osmocom-analog November 2025

osmocom-analog@lists.osmocom.org

2 participants
4 discussions

SDR reccomendation
by nishackle＠gmail.com 24 Dec '25

24 Dec '25

Hi All, I hate reaching out like this, but I'm at the limit of my knowledge. I've got some AMPS handsets i'd like to make use of-back to my PBX if possible. The problem is, i've not been able to get AMPS to work with any of the SDR's I have. I have a HackRF, A URAN1 and a Pluto. I can open the URAN as a USRP device with the following: amps --sdr-soapy \ --sdr-device-args "driver=uhd" \ --sdr-channel 0 \ --sdr-samplerate 1000000 \ --sdr-bandwidth 250000 \ --sdr-rx-gain 20 \ --sdr-tx-gain 30.0 \ -k 334 -T CC/PC/VC \ -k 336 -T VC \ -p -s 192000 -o --fast-math Which appears to work, but the radio doesn't ever actually transmit, the SDR works, because I use it with OpenBTS to make a GSM station. I spent a $400 on a secondhand limeSDR mini, but that turned up broken in the post. Is there an easily obtainable SDR that anyone else has got working? Thanks, Nick

2 1

Help with cable connection from the phone to the SDR.
by George 18 Dec '25

18 Dec '25

Hello, I have been wanting to build a TACS base station with Osmocom analog for a while now, and have decided finally to do it! To avoid regulations, I would like to do it over a cabled connection from the phone to the SDR. I have read that some form of load or attenuators are needed to stop the phone and SDR frying themselves. Unfortunately I have little knowledge on this subject, so I wondered if anyone here can tell be what sort of load I need. Any help would be greatly appreciated

4 3

Osmocom analog RX overflow
by plaskg.90＠gmail.com 27 Nov '25

27 Nov '25

Hello all, I have finally given my wired 1g base station setup a try, and it works! (Sort of) To start with, I got these two message spammed on my screen: DSDR ERROR sdr.c:985 SDR RX overflow! And: DSOAPY ERROR soapy.c:573 SDR TX underrun, seems we are too slow. Use lower SDR sample rate. After a while of tinkering, I managed to get the Sample rate down to 96000, this works a lot better (the phone can now connect (sometimes) and receive/place calls). I can’t seem to get either the audio sample rate or the SDR sample rate any lower. (Although I am still very new to RF and probably missed something!) There are still problems, as I am still getting these 2 errors quite frequently and it causes the phone to not connect properly. My setup is: Windows 11 computer running Ubuntu in an emulator with usb pass though (would running it natively be better as the pass through doesn’t work very well?) LimeSDR mini 2.0 Motorola 4800x The terminal command is: tacs -k 23 -k 24 —limesdr-mini -P 6 -s 96000 —sdr-samplerate 96000 Any help at all much appreciated.

1 0

Can someone mind checking over my 1g base station?
by plaskg.90＠gmail.com 14 Nov '25

14 Nov '25

Hello all, With the help of Harald I have been able to construct a wired base station for the TACS network! I wondered if someone here can check over what I have so far done, to see if I have made any mistakes (which is quite likely!). Manly, I have used some 2w attenuators in the system between the phone and the splitter/combiner and I am worried that the phones I have will transmit at a higher power (I have a Motorola 4800x, Motorola independent (DynaTAC) and a Vodafone VT1) and burn out the attenuators (which would severely damage the transmitter on the phone). I will be happy to send anyone photos of my setup (I don’t believe I can attach them here). Again, I am still quite new to RF in general, so help much appreciated. :)

2 1

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osmocom-analog November 2025