George Rutkay

7 attēli • 14. apr 2019 05:45

Homemade amateur radio project, building my own amplifier for the purposes of trying to reach stations around the world better. I have a scrap metal chassis from a WW2 Hallicrafters SX28 military receiver, so instead of throwing it to the scrap I decided to reuse it. For my neighbourhood and the restrictions I have here, not permitted any antenna towers, so I guess radiated power on shortwave ba...VairākHomemade amateur radio project, building my own amplifier for the purposes of trying to reach stations around the world better.

I have a scrap metal chassis from a WW2 Hallicrafters SX28 military receiver, so instead of throwing it to the scrap I decided to reuse it.

For my neighbourhood and the restrictions I have here, not permitted any antenna towers, so I guess radiated power on shortwave bands doesn’t need to exceed 400 watts.

My radio licence (Canadian radio call letters “VE3GZB”) permits up to 1500 watts but it’s probably not practical to home construct such an amplifier at that power level.

I find type 813 vacuum tubes are still available, they have excellent power and amplification quality. Type 813 are very similar to Russian type GK71 tubes.

So far I have salvaged this chassis, freed all of the corroded components due to mouse infestation, started some metal fittings, drill and tap screw threads where needed, cut and make brackets to support the vacuum tube and the high tension anode choke coil, installed cooling fan and variable capacitors, high tension power transformer to provide about 2000 VDC.