Radio Question
 

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

You mihgt want to do a net search on "active antennas".

Some of the simple 1 JFET designs work pretty well.

If you Eamil my r2000swl@hot... account I will try to dig
one from Monitoring Times, scan it and send it to you.

It is nothing fancy, but with an 18" antenna it will work.

Terry

Whatever you use, the antenna will have to be outside of the metal RV. Make
sure the long wire is insulated. A single strand, insulated conductor, run
around the perimeter of the RV is about as good as you can do. Even though
it is insulated, the antenna should be on short standoffs of some sort, of
an inch or 2 or 3, away from the metal roof. You should be able to run an
antenna of some 20 feet or more by stringing it around the perimeter. Don't
get carried away with length - 20 feet should be adequate.

Bob Swinney

wrote in message
oups.com...
You mihgt want to do a net search on "active antennas".

Some of the simple 1 JFET designs work pretty well.

If you Eamil my r2000swl@hot... account I will try to dig
one from Monitoring Times, scan it and send it to you.

It is nothing fancy, but with an 18" antenna it will work.

Terry

Broadcast stations and shortwave are vertically polarized.It would
behoove you to go vertical as a first choice,horizontal second.From
memory I believe there is a 50 per cent drop if a station is
broadcasting vertical and you are receivng horizontal.

Gunner,

Find some thin magnet wire, e.g. #28 or smaller enamel coated. Use that
to make a long wire antenna, it will be nearly invisible. The main rule
for this type of antenna is "longer and higher", so do what you can.

Maybe you can add some thin sticks (fishing rods?) at the
corners of your RV, and use them to support a long wire or loop a few feet
above your roof.

If you can electrically isolate your TV antenna mast from the RV, you can
use that as a vertical antenna. If the mast is non-conductive, attach
some wire to it. Are there any
height limits on the TV antenna mast? Taller is better.

Lots of hams operate from RVs using fold-over or crank-up antennas and
masts. Antenna goes up when you're using it, and disappears when you're
not.

There are a lot of options, if you think creatively. Many hams operate
from RVs and antenna-restricted apartments, condos and developments.
Check ham sites (www.arrl.net, www.eham.net) and rec.radio.amateur.antenna
for ideas.

Your interference problem will require some work to solve. First, get an
antenna outside, connected to your receiver by coax. That should help a
lot. Make sure your computer and peripherals are well shielded, cases
properly closed and screwed shut. You can add RF filtering (inductance)
to cables by wrapping a few turns of the cable around a chunk of
core material - ferrite torroids are best, but any chunk of steel will do.
Radio Shack and others sell cores for that purpose. Add the cores to
every cable exiting your computer, as near to the device as possible.
You may need to add shielding around your monitor (conductive mesh,
grounded).

-Ron

"Time Traveler" wrote in message
...
Broadcast stations and shortwave are vertically polarized.It would
behoove you to go vertical as a first choice,horizontal second.From
memory I believe there is a 50 per cent drop if a station is
broadcasting vertical and you are receivng horizontal.

HF signals aren't polarised any more by the time they get to the receiver.
Polarisation is only really important at VHF and above. Radio amateurs use
both horizontal and vertical antennas on HF without polarisation effects.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

In article , Gunner says...

out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.

Are you allowed to have a clothesline?

Sounds crazy, but it has been known to work!

Jim


--
==================================================
please reply to:
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==================================================

On Tue, 5 Apr 2005 09:34:56 -0500, Robert Swinney wrote:
Jim sez: "Sounds crazy, but it has been known to work!"

Not so crazy, Jim. In the early days of telephony, sometimes single 'phone
wires were run as the top strand of fences, with the other side grounded,
of course.

Yes, this is known as "category 1" network wiring. Seriously.

Jim sez: "Sounds crazy, but it has been known to work!"

Not so crazy, Jim. In the early days of telephony, sometimes single 'phone
wires were run as the top strand of fences, with the other side grounded,
of course.

Bob Swinney

"jim rozen" wrote in message
...
In article , Gunner says...

out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.

Are you allowed to have a clothesline?


Jim


--
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please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

In article , Dave Hinz says...

On Tue, 5 Apr 2005 09:34:56 -0500, Robert Swinney wrote:
Jim sez: "Sounds crazy, but it has been known to work!"

