New RSP1A owner disappointed with spurious responses

[KevinC]

I have an idea. How about we cut the personal crap? One warning and no need to reply to this.

 

[RFI-EMI-GUY]

And most people will not read a post that long when the op joined today

I seldom check when someone joined before reading an article.

 

[DBMandrake]

I had never tried my rsp1a on sdr++ , sdrconsole, etc before, just tried, while I didn't experience the issues you have shown, the performance wasn't the same as using it with SDRuno. Have you tried sdruno? The rsp1a coupled with sdruno is my preference for HF/shortwave/medium wave, rtl's & airspy for everything else

Thanks for the constructive reply! Yes I've tried SDRUno - I tried it before I bought the RSP1A in fact via the Ext_IO support for the RTL-SDR dongles to get an idea of what it was like to use.

Not my cup of tea I'm afraid, it's heavily geared around a skeuomorphic representation of a traditional ham radio receiver - been there, done that with the real thing! So I never intended to use SDRUno as the primary software with the device, also partly because I'm more interested in data decoding than ham style armchair listening to people talking. (Again, been there done that)

Yes it does work a bit better with the hardware than some of the other software as to be expected as it's more optimised and matched to the features of the hardware - SDR Console in particular seems to have limited support for the RSP1A, more limited than I'd hoped - for example, it doesn't let you adjust the IF bandpass filter width separate from the sampling rate as you can in in SDRUno or SDR++. It also doesn't seem to be able to correct the DC peak in Zero IF mode. (The settings dialogue claims it can but the website says it can't! In any case, it doesn't)

If you're trying to reproduce what my videos show you'd need to be in the right modes and also have the antenna disconnected so that real signals don't swamp the spurious responses. Sample rate should be set to 3Mhz or higher so it's in Zero IF mode and IF gain not set too high so that noise from an overdriven IF mixer doesn't drown them out.

You'd also need to be on certain frequency ranges as there are parts of the spectrum where it does happen and parts where it doesn't, as it doesn't do direct down conversion on all frequency ranges. According to that SDRPlay tech support post (in the post I linked to in my original post) it does direct down conversion from 60-250Mhz and 420Mhz to 2Ghz.

So those are the frequencies you're most likely to see spurious responses. At other frequencies, 0 - 60Mhz and 250 - 420 Mhz they do an additional intermediate mixing step first so results may be different. 120Mhz would be a good place to try a test though because that's where I see some of the worst results.

To give people an idea what sort of software I use with the RTL-SDR and for what purpose:

SDR# - general browsing of analogue signals, it's probably my favourite (on the RTL-SDR) quick go to receiver software if I want to tune in somewhere and/or look at a visual spectrum . It doesn't work with the RSP1A of course, and although there are many plugins for decoding various data systems I haven't really used it for that yet as there are other alternatives.

SDR Console - similar to above - general browsing and listening to analogue signals including AM aircraft and FM ham bands - it's more ham radio operator focused than SDR# but the multiple VFO feature is implemented very well, reception quality is good and it has probably the widest hardware support of any software I've tried so far - I started to learn and use it more knowing that it would not only work on my RTL-SDR card but also on Airspy and SDRPlay devices, so no matter which of the two devices I chose I'd be covered. Unfortunately support for the RSP1A in terms of hardware features like independent adjustment of the IF bandwidth, or DC spike cancellation is not as good as I had hoped.

SDRAngel - while this can also be used for AM/FM etc, it's a bit cumbersome to use as an analogue radio receiver and just tune around casually it's more geared around decoders such as packet radio, pagers, slow scan tv, ads-b etc. For decoding digital signals that it supports SDRAngel is GREAT, at the moment I mainly use it for pager decoding. (It does tend to crash a bit when loading preset configurations though)

SDR++ I don't actually use this normally as it duplicates the functionality of most of the other programs I use, but it is very fast (especially the FFT display and general navigation of the program and tuning) and offers much greater control over the RSP1A hardware than SDR Console or many other applications and gives full control of the IF bandwidth independently of sample rate, offers multiple different Low IF modes with different IF frequencies (SDR Console only offers one) etc... so it was a really good 3rd party program to do this testing on, and to be honest after using it a bit it is growing on me so I might check it out a bit more. It looks like it was written originally as an open source Linux clone of SDR# (so basically duplicates functionality of SDR#) but I'm using the Windows version.

