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/
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