Not so crazy, Jim. In the early days of telephony, sometimes single 'phone
wires were run as the top strand of fences, with the other side grounded,
of course.

Yes, this is known as "category 1" network wiring. Seriously.

The classic party line. I lived in a place like that for a while.

Single wire that went up the canyon, with about ten parties on it.

Everyone had their own ring.

In some areas they used harmonic ringing, and they would play tricks
like polarized ringing, and ringing from one side or the other of
the line, to ground - if the service was a pair.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

On Tue, 05 Apr 2005 10:01:20 GMT, Gunner
said:

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Gunner


Mount a ball and spring mount to the side of the RV, the same way you
would mount a whip antenna to any car. Using 2 inch PVC pipe (about 18
inches long, end caps, yada, yada), some #10 mag wire, a bunch of
threaded fittings, etc..and of course an old 102" whip.. Build
yourself a tunable texas bug catcher antenna. Basiclly you'll have a
102" steel whip mounted on your HOMEMADE RF TRAP, mounted to the RV
just like any old CB antenna.

Google "Texas Bug Catcher antennas" for ideas.

Another option would be to build a wood frame in the shape of an X,
wrap the frame with about 20 feet of bare coppper wire (you are
building an active X antenna) Simply set you frame on the roof of your
RV and turn the antenna till you get the direction you want.
(in fact, this maybe your best choice because you can center the
antenna on the roof, the roof will act as the ground plane).

Here's one I had bookmarked:
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=10174

Google "Homeade SWL antenns" and "low profile antennas" also there is
a book called "low profile ham radio" I forget who wrote it, but it
had tons of hidable antenna plans for SWL.

n.

Jim, I don't think you are referring to old fashioned "grounded" single wire
(literally one wire) telephone service.

Bob Swinney
"jim rozen" wrote in message
...
In article , Dave Hinz says...

On Tue, 5 Apr 2005 09:34:56 -0500, Robert Swinney
wrote:
Jim sez: "Sounds crazy, but it has been known to work!"

Not so crazy, Jim. In the early days of telephony, sometimes single
'phone
wires were run as the top strand of fences, with the other side
grounded,
of course.

Yes, this is known as "category 1" network wiring. Seriously.

The classic party line. I lived in a place like that for a while.

Single wire that went up the canyon, with about ten parties on it.

Everyone had their own ring.

In some areas they used harmonic ringing, and they would play tricks
like polarized ringing, and ringing from one side or the other of
the line, to ground - if the service was a pair.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

On 5 Apr 2005 04:18:07 -0700, wrote:

You mihgt want to do a net search on "active antennas".

Some of the simple 1 JFET designs work pretty well.

If you Eamil my r2000swl@hot... account I will try to dig
one from Monitoring Times, scan it and send it to you.

It is nothing fancy, but with an 18" antenna it will work.

Terry

Thanks in advance

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

On 5 Apr 2005 06:56:26 -0700, jim rozen
wrote:

In article , Gunner says...

out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.

Are you allowed to have a clothesline?

Sounds crazy, but it has been known to work!

Jim

Hummm interesting. Ill check

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

On Tue, 05 Apr 2005 11:10:33 -0400, North wrote:

On Tue, 05 Apr 2005 10:01:20 GMT, Gunner
said:

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Gunner


Mount a ball and spring mount to the side of the RV, the same way you
would mount a whip antenna to any car. Using 2 inch PVC pipe (about 18
inches long, end caps, yada, yada), some #10 mag wire, a bunch of
threaded fittings, etc..and of course an old 102" whip.. Build
yourself a tunable texas bug catcher antenna. Basiclly you'll have a
102" steel whip mounted on your HOMEMADE RF TRAP, mounted to the RV
just like any old CB antenna.

Google "Texas Bug Catcher antennas" for ideas.

Another option would be to build a wood frame in the shape of an X,
wrap the frame with about 20 feet of bare coppper wire (you are
building an active X antenna) Simply set you frame on the roof of your
RV and turn the antenna till you get the direction you want.
(in fact, this maybe your best choice because you can center the
antenna on the roof, the roof will act as the ground plane).

Here's one I had bookmarked:
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=10174

Google "Homeade SWL antenns" and "low profile antennas" also there is
a book called "low profile ham radio" I forget who wrote it, but it
had tons of hidable antenna plans for SWL.

n.


