[Elecraft] Output power being eaten

Tue Dec 28 14:21:40 EST 2021

Lyn:

Can you comment on the balun you are using between OWL and the KAT500 -
Specs, etc?

Thanks 
 Ed McCann
AG6CX

Sent from my iPhone

> On Dec 28, 2021, at 11:06 AM, Lyn Norstad <Lyn at lnainc.com> wrote:
> 
> Bob -
> 
> I don't have the tower issue, but my OWL comes into the house thru soffit vent spaces (the metal vent has been replaced by a plywood panel), runs over ceiling joists (wood) to the balun and short coax to the KAT500.  I bought a 300 foot piece, and used about half.
> 
> https://www.trueladderline.com/w7fg-design-600-ohm-open-wire-feedline/
> 
> 73
> Lyn, W0LEN
> 
> 
> -----Original Message-----
> From: Bob McGraw [mailto:rmcgraw at benlomand.net] 
> Sent: Tuesday, December 28, 2021 12:27 PM
> To: Lyn at LNAINC.com; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Output power being eaten
> 
> Yes, I agree that true open wire line does not have that issue. However, 
> in as much as I have the feed-line from the antenna, standing off of the 
> tower some 18", entering through an eve vent, then through the attic 
> supported under the wood roof rafters, and dropping down through the 
> ceiling to my operating position, using true open wire line would be a 
> challenge.  In my installation, I add 10 twists per 10 ft so as to 
> minimize any adjacent item causing unbalance plus minimize any wind 
> loading.  With true open wire line, this would be a challenge.
> 
> I've used this system for more than 25 years with a great deal of 
> success and very little to zero issues.  It is just ones understanding 
> the need for a slight adjustment of the ATU values to compensate for 
> weather changes.  No different than frequency changes.  The KPA500 or 
> the KAT in the radio handles any needed changes 100%.  The currents in 
> each side of the line are balanced to 5% or better and there is no 
> measurable common mode current.
> 
> I wish more hams understood this and they would likely have better 
> antenna systems, as opposed to some of the haywire crap I've see at some 
> QTH locations.
> 
> Thanks
> 
> 73
> 
> Bob, K4TAX
> 
> 
>> On 12/28/2021 11:46 AM, Lyn Norstad wrote:
>> Bob -
>> 
>> Should you ever feel the need to replace your feedline, open wire line will solve that problem.
>> 
>> 73
>> Lyn, W0LEN
>> 
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bob McGraw
>> Sent: Monday, December 27, 2021 7:36 PM
>> To: elecraft at mailman.qth.net
>> Subject: [Elecraft] Output power being eaten
>> 
>> I doubt that ice on the antenna would have any effect in terms of
>> increased loss.   However, I would expect the resonant frequency to
>> change and thus the need to adjust the tuner.   If it is and ATU /
>> automated tuner, then perhaps a bit too low power may cause the SWR
>> bridge to read incorrectly.
>> 
>> I use a KAT500 and my TUNE power is 20 watts.  This assures the ATU and
>> SWR circuits have adequate signal to perform the desired function.   As
>> to the SPE 1.3K amp, as fussy as they are, I'm surprised it didn't trip
>> off line.
>> 
>> My experience with antenna's changing due to moisture is with my
>> balanced center fed wire which uses window line for the feed.  It
>> accumulates moisture, frost, rain, snow, and ice.  The change I do see
>> is due to the velocity change of the balanced feed.  My measurements of
>> a couple of years back indicated the length of the line changed
>> electrically thus a velocity factor change.  Any loss, wet or dry, under
>> matched conditions was not measurable over a length of 100 ft on 20M.
>> Therefore, I would expect the mis-matched loss to be about as the book
>> say.  Again, either wet or dry.
>> 
>> 73
>> 
>> Bob, K4TAX
>> 
>>> On 12/27/2021 4:10 PM, elecraft-request at mailman.qth.net wrote:
>>> Message: 21
>>> Date: Mon, 27 Dec 2021 14:10:25 -0800
>>> From: Fred Jensen<k6dgwnv at gmail.com>
>>> To: Elecraft Reflector<elecraft at mailman.qth.net>
>>> Subject: Re: [Elecraft] Output power being eaten
>>> Message-ID:<8c012d97-f62d-b342-4ec3-20db2e8f51d8 at gmail.com>
>>> Content-Type: text/plain; charset=utf-8; format=flowed
>>> 
>>> I doubt that pogonip or even solid ice on your antenna would have major
>>> effects [well, except for weight].? Ice forming from water directly from
>>> the sky is a pretty good insulator.? We had a very large Log-Periodic on
>>> the roof of the hangar at my first USAF assignment in the remote
>>> northern interior of KL7.? Lots of ice fog creating rime ice on the
>>> elements in the dead of winter, much of which was -35 C or below.? In
>>> the so-called spring, solid ice would form on them, and there was
>>> essentially no perceptible change in the antenna performance.? If your
>>> ATU wasn't getting enough power to tune, it was probably "eating your
>>> power" rather than the ice on the antenna.
>>> 
>>> At home, I have an HOA "WOOF" antenna [Wire On Organic Fence] at about 2
>>> m AGL.? We've been having a series of snowstorms, the top of the fence,
>>> including the wire, was encased in snow yesterday for the 40 m ECN, and
>>> it worked as good as it ever does.
>>> 
>>> 73 & HNY,
>>> 
>>> Fred ["Skip"] K6DGW
>>> Sparks NV DM09dn
>>> Washoe County
>>> 
>>> Bill Frantz wrote on 12/27/2021 11:48 AM:
>>>> I didn't have a good night in the K1USN Slow Speed Test. I started
>>>> more-or-less on time and tried to answer CQs. None of the stations I
>>>> tried
>>>> could hear me. My SPE 1.3K amp said I was putting out about a kilowatt,
>>>> although the antenna tuning on my normally low SWR 40M dipole needed
>>>> to be
>>>> redone. I was receiving many stations, at normal levels.
>>>> 
>>>> After a few minutes, I started searching for causes, since operators
>>>> calling CQ weren't hearing me and sending CQ again. Some of these
>>>> operators had worked other stations, so I knew their radios were
>>>> basically working. I tried maybe a half a dozen stations.
>>>> 
>>>> Finally, in desperation, I raised the tune power in my K3 exciter to 15W
>>>> and retuned the dipole yet again. Things started working and I managed to
>>>> check into the Elecraft 40M CW net via KD5ONS in OR at 0050z. With only 5
>>>> minutes in the contest left, I managed QSOs with W6SX and VE5MX.
>>>> Thanks to
>>>> both of them.
>>>> 
>>>> My current theory about what was happening is that ice on the antenna was
>>>> eating transmit power, although receive seemed normal. Does ice seem a
>>>> reasonable explanation? What else could be the cause? I'd love to come up
>>>> with a believable answer. Even more so, avoid the situation in the
>>>> future.
>>>> 
>>>> 73 Bill AE6JV
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> 
> 
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