WBFM in milair band

[prcguy]

in 2012 I heard SINCGARS FM (36 kHz bandwidth 15 kHz deviation 150 Hz PL) on VHF and UHF air band.

Texas Military Activity and Frequencies

That is awesome, I really enjoy fighter jets (then again, who doesn't?). I wish they had more military comms here in the Dallas area. What is the website where you can search tail numbers and get the owner info./aircraft info.?

forums.radioreference.com

You will never hear SINCGARS outside of the 30-88MHz band ever. Its impossible to program the radio for VHF hi or UHF as its outside the scope of the programming/crypto hardware. And while in SINGGARS mode within the 30-88MHz band you will never hear them because its rapid frequency hopping with encryption. The whole point of using SINCGARS is to not be heard by anybody.

 

[nd5y]

You will never hear SINCGARS outside of the 30-88MHz band ever.

Then what is the proper name for the non-frequency hopping FM/150 Hz PL mode?

 

[prcguy]

Then what is the proper name for the non-frequency hopping FM/150 Hz PL mode?

On a SINCGARS radio it would be the single channel mode. Actual SINCGARS frequency hopping/crypto mode is rarely used within the US for practice or general use due to the complications of handling the classified status of the radio when loaded with legitimate hopping and crypto. Otherwise its just an FM mode channel.

The current typical spec for newer generation FM mil radios (1980s and later) is +/-8KHz deviation with about 2KHz deviation on the 150Hz tone. Most current radios like the MBITR, PRC-152, etc will do 8KHz, 5Khz and 2.5KHz deviation for compatibility with commercial public service radios. The +/-15KHz deviation radios using 3KHz deviation 150Hz tone were Korean war/Vietnam era and have not been used in decades even though some may be stockpiled somewhere.

 

[d119]

Getting back to the point, I agree that this is a harmonic of a cheap device which has a bluetooth transceiver in it to connect to the mobile phone, and a standard (albeit poorly filtered) FM broadcast transmitter in it, so you tune your car stereo to the frequency of the thing, and it's "pseudo bluetooth". They often plug in to the cigar lighter socket and have a small display on them. They're about $20 on eBay, Amazon, Etc.



I have one of these things in my agency car, and I'm very careful about what I talk about on it. I mostly use it to stream music to the vehicle which has no bluetooth. Many times I've had people pull up next to me when I'm listening to legitimate broadcast FM (I am one of the oldies that actually still does that), and their device is on the same frequency of whatever station I happen to be listening. I hear their music, their phone calls, etc. clear as day, it totally wipes out the broadcast station. For as small as these things are, and the essentially nonexistent antenna they have, they are unusually loud.

These things probably run an excessive amount of power, have little to no harmonic filtering, and that is unquestionably what you're hearing.

87.7MHz *3 = 263.100MHz

88.5MHz * 3 = 265.500MHz

etc. etc. etc.

And it's WBFM. Because that's what FM broadcast is, and that's what the car stereo expects to hear. Next time it happens, divide the frequency you're hearing it on by three, and go listen there. If there's no overriding broadcast station, you'll hear the same traffic.

Since broadcast transmitters (nearly always) have SERIOUS harmonic filtering on them, that's why you don't hear the third harmonic of them.