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Author Topic: SDR software  (Read 7537 times)
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W3GMS
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« on: August 22, 2019, 02:04:22 PM »

I meant to post this under the technical section!  Sorry about that....

A good friend has started to evaluate several different SDR based receivers.  The latest one being looked at is the Airspy Discovery.  That RXis being benchmarked against the RSP1A.  Both manufactures recommend various SDR programs.  My question is, how much of the SDR baseline performance is tied into the particular software package used?  

I am very new to this SDR stuff, but am getting hooked on the technology based on some of the SDR sites online.  

Here is one of the SDR's that is being evaluated: 

https://airspy.com/airspy-hf-discovery

Thanks!

Joe-W3GMS
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« Reply #1 on: August 22, 2019, 02:24:22 PM »

Performance depends largely on the type of A to D converter used.   Sixteen bits is going to have a higher dynamic range than cheap 8-bit dongles, but the dongles hold their own pretty well just the same.  A bandpass filter in the front end may make a difference in some environments. The mainline software is pretty much the same in performance and differs mostly in features and whiz-bangs from one to the next.  And some hardware will only work with some software, but most everything has at least a couple to choose from.
The good news is that, with the exception of the later FlexRadio editions, it's mostly all free and downloadable, so you can get what you need (want), put it on the same PC (not a lot of software is Mac friendly) and try it all with a few mouse clicks.  It's a pretty cool time for Amateur Radio when you can essentially get a new radio for free in a few minutes or less.
73 de Norm W1ITT
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« Reply #2 on: August 22, 2019, 02:40:38 PM »

I've been following SDR's for work and personal interest for about 18 years.

The software is going to be less important to performance than the 1. Bit size of the digitizer (larger is better) 2. Architecture of the receiver 2.a.  Pre-digitizer methods, preamps, filtering.

1.  Digitizer chips are a key factor in the cost of any SDR.  Larger bit size is better as is speed.  Better performance rapidly increases in cost.  

2.  Architecture:  Is the signal largely processed by a dedicated radio-side chip like an FPGA or Video processor which will be faster (and a key cost factor) or is processing sloughed off on an external computer (common in early SDR designs and inexpensive sets).

3.  How does the signal get to the digitizer?   Direct Conversion is the ideal (holy grail) of SDR's since it eliminates devices which add distortion to the signal. However DC is limited by present technology level, primarily overload of the digitizer with resulting distortion, as well as digitizer chip cost.

-Bandpass/Hi/Lopass filtering of the raw RF is important.  Type and quality?

-Preamplification of signal?  Method, quality specs?

-Digitization methods:
A.  Local Oscillator with Mixer converts to from RF to IF input to digitizer.  Typical heterodyne technology with typical distortion, spurs, IF products.  Quality?
B.  Quadrature Detection: Splits signal wave into four sections feeds each individually to digitizers.  Better.

These are things to consider.  The technology is ever improving, so the best you can do is make a choice and jump in, knowing better radios are on the way.  bill
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« Reply #3 on: August 22, 2019, 04:18:24 PM »

A good friend has started to evaluate several different SDR based receivers.  The latest one being looked at is the Airspy Discovery.  That RXis being benchmarked against the RSP1A.  Both manufactures recommend various SDR programs.  My question is, how much of the SDR baseline performance is tied into the particular software package used? 

I am very new to this SDR stuff, but am getting hooked on the technology based on some of the SDR sites online. 

Thanks!

Joe-W3GMS
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« Reply #4 on: August 22, 2019, 08:12:15 PM »

I don't know a lot about the subject but I believe the software has an effect on performance.

I've noticed an issue with sdr console v3 with my sdrplay and a cheap dongle that I used in the past. It seems that the receiver gets noisier the longer it's been running. I never had an issue with sdr console version 2.

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w4bfs
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« Reply #5 on: August 23, 2019, 10:17:22 AM »

anything out there for Apple Mac
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« Reply #6 on: August 23, 2019, 01:13:15 PM »

The performance is definitely a blend of both hardware and software performance Joe. Wonderful hardware with lousy software will disappoint the user and lousy hardware with wonderful software will do the same. It's the most fun for me when my SDR hardware can run multiple software packages, which the RSP and ANAN platforms do very nicely. The implementation of the DSP by the software programmers and the algorithms embedded in the RX chain are the big factors that affect the ADC and DAC conversions so he may find some big differences in the performance of the Airspy depending on what software is used. Should be interesting to see what he comes up with.

