Snake antennas

[sdan...@nyc.rr.com]

It's been hot as heck in NYC for the last couple of days. Yesterday, to
escape the heat, I spent much of the afternoon in Prospect Park,
where's there's usually a nice breeze and cooler temperatures. On a
whim I brought along 100 ft of wire and my HF-150. I laid the wire out
in a 'snake' configuration, right on the ground, and was pretty
impressed with the results. I was in a quiet spot there in the Park.
Even so, when people describe this as a low noise antenna, they aren't
kidding. Using a couple of tree limbs, I raised the wire up about 7-8
ft. The increase in noise was noticeable, and the s/n ratio was a
little worse.

I realize that the classic snake antenna uses coax, not wire. However,
ordinary old insulated wire sure seemed to work well for me yesterday.

I've read around on the web about these antennas and their low noise
characteristics, but I'd be interested to hear about any experiments
the readers of this group have done. I'm especially curious about how
the presence of metal objects in the immediate vicinity of a snake
antenna would affect its performance. For example, suppose you took
200ft of insulated wire and 'stiched' it through the bottow row of
'links' on a very long chain link fence. I can't imagine a stealthier
antenna than this, but would the fence muck things up?

Steve

[r2000...@hotmail.com]

Capacitive coupling to the metal fence would increase
both desired signal and noise. With noise going up faster
then the desired signals. I tried this many years ago
when we lived in a no antenna apartment.

I works with a wood plank fence.

Terry

[cuh...@webtv.net]

You are lucky that somebody didn't rob you of that radio.
cuhulin

[cuh...@webtv.net]

The higher up you can get the antenna,the better,that is what some folks
say.The chain link fence mucking things up,I dont know,but I think it
would.
cuhulin

[David]

Is there an RF ''boundary effect'' at HF (like a PZM microphone for
radio waves?).

[cuh...@webtv.net]

Unless you can see all of that chain link fence,you never know what else
might be hooked up to it.I agree with experimenting with different
things and see what the results are.
cuhulin

[David]

On Sun, 14 Aug 2005 16:29:14 GMT, "-=jd=-" <jd77...@HATpostmark.net>
wrote:

>
>On Sun 14 Aug 2005 10:56:46a, sdan...@nyc.rr.com wrote in message
>news:1124031406....@g14g2000cwa.googlegroups.com:

>Outstanding!
>
>This is a post that should be shown to every new-poster who asks the
>inevitable question, "What kind of antenna should I use?".
>
>Just like sdan...@nyc.rr.com, you use whatever you have and rig it up
>however you can; then post your results.
>
>It seems at times that folks get so tied up in the technical details, and
>trying to *exactly* follow some established design, that they really miss-
>out on finding out something new that can work acceptably for their unique
>set of conditions.
>
>I say lace that wire through the fence and see what you get. Conventional
>wisdom is that you will get Result-A (and you very well may). But, wouldn't
>it be interesting if you got Result-X, Y and/or Z?
>
>-=jd=-

I expect some of your desired energy will be inductively coupled to
Ground through the fence posts spaced every 10 feet. I further expect
an insulated wire on the ground, not near any other metallic objects
will work better.

I have an instinct...

[Honus]

<cuh...@webtv.net> wrote in message
news:4794-42F...@storefull-3252.bay.webtv.net...

> might be hooked up to it.I agree with experimenting with different
> things and see what the results are.

Just can't leave the bestiality out of the thread, can you?

[John Smith]

sdaniel:

Main coupling to the chain link fence with be by capacitive coupling
(inductive coupling, I suspect, would be negligible.

The chain link fence will have a "natural resonant frequency" of its own,
and favor some freq or range of freqs, and those freqs harmonics. This
could have a beneficial and/or counter effect on antenna depending on band
operation. This antennas impedance would be difficult to guess and/or
determine, one might try running the antenna though various ratio baluns
(or a multi-tapped rf transformer) to see if signal can be improved.

Any electrical interference the fence runs close to will increase noise
level. At my location there is a chain link fence which encircles tens of
acres... it boosts my LW TREMENDOUSLY! I have a weird "gamma match"
arrangement I have experimented with and tap the chain link fence with. I
have not experienced "noise" of any type but imagine it can occur under
circumstances favorable to its generation, and under proper conditions
which encourage it...

For the ~9 mhz range, just running an alligator clip to the fence, though
a 9:1 balun seems to work well for me... if you like toying with such
things, can be fun.

Hook it up and experiment, there is someway you can use what exists to
your advantage! Probably get ideas off the web, if you and I and more
have thought about this, probably many more have played with it...

John

[Telamon]

In article <1124031406....@g14g2000cwa.googlegroups.com>,
sdan...@nyc.rr.com wrote:

If you want a low noise antenna use a loop type that is sensitive only
to the magnetic part of the EM wave. Small loops will need amplification.

