Can A Philco 90 Be Modified to receive a frequency of 1540KC - Printable Version
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Can A Philco 90 Be Modified to receive a frequency of 1540KC - Radionut78 - 05-07-2011
My favorite AM station broadcasts on a frequency of 1540KC. Is there anything I can do to my Philco 90 (early version with two 45's) to receive this station? Thanks to any and all for their help and suggestions.
Floyd
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Ron Ramirez - 05-08-2011
Moved to Philco Electronic Restoration by me.
Floyd, since 1540 is slightly above the design limit (1510-1520) of the 90's tuning range, you might be able to purposely misalign the radio just enough to make 1540 come in at the high end. This will throw off your dial scale on other frequencies, though.
I don't have any other suggestions right now, sorry. The only other alternative I can think of would involve a great deal of re-engineering of the radio circuitry such as modifying coils and such; which is not something I would want to do to a 90, especially the early version.
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radionut78 - 05-08-2011
Ron,
Thanks for the reply and info. I tried realigning my Philco 90 (early version) to receive the 1540KC frequency but to no avail The highest frequency obtainable was somewhere between 1510 and 1520, as you mentioned in your reply to my original inquiry. Guess, I'll have to find another favorite station broadcasting on a frequency my 90 is capable of receiving. Thanks again for your reply and suggestion. They are much appreciated.
Floyd in Georgia
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radioroslyn - 05-08-2011
You could lower the value of #43. Should be across the oscillator padder.
Terry
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radionut78 - 05-08-2011
Terry,
Thanks for the suggestion. I'll certainly give it a try. Your help is much appreciated.
Floyd
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - AI2V - 05-09-2011
If you can do it, put a piece of brass (large screw?)in some foam and put it inside the oscillator coil form. This will reduce the inductance possibly enough to allow misalignment and reception of 1540. The screw/foam can always be removed without damaging the original coil. Just be careful not to damage the coil leads in the center of the form.
In any stage where your trimmers are fully CCW, put some brass in the associated coil form to raise the resonant freq. Brass impedes the magnetic flux effectively lowering the inductance.
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radionut78 - 05-09-2011
Pete,
Thanks for the reply and info. It is certainly rewarding to here from those who are more knowledgeable re the technical aspects of tube radio servicing than myself. Your reply and advice is greatly appreciated.
Floyd
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Beckett - 05-11-2011
Why not go through the trouble of connecting the output of some old boom box or something tuned to your station and connect it to a Talking House or something? Of course that's not going to do exactly what you wanted to do - but at least you wouldn't have to modify your radio at all... just a thought.
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radionut78 - 05-12-2011
Thanks Brian,
I had considered something similar to your suggestion but that mellow and certain tone quality of yesterday's tube radio sound would be lost. I appreciate you sharing your thoughts and ideas.
Regards,
Floyd
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Ron Ramirez - 05-12-2011
If your favorite station on 1540 kc has a website that streams their audio, you can connect a computer to an AM transmitter set to a lower frequency, and then transmit the audio to any AM radio in your house.
If the website's audio feed (assuming they offer streaming audio) is of good quality, you won't lose any "tone quality."
Of course, if the station does not offer streaming audio on its website...or if it does not even have a website...then you're out of luck.
When I acquired a Talking House transmitter, I set it to transmit at 660 kc. Two reasons why:
- There are no AM stations within 100 miles of here operating at 660; and
any AM radio I own can pick up the signal, even the older ones such as the 90 which does not tune above 1510 kc.[/list:u]
I have a computer hooked up to my Talking House transmitter, and usually I have it set to play big band music. Occasionally, though, I set it up to retransmit Michael Savage or Armstrong & Getty when I'd rather hear talk radio.
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radioroslyn - 05-12-2011
As Ron said and there is a lot of great stuff that can be streamed and rebroadcast via a low power transmitter or even a signal generator. I was thinking of having a computer buddy of mine to build me a little computer with all of the slots filled with sound cards. Build up 4 or 5 small transmitters and cover the dial with all the streaming favorites. The other thing you could do is put in a reversible modtifaction and add an input connector and switch.
Terry
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - Radionut78 - 05-12-2011
To Ron and Terry,
Unfortunately, my favorite AM station does not have a web site whereby I can listen to their programming. It serves a rather small community approximately 30 miles from my home and is locally owned. It is the station I listen to while piddling or attempting to repair an old tube type radio. It is very difficult, if not impossible, to find a radio station with a format that caters to old timers such as myself (79 yrs old). I appreciate the feedback, comments and suggestions from fellow collectors and those who love the vintage tube type radios. Your endeavors and help are beyond reproach.
Thanks again,
Floyd
Re: Can A Philco 90 Be Modified to receive a frequency of 15 - codefox1 - 05-12-2011
Perhaps you need a compromise. If you could find a radio, any radio old or new that receives the station you wish to listen to, you could pipe the audio signal into your beloved set and listen away.