[Elecraft] [K2] SWR meter reads 'funny' on just 20 meters

[Vic Rosenthal K2VCO]

Well, I see how his dipole might be presenting an extreme value of 
impedance on 20, depending on the length and impedance of the line.

But why is his dummy load weird only on 20M? That's a puzzle -- and it 
needs to be solved first.

On 5/6/2014 6:31 PM, Phil Wheeler wrote:
> Not an Elecraft ATU?  Well, there's the problem :-)
>
> More seriously, perhaps your tuner does not like what it is seeing.
>
> 73, Phil w7ox
>
>
> On 5/6/14, 6:21 PM, inventor61 . wrote:
>> Don (and list)
>>
>>
>> I just replaced my 'back up shack' antenna today (it was a 45/90 OCF
>> experiment) with a 138' open wire fed doublet.  The center is up 50' and
>> the elements are more-or-less installed.  They will get more installed
>> later.
>>
>> I used the 'Ladder-Snap' pieces to make the feedline.  In 35 years of
>> being
>> licensed and active, I have never had an open wire fed antenna.  They
>> look
>> cool, kinda retro, sort of old (like me, I am 53 today), a real classic.
>>
>> Anyway, I fired up the old K2 and hooded it up to the new aerial.  The K2
>> (the same one since 1999) has the KAT2 installed, which works well,
>> but the
>> ATU portion isn't in line for this setup.  Instead, I have a
>> DC-phantom-powered SGC-239 out at the feedpoint.
>>
>> Inside, I have an A-B switch that can steer the rig's output to a lab
>> grade
>> 50 ohm load.
>>
>> On all bands but 20 meters, the outside tuner quickly found a 'solution'
>> for the new doublet, none worse a match that 1.5:1.  Nice.  However,
>> on 20,
>> the K2 said it was 3.0:1  ...
>>
>> Hmm..
>>
>> I flipped to the dummy load.  All bands show 1:1 on the K2 display except
>> for 20, where it reads 1.8:1 ... into 50 ohms.
>>
>> I switched the K2 display to read FWD & REV, instead of SWR, and then the
>> display showed 5.7W fwd and 0.7W reverse into the dummy load.
>>
>> So, what do you think the problem might be?
>>
>> Thanks in advance for the opinion.  Hope you're enjoying the terrific
>> weather.
>>
>>
>> Steve KZ1X
>> Chapel Hill


-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/