[TowerTalk] frustrating rain and connections... update

[Kim Elmore]

Dielectric loading can have profound affects. I wondered if it could be 
that early on in the thread, but I've never experienced it (that I know 
of) in rain. However, it takes very little ice to detune my KT-34A. My 
40-CD2 is less sensitive, but is certainly affected. My 80 M inverted V 
is unaffected by rain, but 1/4" of ice really moved it's resonant 
frequency down a lot. All antennas feed impedance is also altered even 
at resonance, so it's not merely a change in resonant frequency.

Kim N5OP

On 4/13/2016 12:30 PM, Charles Farr wrote:
> I have noted similar changes on my KT-34XA. I've heard that on these 
> antennas that water gets into the capacitors on the elements, causing 
> the tuning to change. It doesn't last very long after the rain stops. 
> Just something I live with when it happens. SWR that is normally 1.5:1 
> or less rises to 2 - 2.5. I also experience a lot of precipitation 
> static when it rains, snows, etc. I've also heard these effects are 
> less on yagi antennas of "plumber's delight" construction. Just 
> observations, no real tests, or science.
>
> 73
> Chuck, W6AJW
>
>
> On 04/13/2016 07:38 AM, john at kk9a.com wrote:
>> I was thinking the same thing. My homebrew antennas have flat SWR well
>> below and above the band edges and I have not noticed any change on my
>> LP-100A's display when it rains.
>>
>> John KK9A
>>
>>
>> To:    towertalk at contesting.com
>> Subject:    Re: [TowerTalk] frustrating rain and connections... update
>> From:    "Joe Subich, W4TV" <lists at subich.com>
>> Date:    Wed, 13 Apr 2016 08:23:51 -0400
>>
>>
>> On 4/13/2016 12:09 AM, Bob K6UJ wrote:
>> I have always noticed a slight change in the swr with hf yagis when
>> it is raining. Just a minimal change though. Nothing like what Gary,
>> K9RX reported.
>>
>> One would expect that the amount of "detuning" would be related to the
>> overall "Q" of the antenna.  Antenna designs with critical element
>> tuning - particularly DE/D1 - will detune more than designs optimized
>> for lower frequency sensitivity (OWA, log-cell, etc.).
>>
>> The KLM/M2 designs have always been rather "fiddly" when it comes to
>> tuning/SWR - specially when compared to some newer designs like the
>> OWA, LFA, etc.
>>
>> 73,
>>
>>     ... Joe, W4TV
>>
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-- 

Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP 
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)

/"In theory there is no difference between theory and practice. But, in 
practice, there is." //– Attributed to many people; it’s so true that it 
doesn’t matter who said it./