Steve:
Thanks for all of these suggestions, and I'll try them out as I can here.
I can tell you at this point that the feedline is stood off away from the
tower by about 18 inches.
Also, I haven't gotten any reports of RFI in the house, but will pursue that
possibility too.
Also, I was thinking of taking my SWR readings at a lower power level, say
10 watts rather than 100 watts, just to see if that made a difference.
Will keep you posted.
73 from Tom Behler: KB8TYJ
----- Original Message -----
From: "Steve Forst" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, September 28, 2008 10:09 AM
Subject: Re: windom question
> Tom,
>
> Howard has been around longer than both of us put together, but I think
> the
> fact is that most of the currently sold off center fed antennas use a
> balun
> at the feed point and coax feed, like you have. The exception is the
> Carolina Windom which uses a section of balanced line to try and put
> feedline radiation to good use.
>
> Here's a few random thoughts in no particular order: Your antenna seems
> short. Alpha Delta, Buxcom, and Array Solutions OCF antennas are 135
> feet
> long. Antennas and More OCF has one at 132 ft. 4:1 balun is more
> common,
> but there is some use of 6:1. There is also a debate on just where
> the
> feed point should be located. All of this stuff will have some effect on
> the final result.
>
> Your 40 meter swr is high and 20 meters is out of sight. You should
> see
> 2:1 or so at band edges on 40 and 20, similar to what you are getting on
> 80.
>
> You should be seeing the very high swr on 15, not 20. In fact there is a
> mod to add 2 parallel wires to the feedpoint to get good swr on 15 and
> 30.
> The fact that
> If antenna design is ok, what else could it be? Maybe too close to the
> tower? Is there any kind of standoff to get it away from the tower?
>
> Sometimes changing feedline length can make a difference. Try using a
> few barrel connectors and short coax jumpers to add various combinations
> of
> coax length and see if things change.
>
> Finally, these things can throw off some RFI. Any RFI in the house? .
> Did
> you wind a coax choke at the feedpoint? (I had to do this.) Stray RF
> could
> be throwing off your swr readings on your talking meter.
>
> 73 good luck, Steve KW3A
> ----- Original Message -----
> From: "T Behler" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, September 27, 2008 9:56 PM
> Subject: windom question
>
>
>> Hi, folks.
>>
>> Here's one for all of you who have used a Windom antenna before.
>>
>> I am interested in what anyone knows about the characteristics of a
>> normal
>> Windom antenna, in relation to SWR readings.
>>
>> As many of you know, I put a Windom up last week, and am now in the
>> process
>> of testing it.
>>
>> The Windom itself is approximately 125 feet long--80 feet to the south,
>> and
>> 45 feet to the north.
>>
>> The center is fed with RG8U coax, and there is a 4 - 1 balun at the feed
>> point.
>>
>> The antenna is up about 35 feet, both at the center which is attached to
>> my
>> tower, and the legs which are attached to conveniently-located trees.
>>
>> The antenna tunes on all bands from 80 through 10 meters, except for 30
>> meters, using the auto-tuner on the TS480.
>>
>> I have already tried the antenna out on 80 meters, and have gotten very
>> good
>> signal reports from participants in a Michigan state-wide net. My SWR's
>> on
>> 80 meters range from about 2.1 to 1 at the top, to about 2.5 to 1 at the
>> bottom of the band, with SWR's close to 1.1 to 1 a little above the
>> center
>> of the band.
>>
>> I did some checking earlier on 40 and 20 meters, and found my SWR's to be
>> less encouraging.
>>
>> On 40 meters, my SWR's range from 3.1 to 1, to about 5.1 to 1.
>>
>> On 20 meters, my SWR's are about 6 to 1 at the bottom of the band, and
>> around 2.1 to 1 at the top of the band.
>>
>> These SWR's are disappointing to me, although the auto-tuner in the TS480
>> seems to tune the antenna fine at various frequencies throughout the 20
>> and
>> 40 meter band.
>>
>> Am I in trouble here, or is this typical of a Windom antenna like this?
>>
>> Thanks, and 73 from Tom behler: KB8TYJ
>>
>
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