FM Frequency Shift

[snoopnoon]

All,

I am trying to see if anyone knows of an "off the shelf" component that will shift an FM frequency about 25MHz.

If there is not an off the shelf item, has anyone created a simple PCB that will does such a request?

 

[MacGyverS2000]

Search for FM mixer chips...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[VEBill]

Shifting frequencies is how a superheterodyne receiver works. Virtually all receivers are superheterodyne. You can Google the word to see how it's done.

If this is a one-off project to simply move an FM station *as received* to a different frequency, then the simplest approach might be a receiver followed by a modulator, joined with an audio cable.

What are you up to?

 

[VEBill]

For completeness, I'll mention that there are also DSP methods that can be used to shift signals up or down the spectrum. Typically not worth the effort unless the system is already digital.

 

[snoopnoon]

Purchased a radio component from Japan by accident and would rather not eat the money on the project.

The receiver will only look at lower than United States frequencies. So I would like to tap into the antenna input before the receiver and shift the frequencies down by about 25MHz so that the radio receiver will recognize them.

 

[VEBill]

If it's a modern radio, then it's very likely that it can be easily modified to cover the 88-108 MHz band.

Sometimes you just need to clip or add a diode, or a jumper.

Or...

http://www.ebay.com/itm/FM108-Japan...der-Converter-FM-88-108-Mhz-GTC-/140971349277

Intended for cars imported from Japan. This one is 10 MHz adjustment, and is just the first example I've found. Dig further using the search terms.

Good luck.

 

[snoopnoon]

How would i know what to clip or where to add the diode without the schematic?

I could not find an example that was not for automotive application to work off the 12VDC.

 

[VEBill]

"How would I know...?"

Google (maybe/maybe not). You'll need to search on the brand and model number and the fairly obvious search terms.

Or, open it up and look at the PCB.

The basic logic here is that no one is going to go to the bother of designing a modern radio for only one market. They'd design variations for most every market. So the CPU and PCB would have band options. Maybe.

I'm out of further ideas at this point. Good luck.