[TowerTalk] Acom 2000 issue

[Jim Thomson]

Date: Sun, 11 Nov 2018 11:54:48 -0600
From: Jeff Blaine <KeepWalking188 at ac0c.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Acom 2000 issue

<A local has one of those - he's very active in contesting and dx so the 
<amp gets used a LOT.? Excellent amp but super sensitive to feedline & 
<switching integrity.? I think in each case he has tracked it down to 
<something out in the field.? Based on the description I would guess 
<there is a problem outside somewhere.

<73/jeff/ac0c

##  One suggested method to test,  is to hit it with a 1.5 kw cxr.   Another,
perhaps safer method is to pulse  tune the amp in question,  with a 20-30%
duty cycle...to the same 1.5 kw pep output.    By pulsing the amp, with low
duty cycle, you end up with the same peak V.  Duty cycle is low enough  you can
leave it on for any length of time, without heating the amp up.  Then you can start wiggling
coax, smacking things about. Smack / twist / the DE / balun / connectors, and anything else that
could possibly cause issues.    You will find out soon enough where the problem is...or in some cases
visually see the issue.    1.5 kw is only   387 volts peak...into a 50 ohm load..which is dick really,
..and perhaps some more with  higher  swrs... and depending where on the feed line, the issue is.

Jim   VE7RF