20-10-2016, 04:12 PM
(20-10-2016, 03:41 PM)Sparks Wrote: The big TRF looks complicated, has a look of multi-waveband and mains powered as well I note some metal valves in it. I prefer the glass versions myself. If any metal ones fall into my hands, I get rid of them as soon as possible. I eventually converted my HL2 receiver to an EF91 receiver as EF91s are very cheap and plentiful.
Bob
Yes, mains powered from a separate PSU, doesn't look pretty does it, it was one of my experimental lash ups, it looks more complicated than it is, it's just an RF amp and Regen detector with a mixer in between and a bit of audio afterwards, two of the valves on there could be dispensed with, one was used temporarily as an experimental osc for the mixer, the other to give some umph to the audio.
In the main I did not use that osc, I used my bench sig gen instead to set the band, the advantage of that receiver was it's constant tuning rate and range on any shortwave band you wish, the tuning range of the detector was 500kHz centered on 3.25MHz that made it ideal for SSB or CW reception on any band as it also included a small value band spread capacitor.
That set up could be done with 1.4 volt battery valves or even ECC82's running at 12 volts or dedicated 12 volt valves, the metal valves and other bits were all I had to hand, have to say though the metal valves are good, a good reliable RF screen unlike a lot of EF89's etc, anyways performance was excellent, received JA Hams on a couple of occasions and VK also, one VK was only running 10 watts. Pity I never got it all tidied up.
The Regen detector was configured as a Hartley.
Anyone recognize the chassis?
Lawrence.
