14-04-2021, 06:23 PM
(This post was last modified: 14-04-2021, 06:30 PM by Mike Watterson.)
Yes, probably the Vanguard. It works well on VHF-FM with the loop aerial disguised as beading hiding the cloth seam. The main restoration issue was the faulty wavechange switch. Probably corrosion from the batteries.
The LW & MW is good too.
I cut one earth on the first DF97 socket and it worked with a DC90, no noticeable tuning shift.
The entire design might work with 1j24b, but with no AGC. A few 1950s Ever Ready sets only had AGC to the DK96 grid, just running the DF96 at full gain. Using even 1j24b + IN60 diode instead of DAF96 and a 1j24b (or pair in push-pull) for audio out.
I think your description of the 1j37b is correct, except it seems that the performance and implications of that are curious. You can use a LO at HALF the desired frequency, suggesting it could be used to implement a stereo decoder. The anode would have L-R audio.
Also if there is a tuned RF pre-amp you'd feed both grids with differential LO and common mode RF, but if there is no preamp, you use a RF transfomer to feed RF differentially to g1a and g1b, but feed the LO to a centre tap on the secondary, so the LO radiated can be nulled out. LO then is the common signal.
I meant 1N60 in above post, not 1N34, as it's more available and also pre-1950 originally. Though the current 1N60 is simply the same part number.
The LW & MW is good too.
I cut one earth on the first DF97 socket and it worked with a DC90, no noticeable tuning shift.
The entire design might work with 1j24b, but with no AGC. A few 1950s Ever Ready sets only had AGC to the DK96 grid, just running the DF96 at full gain. Using even 1j24b + IN60 diode instead of DAF96 and a 1j24b (or pair in push-pull) for audio out.
I think your description of the 1j37b is correct, except it seems that the performance and implications of that are curious. You can use a LO at HALF the desired frequency, suggesting it could be used to implement a stereo decoder. The anode would have L-R audio.
Also if there is a tuned RF pre-amp you'd feed both grids with differential LO and common mode RF, but if there is no preamp, you use a RF transfomer to feed RF differentially to g1a and g1b, but feed the LO to a centre tap on the secondary, so the LO radiated can be nulled out. LO then is the common signal.
I meant 1N60 in above post, not 1N34, as it's more available and also pre-1950 originally. Though the current 1N60 is simply the same part number.
