Now low power portable SSB radio - the ALX-SSB

Discussion in 'Electronics' started by DKR, Sep 14, 2018.

  1. DKR

    DKR Scout

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    Nov 3, 2014
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    Review - ALX-SSB transceiver.

    ALX-SSB transceiver – Front panel view.

    ALX-SSB transceiver rear panel

    What this review covers:
    This review covers a 'new' to the North American market portable, low power SSB radio set. QRVtranics, out of Sugar City Idaho, sell the ALX-SSB radio. See

    What is this radio?
    The ALX-SSB is based on a modified board, sold as the CS series by QRVtranics. See [​IMG]

    The base radio is the CS series from CRkits in China. See

    What's the difference?
    The CS series from CRkits has a digital VFO, but no display - past a simple tri-color LED. In other words, very hard to track your actually frequency.

    The CS series from QRVtranics has a digital VFO and the option of a digital display, two different types, in fact. More on this later.

    The ALX-SSB is the CS main board, a new digital VFO and display as shown above.

    Any of these versions of the radio may be purchased as a kit or as a fully assembled and tested radio.
    Notethere are no SMD parts – this is fully thru-hole. Anyone that would have tried a Heathkit of old can easily build this radio set. There is less point-to-point wring on this rig than in my old HW-7, for example.

    Full disclosure, I have no interest in QRVtranics, but I have provided some suggestions to the vendor for the documentation of the radio set. As an aside, I wrote a 60 page operations and technical manual for the MFJ-9296 (-9200) travel radio a couple years back. The radio has since been discontinued. Still, it was a lot of fun to dig into the rig.

    Alright already, what's the deal on this rig?
    I'm glad you asked. This is a small, single conversion, HF radio that has full band coverage out of the box for any one band and up to five bands within the US Amateur Radio Service. Power out is 10 watts (slightly lower in the higher bands). The rig can be had as a kit or fully built by the vendor. It has full, English language, technical documentation. Yup – Native English, not transliterated Chinese (Chinglish) crud normally seen on the low end market.

    Pretty cool, but the clincher for me is that the VFO is based on an Arduino chip and the software is open source!

    One of the big concerns most hams have with the low cost, QRP rigs seen on the market today is the proprietary MCU (control chip). Lose this and you own a brick. Add in densely packed SMD parts, parts that are unmarked for the most part, no technical documentation or schematics and you have a radio that - if it faults, realistically, goes into the trash.

    The radio is available as a kit, with full build documentation. Repair, maintenance and hacking (more on this later) are a breeze as all the data needed are available. The parts are quality, not take-offs and are well marked.

    Cost for the kit as a single band, with the speaker/mike is $150 US dollars, plus shipping. All manuals are on line at the QRVtronics site as PDF documents with illustrations. Full band coverage and up to 10 watts output. The rig is available as 80/75 Meters, 40, 20, 17 or 15 meters. Ask for a quote for the multiband unit, as several options are available.

    The radio is a common NE602/LM386 kind of setup. The final PA transistor is a IRF-510, which is noted for being more tolerant of high SWR at the antenna. The radio has a reverse polarity protection diode as well.

    If you want to use this in the field, my suggestion is to add the QRPQuys antenna tuner ( I have and use this paired to the rig. The tuner is sold as an easy kit, taking less than an hour to assemble.

    Dimension: 6.0 x 3.75 x 2.0 inches including feet not including connectors and knobs.
    Weight assembled: 12 oz., not including microphone. The dual/multi band version is slightly heavier.
    . Power Supply: 12 to 13.8 V, 3 A
    . Current consumption: 70 mA in RX and about 2 A in TX @ 13.8 V
    . RF output: about 10 W PEP @ 13.8 V typical
    . RF output for 15, 17 and 20 Meters will be lower
    . Sandwich digital VFO integrated with the LED hole pre-drilled
    . Stable and accurate frequency like a crystal
    . Both USB and LSB are be supported by changing BFO frequency in calibration mode
    . Sensitivity: about 0.5 uV at 10 dB SNR – or 0.1 uV for MSD.
    . UNBAL jumper added to intentionally break the balance of NE602 to allow more convenient TX power peak alignment and antenna tuning (to generate a carrier for alignment)
    . Low dropout diode is used to allow a bit more battery life
    . Final power amplifier IRF510
    . Speaker microphone available
    . IF filter: 6 pole crystal ladder filter + 1 pole post IF amplifier crystal filter
    . IF bandwidth: about 2.0 KHz
    . IF frequency: 8.467 MHz
    . Connectors: Speaker, Microphone and Antenna
    . Antenna Connector is: BNC type

    My early bench testing showed that full band overage and power output specs were easily met on my rig. The sensitivity levels were met with no problem. Actually, it took some tweaking to get my SIGEN to that low a power level.

