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Rockbox Ports are now being developed for various digital audio players!

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Author Topic: all region for the fm radio  (Read 7330 times)

Offline MajiKool Dragonâ„¢

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all region for the fm radio
« on: July 01, 2008, 08:47:14 PM »
id like to see the ability to access Japan mode frequencies and US mode frequencies in the same region mode.
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Offline bluebrother

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Re: all region for the fm radio
« Reply #1 on: July 02, 2008, 02:23:56 AM »
This is not really possible -- besides the frequencies limit there is also a setting on the chip (at least for the TEA5767) that is needed to tune in correctly (don't remember of the top of my head what exactly it did -- check the TEA datasheet)

Allowing a wider frequency range is a different thing. Nevertheless, I don't think Rockbox should allow into frequencies that are of no use in a region. If there is no region setting matching your location the region setting should get extended instead.
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Offline LurkAzusa

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Re: all region for the fm radio
« Reply #2 on: July 02, 2008, 09:30:44 PM »
I would also like a wider frequency range to be available.  At one time there was a patch.  I was able to pick up a television station or two and air traffic control frequencies.  As a private pilot, I found that to be very nice.
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Offline TexasRockbox

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Re: all region for the fm radio
« Reply #3 on: July 06, 2008, 04:13:54 PM »
There can be interesting things with a wider range of frequencies.  If one could enable frequencies below 76MHz there are some frequencies (72-76MHz) allocated for assisted listening (some churches, movie theaters, and concert venues).  Aircraft controller frequencies, as far as I know in the USA, utilize AM rather than FM so the reception would be quite unsatisfactory.  Some "all in one" tuner chips incorporate both AM and FM sections (the old iRiver imp-350 and imp-550 come to mind (Philips chip)) but in those cases only external hardware specific to supporting the FM reception (IF filters, inductors, etc.) was utilized so the AM section was left useless.  Additionally, AM is very susceptible to interference from computers (which these players basically are) so it's no surprise that none of them incorporate AM.  The AM coil antenna would be too close to the microprocessor -- or additional (bulky) shielding would be needed.

EDIT: Not looking extensively into these chips it might be possible to extend frequency control higher into the VHF-amateur band (enabling USA weather radio reception) but I would suspect the tuner hardware would begin to sharply attentuate frequencies above the FM broadcast band so one would would probably have to live very close to such transmitters.
« Last Edit: July 06, 2008, 04:34:58 PM by TexasRockbox »
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Offline Alx

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Re: all region for the fm radio
« Reply #4 on: July 09, 2008, 08:45:56 AM »
Yes, all available frequency range can be very interesting.
And many exUSSR countries has a special FM-range: 64-75 and 88-108 MHz together. Many FM stations broadcasting in UHF2 range (88-108), but several stations broadcasting in old UHF1 range.
Another interesting frequency is about 144 MHz, this is radioamateur frequency, but FM chip can not support it.
« Last Edit: July 09, 2008, 08:50:10 AM by Alx »
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Offline Multiplex

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Re: all region for the fm radio
« Reply #5 on: July 10, 2008, 09:32:56 AM »
Quote from: bluebrother on July 02, 2008, 02:23:56 AM
besides the frequencies limit there is also a setting on the chip (at least for the TEA5767) that is needed to tune in correctly (don't remember of the top of my head what exactly it did -- check the TEA datasheet)

I think that'll be the step size and start frequency, if they are not right you won't be able to get a good signal.

At the risk of going outside the purpose of this section there is a plugin (Patch 5448) that drives the radio chip in the H300 outside the usual parameters - it's pretty old but might be interesting to some of the commenters
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Offline MajiKool Dragonâ„¢

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Re: all region for the fm radio
« Reply #6 on: August 28, 2008, 09:33:35 AM »
Quote from: bluebrother on July 02, 2008, 02:23:56 AM
This is not really possible -- besides the frequencies limit there is also a setting on the chip (at least for the TEA5767) that is needed to tune in correctly (don't remember of the top of my head what exactly it did -- check the TEA datasheet)

couldnt' you make the tuner software in the firmware adjust that as you tune? ???
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Offline bascule

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Re: all region for the fm radio
« Reply #7 on: August 28, 2008, 09:52:10 AM »
Did you not believe him when he says it is not possible? The difference is like trying to play an NTSC video on a PAL VCR - it doesn't work because they are different.

