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- Nokia N900 (https://talk.maemo.org/forumdisplay.php?f=44)

- - N900 Radio Transmitter: ways to amplify the radio signal (https://talk.maemo.org/showthread.php?t=38582)

Re: N900 Radio Transmitter: ways to amplify the radio signal

Hi,

OK I have read through this thread. My FM Transmitter is enabled, it works if I hold it right at the base of the antenna for my radio, but I can only just hear it.

Running the fm-boost script, or just echoing 118 (or 120) right into /sys/class/i2c-adapter/i2c-2/2-0063/power_level makes no difference at all, which makes me wonder if I am missing something.

The next thing I tried was putting 88 into the power_level at which point I lost anything I had. So then I incremented bit by bit to see what happened. At about 110 I could just hear my music through the static (and the device is still resting on the antenna). At 114 it's almost clear, but once it gets past 114 there is no noticeable difference in quality with each increment.

So I am wondering if there is something else that I need to do, or if there are any suggestions as to why mine seems to stop getting better at around 114 when most people see a substantial difference going to 118?

My phone is a UK phone, bought from Carphone Warehouse. I am on the latest UK (203) firmware.

Cheers,

Ben

Re: N900 Radio Transmitter: ways to amplify the radio signal

I can only find FM-boost cant find the widget (not sure of name FMTX?) anywhere. Also using fm-boost i hear no difference still static..Using my iphone dock i get crystal clear sound on N900 i still get enough static in background to bother me. im in a suburb of chicago, IL Anyone tell me if widget was taken off or the right name? thanks : )

ps i did read all 28 pages

Re: N900 Radio Transmitter: ways to amplify the radio signal

Quote:

Originally Posted by n1ghtl1fe (Post 593961)

That is correct that is the name of the widget simple FMTX desktop widget.

Re: N900 Radio Transmitter: ways to amplify the radio signal

Quote:

Originally Posted by benh_n900 (Post 586252)

You should show increases to 120 with 118 about peak. FM Boost will do this for you but regard. Every time you change FMTX frequency or plug in anything USB including the charger, you must as you say, echo 118 (or 120) into /sys/class/i2c-adapter/i2c-2/2-0063/power_level all over again. That is why FM Boost is so dang handy. :)

I have also found that depending on the FM receivers signal rejection circuitry, it sometimes helps if you start pumping out signal from the N900 before you tune to the station on your receiver.

Do me a favor fire it all up again then.

1. Start Media Player and pump out a playlist.

2. Enable the FM transmitter and tune it to the frequency you wish to transmit on and hit "save"

(Music should now stop coming from your devices speakers but Media Player will still be chuggin' along.)

3. Keep on rockin' out and minimize. Go to the FM Boost icon and fire it up.

4. Tune your receiver to the frequency that you chose in step 2.

5. Regardless of your signal quality. Minimize it all and keep on rockin'.

6. Fire up Xterm and gain root. Type:

Code:

cat /sys/class/i2c-adapter/i2c-2/2-0063/power_level

After hitting enter the number reported back should be 118.

If it is 118, then your device is doing everything it should be doing and I would try another receiver or antenna.

Re: N900 Radio Transmitter: ways to amplify the radio signal

Quote:

Originally Posted by YoDude (Post 738141)

If it is 118, then your device is doing everything it should be doing and I would try another receiver or antenna.

... or another frequency. In highly populated areas, it can be very hard to find a frequency that is available. Even if there is no recognisable sound on a channel doesn't mean that the frequency is clear. There can be lots of interference there that just sounds like "static" when received by your FM receiver.

Re: N900 Radio Transmitter: ways to amplify the radio signal

What would happen if the power_level would be turned up to something like 130 or 140?

Re: N900 Radio Transmitter: ways to amplify the radio signal

just as a FYI:

I had a crappy USB car charger without the center two (data) pins shorted. This caused caused it to fail to charge the N900 9 out 10 times. But it did have a nice side effect. connecting it would boost the radio signal significantly, so the USB cable/charger was acting as an antenna.

I have since shorted the two data pins in order to fix the charging, and unfortunately the it's no longer improving the radio signal either.

I did also try hooking up just the USB cable without anything on the other end, but I'm guessing vecause of shielding, that doesnt help either.

one thing i might try sometime is cutting a usb cable in half and stripping the shielding away. otherwise i might desolder the data pins in the charger and replace them with a switch or something.

Re: N900 Radio Transmitter: ways to amplify the radio signal

Quote:

Originally Posted by Fötus (Post 738303)

What would happen if the power_level would be turned up to something like 130 or 140?

You could use it to defrost you windshield in the winter time. :)

Earlier in this thread it was discovered that nothing would happen.
The driver or hardware specs found power level should max out at 120, and users who tried many different higher levels above 120 could no longer perceive any increase in quality. In fact the perceived quality improvement seems to peak @ 118.

Re: N900 Radio Transmitter: ways to amplify the radio signal

Hey there,
I tried the steps descirbed by YoDude, but cat will still give me 113 as result. I even got the same signal, if I try to enter the value manually into the config.

Greetings, Blck

Re: N900 Radio Transmitter: ways to amplify the radio signal

I am using this script to boost the fm transmitter power :

Quote:

#!/usr/bin/python

import time

FILENAME = '/sys/class/i2c-adapter/i2c-2/2-0063/power_level'

def main():
while True:
f = open(FILENAME)
power = f.read()
f.close()
if power == '113\n':
print 'Increasing power to 120'
f = open(FILENAME, 'w')
f.write('120')
f.close()
time.sleep(2)

if __name__ == '__main__':
main()

when I write python /home/user/MyDocs/fmboost.py it says me

Quote:

Nokia-N900:~# python /home/user/MyDocs/fmboost.py
Increasing power to 120
Traceback (most recent call last):
File "/home/user/MyDocs/fmboost.py", line 20, in <module>
main()
File "/home/user/MyDocs/fmboost.py", line 16, in main
f.close()
IOError: [Errno 1] Operation not permitted

I am using cat /sys/class/i2c-adapter/i2c-2/2-0063/power_level to check it but it stays at 113 .

This script used to work a while ago , today I noticed it doesn't work and I reflashed but still no success . What could be wrong ?

Also fm-boost application doesn't work .