[Elecraft] KPA100 oscillation during IARU Reg 1 Field Day

[Stephen W. Kercel]

Fellow Elecrafters:

I've had my K2 for only a short while, and I find that Jukka rises a 
point that I've been wondering about. Can the K2 transmit at 100 
Watts (into low SWR) CW (say 20-30 wpm) in a continuous session for 
tens of hours on end without damage?

I usually use my rig in QRP mode, and only occasionally go to 100 W. 
It always bothers me when the fan comes on even though I realize that 
it is normal and desirable behavior. Thus far, I've only made one or 
two extended "rag chew" QSOs where I've made long CW transmissions at 
full power.

Consequently, I have not much feel for how the rig should work while 
transmitting CW at full power for extended periods of time. (As we 
see from Jukka's post, running the rig until one smells smoke is not 
a good idea.) What is a reasonable operational cycle? What is the 
line between acceptable operation and abuse?

Any insight from experienced K2 QRO operators would be most welcome.

73,

Steve
AA4AK




At 04:21 AM 6/5/2006, Jukka Tarvainen wrote:
>Hello!
>
>Sunday afternoon my KPA100 started oscillating, I believe. It happened just
>when heavy rainshower hit our site. I was using a Spiderbeam on 20 meters
>and running small CW pileup with 100 watts. Rig was performing well for 18
>hours on various bands and it was running quite hot. I put fan running high
>continuously in the beginning of contest.
>
>When this happened I disconnected power supply. K2 seem to work normally
>when KPA100 is not active. When KPA comes on it shows "Hi refl" immediately
>when transmitting and draws 20-30 amps from 30 amp power supply. Power
>supply starts to limit and cuts power.
>
>There was some smoke smell coming from K2. Can't see any blown away parts.
>Couple of 2 and 3 watts resistors have been warm, they are bit brownish. Any
>ideas what and where to start looking for? I built my K2 and options, but
>I'm technically challenged :)
>
>Jukka Tarvainen, OH4MFA
>K2/100 #4293
>oh4mfa at sral.fi
>http://personal.inet.fi/koti/oh4mfa
>
>
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