What's the big hassle between switching regions anyway, or do you live somewhere where you can simultaneously receive US and JP broadcasts?
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Offline TexasRockbox

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Re: all region for the fm radio
« Reply #8 on: August 29, 2008, 01:01:50 AM »
Many FM radios (but not all) from Japan cover the 76-108MHz natively allowing for reception of Japan TV audio channels 1-3.  Otherwise 76-90Mhz is the Japan FM band.  Japan made some wonderful component FM tuners for the domestic market but, sadly, these are virtually unusable in the USA.

Again, a wide frequency range (whatever could be received by the hardware) rather than territorial imposed limits could provide some some flexibility.  If I recall, China uses some low power FM transmitters in the 70MHz region -- "college stations".
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Offline Multiplex

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Re: all region for the fm radio
« Reply #9 on: August 29, 2008, 10:07:59 AM »
But you still have the channel problem.

Radio frequencies are allocated in fixed step sizes from a starting frequency, and different territories have different start frequencies and different step sizes.

So you can be in territory A where they start at 90MHz and allocate in 100kHz steps (all numbers made up) but if your radio is configured for Tartary B where they start wt 85MHz and allocate in 75kHz steps you won't be able to tune into your favorite rock station at 90.2MHz

Ask my old boss - he saw a really nice car radio while on holiday in the US and brought it back but it couldn't tune to UK stations - Yes, I did laugh!
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Offline TexasRockbox

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Re: all region for the fm radio
« Reply #10 on: August 29, 2008, 12:25:57 PM »
Change the channel stepping until "one size fits all".  Anolog tuners have an "infinite"number of steps.  Some frequency synthesis component Yamaha digital tuners can actually tune in 0.01MHz steps -- suitable for just about any need.  I imported a Sony radio from England that tuned in 0.1Mhz steps.  No problem, in the USA .1MHz divides into .2MHz with no issue.  Whats common between 0.20Mhz, 0.10MHz and 0.075 Mhz?  0.025MHz.  Use that step.  That method alllows for a bit of off-channel tuning should a neighboring station cause interference.

That's the step that Degen/Grundig uses in their DE1103/G5 radios.
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Offline Llorean

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Re: all region for the fm radio
« Reply #11 on: August 29, 2008, 02:19:26 PM »
What exactly is so bad about having preset regions?

If a region doesn't cover the whole frequency range in that region, it should be a reason to fix that one region...
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Offline lumino

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Re: all region for the fm radio
« Reply #12 on: August 31, 2008, 02:37:32 AM »
Extending the whole frequency is something I'm also interested in because of the ATC
I'm a big Flight Sim fan and I'd really love to hear ATC on my radio.
As far as I know, it's actually FM and not AM, and the range is same for the entire world
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Offline Multiplex

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Re: all region for the fm radio
« Reply #13 on: September 01, 2008, 05:44:37 AM »
Quote from: TexasRockbox on August 29, 2008, 12:25:57 PM
Change the channel stepping until "one size fits all".
I think that for rockbox the standard operation should be for a simple FM radio that suits most peoples' needs, for that you need the right regional settings.

If there are regional settings where the tuning range needs (legitimately) extending then raise a bug and if possible supply a patch to fix it.

For folks who want to 'play' there is already a plugin in Flyspray that allows the radio chip in the iRiver H300 (I think) to be driven to its fullest capabilities, including things like step size, and highside injection (whatever that is); http://www.rockbox.org/tracker/task/5448 and apparently allows Airband reception.

I personally thing this is possibly an interesting intellectual exercise but not very useful - a Portable Music Player as too many compromises to board layout, screening (lack of) and antennae design for it to be useful in this mode - but I applaud the developer for having a go!

I don't know if the patch is up to date or what the capabilities for other integrated radio chips are - but that I suggest is where any work should be bone on pushing the radio capabilities beyond the norm for each region.
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Offline LurkAzusa

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Re: all region for the fm radio
« Reply #14 on: September 01, 2008, 12:16:28 PM »
I don't think that patch is up to date, at all.

How about two more "regions"?  An upper range and a lower range.  That way we could get the ATC frequencies in the upper range, as well as the TV frequencies in the lower range.
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