HackRF GnuRadio help needed

Hey all!

Core team here :slight_smile: We have reached the point in RF and Client development that we need to provide HackRF as a reference design option (for people to use).

The work required is mainly to interface RigCtld (from Hamlib) with GNURadio. An all mode demodulator on GNURadio may be used (or written from scratch), controlled by SatNOGS Client using rigctld. The output may be stdout for now (or even decoded to replace multimon-ng usage in the future).

Any advice, help, takers? Specific requirements can be provided to anyone interested on working on this.


1 Like

Why HackRF?
The HackRF is an interesting piece of hardware for lab tests, but without proper amplifiers and filters it is pretty much deaf. It would be really interesting to implement a transceiver and a LNA + band pass filter + antenna switch + PA to implement an automated base station, but you definitely need the LNA and the band pass to be able to receive satellites with the HackRF

And about the support, just support gr-OsmoSDR and you will be interfacing with a lot of different SDRs

1 Like

The gr-osmosdr suggestion is a good one. I don’t know why any direct integration with GNU Radio would be necessary for RigCtld.

I think the best reasons for HackRF One support are that it is open source hardware and it is the lowest cost transmitting SDR platform. It can be made to perform quite well for particular applications by supplementing it with external filtering and amplification.

1 Like

Maybe using the extra GPIOs in the hackrf for the rotator control, so we have an all-in-one board would be interesing.

1 Like


With some of the basics of satnogs working, I can think about the rotator/radio/antenna part. I have a HackRF One waiting for a job, so this could be it :smile: Any pointers to suitable “external filtering and amplification”?

Fred Jan

I’m new to the HackRF (but familiar with SDR generally) - is it really that much more deaf than an RTL-SDR dongle? I note that [1] seems to have suitable LNAs for about 20 Euros. Someone on the HackRF list claims it will bring the overall NF on a HackRF down to ~1.1dB at 430MHz [2] which is a bit below standard RTL-SDR dongles. There’s also a few open designs around the place, Eg. [3]

I could take a shot at designing one myself, but I’m more experienced at building filters, which you also mention. I’m new to working satellites. Is there a reason why the HackRF would need filters where the RTL-SDR doesn’t? Or have I missed something - perhaps RTL dongles do need filtering also?

FWIW I’m here because I’ve recently talked some people at our local hackerspace [4] into helping me build an amateur satellite tracking station :slight_smile:

[1] http://lna4all.blogspot.com.au/
[2] (omitted because I’m too new to post more than 2 links: google hackrf-dev sensitivity measurements)
[3] https://github.com/loxodes/rtl-sdr-lna
[4] (omitted because I’m too new to post more than 2 links: it’s MakeHackVoid)

1 Like

Hey @csirac2 ! Welcome to the community. Generally I would say that both rtl-sdr and HackRF need filters and LNA. We would love it if you can take a stub on a filter design for VHF and UHF (for now).

For the LNA I would suggest we print and test (can you help?) the loxodes design you linked and cross-compare it with LNA4ALL.


Ok then. I’ve ordered the loxodes PCB and will try to remember the components in my next digikey/mouser/whatever order. I have access to an SDR-Kits VNA (among other things) and could probably set up to compare noise factor with the LNA4ALL but this will probably be a low priority at least for a while.

In the meantime I will be proceeding with the LNA4ALL. I’ve been playing with Coilcraft 0805 SMD inductors on another project but the cost of these add up quick and probably conflicts with the low-cost mission of SatNOGS so I’ll work on sticking to lower-cost passives.