FM on 11 meter (Export Radios)

Funny, I was just trying that out last night and found that my Cobra 19 DX-IV seems to receive FM just fine. It's a little quieter but not garbled up like I though it would be. Maybe it's because both radios are in the same truck.

 

The "radio shack"...

 

By the way @mike5511 ... that's the MFJ941D in its new home.

 

That's a nice looking SRA 198 hook up to it .

 

Well is it doing what you wanted it to? Nice set-up by the way!

 

I like the sound of the Astatic better too. There is a 636L hooked to the N4 just out of frame. I just had the 198 laying around and it sounds way better than the stock Cobra mic.

 

Why do you have a tuner in a mobile for one narrow band?

FM wont move the power needle, if it does, you have a serious problem.

FM shifts the frequency when it is modulated, so you will have what's called deviation from the center carrier based on the frequency of the modulation within a specific limit. It used to be something like 5khz and now it is for many commercial radios 2.5 khz if I remember right.

listening to FM can be done on an am rig, it takes a little skill but listening to am is difficult because the discriminator in the rig that demodulates the fm signal doesn't like am envelopes and that's why it sounds like crap.

IF the frequencies above the cb wasn't being used (which they are for the military) or below the band (for commerical use), I would love to see FM on the band above 27.405 for maybe another 400 khz.

 

I'm not sure yet. I'm knee deep in antenna theory right now and only have a basic understanding of how it is supposed to work.

I did hook it to a fiberglass antenna that was way out of tune and then put my AA-54 on the other end to see what the knobs would do... not exactly like I thought. Maybe the inductor is a little crusty but there only seems to be one position that makes a big change and moves the resonance up in frequency a couple mhz. Or maybe I just don't know what I'm doing yet, lol.

It did help me diagnose a low power output on my N4 which I was unaware of. The fuse had loosened up and wasn't supplying enough current to the radio to operate at full power.

All in all, I'm happy to have more gadgets to tinker with.