losses on
average than coax, but does have to be kept at least a couple of
inches away from anything metallic and thus is more of a pain to
install.

On Sat, 14 Jul 2012 15:48:53 -0700 (PDT), "hr(bob) "
wrote:

You don't want to tape 300 ohm twinlead to the mast, it killls the
signal. Use standoffs or coax cable.

Agreed. However, I would recommend double shielded RG-6/u coax cable
instead of twinlead.

300 ohm has lower losses on
average than coax, but does have to be kept at least a couple of
inches away from anything metallic and thus is more of a pain to
install.

Yep. I dunno about the low loss part.
For the feed lines by themselves:
300 ohm RG-6/u
MHz twinlead coax
100 1.1dB/100ft 2.8dB/100ft

Most antennas are 300 ohms, while modern TV's are all 75 ohm. Add a
300 ohm to 75 ohm transformer for an additional 0.5dB loss to both
transmission lines.

However, when I tried to measure the losses at 100Mhz, with a few
impairments added. Losses are approximate as I can't fine where I
scribbled down the results.

Coiling the entire 100ft of twinlead into about a 2ft dia coil
resulted in an additional 3dB loss due to radiation. While this is
unlikely to happen in a real install, it does indicate that you cannot
store extra wire in a loop in the attic.

Running the twinlead through a nearby metal object (i.e. my bench
vise) resulted in an additional 2dB loss. This was intended to
simulate running through the opening in a metal framed window or door.

Running the twinlead, with one wire close to a handy metal object
(10ft of steel rain gutter) resulted in an additional 3dB loss. This
demonstrates what happens with the balanced line becomes unbalanced by
different capacitance from each wire to ground.

A simulated wet bird, in the form of a plastic bag filled with 2 cups
of water straddling the twinlead, resulted in 2dB loss.

Doing the same with the coax cable, showed no changes in loss.

Bottom line: Twinlead is lower loss, but only if you have an ideal
installation, which I have yet to see. Use coax so that you don't
have to worry about such things.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Jul 14, 7:44*pm, Jeff Liebermann wrote:
On Sat, 14 Jul 2012 15:48:53 -0700 (PDT), "hr(bob) "

wrote:
You don't want to tape 300 ohm twinlead to the mast, it killls the
signal. *Use standoffs or coax cable.

Agreed. *However, I would recommend double shielded RG-6/u coax cable
instead of twinlead.

300 ohm has lower losses on
average than coax, but does have to be kept at least a couple of
inches away from anything metallic and thus is more of a pain to
install.

Yep. *I dunno about the low loss part.
For the feed lines by themselves:
* * * * *300 ohm * * * * *RG-6/u
MHz * * *twinlead * * * * *coax
100 * * 1.1dB/100ft * * *2.8dB/100ft

Most antennas are 300 ohms, while modern TV's are all 75 ohm. *Add a
300 ohm to 75 ohm transformer for an additional 0.5dB loss to both
transmission lines.

However, when I tried to measure the losses at 100Mhz, with a few
impairments added. *Losses are approximate as I can't fine where I
scribbled down the results.

Coiling the entire 100ft of twinlead into about a 2ft dia coil
resulted in an additional 3dB loss due to radiation. *While this is
unlikely to happen in a real install, it does indicate that you cannot
store extra wire in a loop in the attic.

Running the twinlead through a nearby metal object (i.e. my bench
vise) resulted in an additional 2dB loss. *This was intended to
simulate running through the opening in a metal framed window or door.

Running the twinlead, with one wire close to a handy metal object
(10ft of steel rain gutter) resulted in an additional 3dB loss. *This
demonstrates what happens with the balanced line becomes unbalanced by
different capacitance from each wire to ground.

A simulated wet bird, in the form of a plastic bag filled with 2 cups
of water straddling the twinlead, resulted in 2dB loss.

Doing the same with the coax cable, showed no changes in loss.