While I thank you for the link (one Id already followed during my
investigations)...i did make this comment in the original post.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Im sure you are aware that Im quite good at research on the internet,
and did a fair amount of that, before posting my question. But there
are often tricks that individuals have come up that might be
appropriate

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

"Gunner" wrote in message
...
Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.


How about one of the flagpole antennas?

Gunner wrote:

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Antenna matching is only for extremely challenging receiving (which this
is not), or for transmitting.

Unless your radio is real crap you'll be receiving atmospheric noise in
excess of the receiver's internal noise with even a moderate antenna.
Atmospheric noise drops off at the higher frequencies, but the antenna
effectiveness will increase for a moderately - sized antenna. If you
really want to disguise what you're doing then mount the TV mast with
insulators, put in a good radial grounding system, and use the whole TV
mast as an antenna.

This scheme requires that you either build a diplexer to isolate the TV
coax outer shield from ground at the lower frequencies or disconnect the
TV when you want to listen to SW. The former will be moderately
difficult but not insurmountable -- I think you could do this with a 1:1
RF transformer and some dinking. The latter will be easy but
inconvenient -- but you can always start with the connection method and
build the transformer later.

The ARRL sells a book on low-profile and hidden antennas. You can go to
http://www.arrl.org for more information, or see if there's an amateur
radio supply store near you. They also sell books on reducing EMI,
which may help with the computer.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

In article , Robert Swinney says...

Jim, I don't think you are referring to old fashioned "grounded" single wire
(literally one wire) telephone service.

That's what they had up the canyon I think. Everyone was on one
line. A pretty remote area. I don't think it was fence wire
though, it was copper.

Jim


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==================================================

In article , Gunner says...

Are you allowed to have a clothesline?

Hummm interesting. Ill check

Covert feedline (small magnet wire suitably camoflaged) from
a window down to the clothesline. Nothing says the line could
not be some stranded number 14 THHN wire, eh? Tie the ends off
through doubled-over six-pack plastic ties as an insulator.
I would make the wire white BTW.

Hang a few towels, etc on it for further blending in.

A longwire like this works great - I've been using one like this
inside my attic (slate roof over cedar shakes) and with a 20 foot
random wire I can run my National SW-3 just fine. There's plenty
of signal.

I've been meaning to build a trap dipole for the backyard.

Jim


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==================================================
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==================================================

On Tue, 05 Apr 2005 10:01:20 GMT, Gunner
wrote:

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Stealth antennae are very site and situation specific. Think camou:
use your ingenuity to devise a conductor of some extent that looks
like something the rules don't forbid or is invisible because it looks
like something familiar. Flagpoles, cutesie picket fences,
clotheslines, a rabbit hutch made of chickenwire, decorative
low-voltage lighting as is often used on RV's, etc etc.

Electrically short antennae have very very low radiation resistance,
so a tuned matching network can make a big difference. I disagree
with the poster that said they are only suitable for transmitting,
though I will agree that once you reach atmospheric noise threshold
then further gain t without directionality is of little benefit.

The matchbox would need to be tuned along with the rcvr. Tune for max
noise from the radio at the freq of interest. A simple JFET preamp
may help, or not, depending on the sensitivity of the radio. If the
radio has a 3-gang tuning cap then it already has a tuned RF stage.
If it doesn't, then a preamp will help.

Jim,
Likely what you saw up the canyon was what telephone guys call "parallel".
Parallel was just that; two conductors laying side by side, about 22 gauge
or so (I'm sure a Telco guy can correct us here). The conductors were very
hard drawn copper, or an alloy, to give strength against wind and ice
loading. If one didn't know better, it looked like a single wire.

Single wire, ground for the other side, telephone circuits are not possible
today because of all the AC currents they would share the ground with.
Maybe one would work only over a very short distance, say one span or less.
Dunno. I talked on one of the "ancients" about 40 years ago, in rural
Kansas, and it was so noisy as to be almost unusable.

Bob Swinney
"Gunner" wrote in message
...
On 5 Apr 2005 06:56:26 -0700, jim rozen
wrote:

In article , Gunner says...

out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.

Are you allowed to have a clothesline?

