is there a formula for determining a mirror frequency?

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ryangassxx

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I'm trying to tune into something just SLIGHTLY outside of the coverage of my receiver.. Is there a formula to follow that would be able to determine a mirror frequency for the frequency I'm trying to hear?
 

Don_Burke

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ryangassxx said:
I'm trying to tune into something just SLIGHTLY outside of the coverage of my receiver.. Is there a formula to follow that would be able to determine a mirror frequency for the frequency I'm trying to hear?
Double the first IF frequency and that will be how far off the displayed frequency you are are actually listening.

Listening to image frequencies can be tricky sometimes. Individual scanners have different personalities when it comes to this, although the offset will be the same for scanners of the same model. I would try to get tuned into the image of a known frequency near your target frequency to get the hang of it.
 

Tommahawk

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If it is out of the range of your coverage the normal IF that is used is 10.7 (Frequency +- 10.7mhz) I'm not going to promise that you will receive anything but I have used this formula with very good success on my Amateur Radio......
 

slicerwizard

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If it is out of the range of your coverage the normal IF that is used is 10.7 (Frequency +- 10.7mhz) I'm not going to promise that you will receive anything but I have used this formula with very good success on my Amateur Radio......
I don't think too many scanners still use 10.7 MHz IF's. Even my ancient Pro-43's have IF's in the 600 MHz range.
 

kb2vxa

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The old 10.7MHz and 10.8 for Bearcat single conversion IFs went the way of the dinosaurs long ago so that trick won't work anymore. With modern double and triple conversion receivers the IFs are chosen to eliminate images and they do it quite nicely.

What's a "mirror" frequency? The term is "image" FYI.
 
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