QIRX - This one is a bit of an oddball with a strange interface but it has THE BEST DAB/DAB+ decoder that I've found so far, it provides tons of diagnostic data about the DAB streams down to bit error rates, stream ID's, auto bitrates etc and even shows the locations of the transmitters on a map. Reception is solid even down as low as 12dB SNR. It also does ADS-B receiving and has a basic flight radar style feature built in.

welle.io - Another DAB receiver - I stopped using it though as even with a good signal I keep getting brief interruption and loss of sync on the RTL-SDR while QIRX gives perfect reception. Not sure why.

Dump1090/RTL1090 - ADS-B receivers which I use with Flight Radar. Both seem to work but I think Dump1090 does better decoding.

HDSR and Cubic SDR - I've looked at both of these but they don't offer anything compelling that one of the above programs doesn't offer so while I have them installed for testing I don't actually use them in any regular way.

There is plenty of other specialist data decoding stuff that I'm yet to look at like trunk decoders etc.

 

[DBMandrake]

I seldom check when someone joined before reading an article.

I thought it was an odd thing to say too. I use many forums across many different disciplines and don't even look at the post count of a poster before reading. If a subject pulls me in or a skim of the post looks interesting I read it and judge it on it's own merits whether someone has one post to their name or 1000. I don't care if someone is a regular or not.

Forum "regulars" (of which I am one of on some other forums) have to remember that a lot of people are "lurkers" that often read some forums without ever signing up because they don't have anything to say, until the day that they do have something to say, then they're a "newbie" with a post count of 1 waiting for moderator approvals to their posts even if they've been aware of and read posts/articles from that forum for years but just never felt a need to say something before as the information they were looking for could be found by browsing existing threads.

I've read this forum many times before (it comes up a lot in Google searches) as well as some other SDR related forums but it wasn't until I was seemingly having problems with this RSP1A and had to make a quick decision within a few days whether to return it that I felt I needed to reach out and get some feedback from others on these issues I was seeing.

I picked this forum over some of the others to make that first SDR related post on because the conversations seemed to go into a lot more technical detail that some of the others (which suits me perfectly) and I also liked the look of the other subject areas in the forum so it seemed like a good forum to sign up to. So I was a little dismayed to get attacked for my very first post to the forum and basically be called an idiot by someone who clearly has a difference of opinion.

As for long, detailed posts, I make no apologies there, that's just how I roll and if you look me up on any other forum you'll find the same thing there. Yes, I am a little obsessive about detail and precision, especially if I'm discussing a complex technical issue. (otherwise why would I record 4 youtube videos and link their to a forum post ? )

Anyone who doesn't like reading long, detailed posts or analysis like this please hit that thread unsubscribe button - don't torture yourself reading something that you're not interested in. I've never quite understood the need some people have to reply in a totally unconstructive way when it would be easier to just ignore the temptation and skip to the next thread.

 

[DBMandrake]

You need glasses

If you're referring to the word document link in post #3 then I either missed it somehow or you edited the link in later - I note that the post with the link says it was edited after initially being posted.

Either way, all I remember reading is the text in the post which in hindsight is a copy/paste from the document but at the time it wasn't clear that you were quoting part of a support document rather than just speaking for yourself, which is how it came across.

Regarding the architectural diagram in the document showing where the gain stages are - I've seen it before and it's relatively straight forward as receiver block diagrams go...

Aside from the preselection/notch filters at the front there is just the RF gain before the mixer and IF gain after the mixer - pretty basic stuff. It only takes a few seconds to adjust both of them to find the optimal for a given signal condition, that's never been a question. Some software also exposes the IF frequency offset (zero or some offset) and filter width - SDR++ can adjust all these manually for example which is why I was using it for some of my testing and so can SDRuno. (Although I just don't like SDRuno so I'd rather not use it or rely on it)

Ironically SDRPlay's openness with their architectural design and extensive performance data tables on their website is one thing that made me lean towards their device, whereas Airspy are a lot more secretive, don't give nearly as detailed specs, and basically just say "trust us, it's really good!" without going into too much detail beyond the headline spec figures.

