03-31-2023, 09:53 AM
For the folks following at home: https://philcoradio.com/library/download...%20129.pdf
I doubt you would be able to get an osc coil design for a 455kc IF to tune down low enough to use it at 260kc. That's just shy of 200kc. It's got a slug but maybe it will adjust 20kc not 10x that. Adding more capacitance across the two tuned circuits may work. But at some point the C overcomes the L and it doesn't work. At 200kc I thinking your past that point.
Philco didn't use the 260kc IF in very many of there sets. Most are right around the same time frame as the 91. Like one version of the model 90 did and I think the 200X may have. You can go there the alignment data and look for the 260kc IF.
Wouldn't think about changing the osc and IF to 455kc because then you will have tracking issues.
It's a bit of a pickle
I doubt you would be able to get an osc coil design for a 455kc IF to tune down low enough to use it at 260kc. That's just shy of 200kc. It's got a slug but maybe it will adjust 20kc not 10x that. Adding more capacitance across the two tuned circuits may work. But at some point the C overcomes the L and it doesn't work. At 200kc I thinking your past that point.
Philco didn't use the 260kc IF in very many of there sets. Most are right around the same time frame as the 91. Like one version of the model 90 did and I think the 200X may have. You can go there the alignment data and look for the 260kc IF.
Wouldn't think about changing the osc and IF to 455kc because then you will have tracking issues.
It's a bit of a pickle
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!
Terry
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