Date: Mon, 11 Jun 2018 07:29:39 -0700
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
To: terry burge <ki7m@comcast.net>, topband@contesting.com
Subject: Re: Topband: cutting coax stubs for 80 meter 4-square
On 6/10/2018 8:01 PM, terry burge wrote:
> All's well that ends well I'm happy to report. K2AV, Guy suggested I check
> the SO-239 on the Rig Experts AA-170 and I found an open solder joint between
> the back of the connector and the circuit board. Even with my close in
> glasses and a magnifying glass it was hard to be certain. So a little solder
> and 'hop-a-long' rides again! It's working. Will check out the coax stub
> again to see what the RE reads now.
> Terry
> KI7M
<My AA-55 is a different model than yours, but the instructions
have curious warning about not putting too much force on the
UHF connector. I am thinking that RE realizes they have a
weak mechanical mounting, relying on solder. I think I will
revise my advice:
1. Always use a DC block
2. Carefully attach a short flexible coax jumper and leave
in place. Calibrate it out. Then connect the DUT to the
end of the jumper. No mechanical stress on the UHF.
Rick N6RK
## Is there room inside those rig experts units to install a .01 uf disc
ceramic cap ??
A 50-100 volt cap would be smaller diameter than a 1 kv cap. There is
your DC
blocking right there. .01uf = 10,000 PF..which is ample. .01uf = just
8.846 ohms of XC
on 1.8 mhz...and WAY less Xc, when on higher freqs.... like 4 ohms on
80m..and 2 ohms on 40m.
If a .02 uf cap was used, the XC would be half again.
## On a similar note, re the MFJ-259B. Can a HP filter be used, to kill AM
broadcast
junk...or will the HP filter screw things up too much ?
Jim VE7RF
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