--
Telamon
Ventura, California

[cuh...@webtv.net]

There is always the danger of lightning hitting a metal fence too.
cuhulin

[RHF]

Steve - Sound like you had a 'mini'
Beverage-on-the-Ground (BOG) Antenna. ~ RHF
http://www.hard-core-dx.com/nordicdx/antenna/wire/beverage/view1.html
.
Car DXing - by Hans Johnson
http://www.anarc.org/naswa/issues/0898/swc0898.html

. . . . .

[Telamon]

In article <1124058214....@f14g2000cwb.googlegroups.com>,
"RHF" <rhf-new...@pacbell.net> wrote:

This is not a mini-Beverage. A Beverage needs to be near but off the
ground.

The snake antenna uses a coax with the outer shorted to inner at the far
end from the radio.

A wire on the ground is just a wire on the ground and as you found out
will pick up signals. depending on what you need it to do it can be a
good antenna.

I occasionally take a portable (Sony 7600G) to the park and listen to
Australia on 21,740 during the day. I elevate a wire in the trees to get
better reception and this is on a hill over looking the pacific ocean.

--
Telamon
Ventura, California

[David]

[RHF]

Telamon - When is a Beverage Not a Beverage ?
When it is a BOG = A Beverage-On-the-Ground !
.
http://lists.contesting.com/pipermail/topband/1999-December/003281.html

.
http://lists.contesting.com/archives/html/CQ-Contest/1996-03/msg00130.html

.
http://www.booksandtubes.com/160meters.htm
.
http://www.anarc.org/naswa/issues/0898/swc0898.html
.
but what do i know - iane ~ RHF

[Mark Zenier]

In article <1124031406....@g14g2000cwa.googlegroups.com>,
<sdan...@nyc.rr.com> wrote:

Back last fall, I ran a snake antenna (60-80 feet of 24 ga. insulated
wire) through the bushes back into the woods behind my house. (This goes
to the high impedance, 500 ohm, input of my R-1000). The idea was a
total stealth antenna, down in the ground cover.

That seemed ok for a while. Then I decided to go walkabout with my
Grundig FR-200 at the same time as I was listening with my R-1000 on
wireless headphones to Radio Australia on 17795 at 4 PM local time.
When your $40 radio picks up better off the whip than a tabletop with
80 feet of wire, you know you've got antenna problems. Like damp ground
and snake antennas and anything above 6 MHz being mutually incompatible.

Tossing the same wire 20 feet up into the trees, and 17 MHz went
from below S1, down in the mud, to a reasonable S4.

Similar results this spring. (I was getting a bunch of interference
from the house remodel next door. My guess is that construction guys
must have done something to the phone wiring on a DSL line or broke
a ground connection on digital TV cable. Sounded like broadband
data comm crap all over). I ran about 80-100 feet about 3 feet off
the ground in the opposite direction from the first antenna. The
interference was much reduced, but it was much poorer than the other
antenna above 9 MHz.

Dampness in the ground and vegetation may be a factor. Here in
Seattle, you can count on that for about 9 months of the year.

Mark Zenier mze...@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)

[John Smith]

cuhulin:

Make a homemade "coherer" and use it on the antenna wire to ground...

John

[cuh...@webtv.net]

Beware of old sneaky snake.
cuhulin

[RHF]

MZ,
.
Building a "SNAKE" Antenna [Hidden / Stealth] (End-Fed-Dipole)
[ Day-in-the-Park / Camping / Emergency Antenna ]
.
Take 50 to 100 Feet of TV 'type' Coax Cable.
.
Hold it in Half - Tip-to-Tip. (Find the Mid-Point)
.
Remove about an Inch of the Outer Insulation Cover and Shielding
at the Fold in the Coax Cable. Do not damage the Inner Insulation
and Center Conductor. Tape this Area around the exposed Inner
Insulation and Cover it well.
.
Take one End of the Coax Cable (Remove the "F" Connector) and
Join together the Inner Center Conductor and the Outer Shielding.
This is now the "Far-End" of the Antenna.
.
Lay-out the Coax Cable On-the-Ground (In-the-Grass).
.
Connect the end of the Coax Cable with the "F" Connector via an
Adapter to your Radio.
.
Now you have built your self a "SNAKE" Antenna (End Fed Dipole)
to use with your Radios.
.
NOTE -This same End-Fed-Dipole Antenna when Camping can be
Elevated at the Center from a Tree Limb; Strung-Up Vertically; or
Hung-Up-and-Out as a Sloper.
.
.

[Telamon]

In article <ddqdlv$r79$1...@eskinews.eskimo.com>,
mze...@eskimo.com (Mark Zenier) wrote:

Next time you try a wire on the ground use the radios 50 ohm input if it
has one. It might work better than the high impedance input. The wire up
in the trees will probably work better on the high Z input.

--
Telamon
Ventura, California