Bottom line: *Twinlead is lower loss, but only if you have an ideal
installation, which I have yet to see. *Use coax so that you don't
have to worry about such things.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558begin_of_the_skype_highlighting*FREE*831-336-2558

Jeff - I installed antennas in the mid-1950's in Ft Pierce, FL.
Nearest tv broadcast station was Miami @ 125 miles. We used antenna-
mounted signal vacuum tube boosters, and 300 ohm twinlead with
standoffs to get the maximum possible signal to the tv sets. When
West Palm Beach came on the air, only 50 miles away, we were able to
drop the boosters, but kept the 300 ohm twinlead. There was also a
hollow tube 300 ohm twinlead that claimed slightly lower losses in wet
weather, but that required sealing the tube at the top or it could act
like a small pipe and be worse than regular flat twinlead. Coax
losses were just too great at those signal levels/distances.

On Sun, 15 Jul 2012 21:24:57 -0700 (PDT), "hr(bob) "
wrote:

Jeff - I installed antennas in the mid-1950's in Ft Pierce, FL.
Nearest tv broadcast station was Miami @ 125 miles. We used antenna-
mounted signal vacuum tube boosters, and 300 ohm twinlead with
standoffs to get the maximum possible signal to the tv sets. When
West Palm Beach came on the air, only 50 miles away, we were able to
drop the boosters, but kept the 300 ohm twinlead. There was also a
hollow tube 300 ohm twinlead that claimed slightly lower losses in wet
weather, but that required sealing the tube at the top or it could act
like a small pipe and be worse than regular flat twinlead. Coax
losses were just too great at those signal levels/distances.

In the 1950's, antenna mounted tube amplifiers were all you could buy.
In the mid 1970's, I inherited some Jerrod tower mounted amps (6AG5
tubes) that I used for the local do it ourself CATV system receivers.
They worked, but when proper dual gate MOSFET amps arrived, I junked
them.

According to theory, as long as your antenna mounted amplifier has a
reasonable noise figure, and your amplifier gain is a few dB more than
your coax cable losses, it will work as well as if the receiver was on
top of the tower. The purpose of the RF amp (not normally called a
booster) is to eliminate the effects of the coax cable. Had you left
the amp up the tower, you would not have needed to squeeze every last
dB out of the twinlead. Coax would have worked.

However, since you enjoy living in lightning country, I suspect that
tower mounted electronics have a short lifetime. Maybe mounting the
amplifier a few feet below the top the of the tower might be better.

Incidentally, I worked with the low loss twinlead. The center "core"
was filled with some kind of foam rubber. Judging by the density, it
was probably open cell foam. Left open to the atmosphere, it would
absorb water from the air, wick it into the coax, and eventually fill
with water. I used some of that stuff in the Smog Angeles area. That
was when I was into using the best, not matter how much it cost my
parents. I sealed the top of the twinlead, but didn't think I needed
to seal the bottom. After a few months, it was dripping water out the
bottom. Oddly, the reception wasn't affected, but we were in a strong
signal area, so a few dB didn't matter.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:

On Sun, 15 Jul 2012 21:24:57 -0700 (PDT), "hr(bob) "
wrote:

Jeff - I installed antennas in the mid-1950's in Ft Pierce, FL.
Nearest tv broadcast station was Miami @ 125 miles. We used antenna-
mounted signal vacuum tube boosters, and 300 ohm twinlead with
standoffs to get the maximum possible signal to the tv sets. When
West Palm Beach came on the air, only 50 miles away, we were able to
drop the boosters, but kept the 300 ohm twinlead. There was also a
hollow tube 300 ohm twinlead that claimed slightly lower losses in wet
weather, but that required sealing the tube at the top or it could act
like a small pipe and be worse than regular flat twinlead. Coax
losses were just too great at those signal levels/distances.

In the 1950's, antenna mounted tube amplifiers were all you could buy.
In the mid 1970's, I inherited some Jerrod tower mounted amps (6AG5
tubes) that I used for the local do it ourself CATV system receivers.
They worked, but when proper dual gate MOSFET amps arrived, I junked
them.

According to theory, as long as your antenna mounted amplifier has a
reasonable noise figure, and your amplifier gain is a few dB more than
your coax cable losses, it will work as well as if the receiver was on
top of the tower. The purpose of the RF amp (not normally called a
booster) is to eliminate the effects of the coax cable. Had you left
the amp up the tower, you would not have needed to squeeze every last
dB out of the twinlead. Coax would have worked.

