[Elecraft] KPA500 Issues

Gary Hinson Gary at isect.com
Sat Jun 9 22:00:15 EDT 2012


Hi Kent.

It could be an RFI issue but it could also be a faulty connection somewhere
that won't pass enough current for high power.  

Do the KPS's  SWR LEDs light up like a Christmas tree when you operate
barefoot at about 100W with the KPA in standby?  If so, you clearly have a
problem with your antenna or feed.  

With the KPA in operate mode, watch those SWR LEDs as you gradually increase
the drive from 5 to 25W: if it seems OK at the low end but suddenly flashes
the oranges/reds and faults out, I'd suspect a dodgy connector, most likely
one outside that has corroded or loosened.

73 
Gary  ZL2iFB
K2 K3 KPA500 W2 Mojo

PS  You can search the archives for lots more through Nabble e.g.
http://elecraft.365791.n2.nabble.com/template/NamlServlet.jtp?macro=search_p
age&node=365791&query=kpa+swr 


> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
> bounces at mailman.qth.net] On Behalf Of Kent Tiburski
> Sent: Sunday, 10 June 2012 1:33 p.m.
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] KPA500 Issues
> 
> Hi,
> 
>   I have a KPA500 amp and have some issues with it.  I ran on my Cushraft
R-8
> vertical with fault (SWR) problems.  I went to use it on the VHF contest
with
> my meager 3 element yagi and it faults out?  Hunhh?  Checked the VSWR
> with a meter and my antenna analyzer and it shows a 1.2 to 1 ratio.  OK I
> thought there was feedback so I put a bunch of ferrite cores and even
> wrapped 8 turns on the coax (balun) to no avail.  What gives?  This was
mainly
> on 6 meters but to some extent on other bands also.  Checked VSWR with a
> meter on radio (FLEX 5000A).  I think it's in KPA500 circuit.  Any ideas?
I'm a
> newbie here so not familiar with what's been discussed. Thanks.
> 
> 73, Kent, K6FQ
> 
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