SDR Software Feature Ideas

[Robz]

What features would you like to see in an SDR program?

What are some other things you would like to see me implement?

Two suggestions:
1. I would like to see frequencies color coded, similar to ARRL's band plan color coding. Also allow for custom color coding for any frequency.

2. I use Windows 10; however, I do not believe that it is robust enough for SDR use. Many utility programs will access the hard drive and severely interfere with decoding. For example HDSDR normally runs with only a few percent of use; but jumps to very high CPU percentage when disk access programs, such as backup software, virus hunters, Cortana and others decide to kick in. Audio breaks up and makes SDR reception useless. Not even an SSD or fast CPU will help; I am using a Samsung SSD Pro 850 512 GB. The CPU is an Intel i7 CPU about 3+GHz.
SDR applications face an an UN-known. What happens to a transmitted spectrum when Cortana or a spyware hunter decides to do a disk scan and messes up the transmitted spectrum? My experience has been far better with Linux or even Windows 7 (Cuz NO CORTANA). May be your SDR program could run in a critical section and prevent others from running.

SDR hardware:
1. Ettus b200 transceiver
2. SdrPlay
3. Soon to receive, the Lime MIMO transceiver
4. QS1R/E Transceiver

Good luck with your SDR program

 

[Jim S.]

Audio breaks up and makes SDR reception useless. Not even an SSD or fast CPU will help; I am using a Samsung SSD Pro 850 512 GB. The CPU is an Intel i7 CPU about 3+GHz.

That almost sounds like too many devices using the same interrupt line. I wonder what would happen with the SDR attached to a different USB interface?

 

[Robz]

That almost sounds like too many devices using the same interrupt line. I wonder what would happen with the SDR attached to a different USB interface?

Jim, thank you for your reply.

Briefly, I have two USB 3 ports and the problem exists regardless of port. Also, I typically set the sample rate to about 20 MHz. All works great until CPU resources are diverted for auto backup (cannot shut off, regardless of schedule setting), Cortana, spyware cleaner and others. These programs are UN-predictable, they can activate on their own; and severely interfere with SDR performance. Sometimes it works great, sometimes its a disaster. This is not robust behavior; its a problem mainly with Windows 10. There is a simple solution; an on off switch to disable these programs from running. Do you think there is a chance getting Microsoft, Acronis, Kaspersky and others to corporate? I only mention the problem as a caution and do not want to hijack the thread.
Rob

 

[Jim S.]

Oh, 20 MHz... I've never had an SDR with more than 2.4MHz bandwidth, so that could be a factor My Windows 7 system does have Windows Indexing and whatnot shut off as a legacy of my pre-SSD days, and auto-defragmenting shut off post-SSD. I do have my antivirus set to do scheduled scans, but I don't believe I've ever been using the SDRs when it's kicked off.

 

[N6BY]

Oh, 20 MHz... I've never had an SDR with more than 2.4MHz bandwidth, so that could be a factor ....

A 20 MHz bandwidth challenges the best of systems.

For every I/Q sample coming in, the program has to mix it with a 'difference frequency' to bring it down to baseband. When sufficient samples are collected it does an FFT. Then it has to run through multiple stages of filtering/decimation to bring the bandwidth down to approx. audio bandwidth. Once its down to near audio bandwidth it is demodulated, which is very fast since there is a lot less data to deal with.

While first getting my program up and running it was unable to process more than 2 MHz bandwidth. I had to find several ways to optimize the filters, including the use of the Intel SIMD instructions and lower precision filters. Now the program can do 8MHz bandwidth with about a 10% load on an i7 CPU (Windows 7). I have not yet tried Windows 10.

My son (who recently graduated with a computer science degree) has suggested 'OpenCL' which uses the graphics card to accelerate parallel processing. I think it could speed things up by an order of magnitude.

... The program is coming along OK. I finally got LSB and USB modes working, and I am done with the frequency control, the signal graph window and the FFT display. The main thing left is to switch from vender specific SDR API calls to the standard ExtIO API.

