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
I used a return loss bridge and measured a TEE fitting with a good 50
ohm load on one port the length of cable on the other side. The antenna
analyzer will read a perfect 50 ohm match when the cable is 1/2
wavelength long. If the cable is an open quarter wave, your analyzer
will show high VSWR
Hi guys and gals,
Well, to make a long story short my Rig Experts AA-170 has quite working. Looks
normal but a 56 ohm resistor at the end of the 75 ohm coax reads infinite. On
the MFJ-259b it reads 56 ohms. Check SWR and the MFJ reads 7.499.2 Mhz 1.1:1
SWR R=56/57 ohms X=0. Coax is 55' 4 3/8"
Good point Wes. I will see if I can find a decent value of resistor. My Rig
Experts AA-170 was purchased because I did not trust the readings my MFJ-259b
was giving me while working on my hytower. Pretty penny for these antenna
analyzers. But I will bet if it won't do the stub frequency checks
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
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
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
Hi Ed,
Unfortunately I don't get any indication per the Rig Experts manual with an
open. The R/X just does not get any indication from 1982Khz all the way to
10,500+ KHz. On my MFJ-259B (old one) with a short I get at 7.234 Mhz (or
about) R=1 and X=0. Suspect the R indicates the short of
Ok Terry, well 1/2 wave at 7234kc will = 1/4 wave at 3617kc, so trim
until u get near 7500kc
and cut all lines that length and u should be ok. Back in the 1980s when
I built my 4 square, I used a noise bridge
to build my lines.
Ed
KG4W
On 6/9/2018 5:19 PM, terry burge wrote:
Hi Ed,
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
Hi Terry, see page 16 of this site
https://www.rigexpert.com/files/manuals/aa170/aa-170-manual.pdf
when looking for a 1/4 wave, leave the far end of the coax under test open.
when looking for a 1/2 wave, short the far end of the coax under test.
Your 57'7" pc of would be 1/4 wave at 3750 if
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