Sounds crazy, but it has been known to work!

Jim

Hummm interesting. Ill check

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

"Gunner" wrote in message
...
On 5 Apr 2005 04:18:07 -0700, wrote:

You mihgt want to do a net search on "active antennas".

Some of the simple 1 JFET designs work pretty well.

If you Eamil my r2000swl@hot... account I will try to dig
one from Monitoring Times, scan it and send it to you.

It is nothing fancy, but with an 18" antenna it will work.

Terry

Thanks in advance

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

Also do a search on "broomstick antennas". Could ask over in
rec.radio.shortwave too...

Gunner wrote:
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi.

Make an insulated base for the yagi pole and put insulators in the guy
wires. Now you've got a 12' whip antena. Should work pretty good.

Ted

In article wwC4e.3298$vt1.569@edtnps90, Ted Edwards says...

Gunner wrote:
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi.

Make an insulated base for the yagi pole and put insulators in the guy
wires. Now you've got a 12' whip antena. Should work pretty good.

Hmm. I like that. Could even be loaded at the bottom. The
trailer roof now makes a lovely ground plane. Am I allowed to
say 'ground plane' now?

Jim


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==================================================
please reply to:
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==================================================

On Tue, 05 Apr 2005 10:01:20 GMT, Gunner
wrote:

snip
Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.
snip

How about a "telephone wire" or "intercom wire" from your RV to
another one? You can decouple the RF with capacitors so that the wire
can also be used as an antenna as well as its official purpose.
--
"A Springfield woman who began lobbying against gun violence after
her son was shot to death in 2002 was arrested last week when
police allegedly found an illegal gun and drugs in her home."
--- The State Journal-Register Online - Springfield, Illinois,
1 March 2005. More details at: http://www.tincher.to/stevens.htm

On Tue, 05 Apr 2005 16:16:13 GMT, Gunner
said:



Im sure you are aware that Im quite good at research on the internet,
and did a fair amount of that, before posting my question. But there
are often tricks that individuals have come up that might be
appropriate


LOL...Yeah Gunner, I know you google, etc...
Which leads me to believe that you posted this as a spark (some on
topic for a change), there are a half a dozen site with plans for
simple magnetic (Ferrit bar and magnitic wire, you know the crap they
call an antenna inside an el-cheapo transister radio) which is most
likely what you'll end upmaking in the long run with your requirements
for 'low profile' Hell Gunner, just whip up one of those damn magnetic
antenns, make sure you've got plenty of lead wire, and simply set the
damn thing in which ever window works best for the station you are
tuning to. You can't get no lower profile then that and expect to
actually pick up anything., Heck, with a say 24 inch piece of ferrit,
wrap it with around 30 feet or so of magnetic wire. You can even add a
tuning cap if you want to get fancy, but as a general coverage antenna
you don't need all that for just receiving, YMMV. You can mount this
type of antenna in the window(s) either flat or top side.

If you need to be lower profile then the above, might I suggest a coat
hanger.

n.

Ron DeBlock wrote:
Gunner,

Find some thin magnet wire, e.g. #28 or smaller enamel coated. Use that
to make a long wire antenna, it will be nearly invisible. The main rule
for this type of antenna is "longer and higher", so do what you can.

Maybe you can add some thin sticks (fishing rods?) at the
corners of your RV, and use them to support a long wire or loop a few feet
above your roof.

If you can electrically isolate your TV antenna mast from the RV, you can
use that as a vertical antenna. If the mast is non-conductive, attach
some wire to it. Are there any
height limits on the TV antenna mast? Taller is better.

Lots of hams operate from RVs using fold-over or crank-up antennas and
masts. Antenna goes up when you're using it, and disappears when you're
not.

There are a lot of options, if you think creatively. Many hams operate
from RVs and antenna-restricted apartments, condos and developments.
Check ham sites (www.arrl.net, www.eham.net) and rec.radio.amateur.antenna
for ideas.

Your interference problem will require some work to solve. First, get an
antenna outside, connected to your receiver by coax. That should help a
lot. Make sure your computer and peripherals are well shielded, cases
properly closed and screwed shut. You can add RF filtering (inductance)
to cables by wrapping a few turns of the cable around a chunk of
core material - ferrite torroids are best, but any chunk of steel will do.
Radio Shack and others sell cores for that purpose. Add the cores to
every cable exiting your computer, as near to the device as possible.
You may need to add shielding around your monitor (conductive mesh,
grounded).

