SMArt vs SDRplay vs FCD pro+

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pe1etr
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Joined: 07 Oct 2014 00:40
Location: Blackpool UK

SMArt vs SDRplay vs FCD pro+

Post by pe1etr » 23 Dec 2016 10:09

Comparsion SMArt vs popular brands sdrplay fcd pro+

Nooelec SMArt rtl sdr (Premium device in aluminium box with additional internal shielding) versus SDRlay and Funcube dongle pro+. FM sensitivity and selectivity.

https://youtu.be/1zZjksugudQ

Peter Blackpool

daveB
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Joined: 07 Oct 2014 16:49

Re: SMArt vs SDRplay vs FCD pro+

Post by daveB » 23 Dec 2016 12:08

Interesting - but surely selectivity is 100% down to the SDR software - not the hardware e.g. SDR# build 1488 has a much sharper drop off than build 1430 - and makes a difference.

Also any device using an 8 bit ADC is going to be more prone to overload than a 12bit (SDRPlay/AirSpy) or 16 bit (FCPro) ADC. So anything with an RTL2832U chip is no good for weak signal work in the south-east unless I notch out the strongest station - and/or have the aerial pointed away. I do however find the RTL based dongles really useful for 24/7 SpE monitoring during the season. SDR# with FMSuite and RDSSpy works a treat.
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

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pe1etr
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Location: Blackpool UK

Re: SMArt vs SDRplay vs FCD pro+

Post by pe1etr » 23 Dec 2016 15:06

Hello Dave thanks for watching my video.
Maybe it wasn't clear to you but the SMArt RTL dongle had the same gain setting for reception of the weak station on 92.1, and of my very strongest station on 96.5 and the weaker station 200 kHz below it (Capital Colwyn).
I just did a similar experiment with my two worst RTL dongles (the white ones in my SMArt Unboxing video)
In each case I whacked the gain up so that I could hear 92.1 Wirral Radio. I then re-tuned to 96.5 Radio Wave (my strongest station) and tried to hear the stations 200 kHz away at either side. No matter what the selected IF bandwidth in the software was I couldn't hear anything beneath the Radio Wave splatter.

It would be nice if you made a video of your RTL dongle versus Airspy Mini and SDRplay instead of just saying I am wrong.
Regards
Peter Blackpool

daveB
Posts: 991
Joined: 07 Oct 2014 16:49

Re: SMArt vs SDRplay vs FCD pro+

Post by daveB » 24 Dec 2016 13:46

Hi Peter,
Apologies if you think I said you were wrong - I've not said you're wrong as your video doesn't present any conclusions - you haven't actually said which device, if any, is better/worse. Even with headphones on I wouldn't like to say which is better. But if I understand your added comment about testing the cheap RTL dongles and not being able to hear stations 200 kHz away from Wave - that adds a new parameter.

Your comment that the cheap RTL dongles wouldn't resolve the signal on 96.3 would appear to validate my observation that in a strong signal area they are no good for weak signal work. I have to be very carefuI when setting the gain parameters of the dongle to maximise sensitivity whilst avoiding overload. Whilst I find they can't be used for weak tropo work they are very useful for when there is a tropo lift and there are loads of stations at RDS level.

I missed your unboxing video - but are the cheap white ones using the R820T2 tuner or another tuner chip? (I shall go find it)

Actually what would make a very informative video - is comparing the cheap dongle performance to the SMart dongle

EDIT: Just found (17:45) your video comparing some dongles - hiding down the list - after I sorted on "Receivers"

Just for info the settings that I've found to work well for my dongles, with R820T2 tuner - using the RTL-SDR (R820T) driver are LNA 10, Mixer 3, VGA 4 (that is ticks from the left). I'm also using build 1430. At some point I will see if I can compare the performance of later SDR# builds as work to improve the Airspy performance around the R820T2 chip may also benefit RTL dongles with the 820T2 chip.

Another observation - I wonder if you have noticed the same? We are told that the dynamic range of the RTL2832 chip is 50 dB as it is 8 bit. How come I am getting 55-60 dB SNR on stronger stations with no indication of overload or apparent spurious signals? See the screen shot. Sample rate was 1.92 MHz with no decimation. Music tended to be around 50 - 55 dB this was speech. I've chosen 1.92 MHz sample rate as the one least likely to show up spurious signals from aliasing. [to make it clear what is being shown is RF SNR - not AF].

https://app.box.com/s/un054wxc00nsow49q624wnq8u1qj8rbz

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

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