[Elecraft] KX3 Extended VFO temperature compensation procedure

[Dominic Baines]

Having run my KX3 in 40'C ambient temp just for ssb or cw and the odd 
bit of data and seem high pa temps and the kx3 folding back you 
absolutely have to consider better/decent cooling if you seeing pa temps 
consistently at this level.

You trying to run at 10W non stop then wind the power levels down? 
Running at this level with high temps is a bad idea without better cooling.

A simple extra external heatsink can be added to the current heatsink 
plate, with or without fan cooling and that should make a huge difference.

Or

Use the KX3 at 1-3 W and add a PA.

72

Dom
M1KTA

On 18/03/2014 19:19, Phil Wheeler wrote:
> At this point I wouldn't characterize my experience as a concern. So 
> far as I can tell the calibration worked well, though I was surprised 
> to see the tone vs. temp behavior above about 45 deg-C. My impression 
> is that the calibration is done with a table, so such nonlinear 
> behavior should not be an issue, so long as it is repeatable. The post 
> by Bob, WB4SON early today in this thread described some "crazy" 
> behavior which would concern me.
>
> Of more concern in such modes might be the power limitation at higher 
> temps. There is some temperature at which the PA power will be 
> limited. I don't know if that limit is of concern for JT65 operation 
> or not. I know there have been discussions in the Yahoo KX3 group 
> about different ways to add cooling to the KX3 for portable ops -- 
> including fans, larger heat sinks with fins, and in one case leaning a 
> cold cooler against the rig.
>
> 73, Phil w7ox
>
>
> On 3/18/14, 11:39 AM, Jack wrote:
>>
>> I have been following this thread with interest.
>>
>> Given our change in living arrangements, from a house with plenty of 
>> space for antennas to an apartment with no place for antennas, we are 
>> forced to do mobile and portable operation. In that case we can no 
>> longer easily operate our K3/P3 and have been considering getting a 
>> KX3 instead. This thread causes me to wonder if this would be a good 
>> idea since one of the things we would want to do, while operating 
>> portable, are various digital modes, including JT65.
>>
>> Is this VFO temperature compensation problem serious enough to make 
>> reconsidering the KX3 wise?
>>
>> Thanks,
>>
>> Jack, W6NF/VE4SNA
>