PA-47 at High Power !

The little Class "C" PA-47 RF Power Amplifier has grown up, I have doubled the original output of 4.7 Watts, to greater than 14 Watts.

PA-47 Ready for Modification
The new FET Leads will be bent
to Accommodate the Existing PCB Holes

I have replaced the general purpose IRF510 Power FET with an actual Special Purpose RD15HVF1 HF Power FET (from RFParts), and then connected the PA to a large stable DC Supply (Battery).

The results at full power, are;

• With a 12.51 Volts DC supply running at 2050 ma (25.7 Watts DC Input with FAN)
• Exciter provides 12 mWatts Input at 10.140MHz
• The PA-47 output is 75 Volts PP RF measured at a 50 Ohm Load, which is: 14.1 Watts
• The HeatSink Temperature at the FET raised about 20 degree to 94.7 Deg F

This is a gain of 30.70dB and a Efficiency of about 66%.

I am a real Happy Camper !

Note: this is a very small 1 x 1.5 inch PCB, with a large CPU HeatSink.

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I plan to re-layout the PCB to accommodate a Fan Control circuit and correct the small layout errors as explained on previous posts.


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