-Ron


Maybe a flagpole on the roof with an American flag. Who could object?. Of course
the halyards are your antenna....

Gunner wrote:

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.


Others have answered the antenna part. As for the connection, you want
good-quality coaxial cable, with the shield terminated well at the receiver
and at the place in the RV's wall where it passes through. This effectively
places the entire receiver "outside" the RV, as a shield wall completely
surrounds the receiver (you hope) and is then carried out through the shield
of the cable. This is how it is done on aircraft, which are also pretty
horrible
EMC environments inside the fuselage. You may have to put a line filter
on the power plug to the receiver to keep computer hash from sneaking in
on the power cord.

Jon

On 5 Apr 2005 10:18:16 -0700, jim rozen
wrote:

In article , Robert Swinney says...

Jim, I don't think you are referring to old fashioned "grounded" single wire
(literally one wire) telephone service.

That's what they had up the canyon I think. Everyone was on one
line. A pretty remote area. I don't think it was fence wire
though, it was copper.

Jim

I've seen something like that in far west Texas, near London. There
were glass insulators spiked in the top of fence posts.

Pete Keillor

On Tue, 5 Apr 2005 13:12:27 -0500, "Robert Swinney"
wrote:

Jim,
Likely what you saw up the canyon was what telephone guys call "parallel".
Parallel was just that; two conductors laying side by side, about 22 gauge
or so (I'm sure a Telco guy can correct us here). The conductors were very
hard drawn copper, or an alloy, to give strength against wind and ice
loading. If one didn't know better, it looked like a single wire.

Single wire, ground for the other side, telephone circuits are not possible
today because of all the AC currents they would share the ground with.
Maybe one would work only over a very short distance, say one span or less.
Dunno. I talked on one of the "ancients" about 40 years ago, in rural
Kansas, and it was so noisy as to be almost unusable.

Bob Swinney

What I saw in west Texas may have been out of service, glass
insulators with what appeared to be a single wire. On the other hand,
there was nothing near that road but more road, brush, and miles and
miles of not much else. There were no power lines in sight along the
road, IIRC.

Pete Keillor

"Gunner" wrote in message
.. .
On 5 Apr 2005 06:56:26 -0700, jim rozen
wrote:

In article , Gunner says...

out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.

Are you allowed to have a clothesline?

Sounds crazy, but it has been known to work!

Jim

Hummm interesting. Ill check

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

"Time Traveler" wrote in message
...
Broadcast stations and shortwave are vertically polarized.

AM broadcast band signals are vertically polarized when they're propagating
in ground-wave mode: in other words, over distances up to 150 miles or so.
Once it bounces off the ionosphere, as in late-night skip, the polarization
is random. It doesn't matter which way your antenna is polarized then.

Short wave is almost all ionospheric-skip, so it never matters which way
your antenna is polarized.

It would
behoove you to go vertical as a first choice,horizontal second.From
memory I believe there is a 50 per cent drop if a station is
broadcasting vertical and you are receivng horizontal.

That's the rule-of-thumb, but it only applies to line-of-sight (VHF) or
other space-wave transmission (some ducting, satellite, etc.). There's no
way to predict polarization in sky-wave, which is ionospheric skip. And true
ground wave is always vertical, as one end of the wave is "sunk" into the
ground.

This stuff is covered well in all editions of the ARRL Antenna Book.

--
Ed Huntress

Pete sez: "I've seen something like that in far west Texas, near London.
There
were glass insulators spiked in the top of fence posts."

More'n likely.

Bob Swinney

"Peter T. Keillor III" wrote in message
...
On 5 Apr 2005 10:18:16 -0700, jim rozen
wrote:

In article , Robert Swinney says...

Jim, I don't think you are referring to old fashioned "grounded" single
wire
(literally one wire) telephone service.

That's what they had up the canyon I think. Everyone was on one
line. A pretty remote area. I don't think it was fence wire
though, it was copper.

Jim


Pete Keillor

Could have been an "electric fence" also.

