Alinco DX-SR9 Hybrid SDR Transceiver Review

Introduction If Alinco’s DX-R8  receiver and the DX-SR8 had a child, it would be the DX-SR9. The DX-SR9 inherits the brains of the DX-R8 and the brawn of the DX-SR8 to create More »

Afedri SDR-Net 2.3a Review

Introduction Ham Radio Science occasionally get emails from our readers on suggestions for a good reasonably priced HF SDR radio that won’t break the bank. So, we spent a little time investigating More »

Android Meets the RTL2832U

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Alinco DX-SR9 Hybrid SDR Transceiver Review


If Alinco’s DX-R8  receiver and the DX-SR8 had a child, it would be the DX-SR9. The DX-SR9 inherits the brains of the DX-R8 and the brawn of the DX-SR8 to create the DX-SR9 hybrid amateur radio transceiver. Hybrid SDRs are generally a standard radio receiver with buttons and knobs that feature an IQ output to allow its use with SDR software programs. This gives you the best of best worlds. You get a radio with standard buttons and knobs that you can quickly use when you don’t feel like firing up the shack computer for SDR. The Hybrid SDR also allows you to use it in situations where you would like to not have to fool with the computer like in the field or mobile. Unlike the black box SDR radios, you are not always tied to a computer for operation. The Hybrids also offer a more friendly introduction to SDR for new users. They can plug the rig in and use it immediately and come to grips with the SDR part later. When SDR software is added, then the radio gains some of the features of far more expensive radios such as panoramic displays and additional filtering. What’s the downside? IQ based SDR radios don’t offer some of the perks of direct sampling SDR radios such as larger bandwidth and better signal processing. IQ based SDR radios can sometimes take a little more fiddling to get setup and running well. Hopefully more amateur radio manufacturers will consider offering more Hybrids in the future. The Alinco DX-SR9 retails for $799 with a street price of around $699 to $775. The nearest competitors to the 100 Watt Alinco DX-SR9 as of this writing is the 10 Watt Elecraft KX3 SDR hybrid at $899 (kit) and $995 (assembled). If you want to add the 100 watt power amp, that will be another $699 (kit) or $749 (assembled).  For the price of the KX3 and amp, you could buy the DX-SR9 and have money left over for a very nice shack computer. However, with that said, Elecraft does make excellent radio gear. The only other sort of close competitor is the 5 watt Flex 1500 black box IQ based SDR transceiver for $699. Having used and tested the Flex 1550, this is an excellent little QRP SDR transceiver. So, basically at this point it is fair to say that Alinco as no real competition in the 100 Watt SDR radio category in the $799 price range or frankly the $1500 and up range. The next step up would probably be the older 100 Watt Flex 3000 black box SDR at $1749.  Now to be fair, once you cross the $1500 range in SDR radios, it gets to be more of an “apples” to “oranges” comparison. The point is that the DX-SR9 presents a very attractive value for amateur radio users looking for an entry level radio and would like to experiment with SDR. The DX-SR9 was released earlier this year, so it is a relatively new product. The observations in this review are based on the current shipping firmware.

Note* The DX-SR9 does not cover 6 meters as most of the above mentioned radios do, however it does include FM modulation.


