Tuesday, February 4, 2020

Some bits from Greece

A valve, some variable capacitors, a UHF diode and a circuit. What could it possibly be? Find out as I open this box generously sent by SV1GCS!

Oh, if you're curious about the circuit, it's below.

As it turns out there was a huge underground pirate radio tradition in Greece when it was a dictatorship. There are other circuits of similar transmitters around. If you were going to do experiments these would be better starting points due to safer power arrangements (the above circuit should not be built). Though there will still be frequency drift - a significant consideration now where the FM band is crowded. Especially in countries where 6 metres is 50 - 54 MHz you could easily put it there and not cause any trouble if you were a ham (though watch the harmonics). 


PS: Enjoy building antennas? Many hams do. Hand-carried QRP antennas, my first antenna book has been very popular. That concentrated on basic concepts and the lower HF bands. Anyway here's the follow-up. Called More Hand-carried QRP antennas it describes more than 30 antennas and accessories that you can easily build. And there's more of an emphasis on upper HF, VHF and UHF antennas that the previous volume didn't have so much on.

1 comment:

  1. The PL504 was the main stay of a Black & White TV Line Oscillator stage used with its companion the PY81, PY800/801 boost diode sitting beside it operating at well over 1000V!! Both in a screened can, used in TVs from the 1960s until the late 1970s. I used to change hundreds down at the TV shop in the seventies. There was a difference between the EL and PL version PL being series fed heater 6.3V and El I think was Parallel fed heater but higher voltage.. Noted the Name Mazda was a division of Thorn industries who I worked for, but there were other manufactures Mullard being the main one, Pinacle and a few others. I have heard of HF linears being made with the Colour TV version PL519/ 509 I think there used to be one in the RSGB Radio Comms Handbook. Use at your peril meaning I hope you know what your doing!!


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