multi-fm and decoder or multimon-ng and multi-fm

[bertonumber1]

First of all thank you for your work on the project Not so much an issue but a cry for help. Please delete if inappropriate and accept my apologies.

I am currently using a Raspberry pi, Rtl-sdr and multimon-ng and rtlfmto decode a pager frequency. It works.

However, I would like to be able to decode further two frequencies simultaneously. The problem apart from my Linux skills being basic is I am unsure how to send multiple frequencies to be decoded.

Am I better scrapping multimon-ng/rtl-fm and using multi-fm and decoder to achieve this?

The frequencies I am interested in are all 153mhz allocated but one is on 147.800 mhz which is outwith the RTL bandwidth.

Any assistance / advice would be a real help and greatly appreciated.

Thank you

[pvachon]

Hi there. I think your best bet is two RTL-SDRs: 1 for the 147.8MHz band, and one for the channels around 153MHz.

MultiFM will help you extract the channels around 153MHz (see the sample config at https://github.com/pvachon/tsl-sdr/blob/master/etc/multifm.json for FLEX... there is a similar config for POCSAG in that directory), which it will then pipe into two FIFOs, which must be created with mkfifo before launching multifm. Then you can follow the instructions at https://github.com/pvachon/tsl-sdr/wiki/Using-Decoder to use the POCSAG/FLEX decoders.

Let me know if you have any troubles following the documentation, it might be a bit sparse.

[bertonumber1]

Hi @pvachon Thanks for your response and providing the links to these configs. I will have a look and play around with them when home from work. I was thinking along the same lines as the 147.8 frequency outwith the 153.0mhz bandwidth.

I am having good results with a nooleec sdr and a piece of rigid wire inside the inner core of the SMA connection. Due to the high power the pocsag transmissions I guess.

I have another rtl dongle so I will get to changing the serial and hook it up.

I'll report back with results.

Thanks again

Rab