Baofeng Disabling FM broadcast - any benefit?

[nanZor]

I'm wondering if by disabling FM Broadcast in Chirp, if all it does it disable the side-button, or if it actually somehow limits what the front-end of the rx-chip's LNA is seeing?

This might be a placebo-effect, but by disabling FM broadcast, I *think* that the 220 band on my tribander is a little more stable and quiet.

So I'll put it out there - has anyone who has done this notice any effect / improvement, especially if they suspect overload/desense from nearby fm broadcast facilities?

So don't hold me to it, but it *seems* like disabling fm may provide a smaller spectrum for the sdr receiver to look at. Maybe I'm just fooling myself.

 

[mancow]

The FM broadcast is handled by entirely separate dedicated all in one receiver chip. I doubt they are doing RF re-routing and it's likely just not enabling use of it - actually I'm certain they aren't from what I recall of schematics. So, no. It shouldn't matter.

 

[nanZor]

Thanks mancow - you are absolutely right - no difference..

It was a good placebo while it lasted though.

 

[VK4FAST]

That was interesting. How could it be determined what Baofeng it is?
I know the UV5R has a single chip FM radio, but is that the case for every Baofeng HT?

 

[nd5y]

That was interesting. How could it be determined what Baofeng it is?
I know the UV5R has a single chip FM radio, but is that the case for every Baofeng HT?

They are all mostly the same. They all use the AT1846S (or RDA1846S) transciever chip, which is doesn't cover the FM broadcast band and isn't capable of 200 kHz wideband FM, and the RDA5802N FM broadcast receiver chip.

 

[VK4FAST]

I wonder if disabling it in Chirp actually turns it off, or just disqualifies the band as far as the user defined freqencies are concerned.
The audio output of both chips are tied together before the output audio amp.
There would be some difference in audio noise to turn it off, but the FM radio chip should be put to sleep whenever it’s not in use anyway.