Aircraft Radio question

[swatgig]

Question for those who understand these things: Why can I pick up FM radio on an AM airplane radio?

I used to have a plane. It had an old VOR received in it that would pick up and play "Kiss 108" (WXKS - 107.9). 108.00 was the lowest setting on that radio, and I could listen to the radio on that. I don't understand why.

As far as I know, aircraft use AM radio. The VOR receiver also (according to wikipedia) also uses AM for voice.

So how could I listen to 107.9 on an AM radio?

 

[n1bsbri]

Here you go, good reading.

http://www.radio-electronics.com/in...reception/fm-slope-detector-discriminator.php

 

[blindfire]

Geeze...I was just going to say it is FM technology.

FM = Freakin' Magic

Good article tho!

 

[swatgig]

Here you go, good reading.

http://www.radio-electronics.com/in...reception/fm-slope-detector-discriminator.php

OK, this says it's possible, with the right circuit, and likely what I experienced. The next question is "Was this intentional or a fluke?"

- - - Updated - - -

Geeze...I was just going to say it is FM technology.

FM = Freakin' Magic

Much easier concept to grasp. Thanks.

 

[n1bsbri]

OK, this says it's possible, with the right circuit, and likely what I experienced. The next question is "Was this intentional or a fluke?"

The quality of the result will depend primarily on the bandwidth characteristics of the two radios involved (transmitter and receiver). In this case, the FM broadcast signal is relatively wide bandwidth, and the AM aircraft radio is relatively narrow, so the received signal on the AM radio was likely not great quality.

But pretty much any AM receiver will pick up FM signals to some extent using slope detection.

 

[swatgig]

The quality of the result will depend primarily on the bandwidth characteristics of the two radios involved (transmitter and receiver). In this case, the FM broadcast signal is relatively wide bandwidth, and the AM aircraft radio is relatively narrow, so the received signal on the AM radio was likely not great quality.

But pretty much any AM receiver will pick up FM signals to some extent using slope detection.

This has been bugging me for a while. (I sold my plane in 08). It took you THREE MINUTES to answer my question.

NES RULES!

 

[RUT]

I used to listed to AM radio on my ADF when flying years ago. Doubt if they're even used anymore.

 

[FPrice]

I used to listed to AM radio on my ADF when flying years ago. Doubt if they're even used anymore.

I did the same thing back in the 70's when I was flying my cross-country training flights down south. It helped pass the time.

 

[RUT]

Yes, that's exactly the time frame I'm talking about. My, how time flies!

 

[cookiecutter]

I haven't been in a cockpit in 25 years ... do they seriously not have ADF's anymore? I did a couple of cross country trips (CA to MA) and the ADF was a sanity saver over Kansas With a GPS (they must all have those, I guess), I suppose that no one needs to mark their position with the passing of an AM radio tower anymore. I guess I'm old school (or maybe just old ) ... I even have a sextant that gets me to within a half mile on the water, and it never runs out of batteries

CC

 

[swatgig]

I haven't been in a cockpit in 25 years ... do they seriously not have ADF's anymore? I did a couple of cross country trips (CA to MA) and the ADF was a sanity saver over Kansas With a GPS (they must all have those, I guess), I suppose that no one needs to mark their position with the passing of an AM radio tower anymore. I guess I'm old school (or maybe just old ) ... I even have a sextant that gets me to within a half mile on the water, and it never runs out of batteries

CC

I learned to fly in 1995 and was never shown how to use an ADF. I read about it in the manual, and answered the questions about it on the test, but never turned one on.