FM Mono on Sansa e250?

[mcf57]

I have a Sansa e250 with Rockbox. I really love the Rockbox interface, but was wondering something. My Sansa player has a FM radio. While I don't use it and the reception on it is not that great to begin with, is there any way of tuning in a station and forcing it to be MONO instead of stereo.

The reason I ask is cause there is a talk radio show I sometimes like to listen to, but it always tunes in with stereo and since the FM tuner is weak to begin with, I wind up getting hiss. I was thinking if I could somehow make it tune in to MONO instead, it would reduce some of the hissing and I could tolerate it better.

I can't seem to figure out how to tune in everything to MONO. Any suggestions?


****UPDATE****
Since you can't double post back-to-back and I couldn't figure out how to delete this post, I JUST figured out how to force the FM reception into MONO. Basically, you get into the FM radio menu by selecting the FM radio option and then holding down "select" button and the option to "force mono" is in there. Sorry about that.

[Chronon]

Hi.  There should be an option in the Context Menu to "Force Mono".

[karashata]

I doubt forcing mono output would help the reception any, you'd be better off tweaking the frequency being listened to up or down slightly until it comes in the clearest you can get it. The only thing I can see forcing mono doing is making the static hiss you're hearing equal in both ears and possibly a little easier to tune out.

[Chronon]

That's not necessarily true.  Here's a page that indicates otherwise: http://www.913thesummit.com/reception.htm

[karashata]

Ah, I am mistaken.  I've never seen much improvement from a bad signal by forcing mono, though most of the time the signal's only being picked up as mono anyway...

[bertrik]

A nice feature I've seen on the another fm chip (si470x) is that it reduces the stereo width as signal strength decreases (and starts turning down the volume as the received signal strength drops further). So instead of fully mono or stereo, there is a more gradual transition between stereo and mono, depending on the received signal strength.

The lv24000 chip in the e200 series cannot do this automatically, but it does allow setting the stereo width in 8 steps. Maybe the stereo width algorithm could be implemented in software for this chip.

[Chronon]

That would be a nice feature.

[donp]

Another technique, first done by Carver, I think, is to low-pass the separation signal.  SO it reduces a lot of HF noise without affecting the sound stage that much.

On the "summit" post:
One real reception killer is lamps with "touch" switches.

Generally the tiny radios (including DAP's) use the earphones as an antenna.  Different phones will perform differently as antennas, esp regarding L and R wires being split, or shielding in the wire.

My Sansa with a cassette tape adapter actually receives pretty well in my car.

[Chronon]

If someone wants to suggest some of these ideas, they should be posted to the Feature Ideas forum.