However, since you enjoy living in lightning country, I suspect that
tower mounted electronics have a short lifetime. Maybe mounting the
amplifier a few feet below the top the of the tower might be better.

Incidentally, I worked with the low loss twinlead. The center "core"
was filled with some kind of foam rubber. Judging by the density, it
was probably open cell foam. Left open to the atmosphere, it would
absorb water from the air, wick it into the coax, and eventually fill
with water. I used some of that stuff in the Smog Angeles area. That
was when I was into using the best, not matter how much it cost my
parents. I sealed the top of the twinlead, but didn't think I needed
to seal the bottom. After a few months, it was dripping water out the
bottom. Oddly, the reception wasn't affected, but we were in a strong
signal area, so a few dB didn't matter.


You might enjoy this website:

http://theoldcatvequipmentmuseum.org/index.html

In message , Jeff Liebermann
writes




Coiling the entire 100ft of twinlead into about a 2ft dia coil
resulted in an additional 3dB loss due to radiation.

Coiling the coax shouldn't make a scrap of difference.





--
Ian

On Mon, 16 Jul 2012 19:49:21 +0100, Ian Jackson
wrote:

In message , Jeff Liebermann
writes
Coiling the entire 100ft of twinlead into about a 2ft dia coil
resulted in an additional 3dB loss due to radiation.

Coiling the coax shouldn't make a scrap of difference.

True for coax cable. However, coiling twinlead added 3dB in loss.
It's common practice to coil the excess cable rather than cut it. Not
a problem with coax, but potentially a bad idea with twinlead. Nobody
is going to coil 100ft of twinlead into a 2ft diameter coil, so the
3dB loss is probably worst case.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In message , Jeff Liebermann
writes
On Mon, 16 Jul 2012 19:49:21 +0100, Ian Jackson
wrote:

In message , Jeff Liebermann
writes
Coiling the entire 100ft of twinlead into about a 2ft dia coil
resulted in an additional 3dB loss due to radiation.

Coiling the coax shouldn't make a scrap of difference.

True for coax cable. However, coiling twinlead added 3dB in loss.
It's common practice to coil the excess cable rather than cut it. Not
a problem with coax, but potentially a bad idea with twinlead. Nobody
is going to coil 100ft of twinlead into a 2ft diameter coil, so the
3dB loss is probably worst case.

Ah yes, sorry. I missed the 'twinlead'. I've never really thought about
what happens what happens if you have a roll of twinlead coiled up. It's
simply something you don't do!
--
Ian

Ian Jackson wrote:
In message , Jeff Liebermann
writes
On Mon, 16 Jul 2012 19:49:21 +0100, Ian Jackson
wrote:

In message , Jeff Liebermann
writes
Coiling the entire 100ft of twinlead into about a 2ft dia coil
resulted in an additional 3dB loss due to radiation.

Coiling the coax shouldn't make a scrap of difference.

True for coax cable. However, coiling twinlead added 3dB in loss.
It's common practice to coil the excess cable rather than cut it. Not
a problem with coax, but potentially a bad idea with twinlead. Nobody
is going to coil 100ft of twinlead into a 2ft diameter coil, so the
3dB loss is probably worst case.

Ah yes, sorry. I missed the 'twinlead'. I've never really thought about
what happens what happens if you have a roll of twinlead coiled up. It's
simply something you don't do!

Unless you use shielded twin lead. I used it on an antenna way back. Seems
like strange stuff, but didn't require transformers.

Greg

On Tue, 17 Jul 2012 23:55:22 +0000 (UTC), gregz
wrote:

Unless you use shielded twin lead. I used it on an antenna way back. Seems
like strange stuff, but didn't require transformers.

I think you mean Twinax:
http://en.wikipedia.org/wiki/Twinaxial_cabling
The stuff is about 75 ohms between pairs. Strictly speaking, it
doesn't require a matching transformer, but really should have a 1:1
balun to deal with the balanced Twinax to unbalanced (F connector)
system.

The stuff was designed for data, not RF. Impedance, balance,
capacitances, and data performance are specified in MlL-STD-1553B,
attenuation at RF frequencies is not. I'm surprised that it worked at
FM/TV(?) frequencies.

