26-11-2012, 07:14 PM
Hi Al, not looked at the circuit since I posted it, not sure what a defacto definition of a short superhet is either (it seems to vary) so bear with me.
I think the Jones supergainer can be traced back to the late20's/early 30's.
As you can see the mixer is regenerative as is the detector, the regen in the mixer stage employs a Hartley arrangement ie: tapped cathode feedback which you will be familiar with.
The cathode tapped feedback would be difficult to homebrew for the detector (450 Khz transformer) ie: you would have to unwind, tap, and rewind the secondary, for most constructors, this would be a hit and miss affair, so a seperate cathode feedback winding is used (L5) so you can use a standard unmodified IF transformer.
Electrically it's the same as a tapped cathode coil in a Hartley arrangement so far as I am aware.
Any IF frequency can be used within reason, if the IF transformer has a wide bandwidth then it can be tuned across that bandwidth, that's the same as my Regenerodyne receiver, but you will know that anyway. The forunner to the R1155 receiver (forget the model number off hand) used a regen RF as well as a regen detector (No IF) they were quite sensitive apparently in the hands of an experienced operator, safe crackers fingers being a pre requisite.
Lawrence.
I think the Jones supergainer can be traced back to the late20's/early 30's.
As you can see the mixer is regenerative as is the detector, the regen in the mixer stage employs a Hartley arrangement ie: tapped cathode feedback which you will be familiar with.
The cathode tapped feedback would be difficult to homebrew for the detector (450 Khz transformer) ie: you would have to unwind, tap, and rewind the secondary, for most constructors, this would be a hit and miss affair, so a seperate cathode feedback winding is used (L5) so you can use a standard unmodified IF transformer.
Electrically it's the same as a tapped cathode coil in a Hartley arrangement so far as I am aware.
Any IF frequency can be used within reason, if the IF transformer has a wide bandwidth then it can be tuned across that bandwidth, that's the same as my Regenerodyne receiver, but you will know that anyway. The forunner to the R1155 receiver (forget the model number off hand) used a regen RF as well as a regen detector (No IF) they were quite sensitive apparently in the hands of an experienced operator, safe crackers fingers being a pre requisite.
Lawrence.