73,

Rob
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« Reply #7 on: August 23, 2019, 02:18:45 PM »

The Discovery is looking to be my next SDR purchase, when it is available. I missed the initial build run opportunity, but they are beginning to be delivered. Hardware wise it has better dynamic range than the RSP1A but you won't be able to look at 1o Mhz of spectrum at once with it. I am ok with that. I agree with Rob on the DSP stuff. And that may be a user preference situation. A good thing would be to watch whats going on in the user forums for Airspy and SDR console on groups.io. There are some very smart people in those. That is what I am doing.
Larry
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« Reply #8 on: August 25, 2019, 07:48:51 AM »

I am running a Hermes Lite.

www.hermeslite.com

I mainly use PowerSDR. Hermes Lite also has a dedicated application called Spark. Quisk also supports the board.

John
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« Reply #9 on: August 25, 2019, 09:27:30 AM »

On the hardware side, keep an eye out for the TAPR TangerineSDR project from TangerineSDR.org.  It's probably at least a year out yet, and the project leans toward a global network of space science monitoring the real time changes in the Earth's magnetic field.  But the package will include a one- or two- receiver RF card with a transmitter, sitting on a data engine, sitting on a RaspberryPi4 (at this point).  And the project goal is to bring the whole hardware stack in for under $500..  I suspect transmitter output will be in the milliwatts, but a linear amplifier can cure that.  I think it will run HPSDR software, but that can change over time.
It was originally a TAPR project that developed what is now the HPSDR series which led to Anan.  There are some very capable people working on this project.  It's a good time to be a Radio Amateur.
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W3GMS
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« Reply #10 on: August 25, 2019, 10:45:38 AM »

The performance is definitely a blend of both hardware and software performance Joe. Wonderful hardware with lousy software will disappoint the user and lousy hardware with wonderful software will do the same. It's the most fun for me when my SDR hardware can run multiple software packages, which the RSP and ANAN platforms do very nicely. The implementation of the DSP by the software programmers and the algorithms embedded in the RX chain are the big factors that affect the ADC and DAC conversions so he may find some big differences in the performance of the Airspy depending on what software is used. Should be interesting to see what he comes up with.

73,

Rob

Thanks very much Rob.  This is my first dive into the SDR world, so it should be fun!

73,
Joe-W3GMS
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« Reply #11 on: August 28, 2019, 11:30:06 PM »

There are some performance variations across software packages. But the harware must be up to the task before software can do much. Also, the biggest variations in across software are the user interaction. Much of this is up to the taste and use-case(s) of the user. What I've found with the software I've messed with is that each has some attributes that are superior to the others. But NONE of them do everything I want. So it goes.

For reference I have the SDR Play RSP-1A. I've used SDR Uno, SDR Console v2 and V3 and HDSDR software with the RSP hardware.



A good friend has started to evaluate several different SDR based receivers.  The latest one being looked at is the Airspy Discovery.  That RXis being benchmarked against the RSP1A.  Both manufactures recommend various SDR programs.  My question is, how much of the SDR baseline performance is tied into the particular software package used? 

I am very new to this SDR stuff, but am getting hooked on the technology based on some of the SDR sites online. 

Thanks!

Joe-W3GMS
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« Reply #12 on: August 28, 2019, 11:47:37 PM »

I am far from an expert on this subject.  But I have one experience that I wish to share.  During the last AM Rally event, I attempted to work several stations on 75M with my PP 250-TH rig.  Listening with a 75A3 or 51J4, the noise level made copy impossible.  I was using a 126 foot doublet at about 40 feet elevation, with 600 ohm ladder line (not the crappy brown stuff) to an ugly link coupled tuner. 