You could fake shielded twinlead with two runs of 75 ohm line. That
will give you 150 ohms between center conductors, which can be
converted to either 75 or 300 ohms with a 2:1 (trifilar) balun.
Unfortunately, the loss would be twice that of a single run of RG6/u,
so there's no benefit.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
On Tue, 17 Jul 2012 23:55:22 +0000 (UTC), gregz
wrote:

Unless you use shielded twin lead. I used it on an antenna way back. Seems
like strange stuff, but didn't require transformers.

I think you mean Twinax:
http://en.wikipedia.org/wiki/Twinaxial_cabling
The stuff is about 75 ohms between pairs. Strictly speaking, it
doesn't require a matching transformer, but really should have a 1:1
balun to deal with the balanced Twinax to unbalanced (F connector)
system.

The stuff was designed for data, not RF. Impedance, balance,
capacitances, and data performance are specified in MlL-STD-1553B,
attenuation at RF frequencies is not. I'm surprised that it worked at
FM/TV(?) frequencies.

You could fake shielded twinlead with two runs of 75 ohm line. That
will give you 150 ohms between center conductors, which can be
converted to either 75 or 300 ohms with a 2:1 (trifilar) balun.
Unfortunately, the loss would be twice that of a single run of RG6/u,
so there's no benefit.

The stuff was 300 ohms. I'm pretty sure the name was belden super permaohm.
This was back in the 60's . The only reference I find, is my own. I do find
another name, city color by belden. Twin 26 gauge wires with foil shield.

Greg

On Wed, 18 Jul 2012 03:24:41 +0000 (UTC), gregz
wrote:

The stuff was 300 ohms. I'm pretty sure the name was belden super permaohm.
This was back in the 60's . The only reference I find, is my own. I do find
another name, city color by belden. Twin 26 gauge wires with foil shield.
Greg

It was called Belden "Permohm" and later changed to Belden "City
Color". Belden recommended it for locations with high interference
levels. The loss is about the same as the equivalent length of coax
cable. I checked the online Belden catalog and didn't find any manner
of twinlead. Belden allowed the Permohm trademark to expire in 2001:
http://www.trademarkia.com/permohm-72089125.html
City Color is a listed trademark, but not by Belden.

Scroll down to "WR-TWIN-TV" and "WR-TWIN-TV-100":
https://www.fairradio.com/catalog.php?mode=view&categoryid=228
That's not a Belden part number. I don't know where they got the
stuff. Belden may have sold the product to someone else.

Drivel: We had a local ham that spent some time characterizing the HF
transmission line characteristics of 12-2 Romex power cable. It
actually worked reasonably well until the price of copper made it
uneconomical. Ummm... not recommended for TV or FM use.




--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Jul 17, 11:59*pm, Jeff Liebermann wrote:
On Wed, 18 Jul 2012 03:24:41 +0000 (UTC), gregz
wrote:

The stuff was 300 ohms. I'm pretty sure the name was belden super permaohm.
This was back in the 60's . The only reference I find, is my own. I do find
another name, city color by belden. Twin 26 gauge wires with foil shield..
Greg

It was called Belden "Permohm" and later changed to Belden "City
Color". *Belden recommended it for locations with high interference
levels. *The loss is about the same as the equivalent length of coax
cable. *I checked the online Belden catalog and didn't find any manner
of twinlead. *Belden allowed the Permohm trademark to expire in 2001:
http://www.trademarkia.com/permohm-72089125.html
City Color is a listed trademark, but not by Belden.

Scroll down to "WR-TWIN-TV" and "WR-TWIN-TV-100":
https://www.fairradio.com/catalog.php?mode=view&categoryid=228
That's not a Belden part number. *I don't know where they got the
stuff. *Belden may have sold the product to someone else.

Drivel: *We had a local ham that spent some time characterizing the HF
transmission line characteristics of 12-2 Romex power cable. *It
actually worked reasonably well until the price of copper made it
uneconomical. *Ummm... not recommended for TV or FM use.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Never thought of using Romex for RF. It would indeed be interesting to
see what it's characteristic impedance would be at different
frequencies though. I wish I had the time to experiment with that. Too
busy trying to pay the electric bill. I suppose if I'm ever on a
desert island and have to get the transmitter on the air and all I
have is Romex well, I suppose I'd give it a try.

