Since he said the coax was 75-ohm, a 75-ohm termination would be better.
On 6/9/2018 5:07 PM, Richard (Rick) Karlquist wrote:
As a sanity check, terminate the coax with a 50 ohm resistor and verify
that you have good coax. Flat line at 1:1 SWR, etc.
Rick N6RK
On 6/9/2018 4:57 PM, terry burge wrote:
I don't know what is wrong here but I keep getting in this situation where my
typing starts running back over my writing. I will try again to reply.
Joel,
I have tried all that the manual says without success. All I see is the
horizontal solid and dashed lines of R and X. No indication of a resonance
point anywhere from 1880 KHz up to 10,500 KHz. Go figure? At least my
mfj-259b is working old as it may be. Rig Experts is going to get a nasty
note I think. Disappointing, huh?
Terry
KI7M
On June 9, 2018 at 2:54 PM Joel Harrison wrote:
Hi Terry,
I replaced the 1/4 lines on my 80 meter 4 square this past fall and used
my AA-170 to set the length with no problem.
Just select "all" for the mode and set the freq you're aiming for and then
trim the line until X equals zero with the far end open. Should work fine.
I always calculate the length x VF then add a few feet to start.
73 Joel W5ZN
> > Hi guys and gals,
I have got DX Engineering 75 ohm foam coax to make the
stubs/feeders for
my Comtek 80 meter 4-Square and am finding some difficulty.
Neither my
MFJ-259B nor my Rig Experts AA-170 seem to indicate a 1/2 WL at
7500 KHz
or a 1/4 WL at 3750 KHz? Or any frequency up or down from there.
Seems to
me the last time I did this a few years ago I didn't have a problem
getting a 1/2 WL dip indicating a resonance location. But now I
just don't
get any indication of a resonance.
DX Engineering said they had got some 75 ohm foam coax that
instead of
0.84 VF was more like 0.80 down to 0.76 VF. But checking all the
way down
to 6000 KHz on 40 meters or 2500 KHz on 80 meters fails.
My test is to use either antenna analyzer with a PL-259 installed
at one
end and an open or a short at the other. I started with 57'7" of
coax.
Tried both with the coax in a roll and strung out. What am I doing
wrong?
Terry
KI7M
😞
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