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 HF Amplifier project 4x PL504 parallel tuning output about 160W PEP = 40W AM carrier  

 Complete schematic will follow when working.

 

                                                                                                               

(picture) small capacity.pdf



I came with the idea to make a loop antenna for the FM band, from a simple aluminium tennis racket, we want to trow it away .

But it turned out to be just the right size for a loop .

This one works perfect on 104.6Mhz .

You can hide this one evrywhere for your local work.

Watch out with power on this, playing with 5W a few hours you will feel in your head.

(picture) coupling 50ohm cable.pdf





I have tested a IRF510 mosfet as amp. in a shortwave TX.

TX is with a X-tal oscillator a driver the IRF510 and a NPN transistor as series modulator in the supply.

(picture) all on a small printboard.pdf

The TX works perfect, is was tested on 5.8Mhz and 6.4Mhz .

The max power with 24volts was 30watts and more is possible if  you make it 28volts.

Higher voltage than there wil be more heat in your series modulator (to mutch ) and there is no need.

With 30w on peak only using 5w carrier for a strong AM modulation.

You will notice the difference on the audio pressure between 10 - 5w.

schematic QRP AM-TX 3.5...8Mhz + series modulator.pdf

When testing on the antenna i made repports all over Europe with only 5Watts.

From the Netherlands to UK , Finland, Germany and Italy in the evening hours.

I must admit there where some nice conditions in the E-layers otherwise it,s simply not possible.

But it gives me nice feeling to get there with sutch a small TX .




Power transistors HF VHF.pdf