SDRAngel 3.7.3 and the LimeSDR...Here's what you can expect...COOL!

Applications Amateur Radio
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Check out the YouTube video here to see the SDRAngel 3.7.3 and LimeSDR goodness on a 2.2GHz I5 Quad Core machine…Still playing with my LattePanda microPC on this configuration and may have to overclock it a little to keep up…But SDRAngel 3.7.3 and the LimeSDR play nice and clean on the higher horsepower Intel Windows Box.

See the goodness here ----> https://www.youtube.com/watch?v=TFasBv9IPzs

Thanks to Edouard @F4EXB for keeping the SDRAngel development going and improving with every release…Also thanks go out to @brendanthebig for his continued research with SDRAngel, too…

73 de Marty, KN0CK

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@martywittrock For some reason I can’t get sdrangel to receive or transmit using my LimeSDR. I’ve tried changing settings of Low pass bandwidth (40-100mhz), Sample rate 5-8msps, gain (manual every combo, and auto=50-70), etc. Transmit just plain doesn’t work. Almost no options on the sink to adjust so not sure what is wrong there.

I’ve been able to barely pick up some CW on 20m and 40m, but it is of very poor quality with a low SNR. Any ideas what I’m doing wrong?

Signal is of high quality in GQRX and works exceptionally well.

Any help is appreciated!

Thanks,
Justin

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@jslatten - Justin,

Okay - so let’s start with some questions first and then I can answer back on that to help you get started. SDRAngel should work just as well as you see in the video - and if you’re not getting that, then there’s definitely a setup problem. First the questions:

1.) Are you using ZADIG to load the correct driver for the LimeSDR? SDRAngel is predicated on using ZADIG to load the driver (so you have to launch it and you have to select the LimeSDR before you launch SDRAngel)

2.) If you’re using ZADIG and you open SDRAngel, can you select your LimeSDR from the Source and Sink Device menu?

3.) If you have a LimeSDR selected as a source (receive) device, have you selected the LO antenna port connection (this is the only one that works for the app that I’m aware of)

4.) If you’ve loaded the LO antenna to be used, is there an SMA connection on the RX1 LO port (it’s just a cockpit error question).

5.) Have you adjusted the gain controls on the LimeSDR in AUT mode for 70 on the first adjustment, and then selected the MAN mode to adjust the settings to 32, 3, and 30 respectively?

5A.) Ensure that you have a demodulator selected (AM, SSB can be loaded and used simultaneously).

6.) Please set your sampling rate to 7.000.000

7.) Set the H pulldown menu to select 16, S pulldown menu to select 64

8.) Set the Low Pass Filter to a value of 099.000

9.) Set the FIR filter to 02.100

10.) Set the upper frequency adjustment from 435 MHz to 30 MHz (shown as 0.030.000)

10A.) Ensure that the NCO button is illuminated (selected) and also ensure that the DC button is also illuminated (selected), too.

11.) Set the actual tuned frequency to where ever you want it - - use 10.000 MHz (0.010.000) initially to hear WWV or tune to 7.000 MHz (0.007.000) to listen for CW signals and tune from there.

Let’s start with this and then let me know if you’re either hearing something or there are other issues - Here is a picture of a typical setup for HF on SDRAngel - - I’ll take some more setup pics tonight and post them, too - but for now, try to mimic this:

Typical Setup Screen for HF
Typical Setup Screen for HF.jpg1599×861 269 KB

73 for now, Justin,

de Marty, KN0CK

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If you ordered a HF modified LimeSDR, then make sure you use the W antenna input as that is the one that has been modified to improve HF reception.

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@jslatten - Justin,

Brendan is right about that and if my (crumbling) memory serves me you can use the W(ideband) port or the LO(wband) port on the LimeSDR for receive. I’m not as familiar with what port Crowdsupply had modified to allow HF reception on the LimeSDR but whatever port they used for HF then make sure that’s selected in SDRAngel for both transmit and receive.

Keep us advised on your efforts there, Justin -

73 de Marty, KN0CK

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My board came with the Matching Network Inductor removed from RX1_W. I have also removed the inductor from RX1_L. I have not noticed much of a difference between the 2 inputs as far as RX sensitivity goes. It is handy to be able to swap between 2 RX antennas…
After killing my RX1 front end, I have now removed the inductors from RX2_L and RX2_W and all is working well.

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I’m just being pedantic here Marty :grin:, but can’t select modified antenna input for TX. Best antenna to use for HF TX is TX1_1 (LO antenna selection for LimeSDR sink device).

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Thanks @martywittrock. It looks like I just didn’t play around enough with the settings. I think my gain settings were just off. I backed down the LGA, TIA, and PGA which dropped down the noise and raised the SNR to a respectable level. Although I tried messing with the FIR filter setting, It made the noise floor jump significantly but I couldn’t discern anything due to the high noise level. Not sure if the “fixes” I performed on my board screwed up anything.

I think I can work receive with my current settings though without the FIR filter.

What about the transmit side? What settings do you use for transmit?

I appreciate the assistance!

  • Justin
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@jslatten - Justin,

I’ll take some pictures of the transmit side this evening - I meant to do that yesterday night but I got caught up in some laser engraving at the shop and I couldn’t get loose from it. But this evening I have nothing planned so I can take those pics and get them to you here. In transmit, the sampling rate will be the same as it is for receive - you don’t have any control of that. But the antenna setting, transmit gain control, and the modulation type all have to be loaded and set up to make it work correctly. So, again, I’ll take pics to show the differences in SSB and AM. FM is pretty easy to use and is self explainable.

Also, pertaining to noise floors and such - One thing about the Lime…It’s a wideband input regardless if you use the W(ideband) input or the LO(wband) input. The matching networks are capable of going down to 1 MHz, but I have found through application that if you plan to use the LimeSDR on HF you’ll need to have a 30MHz Low Pass Filter in line with the antenna input and attached to your HF antenna to remove the FM broadcast band images that are strong and can affect the gain of the receiver by desensitizing it. When you have an external Low Pass Filter applied then you’ll have better HF performance in receive - it’s just the nature of the beast. It doesn’t mean that without the LPF that you won’t receive anything - it’s just means that you won’t receive as well because the strong nearby FM stations will be within the capture range of the input filter for the Lime and will be ‘desensed’ for HF. Adding the external 30 MHz LPF will fix that.

Okay - more later as I have it…Stay tuned…

73 de Marty, KN0CK

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@jslatten - Justin,

Okay - sorry for the slight delay, but here is a picture of what I have my transmit settings:

HF TX Settings
HF TX Settings.jpg1270×714 177 KB

Now, these should be used as a starting point and you can play with the parameters as you go. I will tell you that it’s entirely possible to lose receive if you make an adjustment (like sampling rate). I think this is a latent bug that I’ll have to report, but it only seems to happen when I’m playing with it on my LattePanda microPC - not my full-up I5 quad core machine. But play with the parameters in transmit and let us know how you’re getting along.

73 de Marty, KN0CK

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FYI 3.7.8 is fixing issues in both LimeSDR and also PlutoSDR.

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