Alinco DX-SR9 Hybrid SDR Transceiver Review

Amateur Radio Projects and Software Defined Radio

Alinco DX-SR9 Hybrid SDR Transceiver Review


Now for the part we all have been waiting for. How well does the DX-SR9 as an SDR transceiver? The answer in a nut shell is reasonably well with a few caveats. SDR reception is achieved by using the IQ jack on the back of the DX-SR9 and plugging in a 3.5mm stereo cable to the stereo mic / line jack of your PC’s sound card. The bandwidth of the IQ jack is approximately 48KHz. These means that you will see 24KHz of the band on either side of the center frequency. While not as large as some dedicated direct sampling SDR receivers, the 48KHz is adequate for Amateur radio use allowing you to see activity close to your operating frequency. Transmitting is achieved by routing audio from you PC’s speaker out via a 3.5mm cable to the DX-SR9’s rear MOD jack. Keying, Frequency settings, Mode, Power settings, etc can be controlled by your PC through the use of Alinco’s ERW-7 cable (Approx. $60) or equivalent. The ERW-7 cable is basically a USB to serial converter that terminates in a 3.5mm stereo jack.

Setting up the DX-SR9 for SDR

Front SDRAs mentioned above, you will need to use two 3.5 mm stereo cables to connect the DX-SR9 to your PC’s sound card plus the ERW-7 for computer control to a USB port. If they don’t automatically install, you may have to download and install the drivers for the ERW-7. Using Windows 8.1 the ERW-7 chipset drivers auto installed and worked fine. One thing you might need to be aware of that the IQ output needs to be connected to a STEREO input on your sound card. This is important for the SDR function to work correctly. If you have a desktop PC in the shack, this probably won’t be a problem. If you have an all-in-one desktop computer or a laptop, you maybe out of luck. A large majority of these systems on have a mono mic jack available for audio input and this is not going to work. However, the answer is to add an inexpensive USB sound card. This is a great idea anyway, since you can pretty much dedicate that device to using the DX-SR9 and you won’t have to recalibrate the sound settings for the DX-SR9 after changing your PCs audio settings for another application. The DX-SR9’s audio input requirements are not very demanding, since the most they require is a 48MHz sampling rate. Going any higher won’t gain any more bandwidth from the DX-SR9. Just be sure to check the soundcard’s input sample rate settings in your PC, since they are usually set less than 48MHz. Several USB  audio adapters that were on hand were tested with the DX-SR9 and as expected they worked fine with a couple of exceptions. One USB audio adapter that was advertised in the specs to have a stereo mic in wound up to actually only have a mono input. Another adapter would not work correctly with the DXS-SR9 and the included KGTRX software. The problem turned out to be after some head scratching is that the DX-SR9’s IQ output is inverted. With SDR you can always tell when this is a problem because USB and LSB modes are reversed. KGTRX handles the IQ correction internally so there is generally no problems with the majority of sound cards. The problem with this particular USB sound adapter was that out of the box it’s left and right input channels were switched causing much confusion. It is important to realize that the DX-SR9’s IQ output is inverted when being used with 3rd party SDR software. Fortunately most SDR applications have a setting to let you switch Left and Right inputs via the software to compensate for an inverted IQ input. Of the inexpensive external soundcards tested, the best performance was achieved by the Creative Soundblaster X-Fi Surround 5.1 Pro USB Audio System with THX SB1095. The X-FI has a very low noise floor and provides  very nice quality audio output making the DX-SR9 very pleasurable to listen to. You won’t use most of the features available on this card and you probably won’t to be sure that some of the DSP features are turned off. On the other hand, you might find some useful such as the equalizer function. The X-FI can also sample at 96MHz, but it won’t gain you much of an advantage since the DX-SR9’s IQ is pretty well locked in at 48KHz of bandwidth.

DX-SR9 Testing Setup Core I3 AIO Computer External SB audio interface External Antenna Tuner Samason G Track USB Microphone Power Supply

DX-SR9 Testing Setup
Core I3 AIO Computer
USB X-Fi Pro audio interface
External Antenna Tuner
Samason G Track USB Microphone
Power Supply

Connecting a microphone to the DX-SR9 can be as simple as plugging in an cheapo USB mic / headset (remember your soundcard mic input may be taken up by the DX-SR9’s IQ input) to a high quality USB microphone such as Blue Microphones Snowball USB Microphone (Gloss Black). One thing to realize, is that there will be a slight delay in the transmitted audio due to latency of processing the audio. This shouldn’t be a big problem for most modes except maybe for  CW. If you prefer using studio microphones you might want to consider using one of the professional external sound cards that offer XLR inputs and Phantom power for condenser microphones. It’s pretty much up to you how you want to customize the output audio even with using 3rd party sound processing applications. However, it would be definitely handy to have a second HF radio around to allow you to tweak your audio settings and see what the DX-SR9 would potentially sound like over the air. As mentioned before, there will be some latency in the transmitted audio depending how fast your PC processor is. Usually the latency only involves a few milliseconds. On some of the higher end audio interfaces the latency can be reduced to 0 if your PC can handle it. You will know if it can’t by hearing crackling or stuttering in the audio.


22 Responses

  1. AE5YJ says:

    Great review! Thanks for going so in-depth with this rig. 73

  2. George says:

    Excellent review! Nice to see a semi-major manufacturer embracing the improvements SDR offers and including it in their rigs.

  3. DL8YJ says:

    Thanks a lot for the review and the Omnirig.ini. It works well with SDR-Radio.
    Is there any (more or less official) list of the Alinco commands?

