[Lowfer] PA transistor getting hot - need advise

[Mike WE0H]

I had the same issue with my Lowfer transmitter. Bill Ashlock has the 
part numbers of transistor's that run at equal temps. I don't remember 
what they are but they do work well and are a better match than the 
2907/2222 combo.

Mike
WE0H


Andy - KU4XR wrote:
> Hello LOWfers:
>
> I have a question, that someone probably has the answer for. I built the LOWfer xmtr using the 2222 / 2907 pair in the PA. The issue is that the 2N2907A is getting very hot under keydown.
> The 2N2222A just barely gets warm. The xmtr is working ( apparently ). Running into a 50 ohm dummy load, with 18 volts on the PA, I'm drawing around 77mA of PA current. I can hear the signal about a mile away on a portable radio, while xmit-ing on my LOWfer vertical, so I know the xmtr is generating RF. I am concerned about that one transistor getting so hot. It's not blown out so far, even after days of continous keydown ( burn-in I'll call it ). I've checked all the parts layout, and the parts themselves for defects, all is fine. This may be a normal condition
> with this type of PA layout, I'm not sure since this is my first LOWfer xmtr built. I would assume though that each transistor should be about the same temperature. Anyone else experience this, or have any thoughts ??  Thanks for your time: 
>
> Andy - KU4XR