How does rain effect antennas
 

When transmitting what effect does moisture and/or
precipitation have on various kinds of antennas, also what is
the effect of rain on say uninsulated ladder line.

What is the general effect of moisture on antennas and feed
lines as power is increased?

Bill

zeno wrote in message ...
When transmitting what effect does moisture and/or
precipitation have on various kinds of antennas, also what is
the effect of rain on say uninsulated ladder line.

I'm sure it could vary to freq being used, but overall, very little.
Rain will not have much effect on ladder line, unless there is a way
for water to bridge the gap between wires. You will see increased loss
with twin leads, but very little with ladder line that has mostly air
between the wires.

What is the general effect of moisture on antennas and feed
lines as power is increased?

Well, again could vary, but overall not a whole lot in general. With
my coax fed dipoles, it doesn't matter if it's raining or not up to
1500w. There is no difference in performance. I could see water maybe
having more of an effect on say real high freq antennas. UHF, etc..
HF, there is little difference unless you have a problem caused by
water. IE: waterlogged coax, twin lead that is wet, etc. MK

Hi Mark,

Thanks for the response. Good, I won't worry about it. But I do know about coax
seal, rubberized electricians tape, and being throrough with my connections.

tnx agn.

73

Bill

Mark Keith wrote:

zeno wrote in message ...
When transmitting what effect does moisture and/or
precipitation have on various kinds of antennas, also what is
the effect of rain on say uninsulated ladder line.

I'm sure it could vary to freq being used, but overall, very little.
Rain will not have much effect on ladder line, unless there is a way
for water to bridge the gap between wires. You will see increased loss
with twin leads, but very little with ladder line that has mostly air
between the wires.

What is the general effect of moisture on antennas and feed
lines as power is increased?

Well, again could vary, but overall not a whole lot in general. With
my coax fed dipoles, it doesn't matter if it's raining or not up to
1500w. There is no difference in performance. I could see water maybe
having more of an effect on say real high freq antennas. UHF, etc..
HF, there is little difference unless you have a problem caused by
water. IE: waterlogged coax, twin lead that is wet, etc. MK

Precipitation in general, and snow in particular, can have another effect on
the antenna. And that is static buildup. You can get static voltages large
enough to damage sensitive semiconductors, such as MOS transistors. It is
usually recommended that you have the antenna either DC grounded or have
some type of sparc gap for the static to jump across. Of course, your
antennas should be grounded when not in use but not everyone does this.

In the winter, don't forget, you can get ice buildup on your antenna and
feedline

From personal experience---I was a memebe of the radio club at Ohio State
(W8LT) many years ago when they were located in the OSU stadium. We had a
genuine long wire run from the stadium over to a smoke stack on the power
plant it was a few hundred feet long. In the winter when ever we had a dry
snow there would be quite a static build up. There was a sparc gap inside
the antenna tuner, and you could hear it going snap snap snap as the charge
would build up and then arc over. I certainly wouldn't want to get my
fingers across the thing under those conditions.


--
Jim
N8EE

to email directly, send to my call sign at arrl dot net

"zeno" wrote in message ...
When transmitting what effect does moisture and/or
precipitation have on various kinds of antennas, also what is
the effect of rain on say uninsulated ladder line.

What is the general effect of moisture on antennas and feed
lines as power is increased?

Bill

Hi Zeno

Some will say it don't affect it all, others will say it will affect
it a little bit and other will say it affects it alot.

I had several little 1/16th watt neon lights laying around doing
nothing. I would toy with them, lining them on dipoles to find the
highest area of RF on the dipoles, once found, I would solder these
little rascals to the dipole so they wouldn't move in the wind.

Besides looking cute, they offered a little bit of help too.
When it was raining, they wouldn't lite at all on a couple of
antennas, and on others were very dim.
This alone tells me that there is some affect of rain on the antennas.

But one question has always perplexed me to no end.
Why will the light light up if placed on the end of my 10 meter mobile
antenna, but not on the end of 10 meter ground plane. It lights up
just fine about 19 inches below the top on the ground plane and about
22 inches below the top on a vertical with an underground radial bed.

