Videos showing the LimeSDR in Action on HF with GQRX

Over on YouTube LimeSDR beta tester Marty Wittrock has uploaded several videos showing the LimeSDR receiving HF frequencies. In the first video Marty shows it receiving the USB voice on the 20m band during the 2016 ARRL field day. The second video shows reception of PSK31 signals. More videos are available on his channel if you are interested.

In the videos he uses GQRX and his own KN0CK HF upconverter. The LimeSDR should be able to receive HF on its own without an upconverter, but at the moment the HF capabilities have not been programmed into the drivers yet, so during this beta testing period an upconverter is required.

Marty also wrote in to us to make some comments on his experiences with the LimeSDR. He believes that the LimeSDR is amazing and writes:

The quality of the receive and audio [of the LimeSDR] is incredible against other SDRs I have in the house (Flex 5000A, RTL-SDR, HackRF, Red Pitaya – and soon SDRPlay).

Marty also writes that he will soon have more videos of the LimeSDR operating in Windows with SDRConsole in the near future, and we will post those videos too when they are ready.

LimeSDR Receiving 20m Voice on USB

LimeSDR Receiving PSK31 on the 20m Band

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When he was picking up WWV I could hear a radio station in the back ground , I don’t know if it was a problem with the up converting or the selective is bad on the LimeSDR ??????????????????????


Robert – There is an overlapping station in the WWV video that has been transmitting there for some time now – it’s not image issues with the LimeSDR


I live in Pensacola Florida and none of the wwv stations have a am station over riding the signal , so this come as a surprise to me . You must live across the Atlantic from were I am . Do you know who is doing this ????????????????


Why is he using a upconverter if LimeSDR can receive from 100 khz? Isn’t it good enough?
These tests are almost useless with an upconverter. No doubt that LimeSDR can receive a signal coming from the upconverter but i would like to see a signal coming from the antenna!


Please read before you comment.


Yes, i went straight to the video. But this does not change the results; if it is not ready for HF i guess people interesed in HF will have to wait before purchasing it and if you have to use it with a upconverter a RTL dongle is more than enough to tune to the upconverter’s output. Again i think that if this demo make some sense to you then i could show you my MP3 player receiving the 20 m. band….. after feeding it with the audio file.


The hardware supports it, the software does not (yet). It is not like the hardware will be available until October for some, November for most. There is a lot of time between now and then for the software developers to iron out the kinks. And refactor the code base a few times. You seem to be inventing problems where there are none (yet), come November if it still does not support HF out of the box, that will be a different story.

But since you endorse using a RTL dongle for HF, I’m taking everything you say with a large grain of salt (In HF you can have extremely strong local signals right beside extremely weak signals from nearly the other side of the world, with ideal conditions, and 48dB of dynamic range means that you will only every see the strong signal).


I am not inventing any problem, i just say that if it cannot receive HF yet the tests should be made on higher frequencies. Or should we be impressed from the quality of the upconverter? In this test LimeSDR did not receive HF but VHF.
I did not suggest to receive HF with the RTL dongle, i suggested to receive the upconverter with the RTL dongle, it’s a different thing and different frequency. I suggested to do it untill the developement of the software is completed; if you are only interested to HF and not as the final setup. But of course if you buy it now to receive higher frequencies you can use it to tune to the upconverter as well. I do not know why i find myself repeating obvious things.


Max – The article clearly states that HF isn’t ready yet and the LimeSDR team is working that diligently. Give it time – they will bring the entire spectrum to the LimeSDR.


Bertie – I agree with your assessment. I find it odd that one would post comments like that when the article clearly states that HF is under development still.


I will give them all the time they need, i am not in a hurry to buy anything that it is not ready yet. I just find it odd that in the meantime you find relevant a test showing the reception of HF using an external device. Yes, the article clearly states that, me too.

Michael Jackson

I’m not filled with inspiration when I ‘hear’ amateur radio operators and ‘see’ VHF airband frequencies! Is this a feature of LimeSDR?


Yeah, he’s using a 120 MHz IF.

134.258 = 120 + 14.258 (typical USB frequency on the 20 meter band).

I think he *could* have programmed in an offset to gqrx, but this is strictly aesthetic. I’ve never used an upconverter per se but I do have a cable tapping the 1st IF on my Icom 703 (I cut the coax from the cheapy MCX antenna on the NooElec blue, and used that to tap). It basically allows my radio to function as a pre-amp + upconverter in this configuration (I can also still listen to a second channel using the meatspace UI). I’ve found using an offset is really helpful in preserving my sanity (I’d much rather see 7.037 than 64-something!)

I put the YouTube video describing this setup in the website link.

MEANWHILE – back to the OP – I am really excited about the LimeSDR!


Admin – that’s correct. The offset is 120 MHz that was used in the KN0CK HF Upconverter design for the RTL-SDR.


Michael – The LimeSDR team is diligently working HF (amongst other higher frequencies) to bring the entire spectrum to the LimeSDR. Give them time – they will produce a magnificent radio…I know, I’m on the beta team and the results thus far are really impressive – the best SDR I’ve ever ran.