  • Coverage of All short-wave and HF amateur bands
    Covers the 160m to 10m amateur bands including 5.3MHz in SSB, CW, AM ,FM and IQ output modes. Output power is 100W SSB/CW and FM, 40W in AM with low and super-low power settings for QRP operation. In addition, the general coverage receiver covers 135KHz to 30MHz in all modes. (The RX sensitivity and selectivity are not guaranteed out side of the ham bands.)
  • Internal VOX
    Eliminates optional interface box for PC connection to operate data modes like PSK31.
  • Detachable front control panel
    Completely detachable front control panel with large LCD display lets you install the radio with greater flexibility whether in your car, boat or your shack. (Optional EDS-17 cable required)
  • Direct DATA entry via the key pads
    While the main dial tunes at the default 10Hz/resolution (adjustable in set mode), the numerical key pads can be used for fast direct frequency input, band selection and more.
  • Fight QRM with these STANDARD features
    Reject unwanted signals with the IF shift. Choose a narrow filter(AM 2.4KHz/SSB 1KHz, CW 0.5KHz audio-filtering), a noise-blanker or use RIT/TXIT to stay out of QRM.
  • Emphasis on CW Operation
    An electronic keyer unit is standard. You can receive CW using either upper or lower side of the carrier frequency. Choice of side tone pitch, FULL (QSK), Semi or Auto break-in, split, narrow filter, AGC and RF gain.
  • World-class transmit audio quality
    A dynamic microphone (T/E models) and a speech compressor come standard for sharp, clear and powerful transmitting audio.
  • Enhanced scan modes
    A variety of scan modes are available including Priority, Search, Busy, Timed, Memory and Programmed search. Timed scan setting does not require squelch-mute so you are able to monitor data-modes and broadcasts simultaneously with memory search scan.
  • Additional convenient features include
    RF Attenuator and Pre-amplifier selectable in 4 steps, / 3 TX power output levels with a Super-Low setting (QRP 0.1W~2W variable) / Dual VFO / 600ch memories in 3 banks / Connections for Auto-antenna tuner and Liner amplifier ALC output / Fully independent AF level, squelch, RIT and IF shift knobs / Dial lock and key lock / TX-RX lamp / Alphanumeric display / Auto-power-off / CTCSS encode for 10m FM repeater accesses / Microphone, Headphone and External speaker jacks on the front panel / Large, temperature-controlled internal cooling fan with anti-overheat output power limiter/ High-SWR protection and more!

New Forum for Ham Radio Science

New Forum

As of today, HRS has decommissioned the old forum. We were just getting too many spammers. The new forum will allow us a better opportunity to help reduce some of the spam. Unfortunately, we were not able to move the user database or the old posts to the new forum. If you were a member of the old forum, you will need to sign up again. The old forum will be available for a little while longer, but we will eventually remove it. Let me encourage you to try to post your comments and questions in the forum. I have noticed that the comment sections of some of the articles are getting a little unwieldy. You will probably stand a better chance of getting an answer to your questions, if you post them in the forum.

Thanks for your patience!


GNU Radio The Easy Way


Ready to take your RTL Dongle to the next level or learn more about how Software Defined Radio works? Try GNU Radio. GNU Radio opens up a whole new world of experiments you can do with SDR radio. GNU Radio also allows you learn more about how SDR radio works. Once you get your head around it, you can start building your own custom SDR radio applications. One of the show stoppers for a lot of people who would like to get involved with GNU radio is the requirement to install Linux on your PC. Then you have to download and build GNU Radio. This certainly can be daunting for those who are new to the Linux operating system. Well, you don’t really have to go through this anymore to experiment with GNU Radio thanks to Kali Linux.

Afedri SDR-Net 2.3a Review


Ham Radio Science occasionally get emails from our readers on suggestions for a good reasonably priced HF SDR radio that won’t break the bank. So, we spent a little time investigating what was available in the under $300 price range. Frankly, there is not much to be found with the exception of a few kits. The kits are great learning tools, but some of our readers may not prefer trying to build a kit that includes tiny sma parts. Also the kits and some of the less expensive SDR radios are still sound card based and we were really looking for a direct sampling receiver. The $249 Afedri SDR-Net HF SDR met our requirements and more. The Afedri Net-SDR allows for connection to your pc via an USB interface and what truly puts the Afedri SDR-Net in a class of its own is the ability to connect via TCP (Lan connection). After looking into the very positive comments on the internet regarding the Afedri SDR-Net, we thought it would be well worth investigating this amazing little budget HF SDR receiver. The Afedri SDR-Net is made by Alexander Trushkin 4Z5LV and is available in a case for $249 or as a board for $199 from Alexs’ website. We highly recommend the version with case, since the case is very well constructed. We contacted Alex and he sent us out a sample Afedri SDR-Net Vers. 2.3a to take a look at. We have been using the Afedri daily for HF monitoring for about a month and have been very impressed with what you get for the price.