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Antenna couplers used on 1940s Philco radios
#4

Without the coupler I've tried connecting a long antenna to it and it worked BUT the image rejection was poor on my 41-300. As for the resistors I would say that higher values are more likely to drift but that doesn't preclude checking the lower one's values. If you have some time to kill you can use these: https://philcoradio.com/library/index.ph...-envelope/  to put your resistor in.

Now you do realize that this set was never designed to receive signals from what is known as the fm 100 band just the fm 50 band. It tune from 42-50mc. This means that ant and rf circuits are not going to be resonant at the fm 100 band. Nor is the local oscillator. So what is happening is that your incoming signal @ 84-100mc has to have enough power to plow thru ant and rf stages because they are passing signal @ 50mc or so. Then the mixer has to try to mix with the 2nd harmonic of the oscillator (this is why the sensitivity sucks) so the it can tune the lower half of the fm band. So unless you have a second mixer that converts the 42 to 88mc. With that the set only tunes 8mc it would tune 88-94mc.

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!

Terry


Messages In This Thread
RE: Antenna couplers used on 1940s Philco radios - by Radioroslyn - 10-25-2023, 09:22 AM



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