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Re: 432 MHz linear amplifier



Thank you for the offer.  I went ahead and ordered the 50 mW input and 30 watt output kit from VK5EME.  There has been a pretty good increase in the exchange rate between the Australian dollar and the United States dollar in favor of the United States dollar in the past few days.

The price of the complete kit (including the power module) including air mail to the United States is $89.00 Au which is now $59.07 US.  I decided not to take a chance on the US dollar going back down in value!  Of course it might go up but $59 was a good price.

My 4CX250B 432 MHz amplifier is actually from an old Motorola 100 watt output FM unit.  It works great for CW and all that I have to do to use it for SSB is to change the bias circuit.  On 432 MHz operating CW it puts out an easy 150 watts and can do more if I increase the plate voltage.

Glen, K9STH

Website:  http://k9sth.com


--- On Sun, 10/12/08, i8cvs <domenico.i8cvs@tin.it> wrote:

From: i8cvs <domenico.i8cvs@tin.it>

I am using a transverter Microwave Modules MMT 432/28 S to drive my 4CX250B linear amplifier. If  your original 10 watt  linear amplifier board was missed I can send to you the schematic diagram of it and a picture showing how the components of it are placed over the PCB. Into the transverter board you already have a 250 mW driver stage with a 2N6256 or a CTC CD 3649 or a BL524 depending on the year of production. To duplicate the original power amplifier you need a 2N5944  a  2N5946 and two pin diodes UM9401 plus a 5 volt regulator. The rest of the circuit needs only few air trimmer capacitors of 5pF, 10pF and 27pF .

The above power amplifier do not use a PCB with striplines but only 4 small silver plated copper wire air wound coils for the inductances so that if you are able to found the above active devices at a reasonable price you can use your skill to build the amplifier by yourself.
 
It is even possible that someone reading on this BB particularly here in EU hown an old and unused MMT 432/28 S transverter and send to you only the aluminum box with the 10 watt power amplifier in it.


      
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