I used that shielded 300 ohm Belden Permohm back in the 60's when I
lived in The Bronx. I think I still have a bunch of it around here
too. I had a Vbeam antenna, (just about everyone did). All NYC TV
stations were VHF except for 31 which was municipal and 47 which was
Spanish. I received them all on my Vbeam. All but 47 which was from
New Jersey and mostly ran test patterns, (remember test patterns),
broadcast from the Empire State Building 15 miles away in Manhattan.
Reception was never a problem. I had no pre amplifier but used a rotor
for DX'ing. I sometimes could get low band from Boston and Connecticut
and once pulled in 13 from Prince Edward Island Canada. We had a 1951
TV/FM console receiver made by Pilot Radio. This was like the wild
west of TV. That was pretty thrilling for a kid. Lenny

On Thu, 19 Jul 2012 06:56:18 -0700 (PDT), klem kedidelhopper
wrote:

Never thought of using Romex for RF. It would indeed be interesting to
see what it's characteristic impedance would be at different
frequencies though.

Nope. It's quite constant. As I vaguely recall (and can't find my
notes), it's about 110 ohms between outside conductors for 14-2 NM-B.
There's nothing in the dielectric and insulation to absorb power, so
the impedance is going to be constant up through UHF frequencies.
However, the insulation breakdown voltage is only about 600V making
Romex rather useless for high power RF.

The big problem is what to do with the "extra" ground wire in 12-2
cable. Grounding or floating the extra ground wire allegedly didn't
seem to do anything, but I'm suspicious.

I haven't tried to design an antenna that would take advantage of this
ground wire. Perhaps a motorized yagi that uses the feed line to
supply power. With all that copper, the IR losses will be small.

Hint:
LMR-400 about $0.80/ft
450 ohm ladder line about $0.44/ft
14-2 Romex about $0.30/ft
RG-8/u about $0.17/ft

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article ,
Jeff Liebermann wrote:

On Thu, 19 Jul 2012 06:56:18 -0700 (PDT), klem kedidelhopper
wrote:

Never thought of using Romex for RF. It would indeed be interesting to
see what it's characteristic impedance would be at different
frequencies though.

Nope. It's quite constant. As I vaguely recall (and can't find my
notes), it's about 110 ohms between outside conductors for 14-2 NM-B.
There's nothing in the dielectric and insulation to absorb power, so
the impedance is going to be constant up through UHF frequencies.

The impedance may not change, but I'm pretty sure the insulation in
Romex is vinyl, and I'm pretty sure it has a serious loss factor above
HF. There's a good reason you see polystyrene, mylar, mica, glass, and
teflon capacitors, but not vinyl capacitors.

Isaac

On Thu, 19 Jul 2012 22:16:45 -0700, isw wrote:

In article ,
Jeff Liebermann wrote:

On Thu, 19 Jul 2012 06:56:18 -0700 (PDT), klem kedidelhopper
wrote:

Never thought of using Romex for RF. It would indeed be interesting to
see what it's characteristic impedance would be at different
frequencies though.

Nope. It's quite constant. As I vaguely recall (and can't find my
notes), it's about 110 ohms between outside conductors for 14-2 NM-B.
There's nothing in the dielectric and insulation to absorb power, so
the impedance is going to be constant up through UHF frequencies.

The impedance may not change, but I'm pretty sure the insulation in
Romex is vinyl, and I'm pretty sure it has a serious loss factor above
HF. There's a good reason you see polystyrene, mylar, mica, glass, and
teflon capacitors, but not vinyl capacitors.

Isaac

Romex is vinyl jacketed PVC. Not the best of insulation for RF. I
couldn't find a value for loss tangent, probably because it varies by
composition, manufacturer, color doping, position of the moon, etc.
http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm
You're probably right that it's not useful at UHF, but I'm too
lazy/busy to test it.

The ham doing the Romex testing was Dave Stoddart W8FLL (SK) who died
in 2008.
http://www.k6bj.org/profiles/w8fll/


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558