[Elecraft] KPA-1500 failing on 160...AGAIN!

[Bob McGraw K4TAX]

 Check for burn marks or carbon traces, both on the inside and outside, of the SO-239 connectors.  These may look good with the antenna analyzer but fail under power. 

I've also had PL-259's arc from center pin to shell on the inside. These required removal/ disassembly of the coax in order to actually find the fault. 

In all cases, once a flashover occurs, replacement of the connector is the only solution. 

Bob, K4TAX


Sent from my iPhone

> On Sep 27, 2019, at 6:00 AM, John Langdon <WOYB10051 at outlook.com> wrote:
> 
> If it also happens with a dummy load, and the antenna analyzers shows the same graph as before for R, X, then it is likely one of the connectors between the KPA1500 output and the antenna. The one such problem I had was old jumper I had put in to add an SWR bridge/monitor. It looked okay, and was finger tight, but when I replaced it in an A/B test, the problem went away.
> 
> The other time, the antenna had changed its impedance curve, but was still 'okay' and the tuner was trying to retune for it.
> 
> 73 John N5CQ
> 
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of Jim Brown
> Sent: Friday, September 27, 2019 4:19 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KPA-1500 failing on 160...AGAIN!
> 
>> On 9/26/2019 10:26 PM, Peter Dougherty wrote:
>> Any idea where to start looking here?
> 
> And if it's a vertical, what about the radial system?
> 
> 73, Jim K9YC
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