 

[KE4EST]

My son (who recently graduated with a computer science degree) has suggested 'OpenCL'

 

[N6BY]

... The main thing left is to switch from vender specific SDR API calls to the standard ExtIO API.

Finally got ExtIO working for 3 different SDR devices - SDRPlay, AirSpy, and RTL-SDR. It wasn't easy, and at one point I had considered giving up with ExtIO. It's not well documented and some of the ExtIO modules available for the RTL-SDR are buggy, or deviate from the specification. Of the three RTL-SDR ExtIO DLLs, only one of them seems to work. But the SDRPlay and AirSpy ExtIOs work well.

It's really nice having ExtIO because I really don't have to do anything for the device dependent features and available sample rates -- saves a lot of work for me.

On my 'to do' list: Add a signal strength indicator, squelch control, volume control, and fix some bugs.

The first release will just have enough functionality to be useful -- have to cover the basics before anything fancy.

 

[KE4EST]

Glad to hear you are that kind of programmer. I hate when a smart phone is great on say loading facebook, but sucks as a phone!...for sure basics first and make sure they work good, before fancy stuff.
Looking forward to seeing this. Got any early screen shots? or are you just going to wait for the first public beta?

 

[N6BY]

... Got any early screen shots? or are you just going to wait for the first public beta?

I have attached a screen shot of what I have now. Compared to the previous one I posted -- the signal graph is labeled, there is a frequency digit control, some slider controls for adjusting the range of the signal graph, and a signal level display.

Almost everything on the left side of the screen is a work in progress and very likely to change before the first release.

Today I got the volume control working and started on the signal bar.

The screen shot below was reduced in size and the lines in the signal graph seem to have been lost.

 

[KE4EST]

Another future "fancy" feature: Ability to move the control panel to the other side, top, or bottom.

 

[N6BY]

...
If you're doing swept spectrum (i.e. a much greater range of frequencies than the 2 MHz to 10 MHz 'native' of the SDR devices), then satellite recognition would be useful. There is an implementation of this in an application created by a European developer using transponder definition files that are freely available. I have used it successfully for pointing a C-band dish. That implementation is for an SDR device that utilizes the ADF 4351 chip, but it would be good to have it available for RTL-SDR, AirSpy and SDRPlay as well. (The swept range would need to be most of 950 MHz to 2150 MHz.)....

Today, rtl-sdr.com posted an interesting new development with the HackRF: http://www.rtl-sdr.com/scanning-spectrum-8ghz-per-second-new-hackrf-update/ It can now scan 8 GHz per second with a new firmware update. That's a lot of spectrum in one second!

The article also mentions that the Airspy can do 1 GHz per second -- much more than adequate for quickly sweeping 950 to 2150 MHz.

... Meanwhile, with my current project I have FM squelch working and am almost done with the signal strength indicator. And last night I got the program running well with Windows 10 Had to make some changes to work with Windows 10 audio.

I expect to release a stable beta of the program with just basic functionality in a week or two. After Feb 28th I will only work on it part time -- I need to get back to my real job. Also that's when my wife begins 4 months of strong chemotherapy, followed by 8 months of radiation and minimal chemotherapy.

 

[Titanium]

Interesting link!

Will be sending you and your wife positive thoughts and remembering her in prayers for successful treatment. My wife completed her chemo treatments about this time last year and celebrating another 6 month anniversary of clear tests.

 

[N6BY]

Back here after a long break from SDR (was doing weather satellite programming for much of 2018). And 2017 wasn't easy but my wife got through the chemotherapy OK. Then she had peripheral nerve damage as an after effect of the chemotherapy. But she is well now and clear of breast cancer.

Apparently SDRs don't like sitting unused for over a year. My SDRPlay RSP1A is now giving me strange error messages, like "device ID out of range" and if I manage to get it past that it works for a while and then reports "ADC Overflow" in the ExtIO dialog. So I tried updating to the latest software on the SDRPlay website and it didn't seem to make any difference.

I wanted to resume work on DR Processor. I'll try again tomorrow with my Airspy.