Jim,
There is room that the 0.01-0.02uF cap could go in. Due to the surface mount
circuitry I would want to take the wire itself to the SO-239 and install it
there rather than try mounting it on the board. But I would definitely remember
to short the antenna/coax connection just to protect from static electricity. A
dedicated flexible coax installed semi-permanent is a pretty good idea too. But
I keep my AA-170 in one of those metal carrying cases from Harbor Freight with
associated accessories with thick foam. That could make having something hooked
up all the time to the connector could be a problem.
Terry
KI7M
> On June 11, 2018 at 9:50 AM Jim Thomson <jim.thom@telus.net> wrote:
>
>
> 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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