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FW: RF build up

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Alan Slusher

FW: RF build up

Tony:

I am sure that you can find evidence of the effect of weather on rf (see
below).

One of the things I notice is that cw signals sound weaker while it is
raining. I always thought that that was because the rain was washing some
of the rf out of the air, leaving a smaller amount of radio waves to induce
emf in my antenna wire. Since it is also possible that the rain may be
washing voltage off the antenna wire itself, I've been thinking of bring the
antenna inside the garage, so that the metal roof could shield it from the
rain.

The other thing I notice is that all the ham bands seem to get weak towards
the middle of the day and in the early afternoon. I always thought that had
to do with the effects of the heat of the sun. You know how hot and tired
you get at 2pm in the afternoon if you are out in the sun. All you want to
do is to relax in the shade with a long cold drink. Why not the same
situation for radio waves? After all, they are as much a part of nature as
you and I. What you say? How come the waves are also weak if it is raining
and overcast in the middle of the day? I thought I answered that in the
preceding paragraph.

What I don't seem to follow, and there doesn't seem to be an explanation for
it, is what happens to the feedline when rf is frozen on the antenna, and cw
coming from the transmitter at 27wpm leaves the antenna at 18wpm. There has
to be some build-up of cw characters somewhere. My guess is the feedline.
That is perhaps why old coax always seems to be fatter than new coax: lots
of unsent cw characters have distended it. My question is: what happens if
there are more characters building up than the feedline can hold? Isn't
this the real explanation for swr? Isn't swr higher in winter than in
summer?

Cheers, and Merry Christmas

Alan 8P9BM

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Tom Mc
Sent: Tuesday, December 21, 2004 13:48
To: Thom R. Lacosta; David A. Belsley
Cc: Elecraft Reflector
Subject: Re: [Elecraft] RF build up

It's my understanding (from reading another list which is addressing this
problem) that some of the RF will, in fact radiate, but that it slows down
the speed of the signal. For example, one guy reports sending 27 WPM from
his K2 but by the time it gets through the frozen RF build-up on his
antenna, it was only 18 WPM.

With this in mind, it might be a good time for me to go for the ARRL high
speed endorsements on my code copying certificate.

Just a thought...

Happy Holidays

Tom, WB2QDG
K2 #1103
-----Original Message-----
From: Thom R. Lacosta <[hidden email]>
To: David A. Belsley <[hidden email]>
Cc: Elecraft Reflector <[hidden email]>
Date: Tuesday, December 21, 2004 10:28 AM
Subject: Re: [Elecraft] RF build up

On Tue, 21 Dec 2004, David A. Belsley wrote:

> Does anyone know of a good way to remove frozen RF from an antenna?

Considering the season, you might want to find some eggnog and see if it
helps the RF escape. Even if it doesn't, if you drink enough, you may no
longer be aware of/plagued by the frozen RF.

73,Thom-k3hrn
www.zerobeat.net Home of QRP Web Ring, Drakelist home page, Free Classified
Ads for amateur radio, QRP IRC channel Elecraft Owners Database
www.tlchost.net/ Web Hosting as low as 3.49/month
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John Payne-6

Re: FW: RF build up

Alan, I think you may have unwittingly hit on one explanation for Long
Delayed Echos. All those CW characters freeze on the antenna and stay
there untill a thaw, then they melt and radiate(at least some do, many
may just drip onto the ground). Then, you hear them and think, "AHA,an
LDE!!". Another mystery solved!!

73 and a tounge-in-cheek Merry Christmas to all,

John N4FLJ

Alan Slusher wrote:
> Tony:
>
> I am sure that you can find evidence of the effect of weather on rf (see
> below).

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Ron D'Eau Claire-2

RE: FW: RF build up

Lo' these all-too-many-winters ago there were actual reports of Hams using
folded dipoles with open wire line in heavy ice/snow regions. As y'all
probably know, a folded dipole has a direct current continuity across the
feeders, since it's essentially a dipole with an extra wire running parallel
to the dipole radiator and connected at each end.

If a dangerously heavy ice coating appeared, they'd connect the feeders to a
variable power source and allow enough current to flow to heat the wires and
melt the ice. Took a while, but it beat trying to splice and raise the
antenna again in mid-winter.

