[70cm] 432 MHz amplifier

[Glen Zook]

I have been on 432 MHz CW "off and on" for going on 40 years.  However, until a couple of weeks ago I have never had a "real" transverter so that I can use SSB as well as CW.  Basically, I traded for an older Microwave Modules 432-28 transverter that works very well, EXCEPT that it is missing the power amplifier board.  Now I knew that this board was missing before making the trade.

Right now the output power is right at 250 mW and I am looking for either an amplifier board that can take this power up to at least 10 watts and 20 watts or more would be great.  I need at least 10 watts, and preferably 15, to drive my single 4CX250B amplifier.  Right now the amplifier is set up for Class "C" but I should have no problems changing it over to a true linear.  This amplifier is from a Motorola C74BBB-3100A station and after retuning to 432 MHz and eliminating the bandpass filter on the output it easily puts out over 150 watts.

Being on a fixed income (Social Security disability) I do have to be very frugal (OK, "cheap") and do not have a lot of available cash.  However, I do have quite a number of parts and the ability to build things if I cannot find a suitable solid-state amplifier that I can trade for.  I have all sorts of equipment and parts for trade.

If I cannot find a suitable solid-state amplifier I can build a tube-type using maybe a 6939 and then something like a 6907 (I have plenty of 6939 tubes and a couple 6907).  That should give me at least 20 watts output.  But, I would rather go with solid-state.  Building such would not be difficult and I have plenty of parts and several potential circuits on hand.

Anyone have a suitable linear that they would be willing to trade?  Or, does anyone have a suitable construction article for a solid-state amplifier?  I have looked over the Internet but have only found a couple of articles.  Most of those require a couple of watts drive and I have only 250 mW.

Glen, K9STH

Website:  http://k9sth.com