[Elecraft] K2/100 Problem with Hi Reflected Power driving amp

[Don Wilhelm]

John,

Just how high is the reflected power (do a TUNE and it will be 
displayed).  The KPA100 throttles back power if the SWR is greater than 
2.0-1.

There are several possibilities, and only some have to do with the 
K2/100.  One is a bad coax, another is a PL-259 that is not properly 
tightened to the KPA100 (or anywhere else in the system).  What happens 
when you transmit into a dummy load? 

Your problem may be in the input of the amplifier and not the K2.  If 
the amplifier drive impedance changes when it sees RF, then it may not 
be usable without modification.  Is there any chance that the input 
circuit to the amp is not fully switched and the bias stable within the 
15 ms. period after the K2 key is closed?
Does the problem show up only on CW or do you get the same result when 
operating SSB with PTT?  If that is the problem, you will have to 
speed-up the relay in the amp (or replace it with a faster relay).

If this is a recently constructed KPA100, I have a different set of 
questions?  Do you find the same result on all bands or only one or 
two?  Does the Hi Refl message appear when working the KPA100 into a 
dummy load?

73,
Don W3FPR

John wrote:
> Hi all. I have a K2 with the KPA100 installed. I'm using the K2/100 to drive
> a tube amplifier through a tuner. The K2-100 keeps tripping off with the
> HiRefl message showing not every time, but often enough that a QSO is
> impossible. The K2/100 doesn't 'reset' (has no output) when rekeyed unless I
> rotate the power setting knob ever so slightly. 
>
> What am I doing wrong? Any way to increase the delay before the High
> Reflected power takes effect as I suspect it's transient? I also have the 
> t-r rel
>
> Any assistance will be greatly appreciated.
> 73, John  WA6YSY
>   
>