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Author Topic: SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery  (Read 1912 times)

Offline ChrisSmolinski

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SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery
« on: August 21, 2019, 1949 UTC »
Another SDR DGPS shootout, this time the SDRplay RSPduo vs AirSpyHF+ Discovery. Again, the 950 ft Log antenna through a low pass filter and splitter, so each SDR was running at the same time. I ran two instances of SDR# to keep things as fair as possible. The test was run mid afternoon, so not much DX expected. I used the Hi-Z port on the RSPduo, fed with one of my Cyclops transformers in reverse, which seems to produce higher signal levels vs the COAX input.

The DGPS band is 285-325 kHz, so these results may be applicable to NDB enthusiasts as well.

The 950 ft LoG (Loop on Ground) antenna is fed via one of my Cyclops antenna transformers and then coax to the shack
https://www.blackcatsystems.com/rf-products/cyclops_rf_ham_shortwave_radio_matching_transformer.html

All decoding done with Amalgamated DGPS of course, the premier DGPS decoding software. https://www.blackcatsystems.com/software/dgps_decoding_software_sdr.html

I think it was pretty much a tie?

RSPduo:
Count    ID   ref1 ref2 kHz   Baud City                           Country              Lat      Lon      km     Deg
100      799  044  045  290.0 200  Penobscot, ME                  United States        44.453   -68.776  858    49 
949      778  192  193  292.0 100  Kensington, SC                 United States        33.491   -79.349  723    198
207      929  312  313  296.0 200  St Jean Richelieu, QC          Canada               45.324   -73.317  693    24 
70       838  116  117  319.0 200  Detroit, MI                    United States        42.306   -83.103  590    301
4178     772  198  199  306.0 200  Acushnet, MA                   United States        41.749   -70.889  561    64 
3896     844  094  095  324.0 200  Hudson Falls, NY               United States        43.272   -73.542  489    35 
1682     839  118  119  322.0 100  Youngstown, NY                 United States        43.239   -78.972  427    338
3078     803  006  007  293.0 100  Moriches, NY                   United States        40.794   -72.756  378    70 
2816     806  012  013  289.0 100  Driver, VA                     United States        36.963   -76.562  307    173
4824     804  008  009  286.0 200  Sandy Hook, NJ                 United States        40.475   -74.02   266    70 



Discovery:
Count    ID   ref1 ref2 kHz   Baud City                           Country              Lat      Lon      km     Deg
109      799  044  045  290.0 200  Penobscot, ME                  United States        44.453   -68.776  858    49 
1000     778  192  193  292.0 100  Kensington, SC                 United States        33.491   -79.349  723    198
208      929  312  313  296.0 200  St Jean Richelieu, QC          Canada               45.324   -73.317  693    24 
65       838  116  117  319.0 200  Detroit, MI                    United States        42.306   -83.103  590    301
4263     772  198  199  306.0 200  Acushnet, MA                   United States        41.749   -70.889  561    64 
4027     844  094  095  324.0 200  Hudson Falls, NY               United States        43.272   -73.542  489    35 
1692     839  118  119  322.0 100  Youngstown, NY                 United States        43.239   -78.972  427    338
3076     803  006  007  293.0 100  Moriches, NY                   United States        40.794   -72.756  378    70 
2829     806  012  013  289.0 100  Driver, VA                     United States        36.963   -76.562  307    173
4829     804  008  009  286.0 200  Sandy Hook, NJ                 United States        40.475   -74.02   266    70 
« Last Edit: August 21, 2019, 2004 UTC by ChrisSmolinski »
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Josh

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Re: SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery
« Reply #1 on: August 21, 2019, 2126 UTC »
Did you have the rsp set to use decimation that would cover the same spectrum as the discovery? Also what IF mode was employed with the rsp?




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Offline ChrisSmolinski

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Re: SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery
« Reply #2 on: August 21, 2019, 2136 UTC »
Did you have the rsp set to use decimation that would cover the same spectrum as the discovery? Also what IF mode was employed with the rsp?

Yes, I used the low IF mode along with appropriate decimation to keep the sample rates as close to the same as possible between SDRs.

Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline MDK2

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Re: SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery
« Reply #3 on: September 20, 2019, 0156 UTC »
Have you run a test on HF? Say, record the pirate band with both?
Denver, CO.
SDRPlay RSP2pro, Icom IC-7100, Grundig Satellit 750, Realistic DX-300, Tecsun PL-600.
W6LVP active loop, G5RV, 20m dipole, homebrewed mag loops.
eQSLs appreciated wickerjennie at gmail

Offline ChrisSmolinski

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Re: SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery
« Reply #4 on: October 22, 2019, 1649 UTC »
I may have done some comparisons a while back (maybe even some audio recordings or a video?). I find them tricky, since unlike the DGPS decoding the results are somewhat arbitrary. It rarely is a case of "I can hear the station on SDR A but not B" but instead "I think it sorta sounds better on A but not really sure oh now it sounds better on B".

My general experiences are:

The netSDR is a tank. It does not overload. It's a direct sampling 16 bit SDR with bandpass filters. You do not see images. If the signal is there it is real. If it can be picked up, you will pick it up. It is what I use for my nightly 43m recordings that hear everything. It works. If you ever see one of these for sale cheap, buy it. You will not be disappointed.

The SDR-14 is kinda old now, it's OK, I would not buy one unless you get an awesome deal.

The SDRplay and AirspyHF+ models all have their pluses and minuses. They're a good deal for the money, about an order of magnitude less than the netSDR. The netSDR is not 10x better, but it is somewhat "better" in that you won't get fooled by overloading or other effects causing images. Also as these receivers all use a form of AGC the signals sometimes bounce up and down which is annoying when you are used to it not happening.  You can mitigate it with careful adjustment of settings.  But you do need to be aware of the fact that you can sometimes fool yourself. Any of these is your entry point for a low cost SDR.

The AFE822x is IMHO an under-appreciated SDR. You get a lot for the money. It's got two inputs and you can do phasing with it with SdrDx. It's direct sampling, so no wonky AGC action. It has a built in adjustable LNA, which I like because I can use it with my passive crossed parallel loop or another antenna with a lowish signal level and max out the A/D bits. Only 12 bits, but it seems to be enough.  It is my main receiver for 48 meter Europirates,  and does well on MW also.

The less said about the RTL Dongle the better. Again in fairness on VHF/UHF it is great for the price, and works pretty well. But not on HF. It's garbage on HF, I will be that blunt. I've noticed then when I run into someone online badmouthing SDRs in general, it's because their only experience is with an RTL Dongle.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline MDK2

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Re: SDR DGPS Shootout: SDRplay RSPduo vs AirSpyHF+ Discovery
« Reply #5 on: October 25, 2019, 1541 UTC »
Thanks for the reply. I'm sort of interested in what SDRplay will have coming out (I feel pretty certain that they're going to unveil a new unit in time for the holidaze) but in my high RF environment it might be worth my while to just save up and get something in the NetSDR/Perseus class.
Denver, CO.
SDRPlay RSP2pro, Icom IC-7100, Grundig Satellit 750, Realistic DX-300, Tecsun PL-600.
W6LVP active loop, G5RV, 20m dipole, homebrewed mag loops.
eQSLs appreciated wickerjennie at gmail