So I set up the RSP-2 with SDR-play.  All the signals came out of the mud, solid copy, even though the local noise floor on the old Collins receivers exceeded the signal strength of the AM stations I wished to copy.  I worked K4KYV until late early morning, no problem with the SDR.  Not sure at this point if there is any reason to keep using the Collins receivers, unless I can identify and resolve the noise floor issues.  The SDR saved the day for that event.
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Rick / W8KHK  ex WB2HKX, WB4GNR
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« Reply #13 on: August 29, 2019, 01:54:08 PM »

.  I worked K4KYV until late early morning, no problem with the SDR.  Not sure at this point if there is any reason to keep using the Collins receivers,

Maybe because they're not just one more computer peripheral …???    Cheesy
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« Reply #14 on: August 30, 2019, 08:45:47 AM »

Howdy Joe,

There are plenty of hardware choices out there but I won't delve into them as that's not your primary concern. The Airspy and SDRplay models are generally in the same category regarding performance, etc. There are a number of more high performance devices out there, but (a) they are generally expensive and (b) not always supported by the vmore popular software packages.

With that out of the way, below is what I found:

(a) HDSDR - nice software package that will generally support any SDR device so long as an EXIO driver for the device is available. The software is free but is updated infrequently. On the whole it works quite well.

(b) SDR-Radio Console - Developed by Simon Brown (the father of Ham Radio Deluxe). Very nice package albeit its complexity  initially can appear overwhelming. Supports a variety of SDR receivers.  Frequent performance and update enhancements. Very active user group.  Simon is very responsive to questions and practical suggestions. Free.

(d) SDRuno - This is SDRplay's proprietary software and only works with their devices. Initial releases were quirky and unstable, however, the current version is pretty good. Free

(e) SDR# - I've used this software years ago and found it to be marginal. Admittedly it may be much better but I haven't tried it in a dog's age. Believe it is the proprietary software for Airspy but it may work with some of the cheaper SDR RTL dongles. Free

(f) Linrad - Tried this a couple of times. Not sure if it's actively supported. For my purposes (panadaptor applications) it didn't offer a lot of value. Free

(g) CubicSDR - I attempted on multiple occasions to get this working. Given I'm not the sharpest tool in the shed I eventually gave up. Free


Below is a link to a variety of applications. You may find this useful, however, I suspect most of these are works in process.  For evaluating the Airspy and SDRplay I would go with SDR-Radio Console v3.  A lot of ops use it for that reason.

https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/


Harry WE1X
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« Reply #15 on: August 30, 2019, 02:05:20 PM »

Rather than respond to each persons information, I will just say thanks for all the opinions on this subject that all of you took time to compose.  Its all great information that is helping me build my knowledge base on the subject.  The SDR site up in New Milford PA kind of got me hooked on the SDR technology.  The best feature for me, is the asymmetrical filter capabilities while listening on AM.  In the past, the only way I have been able to do that, is put the RX in the SSB position while copying AM and either going to LSB or USB depending on were the QRM is.  With the SDR technology, its a snap just moving the filter skirt in to get rig of QRM nearby.  The "band scope" is also a very nice feature as well. 

Rick, it was interesting to hear your comparison report between your SDR and the 75A3. 

I also have one of the 1M RX loops that comes out of England and want to play around with that, while using AirSpy Discovery.     

Again, thanks for all the comments and help.

Joe-W3GMS         
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« Reply #16 on: August 30, 2019, 02:07:07 PM »

Thanks for the list Harry. There is a way to use SDRUNO with the RTL-SDR. I have tried it and it works, but you don't get the functionality that exists with RSP sdrs.
 https://www.rtl-sdr.com/using-the-sdruno-extio-edition-with-an-rtl-sdr-and-other-sdrs/  

SDR# is updated once in a while and there are quite a few plugins to enhance it now. And it works with other receivers, even the RTL-SDR entry level dongle. The interface still sucks, but their SPYSERVER works well with low internet bandwith connections. It Does Not work with RSP unfortunately. If it did I would use it with SPYSERVER, which by the way works on Linux, even on my Raspberry Pi. SDRconsole has a server also, but has a different compression scheme and does not work well with low bandwith connections. Too bad, it is a very nice combination with SDRConsole. And you can have password protected access to the server. Now the downfalls are only with slow WAN internet connection like mine (upspeed .7). Locally on a home network its great. It allows me to sit out on the deck and use the RSP to my hearts content with a laptop.
Oh and I could not get Cubicsdr to work either, don't feel bad.
73.....Larry
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