G4FPH's Amateur Radio Pages - ProjectsHere's a list of some of the projects I've done over the last 25 years or more.
Boot Mark IHF linear amplifier using 2 x QY4-250 tetrodes in grounded grid. Dreadful, dangerous and otherwise not too good. 15-year old schoolboys shouldn't play around with 4 kV! I consider myself lucky to be alive.
Boot Mark IIHF linear amplifier using 2 x TY3-250 tetrodes in grounded grid. Much improved over the Mark I. Less dreadfull, less dangerous, sort of OK and still in use today.
Coastal CommanderHF linear amplifier using 4 x QY4-400 tetrodes in passive grid. In a previous life this was a ship to shore radio, complete with multi-mode exciter and 4CX250 pre-driver. Works well. As pictured elsewhere on this site.
Russian SpecialHF linear amplifier using 1 x GS-35b external anode triode in grounded grid. Uses a G3SEK triode board, which is nice. PSU (separate to RF deck) recently re-built using a 2.2 kVA toroid and voltage doubler. Works OK but needs an RF deck re-build at some point. First time I've ever used an extarnal anode valve and voltage doubler PSU.
Henry 2000D-27 SpecialBomb-proof. As described elsewhere on this site.
GrotboxA valve based, Class-C amplifier using a QQVO6-40A double tetrode. Built in an old Pye Vanguard case this amplifier would do almost 100 W output wit close on 1 kV on the anode. Short overs only though as the output coil used to unsolder itself from the tuning capacitor! This thing gave me the worst shock I have ever had and was afterwards replaced by a KLM 160 W solid state unit.
PMR equipment modification
Pye TelecommunicationsThroughout the 1970's and 1980's, I had a long love affair with anything made by Pye Telecommunications (later Philips and Simoco). I modified it, tweaked it and generally cut my teeth on VHF and UHF with a host of blue (and latterly grey and black) boxes, some of which (those marked with a '*') are still working today, including:
Pye Cambridge AM10D
Pye Cambridge FM10B
Pye Vanguard AM25B
Pye Vanguard AM25T
Pye Westminster W15U*
Pye Westminster W15FM
Pye Pocketphone PF2UB
Pye Pocketphone PF85*
Pye R460/T461 UHF RX/TX
Pye L9U UHF Base station*
Pye F496 UHF Base station*
Pye M2000 System 3 Radiotelephone*
Copyright ©2003 G4FPH - even the spelling mistakes.
Last modified: 4 June 2003