N4PZ Info


First licensed in 1955 as WN9OJI soon to become W9OJI and on to the extra class in 1959 because I was a cocky kid and wanted to impress all my friends. After failing the CW test the first time I HAD to get the extra then. Hi

Interest began in VHF and above in 1957 when I received a Gonset Communicator, 2 meters, for high school graduation and it was never the same again

I build just about all my own gear from antennas , high power amplifiers and anything else I need.

I have been and am an avid builder and experimentor. Current activity is 432 EME and tropo, 1296 EME with a 4.9 meter dish and a VE4MA feed.

The final amplifier on 1296 is a TH-327 tetrode which easily delivers 1500 watts to the VE4MA feed.

10 Ghz is also interesting and I do work rain scatter and tropo on that band where I have a 30 inch dish and 16 watts at the feed.

This summer I will do away with the 10 Ghz tropo system and put it on my 4.9 meter dish for EME.

N4PZ Products produces legal limit + amplifiers for 144 and 432 Mhz using a GS35b on 144 and a GS23b on 432.NOTE, I have just begun building 432 legal limit amplifiers using a russian triode GS35b.

It eliminates the complication of a screen supply and works extremely well.

I am very pleased with the performance, stability and power gain of the GS35b on 432. 1500 watts output is easily obtained with 100 watts of drive.

So far I have built about 22 144 Mhz amps and 57 432 amps.

I have now built and am using a GS35b triode on 432Mhz.

Both will easily deliver 2 KW into a dummy load.

The Russian tubes are cheap and vertually indestructible. 


The picture at the top is a GS35b legal limit 144 Mhz amplifier. Since the picture was taken I have removed the long plate parallel to the plate line and replaced it with a large tuning disc on the cover of the plate compartment. The line was foung to be a wee too short to hit 144 and that big disc allows me t bring resonance down to 144.

The main tuning disc on the front panel provides plate tuning once the resonance point is located. More to come later.

The second picture is a GS23b tetrode amp for 432 Mhz which I no longer build since I have found I can get equal performance out of the GS35b triode with a bit more voltage and drive power.

The GS35b likes 4000 volts where the GS23b will do the job with 3200 volts but with the added complication of a screen supply and screen bypass capacitor.

The bottom picture is the front panel of the 432 Mhz GS23b amp.

The recent developement of the GS35b on 432 Mhz was inspirecd by Mike KL6m. He uses a similar output cavity but a different input cavity. I like mine which I stole from K5GW Gerald. It is symetrical and easy to build vs a complicated coaxial input cavity which I find unnecessary on 432. The coaxial OUTPUT cavity makes the difference between miserable efficiency of the stripline and excellent efficiency IN MY OPINION.

Yes I hear stories about high efficiency with stripline output cavities. I just depend on what works for me after building this stuff since 1955.

More to follow as soon as I have time to build another 432 amp with  the GS35b.

Steve N4PZ n4pz@live.com




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