Bob Swinney
"Peter T. Keillor III" wrote in message
...
On Tue, 5 Apr 2005 13:12:27 -0500, "Robert Swinney"
wrote:

Jim,
Likely what you saw up the canyon was what telephone guys call "parallel".
Parallel was just that; two conductors laying side by side, about 22 gauge
or so (I'm sure a Telco guy can correct us here). The conductors were
very
hard drawn copper, or an alloy, to give strength against wind and ice
loading. If one didn't know better, it looked like a single wire.

Single wire, ground for the other side, telephone circuits are not
possible
today because of all the AC currents they would share the ground with.
Maybe one would work only over a very short distance, say one span or
less.
Dunno. I talked on one of the "ancients" about 40 years ago, in rural
Kansas, and it was so noisy as to be almost unusable.

Bob Swinney

What I saw in west Texas may have been out of service, glass
insulators with what appeared to be a single wire. On the other hand,
there was nothing near that road but more road, brush, and miles and
miles of not much else. There were no power lines in sight along the
road, IIRC.

Pete Keillor

"Gunner" wrote in message
. ..
On 5 Apr 2005 06:56:26 -0700, jim rozen
wrote:

In article , Gunner says...

out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.

Are you allowed to have a clothesline?

Sounds crazy, but it has been known to work!

Jim

Hummm interesting. Ill check

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

Gunner, can you get away with a CB antenna? You really don't need a
lot of antenna for SW reception, a moderate sized mirror mount whip
should work pretty well & I'm sure you wouldn't be the only one in the
park sporting one.

Howard.

On Tue, 05 Apr 2005 10:01:20 GMT, Gunner
wrote:

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

"Robert Swinney" wrote in message
...
Jim,
Likely what you saw up the canyon was what telephone guys call "parallel".
Parallel was just that; two conductors laying side by side, about 22 gauge
or so (I'm sure a Telco guy can correct us here). The conductors were
very
hard drawn copper, or an alloy, to give strength against wind and ice
loading. If one didn't know better, it looked like a single wire.

Single wire, ground for the other side, telephone circuits are not
possible
today because of all the AC currents they would share the ground with.
Maybe one would work only over a very short distance, say one span or
less.
Dunno. I talked on one of the "ancients" about 40 years ago, in rural
Kansas, and it was so noisy as to be almost unusable.

My dad set one of those up at Guadalcanal.

--
Ed Huntress

In article , Ed Huntress says...

That's the rule-of-thumb, but it only applies to line-of-sight (VHF) or
other space-wave transmission (some ducting, satellite, etc.). There's no
way to predict polarization in sky-wave, which is ionospheric skip. And true
ground wave is always vertical, as one end of the wave is "sunk" into the
ground.

Sure this all sounds right in theory. But if there are other metal
items nearby they're going to scramble the polarization, so he
really doesn't have to work too hard to get a vertical antenna.

Other mobile homes count pretty well as devices to convert from
vertical to horizontal.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Robert Swinney wrote:

Jim,
Likely what you saw up the canyon was what telephone guys call "parallel".
Parallel was just that; two conductors laying side by side, about 22 gauge
or so (I'm sure a Telco guy can correct us here). The conductors were very
hard drawn copper, or an alloy, to give strength against wind and ice
loading. If one didn't know better, it looked like a single wire.

Single wire, ground for the other side, telephone circuits are not possible
today because of all the AC currents they would share the ground with.
Maybe one would work only over a very short distance, say one span or less.
Dunno. I talked on one of the "ancients" about 40 years ago, in rural
Kansas, and it was so noisy as to be almost unusable.

Bob Swinney


Well in about 1977 there was a ground return, single wire, telephone
line in Nevada. I don't know
when, or if, it was replaced with paired wiring.

Bill K7NOM

"Gunner" wrote in message
.. .


On 5 Apr 2005 06:56:26 -0700, jim rozen
wrote:



In article , Gunner says...



out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV.


Are you allowed to have a clothesline?

Sounds crazy, but it has been known to work!

Jim


Hummm interesting. Ill check

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

"jim rozen" wrote in message
...
In article , Ed Huntress says...

That's the rule-of-thumb, but it only applies to line-of-sight (VHF) or
other space-wave transmission (some ducting, satellite, etc.). There's no
way to predict polarization in sky-wave, which is ionospheric skip. And
true
ground wave is always vertical, as one end of the wave is "sunk" into the
ground.

