Tom,
Have you checked SWR at the bottom, top, and middle of the band?
I know it took a long time to get the antenna up. Did you install it
in such a way that it can be lowered for adjustment if need be?
73, Steve KW3A
On 6/25/2015 9:40 PM, John Miller wrote:
> I'd bet it's the coil of extra coax. Any time I ever dealt with a coil of
> extra coax, it's caused some sort of similar problem unless it's the 10
> turns at the feed point to the antenna some antennas like. Other than that,
> I've seen more than one coil of extra coax, and not once has it ever led to
> anything good..
> ----- Original Message -----
> From: "Tom Behler" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, June 25, 2015 9:16 PM
> Subject: Interesting Problem With Alpha Delta DXCC Antenna Out Here At The
> RV Camp Site
>
>
>> Hello, again, all.
>>
>>
>>
>> Well, my Alpha Delta DX CC antenna is finally up out here at the RV camp
>> site.
>>
>>
>>
>> It is up a good 30 feet in the trees, with the center and ends being at
>> about the same height.
>>
>>
>>
>> I have done some preliminary testing of the antenna, and all looks good,
>> with one exception.
>>
>>
>>
>> Specifically, the antenna tunes with the TS480 internal auto-tuner across
>> the 10, 15, and 40-meter bands. It even tunes across much of 80 meters,
>> from about 3600 to about 3900 KHZ.
>>
>>
>>
>> However, I cannot get it to tune at all on 20 meters, once again, using
>> the
>> TS480 internal auto tuner. I even put my MFJ auto-tuner extender in line,
>> with no luck.
>>
>>
>>
>> This is a bit disappointing to me, since 20 meters is one of my favorite
>> field day operating bands.
>>
>>
>>
>> As I am scratching my head here to try to determine what might be going
>> on,
>> I have two theories. First, it has to be understood that I am limited to
>> keeping the antenna within my lot space, and have to work with the
>> available
>> trees. This means that the legs of the antenna are probably only about at
>> a
>> 60-degree or so angle from the center. In other words, the antenna is
>> kind
>> of like a folded dipole in some ways. I wonder if this could be
>> de-tuning
>> the antenna on 20, although I'm not sure why it also would not bbe
>> de-tuning
>> it on the other bands I mentioned.
>>
>>
>>
>> My second theory has to do with my coax feed line. It turns out that I
>> probably have about 40 extra feet of coax that I have coiled up underneath
>> my station operating area. I wonder too if this might have something to
>> do
>> with the strange 20-meter behavior.
>>
>>
>>
>> Obviously, I'm happy that the antenna is usable on 10, 15, 40, and 80, so
>> I'm sure I'll have a good Field Day exxperience. But, the 20-meter
>> problem
>> does puzzle me.
>>
>>
>>
>> Does anyone have any thoughts, or suggestions that I might try to get
>> things
>> working on 20 meters?
>>
>>
>>
>> Tom Behler: KB8TYJ
>>
>>
>>
>>
>
>
>
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