Being a "California Boy" in those days - Southern California at that - I
never really had any need to test the idea first-hand. While others were
snowed and iced-in up to their end-insulators, we were praying for a few
drops of rain before the dry season resumed in the spring.

Ron AC7AC

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Charles Bland

RE: RF build up

Ron,

I love it when you wax poetic......

Chuck

From: "Ron D'Eau Claire" <[hidden email]>
To: <[hidden email]>
Subject: RE: FW: [Elecraft] RF build up
Date sent: Wed, 22 Dec 2004 09:04:29 -0800

> Lo' these all-too-many-winters ago there were actual reports of Hams using
> folded dipoles with open wire line in heavy ice/snow regions. As y'all
> probably know, a folded dipole has a direct current continuity across the
> feeders, since it's essentially a dipole with an extra wire running parallel
> to the dipole radiator and connected at each end.
>
> If a dangerously heavy ice coating appeared, they'd connect the feeders to a
> variable power source and allow enough current to flow to heat the wires and
> melt the ice. Took a while, but it beat trying to splice and raise the
> antenna again in mid-winter.
>
> Being a "California Boy" in those days - Southern California at that - I
> never really had any need to test the idea first-hand. While others were
> snowed and iced-in up to their end-insulators, we were praying for a few
> drops of rain before the dry season resumed in the spring.
>
> Ron AC7AC

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N2TK

RE: RF build up

In reply to this post by Alan Slusher

You know Alan, you may have something there. Some points I would like to
make:
When it is a rainy day or a gloomy day you tend to slow down. Maybe that
happens to RF also? Is that a rain effect or a state of mind or state of
electrical field?
Your explanation of swr (slow wave radio) may be correct. Since the CW speed
tends to slow down as it is radiated when you have ice on the antennas, I
wonder if the reverse is also true? If you have ice on the antennas and you
are receiving fast CW, maybe it will be slowed down so it is easier to copy?

Another point I would like to make is about the aluminum in beams. You ever
notice how your shiny new beam works so well? After a few years you get the
bug to buy another bigger and better antenna because you aren't as good in
the pileups anymore? Maybe the aluminum got dull because all the electrons
were radiated? So without enough electrons you don't have as strong a
signal. Just a thought.

Happy Holidays and may you have another box from Elecraft under your tree.

N2TK, Tony
#3481

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Alan Slusher
Sent: Tuesday, December 21, 2004 1:16 PM
To: 'Tony Davis'; [hidden email]
Subject: FW: [Elecraft] RF build up

Tony:

I am sure that you can find evidence of the effect of weather on rf (see
below).

One of the things I notice is that cw signals sound weaker while it is
raining. I always thought that that was because the rain was washing some
of the rf out of the air, leaving a smaller amount of radio waves to induce
emf in my antenna wire. Since it is also possible that the rain may be
washing voltage off the antenna wire itself, I've been thinking of bring the
antenna inside the garage, so that the metal roof could shield it from the
rain.

The other thing I notice is that all the ham bands seem to get weak towards
the middle of the day and in the early afternoon. I always thought that had
to do with the effects of the heat of the sun. You know how hot and tired
you get at 2pm in the afternoon if you are out in the sun. All you want to
do is to relax in the shade with a long cold drink. Why not the same
situation for radio waves? After all, they are as much a part of nature as
you and I. What you say? How come the waves are also weak if it is raining
and overcast in the middle of the day? I thought I answered that in the
preceding paragraph.

What I don't seem to follow, and there doesn't seem to be an explanation for
it, is what happens to the feedline when rf is frozen on the antenna, and cw
coming from the transmitter at 27wpm leaves the antenna at 18wpm. There has
to be some build-up of cw characters somewhere. My guess is the feedline.
That is perhaps why old coax always seems to be fatter than new coax: lots
of unsent cw characters have distended it. My question is: what happens if
there are more characters building up than the feedline can hold? Isn't
this the real explanation for swr? Isn't swr higher in winter than in
summer?

Cheers, and Merry Christmas

Alan 8P9BM

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Bill_Harris

RE: FW: RF build up

In reply to this post by Alan Slusher

As you well know Ron, that heating method works great on any closed loop antenna. I still have my old 304t_ filament transformer around for such occasions. It's good for 5 vac. @ 100 amps. Does a good job on conductive pipes that may freeze up which is normally not a problem here in Western Washington.

Carry-on
K2Bill#973