[Elecraft] K3 and Alpha 91b

[Mike Stover]

OOPS ... K3 SN is 3786 ... senior moment!

Mike N9QR

From:           	n9qr at aol.com
Date sent:      	Tue, 19 Jan 2010 15:59:45 EST
To:             	elecraft at mailman.qth.net
Subject:        	[Elecraft] K3 and Alpha 91b

> I have an Alpha 91b hooked to the K3 (SN 8376) and I'm having an
> "Odd"  
> problem ... on 75/80 meter SSB, if I run the amp at 45 watts, which
> is what  
> works on CW without issue, I encounter significant nuisance tripping
> of the  
> Amplifier to the fault condition.  The amp also exhibits a power
> spike into  
> the 2KW range often times when it faults.  If I reduce the  power to
> 30 
> watts on the K3, the amp runs 1500 watts OK without tripping.  
> Please .... 
> resist the temptation to say "Run at 30 watts then".  All  other
> bands ... 
> except 6 meters which I didn't check, do not exhibit this  issue. 
> Power out from 
> the K3 is 45 watts and the amp runs  1500 watts  out with NO
> nuisance 
> tripping.  I've talked to the tech's at Alpha and at  least one
> other K3 owner 
> has had this same problem.  He asked me to check  the amp with
> another radio 
> so, using my spare radio, Yaesu FT-450, to drive  the amp I have no
> nuisance 
> tripping on any band while running 45-50 watts into  the amp. 
> Neither radio 
> has ALC hooked up, only the TR relay.  Both  radios and amp are
> grounded to 
> the same ground buss.  RF calibration was  done when the radio was
> assembled and I have not re-done that process.
>  
> Any ideas as to why the radio would exhibit a tendency to over drive
> the  
> amp just on 75/80 meters?
>  
> Mike N9QR
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