Competition: Write a Simple Limesuite RxTx Example

I TegwynTwmffat, ugly pirate roaming the seas in search of Treasure, do hereby challenge any Person, Artificial Intelligence or Alien Lifeform to produce a very simple Rx-Tx .ini file to load into Limesuite with the sole purpose of amplifying a received RF signal of bandwidth 30 MHz at 806 MHz and transmitting it once again at the same frequency on the LimeSDR gadget.

The first Entity to successfully produce such a file will win a jar of my famous ‘VERY HOT CHILLI SAUCE’ which will be posted to any terrestrial address:

I have a really good band pass filter, so no digital filters are required. Also, I’ve got this to work in Pothos, but have reached a ‘brick wall’ with this software and am looking for alternative pathways to success.

Thank you!

1 Like

Could you give us some more information on your Pothos version?
I have realised a grc solution with minor success. I could not get a smooth nbfm modulation.

@JMG … Thank you for your reply.

This is the version I’m working with.
As far as testing is concerned, have you got a hardware band pass filter? eg:

This is the simplest possible setup as no digital filters/tuning is required (I think).

Otherwise, I did tests re-transmitting a local FM station to 1 MHz higher than the Rx frequency, which worked well. The Pothos file is here:

I’m actually working on this file at the moment, using Limesuite to scoop up the settings generated by Pothos and then trying to get Limesuite to replicate what I managed to do in Pothos on it’s own. Progress is painfully slow!

The logic of trying to do this is to access the complete set of registers directly and then control the LimeSDR with an Arduino, which currently seems fairly easy IF I can do the ‘Limesuite to replicate what I managed to do in Pothos’ bit.

I successfully managed to scoop Pothos!

Full details, including the Pothos and Limesuite files, here:

Now I need to scroll through the Limesuite panels to see what settings do what functions

If anyone wants to re-create this experiment (UK radio station), open the .ini file, press GUI to Chip, open the FFT module and press start. Tune an analogue radio to 104.6 MHz and listen. Don’t transmit at high power or for more than a few seconds as it may annoy your neighbours!

Sorry everybody … The competition has ended … and the successful contestant was … ME!

Checkout the Pothos and Limesuite files here:

1 Like

Now you need to taste that sauce :smiley:

Don’t worry @9a4db … It’s absolutely delicious … especially on cheese on toast!

1 Like

Good to see the project moving forward.

Man the habaneros! Full speed ahead! I tried Ghost peppers recently. They can alter reality.

BTW I just realized that and are not the same. is a blog and is the project site.

1 Like

Very, very slow progress. You’d think there would be somebody here who actually knows about this stuff? Maybe they’re keeping quiet because it’s commercially sensitive? I’m inclined to use a series of obscene expletives but will refrain.

Actually the Chilli label is slightly inaccurate as I now use ‘hot cayenne’ as the flavour is much better. The habaneros tasted of burnt rubber!

Are you going to post a project on ? There’s some decent prizes/opportunities in the main 2017 competition.

[quote=“TegwynTwmfatt, post:9, topic:1117, full:true”]
Very, very slow progress. You’d think there would be somebody here who actually knows about this stuff? Maybe they’re keeping quiet because it’s commercially sensitive? I’m inclined to use a series of obscene expletives but will refrain.[/quote]

There does seem to be a lot of secrecy around cell comms. From the handset radios to the protocols, etc., etc. Some good videos about this by osmocom folks.

And then implementing something like this seems to be “if they can figure it out great but I’m not putting my name with that” out of fear of the authorities.

Have you got your hands on a commercial femtocell? Oh osmocom were giving away femtocells for free if you can contribute to the project. Not sure if they’re still doing that.

Actually the Chilli label is slightly inaccurate as I now use ‘hot cayenne’ as the flavour is much better. The habaneros tasted of burnt rubber![/quote]

Cayenne are good. The Ghost peppers had one flavor; pain.

Haven’t thought about it at all. But it’s not likely.

Although an idea came up the other day for something I’m making from natural materials but I was thinking of adding an IoT device to it so I will have to see what kind of prizes are awarded.

The hackaday crowd looks to be reasonable too.