I've actually had to dig up some of my info on the architecture of the Airspy and Airspy mini from old posts on this forum from "Prog" who is of course Youssef Touil, one of the developers of SDR# and the Airspy hardware to get a better idea of how the Airspy architecture is designed - information that isn't provided in any detail on their website but can be pieced together from many of his posts on here when the Airspy was originally being developed.

Please block me, I dont want any more OCD based rubbish. Others are querying youre results as well. You are trying to appear professional but youre at best an idiot, at worst a troll. Please seek help. My recommendation is a proper SDR from Flexradio, not cheap but you get what you pay for. Im done.

I see one person - someone quite polite and helpful who has tried to reproduce what I'm seeing and hasn't been able to so far but I've offered some suggestions of more things to try. If my unit has a fault I'd be happier than if it turns out to just be a consequence of the design, unfortunately I need to make a decision fairly quickly whether mine is faulty or just behaving within the limitations of the design.

I see a couple of other posts basically saying "hmm, that's weird", but no indication that they've tried to reproduce anything.

As I said in an earlier post, nobody is forcing you to read this thread, you clearly don't want to be in it. If it upsets you so much please unsubscribe and let those that are interested/curious/helpful continue the discussion. Thanks.

 

[vagrant]

Copper tape is inexpensive as well whether used internally, or on a case, or whatever. Even aluminum foil works. I had a friend hold some foil up against his microwave and voila! The WiFi signal stayed connected. Experimenting is fun until it becomes a hassle. Of course I do not expect my RSP2 to equal an Icom 8600.

Ferrite beads or inline RF chokes can help too near the receiver and definitely at the antenna feed point.

aftermarket aluminum cases were out of stock, so I used aluminum tape lol

 

[PDXh0b0]

Copper tape is inexpensive as well whether used internally, or on a case, or whatever. Even aluminum foil works. I had a friend hold some foil up against his microwave and voila! The WiFi signal stayed connected. Experimenting is fun until it becomes a hassle. Of course I do not expect my RSP2 to equal an Icom 8600.

Ferrite beads or inline RF chokes can help too near the receiver and definitely at the antenna feed point.

you said it , I am going to have an 8600 one day

 

[slicerwizard]

Are there any Airspy mini owners who can report on their performance in similar scenarios to the ones I presented in my Youtube videos (minus the HF testing) and can comment on how clean the noise floor is on these and how resistant they are to adjacent channel interference when used in the full 6Mhz mode ? Or who can do a direct comparison with the rtl-sdr blog v3 device I am using as my benchmark ?

I own an SDRPlay RSP2, Airspy Minis, rtl-sdr.com V3's, Nooelec NESDR SMArtee XTR's, FlightAware Pro Sticks, yadda yadda...

For severe RF environments, I use a Airspy Mini. It gets the job done without overloading and no DC spike. For other settings, I generally use a Pro Stick for its improved RF sensitivity.

The RSP2 doesn't strike me as a great design and I see the same DC spike issues. The big bulky plastic case is kinda weird.

Airspy Mini vs V3? The Mini is the clear winner, IMO.

Mini vs RSP2? I'd pick the Mini.

My use cases are mainly trunking systems with digital voice, 140 MHZ to 950 MHz, plus some ADSB.

Sorry, not going to fire them up and do a bunch of A/B testing tonight. Hope this is of some help.

 

[DBMandrake]

I own an SDRPlay RSP2, Airspy Minis, rtl-sdr.com V3's, Nooelec NESDR SMArtee XTR's, FlightAware Pro Sticks, yadda yadda...

For severe RF environments, I use a Airspy Mini. It gets the job done without overloading and no DC spike. For other settings, I generally use a Pro Stick for its improved RF sensitivity.

The RSP2 doesn't strike me as a great design and I see the same DC spike issues. The big bulky plastic case is kinda weird.

Airspy Mini vs V3? The Mini is the clear winner, IMO.

Mini vs RSP2? I'd pick the Mini.

My use cases are mainly trunking systems with digital voice, 140 MHZ to 950 MHz, plus some ADSB.

Thanks - great reply, and the sort of feedback I was hoping for when I started the thread.

Comparing these two devices first hand has made me think a bit more about what my priorities were when looking for in an upgrade from the rtl-sdr v3, and in order of importance they are:

1) 12 bit or better ADC to give better instantaneous dynamic range and therefore better handling of strong and weak signals within the passband, (avoiding overloading/distortion) particularly when trying to decode multiple signals at once.

The 8 bit ADC is the biggest limitation of the rtl-sdr devices in general IMO - the rtl-sdr v3 has surprisingly good sensitivity, seems to be very free of spurs with a pretty clean noise floor in the absence of signals, and works well when there is only one signal within the selected bandpass and nothing else too near by but there is a relatively small "sweet spot" for the gain adjustment between setting it too low losing SNR and setting it too high resulting in overloading and intermod etc... so a pretty limited usable dynamic range for a given gain setting.

And if you have strong and weak signals within a few Mhz, forget about receiving the weaker one with low distortion and good SNR.

In this regard both the RSP1A and Airspy mini should on paper completely out perform the rtl-sdr v3, and while I have a number of other criticisms of the RSP1A (heh) there is no doubt that the dynamic range is massively better to the point that I can adjust the gain over quite a wide range with both a weak and strong signal in the passband at once without any issues, and no overloading until the gain is nearly maximum, and have no trouble receiving the weaker signal, so decoding multiple signals of varying strength at once is a realistic proposition.

One example of this is decoding pagers in the 153Mhz band - I'm running a test today with SDR++ as the receiver and three copies of PDW as the decoder, with three VFO's tuned to three different pager signals at 153.025, 153.05 and 153.35.

With the RSP1A all three are decoded error free 100% of the time even when transmitting simultaneously, when I try the same with the rtl-sdr v3 they decode fine most of the time but some errors creep in even though everything is adjusted as well as it can be and the spectrum on SDR++ looks clean with no overloading. (However with only 8 bits it can look "clean" to the eye but still experience significant intermod distortion even without outright overloading, and that's the real issue here)

Due to the nature of the pager encoding you can still see a corrupted message with the good and bad parts of the message in different colour so it shows really well when you're only partially decoding a message correctly rather than throwing the whole message away which would cause you to be unaware that some messages were getting corrupted.

I would hope and assume that the Airspy mini is similarly capable in terms of dynamic range as the RSP1A and that's what you seem to be suggesting here. I have actually tried using the Airspy network via SDR# and connecting to a few Airspy Mini's in the UK and US and tuning around the Broadcast FM band to see how they cope with the dense collection of strong and weak wideband FM signals and I have to say they seem to cope well over a wide range of gain settings, so I came away reasonably impressed from that, however because you don't have all the same settings available via a remote connection, (like gain mode vs linearity etc) I can't fully test it remotely.

2) A bit more bandwidth than 2.4Mhz would be nice to be able to receive/decode more signals at once near each other - such as pagers, Trunked radio etc... I'm not sure what frequency groupings trunked radios use in the UK as I haven't got that far yet, so I don't know whether a control channel and audio channels would fit within the same 6Mhz bandwidth or not, but even if it doesn't I believe with the right software I could use the rtl sdr v3 to receive the control channel and let the Airspy tune the signal channels ? Having access to a wider spectrum makes it much faster to browse for new signals as well of course, so is a compelling reason for an upgrade.

I have to be honest that the 10Mhz bandwidth of the RSP1A is one factor that sealed the deal for me, but in hindsight that 10Mhz is not as useful as it could be as (a) you're always going to have that DC spike in the middle due to direct conversion which may or may not cause issues depending on your situation, and (b) at 10Mhz the sigma delta sampler is only working at the equivalent of 8 bit at that speed anyway, so while you might be able to see more spectrum when browsing, I've found the 10Mhz mode doesn't work very well actually receiving stuff and it shows the same hallmarks of easy overloading/distortion in the presence of multiple signals as the rtl-sdr does. I did also notice images starting to creep into the edge of the passbands in 10Mhz mode.

At 9Mhz it runs at 10bit, at 8Mhz 12bit and at 6Mhz 14 bit, according to the spec sheet anyway. And I actually found myself running it in 6Mhz mode most of the time and found 6Mhz to be plenty.

3) Having more than one adaptor is useful for decoding more than one thing at once that's widely separated, for example I'd like to be able to receive ADS-B at the same time as the AM air band speech - so I get that advantage no matter which adaptor I choose to buy as I'll be keeping and continuing to use the rtl-sdr v3 as well of course.

4) I liked the idea of having a device with better HF performance than the rtl-sdr v3's direct sampling mode - and on doing some more detailed testing on HF yesterday the RSP1A really does outperform it dramatically on HF, (as you would hope) albeit I found myself always using it in the Low IF mode with 1.5Mhz bandwidth to get the best out of it. Even without adjusting the IF filter the increased dynamic range makes it a lot more robust listening to weak signals with nearby interference, and I was able to receive signals that were drowned out on the rtl-sdr v3.

Having HF support is another reason I picked the RSP1A even though I probably won't use HF much, however I'm not sure that I want to make sacrifices in the areas of spurries etc to cover an HF band I'll seldom use.

In an ideal world I'd keep the RSP1A and use it to its strengths and buy the Airspy Mini as well, but that's a lot of money....

 

[KE5MC]

I have move up thru the different levels of SDR devices and have settled on the RSPdx and SDRuno. I have found as you have commented that SDRuno improves performance. Which I think is appropriate as you don't have to rely on a extio.dll for hardware and software to work together.

When SDRuno starts for the first time, yes a number of windows popup. That's the default and you have complete control over which windows are opened and where placed. You can setup a 'workspace' configuration to your liking and save it using a suggestive name convention. You can have a number of saved workspace. It does not have to be ham friendly, but there are certain windows required for operation. I used SDR# with its one window display and dropdown selections, so SDRuno took awhile to get comfortable with. No going back now.

SDR gives you access to settings which can really 'mess things up'. Much like audio engineers mastering a recording for vinyl or digital what is known in one format does not translate well to the other. I'm comparing superhet to SDR relative to vinyl or digital.

I've not watched the video or spent much time reading your posts in detail. That not good or bad, just that there is a lot of detail and I don't think I can add anything that will change you experience and mine has been very different. The one configuration on my setup I have notices that can greatly influence the waterfall is an AGC setting. I don't have my SDRuno up and running and it's not AGC on/off or threshold. Its something else, I don't recall.

Really! I wish you the best on your SDR adventure. Just remember it like the chemistry set you got for Christmas. It can take you places that does not have a good outcome. Play with the setting, see what happens, nothings going to break. Unlike the chemistry set and toxic fumes or blowing up the house.

73, Mike

 

[DBMandrake]

Hi Mike,

I have move up thru the different levels of SDR devices and have settled on the RSPdx and SDRuno. I have found as you have commented that SDRuno improves performance. Which I think is appropriate as you don't have to rely on a extio.dll for hardware and software to work together.

Just to clarify, none of the software I was testing with uses the Ext_IO method of interfacing with the RSP1A - they all have native support for the SDRPLay V3 API, which is the same API that SDRUno uses and the recommended API to use.

Really! I wish you the best on your SDR adventure. Just remember it like the chemistry set you got for Christmas. It can take you places that does not have a good outcome. Play with the setting, see what happens, nothings going to break. Unlike the chemistry set and toxic fumes or blowing up the house.

Unfortunately the problems were just too many so I sent it back yesterday and received a refund today. I couldn't get over the massive clock spikes every 24Mhz and the imaging that they cause.

For example here in 3Mhz Zero IF mode tuned into FM broadcast the 96Mhz clock spur is nearly as strong as a relatively strong FM broadcast station, and on either side of these two FM stations are images which change in frequency as you shift the sample window:



Here it is with the same settings and antenna disconnected:



Gain settings are relatively low in these two screenshots - RF gain 3 out of 9 and IF gain at -50dB which is one above minimum - which are about right for optimal SNR on strong broadcast stations without intermodulation.

Sliding the spectrum sideways shows up any aliasing or imaging as the images move backwards or at 2x the speed that you move the spectrum, as in this video where the images of the clock spur move at different rates:

Again, the Low IF modes are a lot cleaner than Zero IF, although out of band IF image suppression could be better....

By comparison here is my humble rtl-sdr v3 adaptor:

There are no real aliasing effects to speak of here to the same degree as the first video although you can see an IF image coming in from the right hand side showing that the out of band filtering could be better, but still not bad for a cheap adaptor.

The Airspy Mini arrived today and I've had a little bit of time to play around with it (although not on the same computer at the same location yet) and I like what I see so far.

It does have some quirks of its own - most of which I knew about beforehand, for example you can't use the bottom and top 0.6Mhz of spectrum, (so 4.8Mhz usable in 6Mhz mode) which SDR# normally hides from view, but other software like SDR++ will show, (there are a couple of carriers at the upper edge of the passband, presumably local oscillator) and there are some small clock spurs on a few frequencies, (albeit, much, much lower level than the RSP1A, about 30dB less) which are comparable to those I see on the rtl-sdr v3, so visible in a few places but not intrusive and only visible at relatively high gain settings instead of visible at all gain settings.

The noise floor is very clean with no birdies that I've noticed so far, very little in the way of spurs, and out of band filtering is excellent, it seems to have a relatively sharp IF filter so if you show the full span with software that lets you see it you can see an out of band signal wrap around slightly as you slide the spectrum then it drops very very quickly before the image would come back into the normal viewing range unlike both the RSP1A in Low IF mode and the rtl-sdr v3 where the image can travel all the way across the spectrum if you move the centre frequency far enough.

SDR# has a tickbox for "tracking filter" (which is a feature of the front end tuner chip, and separate to the IF filter which I believe is performed in DSP) which really does seem to help quite a bit if you have a strong signal just outside the sampled spectrum - what I don't know for sure is whether this tracking filter is enabled by default in other software such as SDR++ and SDR Console which don't expose this setting in the UI. I think it might be on by default but I need to do more side by side testing between programs to figure this out.

Anyway, I'll need a few days of use across a variety of scenarios to get a better handle on this device, and I'll update this thread in a few days with what I find - but my first impressions are already quite good. Unfortunately I can't do a direct 1 to 1 comparison between the two devices since the RSP1A has already gone back, but I do have my rtl-sdr v3 device as a common point of comparison with both devices at least, and the antenna, PC, software etc will all still be the same.

 

[KE5MC]

My opinion only... native support is best seen in SDRuno for their hardware. SDR# would be native for Airspy and again best support. I have not mixed hardware and software so I can't say how well it can work or not when mixed. I suspect authors not connected directly to hardware development are at the mercy of supplied information or reverse engineering. In years pass there has been some tension between various SDR development camps. Things I believe has settled down for the most part, but it's one reason I don't mix.

I did watch the next to last video. Not good and I would not be happy about that response either. With my RSPdx and SDRuno in the FM band my video would look nothing like yours. Different level hardware and matching software support here but does not necessary explain your results. IQ correction is on in your video and typical waterfall response to changing frequency is 'signals' moving backwards. DC voltage difference in I and Q result in spike in center and some software can compensate, but not usually 100%. If I and Q are reversed, I wonder how well it can compensate?

Good Luck!
Mike

 

[cistercian]

I have an RSPDX and have 2 programs that will run it. HDR console v3 and SDR uno. I like the interface much more in console and
the waterfall is fantastic on my 4k monitor. The waterfall in sdruno does not have as nice resolution. On HF I use the rspdx with console and
it works well as long as the gain is properly adjusted.
On vhf and up console does not work well at all and the sdr seems deaf. SDRuno runs it perfectly though. The difference is not subtle.
On the 255mhz fltsatcom birds you can't hardly tell they are there in console...no matter how you adjust it. In sdruno it works beautifully.

My take away is for best performance, use SDRuno. But on vlf through 30 mhz console is fine if you set the gain correctly. At vhf console causes lots of grief for me.
I think the programs differ in the way if gain is handled...but I am not sure...I am just guessing.
I have the rtlsdr usb stick as well. It is nice and sensitive but dynamic range is not so fantastic. It is poor on hf. Great for NOAA wx stations though! My noolectric smart v3 is slightly better for the weather stations. The RSPdx is only ok there. At 433mhz and the frs bands the rspdx is excellent. Its best trick is 1kc to 2000mhz with no gaps. It is wonderful for the price.
None of my SDR radios are as sensitive or as well behaved in the presence of strong in band signals as my R8500 Icom. But in some frequency ranges it is surprising how close they get in terms of sensitivity. All of the SDR radios I own desense when strong signals are too close. All have spurs depending on user settings. Wide views of the spectrum have the most spurs.

Even so, I love my sdrs. RSPdx for hf and up. Airspy HF+ Discovery for Medium wave and lower.

Every SDR I own has it own set of faults and peculiar behaviors. My software is all current as well.

 

[W1KNE]

I had never tried my rsp1a on sdr++ , sdrconsole, etc before, just tried, while I didn't experience the issues you have shown, the performance wasn't the same as using it with SDRuno. Have you tried sdruno? The rsp1a coupled with sdruno is my preference for HF/shortwave/medium wave, rtl's & airspy for everything else

I have/use the SDRuno with a RSPDuo and have been very happy with the results. I do see the clocking signal the OP sees but not nearly as strong as he has, nor as repetitive. I use it for MW and up, and for FM band as well. I do intend to get an Airspy at some point as well.

 

[cistercian]

I have/use the SDRuno with a RSPDuo and have been very happy with the results. I do see the clocking signal the OP sees but not nearly as strong as he has, nor as repetitive. I use it for MW and up, and for FM band as well. I do intend to get an Airspy at some point as well.

The Airspy HF+ Discovery is fantastic for MW and below. It is one of the best NDB receivers I have ever owned. I strongly dislike the plastic case and the mini usb. I hit the connector with caig deoxit pro gold seated it a couple of times and now leave the cable attached to the SDR. (I feared socket failure). That being said, I bought a second one on their black Friday sale as a backup. It really is an excellent MW and lower receiver.
It is also excellent on HF just to be clear. Below HF it is unusually good. I love LF and am amazed at how good it is there.

 

[Ubbe]

I have the msi.sdr that I believe are a RSP1a clone but not a very good one. The component values in the band pass filters for VHF/UHF seems to be incorrect and creates up to a 10dB attenuation to certain frequencies. Shortwave seems to work better with a sensitivity between 1-2uV. Not great but useable.

I have been using SDRUno for two years and have tinkered with all its setting. A couple of weeks ago I installed SDRConsole and it was like using a new receiver. When switching back and forth between the two applications the signal strengths are the same but SDRConsole have much better audio quality for voice communications. The software noise filters in SDRConsole also work much better than those in SDRUno. The waterfall in SDRConsole are much cleaner and I can see even the weakest signal that can barely be heard. In SDRUno those signals are more masked in the waterfall and not seen.

It was almost impossible to monitor the 80m HAM band in SDRUno with all the interferencies I have but in SDRConsole it can actually be done. The SDRConsole are also much quicker and easier to use, for me at least, and works better at being a HAM receiver than what SDRUno manages to do for me.

/Ubbe

 

[KE5MC]

2nd attempt... Seems I was logged in via top banner icon, but I had to log in again to complete post which was lost.

DBMandrake,
I was on the SDRplay site this morning and noticed their posting of counterfeit devices. You finding were so poor I am wondering if your RSP1a was counterfeit or broken if legitimate. I recall you posted you could/have returned it and I'm wondering whom and how much.

SDR is such a wide open door for wide band receive it's always disappointing to me when other have had such a poor experience.

Good luck and hoping you find a hardware/software configuration that meets your expectation.

Mike

 

[ratboy]

I'm not trying to hijack the thread, but I have a bunch of SDRs, and all of them had problems with PC display noise, and/or USB cable noise. Cheap or expensive, it didn't seem to matter. I got the old ferrite chokes out from my Universal M-600A/6000/7000 days, and put a bunch of them on one of the better made (As far as I could tell) cables and got it down to tolerable. I got a metal case for my RSP1 and it helped a little, but there was still display hash from both my laptops I tried to use it with. A third one (The previous new one got dropped, and retired) with an OLED screen is just about the same as the other two. Orientation with regards to the keyboard and display is critical, and touchy to say the least. A quarter inch can make a big difference. On the newer one, the SSD seems to generate a little bit of noise when writing that the same SSD didn't in the previous one. Of any of my SDR's, the Afedri LAN-IQ stand alone seems to be the best performer(alum case), and to be honest about it, it aint great. My apartment is total HF hell, I can barely hear anything, so I do my listening at a friend's place out in the sticks(no transmitters anywhere nearby), or portable. I haven't been able to get things quiet enough so far to really enjoy listening in my car, etc. My scanners do a decent job in my car, but the Afedri beats it listening to the main NS channel 161.070, but not as well as my old Yaesu VX-170 does. I don't really use any of my SDR's above 30MHZ, and so far, I'm still experimenting with portable antennas and solutions to the QRM and display noises. I'm kind of getting to the point I'm going to probably sell almost all my HF capable stuff and there's a lot of it.
I'm going to update my equipment list below..

 

[DBMandrake]

DBMandrake,
I was on the SDRplay site this morning and noticed their posting of counterfeit devices. You finding were so poor I am wondering if your RSP1a was counterfeit or broken if legitimate. I recall you posted you could/have returned it and I'm wondering whom and how much.

This possibility was already discussed earlier in the thread - I was aware of the Chinese counterfeits before buying, so I bought from one of the SDRPlay recommended UK suppliers. (SDR-Kits)

Also as mentioned earlier I opened it up to verify that it was genuine and it was. (I posted a photo of the PCB...)

So I'm 100% sure that it was genuine not counterfeit.

SDR is such a wide open door for wide band receive it's always disappointing to me when other have had such a poor experience.

Good luck and hoping you find a hardware/software configuration that meets your expectation.

I've had an Airspy Mini for a while now (since my last post in January basically) and aside from one minor issue I've been satisfied with it.

It wasn't all smooth sailing because my device seemed to arrive uncalibrated, so the frequency calibration was out by about -2.3ppm which was disappointing. Either it didn't get calibrated at the factory or a firmware update in the supply chain caused the calibration data to be lost. Whether I was unlucky or not I don't know. (The calibration figure was set to zero which is extremely unlikely to be correct...)

I was able to get that resolved though and the device is now calibrated, and if you have a sufficiently accurate reference signal you can calibrate it yourself. (which is what I did rather than send it back)

Nearly all of the issues I raised with the RSP1A are not present on the Airspy Mini.

It doesn't have any problems with DC spike or IQ imbalance, indeed it has very little if any imaging either in band or from out of band signals, and out of band rejection is very good presumably due to the tracking filter. Blocking performance for nearby strong signals also seems very good, so dynamic range is good even at relatively high gain levels.

It does still suffer a little bit from clock spurs - but they are relatively low in level, similar to the RTL SDR v3, so some 30 dB lower in amplitude than what I was seeing on the RSP1A, and only visible above the noise floor at high gain settings. (vs all the time) Also due to the different clock frequency most of them don't seem to fall close frequencies of interest.

So apart from my individual device arriving uncalibrated and the relatively minor clock spurs I can't find much to criticise about it. It just works, works well, and has a very clean noise floor etc. It does run somewhat warm and drifts slightly during warm up, (about 0.5ppm) but once warmed up for 10+ minutes it is extremely stable to about 0.05ppm.

After trying both devices I would say that if you don't care about coverage above 1800Mhz or below 30Mhz, and don't need more than 5Mhz of usable bandwidth the Airspy Mini is the superior device for sure. Its noise floor is so much cleaner, the tracking filter works well for out of band rejection, there's no DC/IQ imbalance issues, and it is supported by more software.

If you really want HF in the same device, more than 5Mhz of bandwidth and don't mind working around some of the limitations then the RSP1A might suit better.

 

[SpaceForceCmdr]

Just to chime in, I'm a new RSP1a owner, and am a bit disappointed with a few things as well, mainly that it doesn't work with SDR# (unless I use an older version), and the DC spike in Zero IF mode. I was running into issues with SDR Console, SDR# and others due to Zero IF. I'm brand new to SDRs and the technical aspects of radio in general, so I guess this is just the nature of the beast. One of the big selling points of the RSP was the 10 Mhz sampling, but I guess I can't use that in Low IF mode.

Overall, it's been fun to experiment with so far. Also, the SDRplay tech support helped me out with this DC spike "problem" I was having. I'm not too thrilled with the Uno software; it's just more complicated than I need at the moment. So far, SDR# and Console are my two faves.