    73, Uwe

    • HRS Staff says:

      Check the Alinco Forum on this site. There is a list of DX-SR8 commands that seem to be pretty much compatible with the DX-SR9

  4. N4OZ says:

    If only it included 6 meters this would be a slam dunk. I think the KX3 still has the edge, even at 90 watts less power.

  5. AE5YJ says:

    Just curious which brands of usb adapters worked and which didn’t. I just ordered a sabrent 7.1 usb card with line in, stereo mic input, etc..

    • HRS Staff says:

      Actually one of the problem devices was the Sabrient SND8. The inputs were reversed. Even though they could be switched in the software for it, the setting wouldn’t always work correctly. The easy work around was to just swap the input cables around. The best performer by far was the Soundblaster SBX external box.

      • AE5YJ says:

        Thanks for the heads up, I will keep that in mind when it comes in. I just got it because it was economical and I am impatient, lol. I will also check on the soundblaster box, I noticed in the videos of the Tokyo Ham Fair that they were running the soundblaster unit.

  6. AE5YJ says:

    When you say swap the cables around, do you mean use a stereo to mono splitter and use the stereo mic input?

    • HRS Staff says:

      It would just me a matter of connecting the Left output to the Right input and the Right output to the Left input by using an adapter or by rewiring a 3.55 stereo cable so the inputs would be reversed.

  7. AE5YJ says:

    Sorry to keep making requests, but could you possibly post a youtube video of the SDR in action in a real receive/transmit environment? Counting down the days until my soundcard gets here lol

  8. AE5YJ says:

    I replaced my first faulty ERW-7 cable and now I have everything working in SDR mode thanks to the information here on this review and in the comments. I run SDR exclusively with this rig, and it works ok. Interesting note is that the I/Q imbalance is symmetrical in my unit, gain dropoff is severe and noticeable at both ends of the panadapter/waterfall. Annoying, yes but much easier to live with when symmetrical. Here is a YT video of the SDR in action:

    73 de AE5YJ

  9. kostas says:

    hello, I have not found the settings transmit filter

  10. Michael Mc Donald says:

    Hi there just set my dx-dr9e radio up with the erw-7 cable along with two 3.5mm audio cable one into line in and one into speaker output.Is there a certain mic I require for use on my pc ? 3.5mm into mic juck or would a usb version work I have tried a basic electric mic but when I key I get a high pitched squeal I then get a notification up on screen saying out of range using a cheap electret mic pluged into my mic jack on pc.Also is there another similar software which will work with the alnico? apart from kgtrx ? thx

  11. Michael Mc Donald says:

    Quick update radio with kgtx working well apart from the tx side when I click on tx I get a nasty squeal and a message saying out of range

    • Dub Campbell says:

      From what I understand the mic jack requires a mono plug and a dynamic mic. An electret mic cannot be used as a direct substitute for a dynamic mic without making some wiring or circuitry changes. The electret mic uses phantom power like a condenser mic and if you plug it into a jack that’s intended for a dynamic mic you’ll have a squealing problem or worse.
      Just plug in a simple, unbalanced dynamic mic and you should be good to go. That is, unless the voltage from the electret mic has caused some damage…but I think damage is unlikely with a low voltage electret. Good luck!
      Dub, k4dub

  12. Urmas says:

    How on earth you program memory channels? If you do what manual says it seems that frequency doesn’t save. Really seem to be overly complicated.

    Mainly now we talk cb-frequencies(receive/transmit same frequency)Mars-mod done to unit.

  13. Mentioned soon after introduction of the DX-SR9T Transceiver was the availability of an optional plug-in “filter board” (Part# EJ-59U) that is still available from ALINCO/REMTRONIX–but has not been mentioned in “factory literature” for well over the last year (2015 & 16). This “filter board” allows the substitution of up to three Eight-Pole COLLINS Mechanical Filters in place of the “stock” Four-Pole MURATA Ceramic Filters. Though not bad to begin with–the improvement in Selectivity is remarkable!! Refer to KZ4B’s comments regarding the DX-SR9T under for much more detail regarding this valuable option.

  14. Chris says:

    Hi. Where can I find now file: DX-SR9_Beta.ini?
    I need this emergency. May be somebody have it?

  15. DF1FN says:

    What a great review, actually it made me purchasing the transceiver. And what can I say? I’m very impressed, what Alinco offers with the DX-SR9, especially considering the relatively low price compared to other TRXs that dont’t offer as many functions, for example FM and the SDR option.

    What I like about the Alinco is the clear and simple design.
    I even don’t mind the three solid power output levels. Where’s the problem? You get a high, low and super-low setting with the possibility to fine-adjust everything on the circuit-board or to limit the high setting to 50 W by soldering a jumper. Working digital modes I set to the “high” level and adjust the output power with the sound level of the PC.

    Ok, what annoys me a bit are the many multifunction buttons at the front, but tell me a similar device that doesn’t have them.

    The KG-TRX software works relatively well but I had to update the TRX to a newer or special firmware to make it work correctly. Otherwise there always was a offset in the waterfall when I changed between LSB/USB/CW mode. I reported to the Alinco online customer service which could help me immediately.

    The Software itself is very basic and clear, what I like very much, because with more options it would tend to be overloaded I guess. Everything works including TX and CW TX.
    The 48 khz is wide enough for me. Ok, there is this signal ghosting but it can be reduced by a high quality soundcard.

    Would I recommend the Alinco? Yes!

    vy 73 DF1FN

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