    NOTE - power output is input voltage dependent. On my 8xAA NiMH battery pack, power was 8 watts on 40M and just under 4 watts on 20M. On a fully charged AGM battery, full power was no problem. My new 10 x AA battery packs work the treat with this rig.

    MORE to follow
    central joe likes this.
  2. DKR

    DKR Scout

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    Nov 3, 2014
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    Part 2 - seems I ran up against the size limit....

    The controls are basic. On/Off. Volume. VFO tuning. No Receiver Incremental Tuning (RIT) or Clarifier. The VFO does provide for very fine tuning. Just no offset. USB'LSB selection is baked into the software and cannot be shifted on the fly. The display either may be an OLED or LED. I chose OLED for the lower power use.

    Attach battery, antenna, speaker/mike.

    Turn the rig on. Set VFO. Communicate. Hard to get any easier than that.

    The radio receiver has no ALC loop. The rear panel connector labeled "Speaker" means just that - use a speaker. Use of headphones is something I would strongly discourage. A near-frequency tuner-upper will leave your ears ringing…

    The speaker/mike is a modified commercial unit with matching 8-pin connector. You can roll your own, but I doubt you could do this for the $10 price – your call.

    Transmitter is clean and puts out enough power to be heard with a NVIS antenna setup for nearby (up t0 300 Miles) communications. This is solid state, broad-band, no tuning required. If you are using a non-resonant antenna, an external tuner is required. With 10 watts output, you will need the distant station to do some of the heavy lifting. Just the same, the rig has more than enough power to work DX, if that is your thing. For disaster comms, 10 watts is a good compromise between power out and power consumption.

    The rig can be had with up to five bands in this new ALX layout. I have the older two band setup for 40 and 20 meters, a good choice for Alaska.


    Dual band filter board. That empty real estate on the side of the board is used for additional filters.

    I have to give Larry, the owner of QRVtronics, a lot of credit. He took a basic kit and modified it for multiband use, with both filers and software to make that possible. Which is my Segway onto the 'hacking' part of this review.

    The VFO runs on a Si5151 chip, controlled by an Arduino computer.


    You can see the Arduino parks nicely on, the (modified) VFO board. It has on-board power conditioning (3.3VDC) to it is truly self-contained.

    The software is simple and easy to modify…let me explain. The rig comes with full band coverage for the US ham bands.

    I, on the other hand, want to read the mail on 30 Meters and have access to WWV for use as a propagation aid. Having the remaining SW broadcast stations is a good deal as well. In addition, the 40 Meter band is different for Alaska than in the L-48. I wanted the rig to come up in the middle of the Alaskan 40 meter band.

    For that, I had to modify the software. Fortunately, that was fairly simple. The Arduino IDE software is a free download and the code for this rig is heavily commented.

    Here is a sample of the code:

    Si5351 si5351;

    // Wiring: Connect common pin of encoder to ground.

    // Connect pin A (one of the outer ones) to a pin that can generate interrupts (eg. D2)

    // Connect pin B (the other outer one) to another free pin (eg. D4)

    volatile boolean fired;
    volatile boolean up;
    volatile boolean khz = true; //tuning step in 1k Hz or 100 Hz in normal mode. calibration mode is not affected by this.
    volatile boolean mode = true; //true = normal mode; false = calibration mode. To enable the calibration mode, press and hold the encoder switch and power on
    volatile boolean CALIBMODE = true; //true = bfo adjustment in 100 Hz step in calibration mode; false = crystal calibration in 20 Hz step in calibration mode.

    If this seems like gibberish to you, there are a ton of sites that will walk you thru the code. Or, you can just save the code in case of a VFO problem. For the remaining commercial gear, and almost all the low-end stuff from China, this is not an option. This software for the rig is available for download, if you wish to look at the entire package. See

    Bottom line:
    This is a good quality, but relatively inexpensive SSB HF rig with 10 watts out. It's simple interface is so basic, a child can operate it. In a disaster situation, simple is better. No menus, no memories, no hassle. You can listen to AM SWB, with some care in tuning.

    The rig offers the opportunity to modify the Arduino code for listening out of band, the radio is made with through hole parts, so local repair is at least possible. Full documentation makes identification of parts simple. And they are obtainable from any numbers of vendors on line. The kit assembly instructions offer trouble-shooting tips as well. Use the supplied links to check any details where you would like to know more.
    RavenLoon and central joe like this.

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