I have a 1938 Zenith with an early FM band tuner. I would like to replace this tuner with a "modern" FM tuner designed for a tube radio chassis, say from an early 50's AM/FM set. Could I simpley switch them? I reakize that the tuning dial face would still be in the "old" frequency range but I could still get FM reception. Is this feasible???

Thanks

:I have a 1938 Zenith with an early FM band tuner. I would like to replace this tuner with a "modern" FM tuner designed for a tube radio chassis, say from an early 50's AM/FM set. Could I simpley switch them? I reakize that the tuning dial face would still be in the "old" frequency range but I could still get FM reception. Is this feasible???
:
:Thanks

Mike:
This question came up a couple of years ago, and, yes you can get a converter to "up" the tuning of a 45mHz. receiver to 88-108, but the tuning will still be 45. I'll try to find you a site.
Lewis

::I have a 1938 Zenith with an early FM band tuner. I would like to replace this tuner with a "modern" FM tuner designed for a tube radio chassis, say from an early 50's AM/FM set. Could I simpley switch them? I reakize that the tuning dial face would still be in the "old" frequency range but I could still get FM reception. Is this feasible???
::
::Thanks

:
:Mike:
:This question came up a couple of years ago, and, yes you can get a converter to "up" the tuning of a 45mHz. receiver to 88-108, but the tuning will still be 45. I'll try to find you a site.
:Lewis

Try here:

http://www.somerset.net/arm/fm_only_simplified_converter.html

:::I have a 1938 Zenith with an early FM band tuner. I would like to replace this tuner with a "modern" FM tuner designed for a tube radio chassis, say from an early 50's AM/FM set. Could I simpley switch them? I reakize that the tuning dial face would still be in the "old" frequency range but I could still get FM reception. Is this feasible???
:::
:::Thanks
:
:
:
::
::Mike:
::This question came up a couple of years ago, and, yes you can get a converter to "up" the tuning of a 45mHz. receiver to 88-108, but the tuning will still be 45. I'll try to find you a site.
::Lewis
:
:
:Try here:
:
:http://www.somerset.net/arm/fm_only_simplified_converter.html

Me again:
The xtal osc can be obtained @ BGMicro.com
Lewis
:

:::I have a 1938 Zenith with an early FM band tuner. I would like to replace this tuner with a "modern" FM tuner designed for a tube radio chassis, say from an early 50's AM/FM set. Could I simpley switch them? I reakize that the tuning dial face would still be in the "old" frequency range but I could still get FM reception. Is this feasible???
:::
:::Thanks
:
:
:
::
::Mike:
::This question came up a couple of years ago, and, yes you can get a converter to "up" the tuning of a 45mHz. receiver to 88-108, but the tuning will still be 45. I'll try to find you a site.
::Lewis
:
:
:Try here:
:
:http://www.somerset.net/arm/fm_only_simplified_converter.html
:Thank you for your help, I'll give it a try

Mike,
You can go the frequency translator route, but performance of old circuits may not be adequate for modern FM broadcast and faithful audio reproduction. If you are inclined to take on a major project, later model Armstrongs may have a tube circuit that can be adapted to your chassis, or stuff a small modern solid state unit in an unused corner of the chassis with appropriate interface to the audio section.

marv

:I have a 1938 Zenith with an early FM band tuner. I would like to replace this tuner with a "modern" FM tuner designed for a tube radio chassis, say from an early 50's AM/FM set. Could I simpley switch them? I reakize that the tuning dial face would still be in the "old" frequency range but I could still get FM reception. Is this feasible???
:
:Thanks

Rather than trying to modify the receiver, better to build an FM down-converter that will translate the modern FM signals down to the pre-war band. You can Google to find plans.

I don't think there should be much interferance. That pre-war FM band is reportedly pretty silent. The original plan was to use it for TV, but that never happened.

A while back, ARRL, or some such organization, got permission to broadcast for a day or two on the old pre-war band. Just for kicks - to let owners of the old sets try them out.
Doug

Doug,
My only question concerns modulation index and pre/de-emphasis at both ends. Do the pre-war radios meet present day specs as noted above. What about stereo sidebands (L-R), pilot carriers, Muzak or any other digital data streams on present day FM carriers?

marv

:Rather than trying to modify the receiver, better to build an FM down-converter that will translate the modern FM signals down to the pre-war band. You can Google to find plans.
:
:I don't think there should be much interferance. That pre-war FM band is reportedly pretty silent. The original plan was to use it for TV, but that never happened.
:
:A while back, ARRL, or some such organization, got permission to broadcast for a day or two on the old pre-war band. Just for kicks - to let owners of the old sets try them out.
:Doug

:Doug,
:My only question concerns modulation index and pre/de-emphasis at both ends. Do the pre-war radios meet present day specs as noted above. What about stereo sidebands (L-R), pilot carriers, Muzak or any other digital data streams on present day FM carriers?
:
:marv
:
Jeez, this is all above my pay grade! I do know that there are FM down-converter designs on the internet. I have never tried them - I've never owned a pre-war FM set. I've been told the pre-war band is relatively silent, but I've not checked it myself.
Doug

Doug,
Well, yea a fixed freq oscillator/mixer would translate the new freqs to the old, but will the old circuits (in perfect tune) do the job. The 42-50mHz band may still be cluttered with older/cheaper RC models, but received freq/ant would be well above that, consequently internal RF leakage would be the only problem with that.

marv

::Doug,
::My only question concerns modulation index and pre/de-emphasis at both ends. Do the pre-war radios meet present day specs as noted above. What about stereo sidebands (L-R), pilot carriers, Muzak or any other digital data streams on present day FM carriers?
::
::marv
::
:Jeez, this is all above my pay grade! I do know that there are FM down-converter designs on the internet. I have never tried them - I've never owned a pre-war FM set. I've been told the pre-war band is relatively silent, but I've not checked it myself.
:Doug

I built a down-converter from this site:

http://www.philcorepairbench.com/tips/svctip32.htm

I am using it primarily with a Zenith 12H689 from 1942 with the old FM band. I have also ahd it hooked up to a Philco 42-350. The only downsides are, first, it wears the 9 volt battery down fairly quick which can be solved with an AC power supply. It splits the band into to two sections, tuning lower or higher sections but not all. Read the article and it explains it. The sound quality is excellent. I have been told the deviation and bandwidth are pretty much the same as 88 to 108 FM sets. There were just less channels on the old band. BTW, the link explains the numbering system used on some early FM sets. 21 to 99 were "Channels" used on the pre-war band. Some post-war sets like Capehart are marked 200 to 300 on the FM band. That corresponds to the 88 to 108 MHz band still in use today.

FR

:Doug,
:Well, yea a fixed freq oscillator/mixer would translate the new freqs to the old, but will the old circuits (in perfect tune) do the job. The 42-50mHz band may still be cluttered with older/cheaper RC models, but received freq/ant would be well above that, consequently internal RF leakage would be the only problem with that.
:
:marv
:
:::Doug,
:::My only question concerns modulation index and pre/de-emphasis at both ends. Do the pre-war radios meet present day specs as noted above. What about stereo sidebands (L-R), pilot carriers, Muzak or any other digital data streams on present day FM carriers?
:::
:::marv
:::
::Jeez, this is all above my pay grade! I do know that there are FM down-converter designs on the internet. I have never tried them - I've never owned a pre-war FM set. I've been told the pre-war band is relatively silent, but I've not checked it myself.
::Doug