Sure this all sounds right in theory. But if there are other metal
items nearby they're going to scramble the polarization, so he
really doesn't have to work too hard to get a vertical antenna.

That's true, but it doesn't address the same issue. The point was that
there's no inherent signal strength advantage in having a vertical or a
horizontal antenna (in terms of polarization) for HF, short-wave reception,
nor for BCB at night.

There are noise issues, and some others. But polarization with a sky wave (a
wave skipped in the ionosphere) is not one of them.

BTW, I found my old antenna handbook, and a bit about why longer antennas
typically pick up more signal than resonant antennas.

--
Ed Huntress

jim rozen wrote:
In article wwC4e.3298$vt1.569@edtnps90, Ted Edwards says...

Gunner wrote:

frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi.

Make an insulated base for the yagi pole and put insulators in the guy
wires. Now you've got a 12' whip antena. Should work pretty good.

If the mast is wood, you could wind a helix around it. If it has guy
wires, you could insulate at the top and bottom and make a sloping V
with multiple feeds to change direction.


Hmm. I like that. Could even be loaded at the bottom. The
trailer roof now makes a lovely ground plane. Am I allowed to
say 'ground plane' now?

Sure.... assume an infinite trailer roof. :)

Gunner may want to look at a grounded horizontal loop running around the
perimeter of the trailer roof, far enough from the edge that the antenna
isn't visible from the ground. Bring the end down the side of the
trailer a couple of inches and put the tuning capacitor inside.

Look at the HF antenna on the Chinook as an example.

Third picture down:
http://www.chinook-helicopter.com/Ju...hyosaur_8.html

Among the disadvantages are non-portability and the need to rip it off
when you move the trailer.

You don't want to get too wrapped around the antenna. Down at those
frequencies it takes a real big directional antenna- like a Beverage or
a Rhombic- to make a big difference. (The one at work that was used to
talk around the world is about the size of perhaps six football fields)
Otherwise you are sucking in as much noise as signal.

Make sure you use Monster cable for good reception.

Kevin Gallimore



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On Tue, 05 Apr 2005 18:28:59 -0400, North said:

On Tue, 05 Apr 2005 16:16:13 GMT, Gunner
said:



Im sure you are aware that Im quite good at research on the internet,
and did a fair amount of that, before posting my question. But there
are often tricks that individuals have come up that might be
appropriate


LOL...Yeah Gunner, I know you google, etc...
Which leads me to believe that you posted this as a spark (some on
topic for a change), there are a half a dozen site with plans for
simple magnetic (Ferrit bar and magnitic wire, you know the crap they
call an antenna inside an el-cheapo transister radio) which is most
likely what you'll end upmaking in the long run with your requirements
for 'low profile' Hell Gunner, just whip up one of those damn magnetic
antenns, make sure you've got plenty of lead wire, and simply set the
damn thing in which ever window works best for the station you are
tuning to. You can't get no lower profile then that and expect to
actually pick up anything., Heck, with a say 24 inch piece of ferrit,
wrap it with around 30 feet or so of magnetic wire. You can even add a
tuning cap if you want to get fancy, but as a general coverage antenna
you don't need all that for just receiving, YMMV. You can mount this
type of antenna in the window(s) either flat or top side.

If you need to be lower profile then the above, might I suggest a coat
hanger.

n.


Forgot a couple of things about ferrit rod antennas. Since you might
be using this antenna indoors (like inside of a window) simply connect
the "Antenna" wire to one end of the coated magnetic wire (remove
coating where required), the magnitic wire should be wound around the
ferrit rod leaving an inch or two or rod unwrapped and each end. You
can tape up this whole mess or stick it inside of a piece of PVC or
whatever (plastic) to make hanging the antenna easier. Because your in
a metal RV, if you ground the radio to the frame, you will increase
the shielding effect of the Rv's body, so I suggest using some plain
old speaker wire cut to the same lenth as the magnetic wire in your
antenna, and lay this wire out on the floor, behind ****, out of the
way, but stretched out. Use this for your antenna ground.
If you place the antenna "outside" then none of this **** matters and
ground away...Anyways, it's not coat hanger and tin foil, but it ought
to work just as well.
n.