Restrict Tuner to 88 - 108?

[Shindig]

Since the only thing I can pick up from 76 - 88 is either TV channel 5 audio or channel 6 audio, (There's no channel 6 in my area anyway) and I don't see myself travelling to Japan anytime soon, what would I need to modify to restrict the extended rockbox tuner to 88 - 108 MHz instead of the 76-108 range?

[lenny]

probably modify the source code and recompile

[Llorean]

Another, possibly more useful method, is to just look up the frequencies of the stations in your area, create a .fmr preset file, and not have to worry about any of the in-between frequencies ever again as well.

[Shindig]

Lenny, thank you. The problem is, I have no idea where to get a compiler or what code to modify. I wonder if someone on here wouldn't mind taking a look at it when they get a chance and modifying it. If it's a matter of changing "76" to "88" in a file somewhere I could probably do it.

Llorean, It's an awesome feature and I've done that for my area. But it's always nice to be able to scan the FM dial when traveling out of the area. Having to scan 76-88 seems like an unnecessary waste of time to me. I can understand the benefits this has for other people.

[Llorean]

You'll probably need to change 76 to 88 and then recompile, but yeah, it *should* be a very simple change compared to most things.

[adam917]

Actually, if you want to really change it, you should change it to 87.5 MHz and not exactly 88, as most of the world (including the US) doesn't start at exactly 88. So, 87.5 to 108 MHz is the range you want.

[lenny]

Shindig-

If you want to give it a go read this over
http://www.rockbox.org/twiki/bin/view/Main/SimpleGuideToCompiling
and note the CygwinDevelopment page it links to to set up the compiler (assuming you're running windows).

as far as what to edit, your guess is as good as mine but my curiosity got the best of me so I decided to poke around a bit

in apps/recorder/radio.c I found this

Code: [Select]

#define MAX_FREQ (108000000)
#define MIN_FREQ (87500000)
#define FREQ_STEP 100000however, the 875 seems to not to reflect the 76, so perhaps this is for a different device (not iriver h1xx)? I really don't know, I don't program. If somebody doesn't answer you here, your best bet is to try the irc channel.

[Mmmm]

Mine already goes from 87.5 to 108!

[pabouk]

Mine already goes from 87.5 to 108!

Mine too! I wondered at the question because I remember that the tuner in Rockbox on H100s has been always limited to European/US range 87.5 - 108 MHz. There was even someone asking for lifting the limit for the Japanese range starting at 76 MHz.

Shindig, you are probably using a modified build of Rockbox. So you can either use the official CVS build, modify and recomplie the modified build or ask the author of the modified build for change.

[Shindig]

I was digging through the source code too and came across the same "Radio" file. I'm not a programmer either so I wouldn't know where to start. The wiki page is a great tutorial, but for someone who's not familiar with the process it's going to take me more time than I'd like to dedicate to this right now.

This is the build I was using: http://homepage.sunrise.ch/mysunrise/remartinelli/html/rockbox.html

I downloaded Mmmm's build and the radio is now working fine from 87.5 to 108.

Slightly off topic:

In my researching the extended tune radio patch I came across this rather interesting bit of info

http://www.misticriver.net/showthread.php?t=43384&highlight=dublin

What caught my attention was the fact that the user was able to tune all the way up in the 118 range. Is it possible that the tuner spec sheet lists 76-108 only because that's the OPTIMAL range the chip was made for and the manufacturer would prefer it used for that range? I have a few ham radios that are spec'ed at one range, but after modification I'm able to transmit on any frequency within the 30 - 500 MHz range. (Not that I would do that as it's illegal anyway). But, taking that info into consideration leads me to think that perhaps the Philips tuner in the h100s and h300s is capable of more than what the spec sheet would have us believe. It would be interesting to try and extend the receive range to 136Mhz with tuning steps of 25KHz (the standard for civil aviation frequencies). The modulation in that range is in AM and I'm not sure how the person who tuned in Dublin airport heard it fine, but it's worth a shot.

[Llorean]

Now that the actual problem is solved, please remember to always always check that something happens in the official build before restarting help or asking here outside the one thread dedicated to that custom build.

[Shindig]

Now that the actual problem is solved, please remember to always always check that something happens in the official build before restarting help or asking here outside the one thread dedicated to that custom build.

Yes mother!   

[Techy_Bloke]

perhaps the Philips tuner in the h100s and h300s is capable of more than what the spec sheet would have us believe. It would be interesting to try and extend the receive range to 136Mhz with tuning steps of 25KHz (the standard for civil aviation frequencies). The modulation in that range is in AM and I'm not sure how the person who tuned in Dublin airport heard it fine, but it's worth a shot.

any cb radio freqs would be ausome...