TTUL
Gary

On Tue, 20 Apr 2004 07:35:50 GMT, zeno wrote:

When transmitting what effect does moisture and/or
precipitation have on various kinds of antennas, also what is
the effect of rain on say uninsulated ladder line.

I've heard rain affects balanced line, but I use standard insulated
450 ohm ladderline to feed a dipole, and I can't detect any SWR
changes when the line is wet or dry.

Bob
k5qwg


What is the general effect of moisture on antennas and feed
lines as power is increased?

Bill

"Gary V. Deutschmann, Sr." wrote in message
...
Hi Zeno

Some will say it don't affect it all, others will say it will affect
it a little bit and other will say it affects it alot.

I had several little 1/16th watt neon lights laying around doing
nothing. I would toy with them, lining them on dipoles to find the
highest area of RF on the dipoles, once found, I would solder these
little rascals to the dipole so they wouldn't move in the wind.

Besides looking cute, they offered a little bit of help too.
When it was raining, they wouldn't lite at all on a couple of
antennas, and on others were very dim.
This alone tells me that there is some affect of rain on the antennas.

But one question has always perplexed me to no end.
Why will the light light up if placed on the end of my 10 meter mobile
antenna, but not on the end of 10 meter ground plane. It lights up
just fine about 19 inches below the top on the ground plane and about
22 inches below the top on a vertical with an underground radial bed.

TTUL
Gary

One question perplexes me - are you so bored that you can't think of
anything better to do other than solder neon lights to your antenna??? My
God, someone please shoot me if I ever get to that stage!!! ;-)

Bob Miller wrote:
I've heard rain affects balanced line, but I use standard insulated
450 ohm ladderline to feed a dipole, and I can't detect any SWR
changes when the line is wet or dry.

Some (biased) experiments have been performed with twinlead laying
on a wooden deck wetted by a soapy solution. Moral: Avoid soapy
horizontal ladder-line. :-)

I use the length of the ladder-line to tune my antenna system to
resonance. I have to change the length by up to 2% to compensate
for the rain, i.e. rain has a negligible effect on the tuning of
my antenna system.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

When I was a kid I remember tuning my antenna with one of those little neon
bulbs soldered to a couple of little loops of wire. One guy would be at the
transmitter, the other guy up on a ladder with the bulb. When the bulb was
brightest your antenna was tuned....or something like that...

Zeno

Marty wrote:

"Gary V. Deutschmann, Sr." wrote in message
...
Hi Zeno

Some will say it don't affect it all, others will say it will affect
it a little bit and other will say it affects it alot.

I had several little 1/16th watt neon lights laying around doing
nothing. I would toy with them, lining them on dipoles to find the
highest area of RF on the dipoles, once found, I would solder these
little rascals to the dipole so they wouldn't move in the wind.

Besides looking cute, they offered a little bit of help too.
When it was raining, they wouldn't lite at all on a couple of
antennas, and on others were very dim.
This alone tells me that there is some affect of rain on the antennas.

But one question has always perplexed me to no end.
Why will the light light up if placed on the end of my 10 meter mobile
antenna, but not on the end of 10 meter ground plane. It lights up
just fine about 19 inches below the top on the ground plane and about
22 inches below the top on a vertical with an underground radial bed.

TTUL
Gary

One question perplexes me - are you so bored that you can't think of
anything better to do other than solder neon lights to your antenna??? My
God, someone please shoot me if I ever get to that stage!!! ;-)

Bill wrote:
"When transmitting what effect does moisture and / or precipitation
have on various kinds of antennas---?"

I worked off and on for 10 years in a medium wave broadcast station with
a 4-tower directional array (separate day and night patterns) fed by
open-wire 6-wire skeletal coax.
Every half hour we recorded the sampling loop currents associated with
each tower and the phase relationships between the towers using an RCA
WM-30A phase monitor. Precipitation and fog didn`t amount to a hill of
beans in nearly all cases. Currents and phases were nailed in place.

Best regards, Richard Harrison, KB5WZI