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  #1  
Old 08-26-2022, 01:51 AM
Electronic M's Avatar
Electronic M Electronic M is offline
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Quote:
Originally Posted by old_tv_nut View Post
I take "tuner output" to mean this is either amplified RF or IF from the mixer. It has to be one or the other if you are going to send it to an FM detector.
Whatever it is, it's not the constant high level local oscillator output. You need to measure the local oscillator frequency and subtract 455 kHz from that to calculate the station frequency you are tuned to.
I own the same model of radio and can assure you that the RCA type TUNER jack is a line level audio output for an external amplifier. The inside of the back flap even has the schematic printed on it...I took a picture and used the pencil to point out the jack at the first audio stage.

It's possible if there's no low pass filter to remove the FM MPX stereo ultrasonic carriers you MIGHT be able to plug an accessory FM MPX decoder from a early 60s console, connect it and get FM stereo demodulation, but I haven't tried it or looked for said filter.

What's interesting is it can function as an audio input too. I've been able to tune to a silent channel then back feed the tuner jack through an adapter on the headphone jack on my phone and use my Zenith as an amplified speaker for my phone (it's the secret behind how I played a specific piece of music on that radio in a YouTube video).
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  #2  
Old 08-26-2022, 06:49 AM
vortalexfan vortalexfan is offline
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Quote:
Originally Posted by Electronic M View Post
I own the same model of radio and can assure you that the RCA type TUNER jack is a line level audio output for an external amplifier. The inside of the back flap even has the schematic printed on it...I took a picture and used the pencil to point out the jack at the first audio stage.

It's possible if there's no low pass filter to remove the FM MPX stereo ultrasonic carriers you MIGHT be able to plug an accessory FM MPX decoder from a early 60s console, connect it and get FM stereo demodulation, but I haven't tried it or looked for said filter.

What's interesting is it can function as an audio input too. I've been able to tune to a silent channel then back feed the tuner jack through an adapter on the headphone jack on my phone and use my Zenith as an amplified speaker for my phone (it's the secret behind how I played a specific piece of music on that radio in a YouTube video).
OK, I wasn't sure, because I know some of the early add-on tuners like old Pilot FM Tuner from the late 1940s worked where it wasn't necessarily a line-level output that it was outputting to the radio it was being connected to.
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  #3  
Old 08-26-2022, 12:02 PM
kf4rca kf4rca is offline
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They sure did make a lot of them.
What you could do is add a digital display, an S meter and a BFO and you would be all set to listen to the pirates on 6925 on Friday and Saturday nites!
You certainly would have enough space in the bottom where the batteries used to sit.
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