How about this idea? The minimalist superhet receiver was a success but that was designed for mains supply use. So how about a battery minimalist superhet receiver? It will recalled the receiver employed an anode bend detector which took the place of the usual IF amplifier and detector.
Been thinking about doing something similar with the Riviera Radio. The triode detector with reaction will be retained except that the valve will demodulate the 465Kc/s IF signal instead of the RF signals. Preceding the detector will be an octode frequency changer valve, an FC2A or KK32, I've got plenty of the latter. The KK32 is an enormous thing. https://www.radiomuseum.org/tubes/tube_kk32.html
The MW/LW aerial coil will be retained and another coil wound for the local oscillator.
Till Eulenspiegel.
The reaction control will make a good Q multiplier for that 465khz IF, really be able to narrow the bandwidth.
Look forward to the result. ?
Frank
The KK32 is an enormous thing. https://www.radiomuseum.org/tubes/tube_kk32.html
Till Eulenspiegel.
Ye gads! It's a golden octopus!
Well, I guess it would be interesting to see what happens.
Hi Marion, here's another huge frequency changer valve designed for battery receivers.
https://www.radiomuseum.org/tubes/tube_tp22.html
Or the seven pin TP23: https://www.radiomuseum.org/tubes/tube_tp23.html
Re the 1D8GT, I can't understand why we didn't see that used in a production radio back in the 1940s, early '50s. It was known as the "hobby valve" for many years.
Another way of using it might be as a neutralised IF amp (triode), diode detector and reflexed audio (same triode) feeding the pentode output stage. AGC on the converter only. A 1A7GT and a 1D8GT could have made a portable radio with performance equal to the usual 4 valve lineup, with a considerable reduction in both size and battery consumption.
On the subject of ideas that might never happen, I had an idea for using the 6Y9 (you'll know its series string version, the PFL200) as a one-valve superhet.
1st pentode, autodyne converter.
2nd pentode, IF amp and reflexed audio output.
Maybe with a few semiconductor diodes, possibly AGC implemented by a series diode attenuator.
It might be fun to model these in LTSpice...
The components from the front end of this scrap Pye P114BQ can be used for the superhet receiver project. The existing aerial coil and waveband switch will be employed. An additional switch will be required for the oscillator waveband selector. It might be possible to use a micro switch for the purpose. The miniature DK96 frequency changer valve will substituted with one one of those huge pre-war valves, FC2A, TP22 or Osram X24. The KK32 is a rebased FC2A.
Till Eulenspiegel.
Found an old type 465Kc/s IF transformer and hooked it up to the grid of the detector valve. Supplied a modulated signal from the signal generator via a low value capacitor. signals monitored on the oscilloscope. Transformer peaks up nicely on 465Kc/s.
Next task will be to remove the old Dilecon tuning capacitor, make an adaptor plate and fit the two gang tuning capacitor that was removed from the scrap Pyw P114. The P114 employed a DK96 frequency changer valve. Can't use that wee thing and the chosen FC valve will be the huge Mullard KK32 or better still the FC2A with the old B7 base.
Till Eulenspiegel
Haven't done anything with the Riviera Radio yet but here's another suggestion what to do with the 1D8GT diode-triode-pentode. I'm presently making an all-dry battery version of the Bush DAC90. A spare cabinet has been bought from an eBay seller and a chassis from a SUG3 is being used for the project. I'm sure the 1D8GT was a valve Bush Radio Limited would have never considered but for the project it's ideal because it frees up more space for the internal batteries.
Till Eulenspiegel.
