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SDRSharp -v- HDSLR

Posted: Mon May 27, 2019 6:21 pm
by Lasithi773
New member using RTL-SDR V3 with inbuilt upconvertor. I have several questions so I will number them:-
1. With SDRSharp I have to insert a -40,000,000 offset. Do I have to do this with HDSLR and if so where?

2, Plenty of ham band signals on SDRSharp and I would dearly love to continue using it. But it does not provide an I/Q signal to CWSkimmer whereas HDSLR does. Is this correct?

3. Signals heard on SDRSharp are good, but are barely visible or invisible on HDSLR. Does anyone else have the same problem. If not, what is the solution.

Many thanks in advance

Re: SDRSharp -v- HDSLR

Posted: Mon May 27, 2019 8:35 pm
by alanzfq
1 RF Front End calibration
2 Think so, not sure
3 Presumably audio is the same? Sliders under the display adjust.
Alan

Re: SDRSharp -v- HDSLR

Posted: Tue May 28, 2019 6:24 am
by Lasithi773
Thanks. Alan, I'll have a look tonight.

Re: SDRSharp -v- HDSLR

Posted: Wed May 29, 2019 8:53 am
by Lasithi773
Just seems very insensitive and nothing I twiddle seems to improve its performance.

Re: SDRSharp -v- HDSLR

Posted: Thu May 30, 2019 2:33 am
by rtlsdrblog
No RTL-SDR V3 has a built in upconverter? Not sure which unit you are using?

Did you adjust the gain on HDSDR?

For CWskimmer can't you just pass the audio into it via virtual audio cable or VBCable? I don't think it needs raw IQ data.

Re: SDRSharp -v- HDSLR

Posted: Thu May 30, 2019 7:46 am
by alanzfq
With raw IQ it can cover 48Khz or, with limitations, 192KHz.

Re: SDRSharp -v- HDSLR

Posted: Thu May 30, 2019 2:01 pm
by Lasithi773
If you pass just the audio, you get persistent messages that it can't successfully translate narrow band audio. Furthermore, I fed 6 call signs that it had translated into QRZ and not one was recognised. I contacted the author of CW Skimmer on two occasions. He suggested it would work far better with HDSDR or any package that provided an IQ output.

When I told him of my difficulties in getting HDSDR to match the sensitivity of SDRSharp, he said that he knew nothing about SDRSharp and suggested I contact an SDRSharp Forum. Hence these questions.

I've looked through all the compatible plug-ins and can't see anything that will alleviate this problem, but have to admit that my knowledge of SDR is very limited. Thanks for your responses.

Re: SDRSharp -v- HDSLR

Posted: Fri May 31, 2019 6:26 am
by alanzfq
" difficulties in getting HDSDR to match the sensitivity of SDRSharp"

This I do not understand. The waterfall displays of various SDR software vary, some might be better at showing weaker signals visually but I never read any comments about the basic sensitivity varying between programs. This is set by the particular SDR and if the same settings are used all SDR programs should produce much the same results. (Some do have extra processing to make a signal sound better but this is irrelevant with IQ.)
Alan

Re: SDRSharp -v- HDSLR

Posted: Fri May 31, 2019 9:07 am
by Lasithi773
I have the v3 with the inbuilt upconvertor and it performs well with SDRSharp. All test results were produced within minutes of each other on the same long wire antenna. I tried to add this information shortly after my last post, but the Forum software wouldn't let me add another posting and I couldn't find a means of editing my previous post. Sorry about that.

In HDSDR, I have set the bandwidth to 48Khz as I have read that this is the maximum it can cope with when using the RTL-SDR. Increasing the RF Gain does not display the same signals as I get on SDRSharp as I would expect. Regarding CW Skimmer, I have only repeated what its author told me in emails, i.e. get a package such as HDSDR which outputs IQ.

Is there anything that stops the author(s) of SDRSharp from modifying their code to output this IQ signal the same as HDSDR? I'm not even sure who the authors are as the whole SDR business seems very fragmented. I do appreciate your help.

Re: SDRSharp -v- HDSLR

Posted: Fri May 31, 2019 9:48 am
by radiolistener
Lasithi773 wrote:
Fri May 31, 2019 9:07 am
I have the v3 with the inbuilt upconvertor
RTLSDR v3 doesn't have upconverter. It has direct sampling mod, don't confuse it with upconverter.
Lasithi773 wrote:
Fri May 31, 2019 9:07 am
Is there anything that stops the author(s) of SDRSharp from modifying their code to output this IQ signal the same as HDSDR?
SDRSharp was interesting platform for modding. But some time ago, author stopped to share it's source code and new versions now private. As I know, author of SDRSharp now has it's own business, he selling AIRSPY devices: https://airspy.com
I don't using SDRSharp now, there is better replacement - SDRuno, it has even better DSP quality than SDRSharp :) SDRuno is not so flexible, but works very nice.

But primary I'm using HDSDR v0.76, it has very comfortable interface and very flexible spectrum pan. It has a little worse sound quality (there is some issue with low frequencies < 200 Hz, but it can be noticeable for high fidelity stations (for example when listening FM) and doesn't affect SW listening much.