Hi @TegwynTwmfatt,
Actually, you do not need an external software at all. You may configure LML of LMS7002M to loop back Rx digital data to Tx. Just not sure what you will get by transmitting the data at the same frequency as Rx… Am I missing something?

Hello @Zack - Thank you for your reply.

I found the LML panel - Maybe this is the key to unlocking the secrets of the ‘Holy Grail’?

In the last test I did, I had the whole 30MHz band 20 base station Tx showing on the LimeSuite FFT, but was unable to re-transmit it - I’m guessing the LML settings were wrong? (I monitor transmissions on a separate SDR rig).

My current project is a ‘simple’ repeater where frequencies received on an external, remote antenna are transmitted once more on a second antenna inside a faraday cage … and yes, I am under the impression that no software is required - it’s just a matter of setting up LimeSuite correctly? Once I’ve learnt a bit more about LimeSuite I can then use the Arduino to create all kinds of fantastic projects (hopefully).

Here’s what I had running at my last experiment … Could you tell me what the relevant settings should be to achieve transmission?

Here’s the LimeSuite file that I was using:

Hi @TegwynTwmfatt,

You have to set data source of TXFIFO to RxTSP and TXFIFO write clock source to RxTSPCLK, check the pictures on how to set LML loopback from Rx to Tx. That’s it.
By the way, if you are not using NCOs , you can bypass CMIX in your RxTSP and TxTSP tabs. It will save you 6dB each.

1 Like

@Zack YES! … That seems to work! I now seem to have the LimeSDR working in full duplex mode with my external duplex filters using the NCOs to upconvert/downconvert and downconvert/upconvert through a center frequency of 826.5. It doesn’t actually help with 4g signal on my own phone yet, but I presume that’s a matter of fine tuning?

There is one thing I’m finding a bit strange and that’s that the LimeSuite FFT won’t show Channel B Rx. Any ideas? I’ve checked that my channel B works on Pothos and there seems to be no problem there.

Here’s the current LimeSuite file if anybody wants to mess about with it, BUT, you’ll need the duplexers to actually build a repeater:

Thank you so much!

@Zack … I think you’ve actually won the competition since my own initial success was only partial. I can send some chilli sauce to Lime HQ in Guildford?

Hi @TegwynTwmfatt,

You have to switch Data reading to Packets MIMO in FFT Viewer. Then you will be able to select A/B channel or both in Display Channel dropbox. Check the picture bellow.

Hi @TegwynTwmfatt,

Thank you, much appreciated! But it is not going to be fair I think. Unless you think differently :slight_smile:

Looks like you’re back in the driver’s seat as Zack hands the wheel back to you and takes the cayenne chili sauce.

You are close to your destination now. Remember “It’s the journey” so don’t come complaining here when you realize the mother-in-law’s calling a LOT with the new and improved reception.

1 Like

OK SDR, sounds good. Let’s do some of that. I went and got my extra ticket in one sitting last June, AC8XA. I ordered myself a LimeSDR board last December 30th, and got it in hand 05 April 2017. I have obsessively collected cables, connectors, adapters, various RF amplifiers, transmit filters, directional couplers, coax, RF relays, heat sinks, an enclosure and 80mm fan, ferrite cores, magnet wire, fiberglass tape, 2 books on transmission line transformers, a nice I7 quad core pc, a USB3 extension cable, have designed a transmit sequencer with an Arduino and am now busy modeling and constructing broadband antennas. I have Xenial Xerius, LimeSuite and Soapy drivers for LimeSDR successfully installed and tested. The self test works! Yaay! I am now lurking on the local 70cm repeater that I participate on with an HT and listen with a few inches of wire stuffed into the end of an SMA extension cable to the LimeSDR. Now what? Dump Linux for now and load up Win7 instead? Pothos PPA for Xenial? GNU - GRC doesn’t look like there are even LimeSDR transmit drivers in alpha. Open source disruptive technology can do anything, yes. It’s wonderful, but I still have no idea how to begin to figure out how transmit a signal… notes at


Hello @TegwynTwmfatt,

I just received an award, thanks!!! :grin:
Here is a photo of Very Hot Chilli Sauce supporting LimeSDR-USB, E-I-E-I-O: