The New FUNcube Dongle Pro+


The FUNcube Dongle Pro+ has the same design aims as the original FUNcube Dongle, but we’ve taken on board many of the comments about the original FCD, and improved both the performance and the functionality. Indeed, although from the outside it might look similar, it’s an entirely new design.

On the performance side, we’ve added 11 discrete hardware filters to the front end, including narrow SAW filters on amateur 2m and 70cm bands. This has a hugely beneficial effect on front-end blocking, particularly at VHF.

There’s also a new LNA used with far better performance, improving the OIP3 to 30dBm (was about 10dBm). In addition, the RF stages are at 3.15V compared to the original FCD’s 1.5V, innately improving dynamic range.

Also added is a TCXO rated at 0.5ppm, althogh typically in practice tests show the accuracy at 1.5ppm (the original FCD used 20ppm crystals).

For functionality improvements, we also took the opportunity to extend the frequency range to add HF, MF and LF, and to provide complete coverage of the amateur 23cm band. The receiver range is now 150kHz to 240MHz and 420MHz to 1.9GHz. In our first 20 units, all have covered 150kHz to 260MHz and 410MHz to 2.05GHz.

Similarly, the sample rate is increased to 192kHz.

Internally the ADC depth used is 32 bits. Initial firmware will provide access to 16 bits of ADC resolution.

The local oscillator phase noise is far less than the original FCD, and typically once an antenna is connected the once-familiar 0Hz spike disappears into the noise. The LO resolution is also down to about 0.5Hz, even at L band.

Some quick stats…

o 240 parts (original FCD: 100)
o 100 BOM lines (original FCD: 28)
o Parts mounted on both sides (original FCD: parts on one side)
o Six layer PCB, two are solid ground planes (original FCD: double sided)
o 21 ICs, 122 capacitors, 49 inductors… on the same space as a 40pin DIP package

Many thanks, Howard

83 Responses to The New FUNcube Dongle Pro+

  1. Francis BOULOT says:

    Hello, I am very interested by your SDR !
    What should be the price & availability ?
    Best 73’s
    Francis, F5MIU

    • admin says:

      Hello Francis

      The first units hopefully will be shipping this week (I am awaiting the final results of my CE conformance and certification).

      The ordering details are here.

      The price in Euros is about €155+VAT.

      Many thanks, Howard

  2. Francois Michaud, Ing says:

    I leave my name and Email adress to be advise when the Funcube Pro + will be avilable for order and never received any feedback
    Am I on the waiting list?
    Francois VE2 MHF

    • admin says:

      Hello Francois

      I’ll be sending out a new batch of email confirmation in the next day or so. The eCommerce waiting list is not very good I’m afraid, so I have to manually extract raw data and ETL it into an email merge batch.

      Many thanks, Hwoard

  3. Peet says:

    Hallo I order a Funcube dongle from ML&s and can’t wait to try it out. I would like to know what is the best software to use and what is the spectrum analyzer’s spread in Mhz.

  4. hank smith says:

    Hello how much would the radio cost plus shipping in us dollars? also what kind of antanna hook up does it use? Hank

    • admin says:

      Hello Hank.

      FCD+ GBP124.99
      Shipping GBP9.42
      Total GBP134.41

      With the exchange rate of GBP1=USD1.59

      Total including shipping to US GBP134.41 * 1.59 = USD213.71, plus whatever Paypal or your card charges for GBP transactions

      Details are in the FCD+ ordering page,

      Many thanks, Howard

  5. Burton Ison says:


    I’m considering purchasing one to use as a panoramic adaptor, feeding it the 3395 kHz IF from my transceiver. Do you have any suggestions what would be the best software for this application?

    • admin says:

      Hello Burton

      Personally I use SDRSharp or Spectravue (although note Spectravue only supports 96kHz span).

      Many thanks, Howard

  6. John says:

    I have the older funcube and am interested in getting the newer one to embed inside my Panasonic Toughbook CF-18. Assuming the pro + is the same size as the old one, there is just enough room for the main pcb and usb connector but not enough for the sma connector. Is there any way I could order a pro + with the antenna connector either not soldered or on a pigtail? I wouldn’t mind paying extra or waiting longer.


    • admin says:

      Hello John

      Thanks for your note. The FCD+ is indeed exactly the same size as an FCD, it uses the same enclosure and cut-outs.

      As part of the testing procedure, we do several full end-end tests including the RF connector: it may surprise you but about 0.1% of these connectors fail!

      It is possible to remove the SMA connectors with a hot air iron, but extreme care has to be taken not to break the PCB tracks. In addition, the original FCD had 1mm vias deliberately placed in the SMA pads which the FCD+ doesn’t have. This means (1) it’s more difficult to remove the SMA for thermal reasons and (2) any pigtail would need to use the SMA pads as there are no through-hole terminations.

      Many thanks, Howard

  7. Rob Styles says:

    Just a reminder to the lucky people who have purchased the FUNcube Dongle, We have two Yahoo groups with hundreds of FUNcube dongle members who are more than willing to help with any issues you may have,or just to get the most out of your dongle.

    FUNcube Dongle Pro
    FUNcube Dongle Pro Plus

    Rob M0TFO

  8. Chris GW6KZZ says:

    Hi Howard, have you seen and read about the new RF board that is taking the Arduino type approach with 260 MHz to 3.8 GHz coverage? Developement board is only 5 cm square and runs at 5 volts. Might be an idea companion that could work in conjunction with the FUNcube dongle Pro+ receiver or the next generation as it could take Amateur radio by storm just as your dongle has done. Email me if you need the link or further info.

  9. Rob White says:

    What aerials perform best , cost least, cover the/
    full spectrum ???

    • admin says:

      Hello Rob

      Good question, but it could be a very long answer.

      At one extreme, I use an un-bent paper clip to pick up local FM radio. In fact sometimes I don’t even need that, I can pick up the local FM radio station here without any antenna but I am on the third floor.

      Of course I don’t recommend a paper clip for optimum reception!

      I use a Maldol HVU-8 for the greatest range but they are not cheap. This gives me LF to UHF.

      For LF through HF, a simple long wire will work, and for reception there’s no need to spend hours tuning it.

      For VHF and above a discone or even a simple whip on a ground plane will get you started.

      Any antenna that’s outside is bound to be better than anything inside.

      Many thanks, Howard

  10. Max says:

    Hello Howard,
    Great works on the FunCube Dongle Pro+.
    I’ve heard the original FunCube Dongle Pro won’t be available anymore. Well, there are some interresting frequencys Funcube Dongle Pro+ isn’t able to receive anymore (e.g. 380 MHz to 400 MHz).
    Is it possible to make this frequencies available somehow? I know the old FunCube Pro was able to handle with this frequencies.

    Greetings from Germany

    • admin says:

      Hello Max.

      I’m afraid the new tuner chip used on the FCD won’t reliably cover below 420MHz, so we don’t advertise it as so. The manufacturer of the tuner chip used in the original FCD went out of business so we changed device. While this gave us vastly improved coverage down to LF and full L band coverage, we did lose from about 260MHz to 420MHz.

      Many thanks, Howard

  11. Tom says:

    Being a SWL for “many years”, I have collected together a number of rx, namely JRC545DSP, ICOM R75, IC 8500,IC-7400,(used as RX) AOR 8200, 8600,Winradio Excalibur and recently the Alinco DX R78e

    That said my rx of choice, for pure ease of use these days is the FC+ with HDSDR
    It “just works” , start HDSR or SDR# and go… and it truly does perform as well as , often better than my larger “boat anchor” receivers.

    Its amazing how technology moves on, when I think what I paid for the JRC and Icoms all those years ago?! The hardware DSP cannot compete with free software and FC dongles of today!
    My current most used setup is a FC and FC+ for full coverage of HF and Air bands, (if I was allowed to listen to Mil Airband that is ;), a wellbrook loop and a diamond AD777 , that mostly covers it! )

    What’s next Howard …. Working on anything ?


    • admin says:

      Hello Tom.

      Many thanks for your note, given all that other equipment that you have I am delighted that the FCD+ is your receiver of choice!

      I wish I had enough time to work on something else! Seriously, there is something but it’s a long way off, and it’s not a dongle. Very early days yet I’m afraid!

      Many thanks, Howard

  12. Steve Belshaw says:

    Hi Howard

    I’m thinking of buying one of these but a friend told me he’d heard a rumour that there’s a newer version coming out quite soon. Is this true, and would any future version have a sampling rate of more than the current 192kHz? I’d like to be able to see most of the MW band on one screen.



    • admin says:

      Hello Steve

      I am not sure where that rumour came from. I have no plans to release a new FCD/FCD+ at present – I wish I could find the time!

      Many thank, Howard

  13. Steve Belshaw says:

    Thanks Howard

    Your reply is appreciated 🙂

    Maybe a suggestion if you *do* ever decide to release a newer version would be to increase the sampling rate?



    • admin says:

      Hello Steve

      Increasing the sampling rate will have a big effect on the entire design. Firstly, it will not be possible for a device to work out-of-the-box without a lot of work on drivers, and we’d need different drivers for different OS’s: that’s potentially an awful lot of effort! Certainly the device would have a proprietary interface, unlike the current generic sound card and HID interface that the FCDs use, so inevitably no front-end software would be compatible without some work on that too.

      Certainly we’d have to move away from using the current PIC MCUs as none of them support high speed USB.

      My current thoughts are to bypass USB and use Ethernet instead, however there is a cost implication in providing an Ethernet interface, not to mention that the device would need to be self-powered. PoE is an option, but again that is an expensive option to implement with possibly few people actually wanting to take advantage of it.

      Back to USB, never say never of course, but it’s not as simple as fiddling a bit of firmware I’m afraid!

      Many thanks, Howard

  14. Earl Bennett, KD2CYA says:

    Hello, Howard: as before: where do I look to straighten out my misinstallation, and, where do I look to get directions to the response!

    Earl Bennett, KD2CYA.

  15. Steve says:

    Hello Howard, I seem to have a small problem with my FCD+ which is present using both SDR# & Simon Brown’s SDR Radio Ver 2
    I can receive FM broadcast & Air bands without any problems but cannot receive Amateur bands.
    On the displays of both of the above I can see a very poor signal but no audio!
    Could this be something I have setup wrong, I have tried to fix this by updating the flash.

    • admin says:

      Hello Steve.

      That sounds a bit confusing. Can you email me some screen shots of your SDR# setup please? What bands are you encountering difficulties with?

      Thank you, Howard

      • Steve says:

        Hello Howard sorry if I confused you but its every thing on the lower bands VHF UHF seems alright.

        I don’t seem to be able to paste any screen shots on here?

        • Steve says:

          Hello Howard still having problems with the 1.8 – 6m
          I use SDR-Radio V2 and have a PMSDR 1.8 – 30 m which works fine if I swap it out with the Funcube.
          Can I return this FCD Pro+ V2.0 Serial No 0011685 for you to check please!

          • Steve says:

            I have now installed this FCD Pro + on another machine with exactly the same problem.
            I still have no low bands.
            I feel that this is a defective item and wish to return it!
            Thank You!

          • admin says:

            Hello Steve

            Certainly, I am happy to resolve this for you. I will email you details for a repair/replacement.

            I apologise for the inconvenience.

            Many thanks, Howard

  16. Juan Munoz says:

    Hello Howard, received my FUNcube Dongle Pro+ and less than a week, great thank you.

    Question has anyone test it using a tablet (maybe like the new Windows 8 Tablets) or an iPad, I’m thinking some kind of portable operation ?

    Thanks 73 de TG9AJR

  17. Sohaib says:

    I have to order funcube dongle device… what is the procedure…. kindly inform me … im runinig short of time

  18. admin says:

    Hello Sohaib

    To order your FCD+ follow this link:

    Many thanks, Howard

  19. John Wiggins says:

    My FCD+ has died.
    Booted up the computer this morning, and it does not recognize the Dongle. tried it in different ports and rebooted the computer, but still no joy.
    Looked in the device manager sound thingy, its not listed. I have run the tuning prog that says its not connected.
    John Wiggins
    Serial No.0011177

    Intel I7
    Windows 7 64 bit

  20. John Wiggins says:

    Tried my FCD+ on a different computer, same result, not recognised.
    Where do I send it to for repair/replacement?


    • admin says:

      Hello John

      Sorry for the problem you’re having with your FCD+ and for the slight delay in responding, I’ve been on vaction over the past week.

      I’m happy to fix/replace your FCD+ free of charge, and I’ve sent you an email this morning regarding this.

      Many thanks, Howard

  21. Earl Bennett, KD2CYA says:

    Hello, Howard: Thanks to the help of Bill, KA3IAS, I now have a fully functional system. This includes a better computer with more memory, and, a lot of experience in head scratching. It turned out that the system that Bill ran the Pro+ on was able to work with was much better than the laptop I had tried and retried when I went back to his home. I had left the dongle at his place and he was sucessful at getting it to work on his system. During the next week I decided to install Sharp and found that my Compaq choked on it. After sending a problem report, and saving a copy in case of a talk through or Bill wanted to see it, I asked for his help and explained the crash. When he tried to do the install he ran into the same problem. This computer, an older Compaq with Athlon processor at about 1400mhz, has other problems that might be why the system would not work. On examining some of the Sharp documentation, Bill put together a system with a Dell, circa 2004, system at 2.4 ghz and over 1gbyte of memory. Once this upgrade was applied to the radio it began performing very well. There are occasional glitches in that the tuning will jump for no apparent reason after I have shifted from course to fine tuning ( shifting the mouth pointer and clicking).
    Several points: Bill asked why the Sharp does not decode RTTY, why the L.F. range does not go down further on the dongle itself, and why there is no keyboard control of frequency selection. Most of these are not dongle problems actually, but, I suspect that the Sharp guys ( people) have answers to the questions related to the great freeware that they provide. I believe we will have to contact the Sharp support line and, when that is done, will report. And about the reason the dongle exists: I may have picked up the Funsat this evening by listening for the telemetry /beacon! This signal “slid” as I listened but I will have to check SATPC32 for presence during that period.
    On frequency coverage: I was thinking of using the dongle system to check oscillator performance including one around 384 mhz for an injection source. I will continue work on other gear for this kind of application. I will also see who else may be using the Pro+ at the Mt Airy VHF and above conference next month!

    Earl, KD2CYA.

    • admin says:

      Hello Earl.

      I’m not sure what the minimum spec is for SDR Sharp. I do run an old 1GHz Atom machine for some of the production tests here which is my “stable” platform, but I use Spectravue with a special version of the frequency control program rather than SDR Sharp as that’s traditionally been my test software since the year dot. For any “proper” listening, I do use SDR Sharp or SDR Radio, but typically it’s on a superior platform.

      It is possible to feed the output of SDR Sharp into the input of another program to decode RTTY, or, indeed any other narrow band mode such as PSK31. This can be done either with a virtual audio cable (ie, software) or a physical cable into a physical soundcard, taking the audio line out into the audio line in. Some operating systems and soundcard combinations allow you to do that in the mixer settings.

      Many thanks, Howard

  22. Earl Bennett, KD2CYA says:

    OOPS! Bills call is KA3AIS, not IAS! Spoonerism strikes again.

  23. Hugh Martin says:

    Hello Howard.
    I purchased a FunCubeDongle Pro+ from Moonraker(UK) Limited recently
    I have a query on the coverage of my particular Dongle.
    The Dongle is working fine up to about 460Mhz but after that I have not found a single signal including the local TV channels, no sound or any sign of tv at all.
    Am I doing something wrong in the software??
    I have both SDR# and HDSDR and the results are the same
    Could you suggest a solution.
    I must say that the results below 460Mhz have been very good.


    • admin says:

      Hello Hugh

      I am not sure, but in your area have you switched to digital TV? The FCD+ won’t receive the digital multiplexes as you need about 8MHz of bandwidth to do that.

      Many thanks, Howard

  24. serge says:

    hi Howard

    I ‘ve just get my fcd+ today. Unfortunately I am only able to receive “noise” whatever frequency is selected . The instruction manual to simply receive broadcast FM does not work for me. It ‘s like having no RF signal.

    W7 see the usb fcd device and sharp# see the device too. Try to on 2 different pc with no success. Updating the firmware does not help. Trying other sdr application does not help too.

    Any idea ?

    • admin says:

      Hello Serge

      I am sorry that you are having difficulties with your FCD. Can you confirm that you are using a standard SMA connection to your antenna and not a reverse polarity (RP) SMA to the antenna?

      Many thanks, Howard

  25. Earl Bennett, KD2CYA says:

    Hello, Howard: I am still trying to receive the Funcube and other satellites, but, am posting about something else: When the dongle is working I can pick up quite a bit on theam and short wave bands, as well as several others up into the vhf range. At uhf my antennae may be insufficient ( inside, aluminum framed windows) and at the 1296mhz range I see occasional non ham signals that sweep through. Or maybe they are artifacts of the problem: after the dongle warms up, which it does, it begins to be hard to select the frequency I am trying to select. The selected digit is activated and the actual frequency jumps to 1Ghz. This is a bit disconcerting, and, when the unit has been running awhile, there is a sudden freezing of the controls. Most of the time I wait for less than a minute and the dongle begins performing again. However: on two occasions I have experienced the apparent loss of all signals and this is only corrected by closing the Sharp console and restarting it.

    Fun! Earl, KD2CYA.

  26. Earl Bennett, KD2CYA says:

    Hello, Howard: Just found out why the Funcube signal I thought I heard was difficult to resolve. My “Radio Tardis” was picking up a signal from the future! Seriously: I thought the satellite was up and the reason that I had not heard it was because it, like the Ao51 I had contributed to, was up and had already stopped operating ( or my antenna was so bad that I could not hear it).

    I am currently waiting an ISS pass and will check the AmsatUK site for the “Real Mc Coy” and its launch date.

    All for now, Earl KD2CYA.

    • admin says:

      Hello Earl

      Thank you for your update, and I apologise for not responding earlier, since returning from my break I’ve had a few things to catch up on here. I’ll take a look at your earlier messages and respond appropriately.

      Many thanks again, Howard

  27. Derek says:

    I have the following issue with my FCD Pro+, I have to unplug and plugin back in the dongle on a daily basis, other wise it will not work. In say HDSDR the dll will pick up the dongle ok, but the onscreen waterfall and frequency will freeze almost immediatly, or it will work but not receive any signal oe sound Unpluging and putting it back in sorts the isue until next time ? Windows 8.1 64Bit

    Any ideas please

  28. Earl Bennett, KD2CYA says:

    Hello, Howard: I have recently been told of a low cost alternative to the FunCube Dongle. I was told about this much cheaper alternative at the Maker Faire, a September 2013 event in New York, but the correspondent mentioned that the device, based on “tuner in a can” ( a description I have seen of such devices) is noisy ( requires a pre amp for “this” satellite application) and can be overloaded by nearby signals. It may be cheaper but it may be a “you get what you pay for” device. As a technologist I can build filters from the Ham handbooks and professional publications, including the RSGB offerings, and pre amps down below .6 db ( with decent dynamic range), but, thats not everyone who would actually need the performance. 73, Earl, KD2CYA

  29. ief kox says:

    Hello Howard,

    I’m afraid i’ve broken my FCD+.
    I see 2 burned out components, caused by a ground loop in my power supply – trough my transceiver – into the coax switch – into my FCD.
    Is this repairable ?
    Can you send me an e-mail, so I can reply you with some pictures please ?



  30. Paul PD0PSB says:

    Hi Howard,

    A question:
    I noticed that enabling the bias-T causes a drastic increase in sensitivity below 5MHz.
    This happens in both my FCDP+. For lower HF it seems the bias-T always has to be switched on.

    What could be the cause for this? Is the bias-T somehow interacting with the lowest BPF?


    • admin says:

      Hello Paul

      Thanks for the note. I don’t pretend to understand why that would be: I did do some investigation the very low end (200kHz and under) which I assumed was to do with the bias T, however when I removed the bias T connection it made little difference.

      I’ll take a look to see if I can reproduce here. The circuit uses a transistor switch followed by a decoupling capacitor and a largish inductor onto the RF input. By design I would not expect to see any difference in sensitivity whether the bias T is on or off, however I’ve not really played around with it at HF to determine this. The sensitivity of the FCDP+ was compared with other receivers, without the bias T switched on, and this was used as the benchmark.

      You will find that the sensitivity below 32MHz is less than that above it: this is where the external LNA gets switched in. On HF, as there is so much more ambient noise there is generally not much point in trying to squeeze out noise figures because of this. The same is not the case of VHF and above of course.

      Many thanks, Howard

      • Paul PD0PSB says:

        Hi Howard,

        Tnx fr reply.

        I am still puzzled as well.
        Further experiments show that lower (around 2 MHz) the opposite seems to happen.

        The only logical idea I could have is that the bias T switched on makes a (induced?) contact with the total system ground, thus using ground as an antenna “extension” on the lower frequencies.

        It is a minor issue.

        I’m still am totally surprised with the overall performance of my 2 FCDP+.

        Mentioning the 32MHz LNA switchpoint: could this be lowered by firmware? I can imagine this could even out the sensitivity “jump” around 32MHz somewhat. Now it seems to drop below 32MHz and climb up again around 27/28MHz.

        Keep up the fun work.

  31. Derek says:


    My Funcube Dongle Pro+ has just failed ( I have only had it a few weeks), I am not getting any output at all, do you have any ideas? Although the software indicates that there is a dongle present. Can you suggest any test?

    I have the previous version dongle which I have substituted and all works OK.


    • Derek says:


      I am responding to my own submission.

      After a lot of messing around I found that my sound card driver had been corrupted (Sound Blaster X-Fi). I have re-installed this Driver and all is OK now.

      I can’t understand why it worked on my other Funcube Pro Dongle though.

      Anyway all OK, this really is a great product, I am doing so much with it.

      73 Derek

  32. admin says:

    Hello Derek

    Thanks for letting me know you solved your problem. I also cannot explain why there was a strange interaction. But at least you got it resolved.

    Many thanks, Howard

  33. Enzo says:

    i just received the Funcube Dongle Pro Plus.
    Pulged it into an usb port and ran the SDRSharp program.
    As i have tried to set the PPM i cannot get the FCD working.
    I mean i have tried to set a Local broadcast radio but i cannot hear it clear.
    It seems i can hear the sound low and the background nois more louder.
    And also it seems to be shifted but icannot center it to hear it clear.
    Please where am i missing?

    • Enzo says:

      please can you tell me how to attach the screenshot?

      Please i would like alo to send the FCDPP for a check but do not know
      how and where to send it

  34. Enzo says:

    Continue from early message.
    I have also noticed that when i close the SDRSahrp Program and the FCD is still plugged,
    i hear a rustle noise coming from the speaker till i do not unplug the FCD.
    Thanks for helps.

    • admin says:

      Hello Enzo

      Could you please email me some screen shots please, showing your SDRSharp setup and the waterfall?

      Thank you, Howard

      • Enzo says:

        Thank you for coming back to my help request.
        Please will you be sokind to send me how to conifgure the FCDPP and also the SDRSharp program or if there is any step by step tutorial for dummies to avoid any mitake?
        Thanks in advance.

  35. Enzo says:

    Please i am noticing that if i set the IF Gain to 20 in the SDRSharp FUNCube Dongle Pro+ configuration, when i close and re open the program, i find it again set to zero.
    Why this ?
    How to fix the value?

  36. Enzo says:

    Hi Howard,
    i am using the SDRSharp v. program with the FCDPP.
    It is a couple of days that I am noticing that while I am receiving, the program stops but the bottom side of the program keeps showing the time scrolling down and I can see vertical Lines, while the top is freezed.
    To restart receiving I have to press the stop/play button and it restart receiving but after a while, I get again the same problem.
    Please can you tell me what has happened and how to solve it?
    Any help will be really appreciated.

  37. Mike says:

    My Funcube Pro+ stopped working can I get it repaired?

    Tried 2 PC’s one w/Win 7 other Win 10

    Can’t remember is there an activity light?


  38. Enzo says:

    Please i have a FCDPP that doesn’t work properly.
    Any chance to send it for a check and if need a repair?

  39. N0ZGO says:

    Here’s hoping Howard still monitors this website after 4 years…

    I have a FCD Pro+ which seems to cause the control program to freeze when I plug it in. If I disconnect the FCD Pro+ and then start the control program, the program says “Can’t find a FCD”. At this point, if I plug in the FCD Pro+, the program will say “Found FCD” and then freeze.

    Any ideas?

    • N0ZGO says:

      So, I believe I’ve found what was causing this lock-up, but I don’t have a good solution.
      The problem occurs when the host tries to read an Input report descriptor (the 64-byte buffer used to return data from the FCDP+) without having first written a command to the Output report descriptor.

      A work-around would be to have the FCDP+ return the same data as the last Input read, so that extraneous reads from the host would not cause a problem.

      Any chance that the firmware can be altered to do this?

  40. N0ZGO says:

    Anyone still alive on this project?

    How does one get G6LVB’s attention?

  41. N0ZGO says:

    I’ve verified that the FCDP+ does not respond to a read on the HID Input endpoint if no command was previously sent to the HID Output endpoint. Unfortunately, FreeBSD’s uhid implementation does just this: reading 64 bytes also causes a second 64 byte read which then hangs forever. Both qthid and fcdctl use hidapi, so they are kerbusted.

    I’ve written a simple command line program using libusb, going directly at the FCDP+ input and output endpoints on Interface 3 (HID). Seems to work fine. I’m going to clean up and then put it on my website for any interested party.

    Howard .. where are you, man?

  42. Phil Karn says:

    I’ve also been trying to get Howard’s attention; I guess he’s been busy.

    I bought a bunch of Pro+ dongles a few months ago and have been hacking on them pretty heavily. I’m writing my own general coverage receiver software from scratch, concentrating on polishing the low level stuff rather than the user interface. I’ve rewritten the fcd library to support multiple devices, including a mixture of Pro and Pro+ units. I’ve spent quite a bit of effort on DC offset compensation and I/Q gain and phase imbalance correction. I carefully handle calibration, including the resulting fractional Hz offsets. My next phase will integrate this with my satellite tracking software to Doppler tune the radio in a smooth, phase-continuous fashion.

    I’m working on the AGC, and I’ve run into some idiosyncrasies. When the gain is too high, something overloads and the output drops to a very low (but nonzero) amplitude. The I/Q gain and phase offsets go to extreme values. I’d also very much like to see even a block diagram showing the filters and especially any gain stages he’s put in front of the tuner chip. I strongly suspect he’s using the Mirics MSi001 tuner (same as in the SDRPlay) but with his own hi-fi A/D rather than the companion MSi2500 A/D as in the SDRPlay. It sure would sure be nice to know for sure. Drop me an email if you’d like to exchange findings.

    • Phil Karn says:

      Some more comments on gain setting. The main thing seems to be to simply leave the baseband gain at the lowest setting whenever possible, and the FCDPP behaves a little more predictably. I generally leave the “LNA” and “mixer” gains turned on, but I’ll drop one or both if the baseband digital signal exceeds -15 dBFS or so. (I discovered that there are several conventions for 0 dBFS. Mine is that 0 dBFS corresponds to a single sine wave that just touches full scale on the A/D without clipping when it’s in phase with either I or Q. This is the strongest sinusoid guaranteed to be handled without clipping. Note that it’s possible for other signals, e.g., a sine wave 45 degrees from I or Q, or strongly clipped noise, to rise as high as +3dBFS.)

      You do want to keep the baseband signal above -60 or -70 dBFS to cover up the phase noise peak around 0 Hz, and also some spurs that IIRC are in the +/- 70 kHz range.

  43. Phil Karn says:

    Can anybody enlighten me on the internal architecture of the Pro+?

    I’ve noticed some aliasing in the upper reaches of the output passband, and would like to know what the nominal figures are. For example, if (in the USA) you tune the FCDPP LO to 10.096 MHz (half the 192 kHz sampling rate above WWV on 10 MHz) and then look just below +96 kHz in the baseband output (which would correspond to an RF frequency of 10.192 MHz) you will hear WWV along with whatever is at 10.192 MHz. The signal is right side up (so it’s not an image), and yes, I have my phases and polarities correct.

    If change the FCDPP LO and my IF in tandem so as to stay on a constant nominal RF frequency of 10.192 MHz, WWV’s signal will steadily weaken and finally disappear as I reach an IF of about +80 kHz (i.e., a FCDPP LO of 10.112 MHz + 80 kHz IF = 10.192 MHz RF).

    In other words, roughly the top 16 kHz of the FCDPP baseband (+80 to +96 kHz) “wraps around” with the bottom 16 kHz (-80 to -96 kHz). One would certainly expect *some* of this as there’s no such thing as a perfect filter, but I would like to know what the specs are and also how the filtering is done. Does the A/D run at some multiple of 192 kHz with digital downsamping and filtering, or is the anti-alias filtering done in analog hardware? I’d expect a digital filter to be a little sharper than this.

    The practical implication of this is that the usable baseband bandwidth from the FCDPP is about 160 kHz, rather than 192, depending on whether there are any strong interfering signals that might alias into whatever part of the baseband you’re using. My own SDR code minimizes retuning of the FCD’s LO, preferring to make small frequency adjustments to its own (software) local oscillator, but the need to avoid the aliasing region means more frequent retuning of the FCD, i.e. whenever the frequency range of the desired signal crosses -80 or +80 kHz in the FCD’s baseband output.

  44. Phil Karn says:

    Just to reiterate, I’m pretty sure I’m seeing aliasing in the FCD’s A/D converters, not an image due to I/Q amplitude and/or phase imbalance.

    I do use a simple frequency-independent method to perform I/Q balancing. After DC removal, I ensure that the two channels have the same average average power (which corrects for gain imbalance) and that the product of the I and Q samples average to zero (which corrects for phase errors). I do not try to do this (yet) on a frequency-dependent basis, which made me wonder if I was really seeing an image.

    An image due to I/Q amplitude or phase imbalance shows up as an inverted signal at the negative of the baseband frequency, e.g., if the desired signal is at +48 kHz, an interfering image will come from the signal at -48 kHz. I ruled this out by changing my IF (i.e., my software LO) in tandem with the FCD’s LO to maintain a constant RF frequency. If the unwanted signal were an image, it would appear to change frequency while the desired signal did not. It would also appear upside down, i.e., LSB and USB would swap. This was not the case. The unwanted signal simply got stronger whenever I used IF frequencies in the range of +80 to +96 kHz, or -80 to -96 kHz.

  45. Phil Karn says:

    Anybody know how the calculations are done for the synthesizer in the FCDP+? I have the Mirics data sheet with the formulas, and I know that the TCXO is 26 MHz, but I’d like to know the precise way the programming numbers are calculated from the integer (1 Hz) tuning frequency. I see fractional Hz quantizing errors, and if I can calculate them myself I can easily compensate for them in my second (software) LO. Thanks!

  46. Phil Karn says:

    Never mind, Howard gave me exactly what I needed. And it works, too!

    • N0ZGO says:

      Any chance you could point Howard toward my HID comments, above? I’d be glad to help him modify the software to fix the issue.

  47. Enzo says:

    Hello i have a Funcube Dongle Pro Plus that has stopped working. It is not even detected by the PC anymore.Please anybody can point me someone for fix it?

  48. Paul Anderson says:


    Is there a list of compatible software, I’m primarily interested for SDR’s and spectrum analyzers.

    Is there a schematic(s) available, a BOM, mainly interested in looking into parts’ specs and parts replacement, although I haven’t had any failures so far.

    Sorry if these are posted but I’ve missed finding them :-\

    Thanks !