Power out seems a bit low... any suggestions ?


Stephen VE6SVJ
 

I eventually got around to fixing my faulty volume pot last night and now everything works great... except, I'm only getting about 2.2W out (as measured by both the rig built-in meter and the external SWR / power meter).

This is from about 13V power supply. I'm not sure if this is normal for the 20m version at that voltage or if something is wrong... and I'm not sure where to start troubleshooting if there is a problem. Any suggestions ?

73,

Stephen.
VE6SVJ


Curt wb8yyy
 

Stephen

Hans cites about 3 watts into a 50 ohm load from a 12 or 13.8 volt supply,  I forget which but mine is doing about 3 watts into a WM2 wattmeter. You can try moving the turns on the low pass filter toroids to see if you can raise the power a little, then cement them in place with hot glue or nail polish. I would not work too hard for the last half watt, even tweaking your antenna tuner will change it some.

Curt


Stephen VE6SVJ
 

Nail polish ! That is a very good idea. Thanks for the response and the tips Curt.

73,

Stephen
VE6SVJ

Sent from an electronic device.

On Mar 30, 2019, at 05:52, wb8yyy via Groups.Io <wb8yyy@...> wrote:

Stephen

Hans cites about 3 watts into a 50 ohm load from a 12 or 13.8 volt supply,  I forget which but mine is doing about 3 watts into a WM2 wattmeter. You can try moving the turns on the low pass filter toroids to see if you can raise the power a little, then cement them in place with hot glue or nail polish. I would not work too hard for the last half watt, even tweaking your antenna tuner will change it some.

Curt


David
 

Hi Stephen, The output power of the QCX is dependent upon the power supply. See page 132 of the assembly instructions. If you have a variable power supply you could try raising the voltage to 15 or 16 volts (the max recommended). I usually run my 20M QCX at 16 volts and get somewhere around 4.5 watts. I also fitted a heatsink on the 7805 voltage stabiliser.
73 Dave M3PMG