I once owned a BC348-M receiver. It was made by Stromberg-Carlson and I think the E, M, O, P and S versions were all made by them. On the BC348-M version, the IF frequency is 915 Khz, +/- 0.1 %. Tuning Capacitor is a 4 section, 14pF to 331 pF variable each section, 9 Stator 10 Rotor plates each section, Army Stock Number/Navy Type Number/British Reference Number 3D9016V-2. The most interesting feature of this particular tuning capacitor is that it contains a variable 3500 Ω, +/- 10%, 1/10 Watt, metalized carbon resistor attached to the shaft that tunes the capacitor, and it varies from lowest resistance to highest resistance with frequency. In other words, Low frequency = Lowest Resistance, Highest Frequency = Highest resistance. If you go to this site, you can see the manual for the E,M,O,P and S versions: www.nj7p.org/Manuals/PDFs/Military/AN%2016-40BC224-3%2021-Sep-51%20Moorer.pdf On page 12, right side, in the heading just above the schematic of Figure 10, there is a section titled “CONSTANT INTERNAL RECEIVER NOISE” that starts the description of what the potentiometer attached to the tuning capacitor does. I think that most people would naturally assume that the IF frequency would be 455 Khz, but that is way off of what it actually is supposed to be.
Hi, you have many nice videos. I got rid of the hacked power supply which was supplying 300 volts and had also burned the small regulator bulb. The external supply is nice and handy with other old radios too. But I'm not able to keep my coffee warm any more on the radio...
Hello, I have re-cap those caps for a BC-224, (2)BC-348O, I opened them with a blow torch from the bottom (careful hot oil will pour out) Dont take apart the nuts, you will be able to run the new cap wire throughout the center hole of the bolt. RE STUFF ALL THE CAN CAPS, AND CHANGE ALL THE PAPER CAPS. I have damage a few transformers by leaving those old caps in. I did cut a 1/4 inch of the capacitor cases. So they dont run to ground with the case. Great project. I have restored about 12 of different manufactures. Love Them
The receiver looks to be in good physical shape (aesthetically), $50 well spent when you factor in the entertainment value and definitely better for "the grey matter" :) Shepp-ar-ton (ˈʃɛpərtən) is around 450km from here as the crow flies. Transmitter site history @ bpadula.tripod.com/australiashortwave/id49.html
I once owned a BC348-M receiver. It was made by Stromberg-Carlson and I think the E, M, O, P and S versions were all made by them.
On the BC348-M version, the IF frequency is 915 Khz, +/- 0.1 %.
Tuning Capacitor is a 4 section, 14pF to 331 pF variable each section, 9 Stator 10 Rotor plates each section, Army Stock Number/Navy Type Number/British Reference Number 3D9016V-2. The most interesting feature of this particular tuning capacitor is that it contains a variable 3500 Ω, +/- 10%, 1/10 Watt, metalized carbon resistor attached to the shaft that tunes the capacitor, and it varies from lowest resistance to highest resistance with frequency. In other words, Low frequency = Lowest Resistance, Highest Frequency = Highest resistance.
If you go to this site, you can see the manual for the E,M,O,P and S versions:
www.nj7p.org/Manuals/PDFs/Military/AN%2016-40BC224-3%2021-Sep-51%20Moorer.pdf
On page 12, right side, in the heading just above the schematic of Figure 10, there is a section titled “CONSTANT INTERNAL RECEIVER NOISE” that starts the description of what the potentiometer attached to the tuning capacitor does.
I think that most people would naturally assume that the IF frequency would be 455 Khz, but that is way off of what it actually is supposed to be.
Hi, you have many nice videos. I got rid of the hacked power supply which was supplying 300 volts and had also burned the small regulator bulb. The external supply is nice and handy with other old radios too. But I'm not able to keep my coffee warm any more on the radio...
Hello, I have re-cap those caps for a BC-224, (2)BC-348O, I opened them with a blow torch from the bottom (careful hot oil will pour out) Dont take apart the nuts, you will be able to run the new cap wire throughout the center hole of the bolt. RE STUFF ALL THE CAN CAPS, AND CHANGE ALL THE PAPER CAPS. I have damage a few transformers by leaving those old caps in. I did cut a 1/4 inch of the capacitor cases. So they dont run to ground with the case. Great project. I have restored about 12 of different manufactures. Love Them
The receiver looks to be in good physical shape (aesthetically), $50 well spent when you factor in the entertainment value and definitely better for "the grey matter" :)
Shepp-ar-ton (ˈʃɛpərtən) is around 450km from here as the crow flies.
Transmitter site history @ bpadula.tripod.com/australiashortwave/id49.html