Q: "Malachit" SDR receiver"??

Discussion in 'Software Defined Radio (SDR)' started by WB2GCR, Mar 13, 2021.

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  1. WB2GCR

    WB2GCR Ham Member QRZ Page

    There are some larger than need be MFJ and similar items.
    Seems to me that this is a clear DIY project, if one wants it to be small enough.
    I was just looking at this myself.
  2. WB2GCR

    WB2GCR Ham Member QRZ Page

    Did you do the two control press-in and then reflash the processor with the firmware?
    Or was it only the Demo firmware?
    I think the Demo firmware can be had too, but I have not looked into that...
  3. N2DTS

    N2DTS Ham Member QRZ Page

    I tried everything repeatedly.
    All it did was increase my blood pressure so I put them in the trash.
  4. WB2GCR

    WB2GCR Ham Member QRZ Page

    With the Chicom Malachit running as the "detector" on the IF OUT of my R-390a, it has so far been
    very useful and good. Running "real" software, not the Demo. Locked on 455kc.

    The NR (noise reduction) function, while not adjustable is quite good and useful, including
    getting rid of static crashes!

    It has been necessary to use an attenuator to drop the level to the ANT input, about 40db
    +/-. I have not quite figured out the AGC threshold settings, but using a KAY switchable
    attenuator in line, it's easy to keep signals in a "sweet spot". More atten when conditions are
    good, and less for weak stations or poor conditions. Not necessary to switch often.

    AM detection is ok, not as good as direct out. I seem to find less highs - and will have to revist
    the bandwidth settings, but they ought to be wide enough, but audio (same speaker) seems not
    quite as crisp or clean. Otoh, is is ok, and being able to kick in the NR is a good thing. I can go
    back to 390A audio quickly, as I want. Not sure the Synch AM actually does anything, but it
    sounds better than the plain "AM". No audible "pull" during lock-up, if it does lock up!?!?

    SSB is killer good. As good or better than any SSB converter I've used. (the total audio on the
    tube type rack mounted TMC converter is better, but...)

    The display is fine. It is useful to see the bandwidth of the bandpass of the 390A.
    (would be nice if they included ORANGE as a trace color, but they don't)

    It is totally unclear what the dynamic range of the display is - no markings. Ha.

    I'll be moving the pickup point to a spot where the IF module gets its feed. That will permit
    a very wide swath to be displayed. We'll see how it performs when presented that signal. I expect
    that I will need a little unity gain buffer module.

    Apparently not all the Chicom versions are NOT equally good or reliable. This one, so far is good.
    I got it cheap, cheap. So, I am satisfied. Personally, I would NOT recommend this SDR for the over
    $100 hardware prices + $55 Ruskie software. Not. But one may be able to pull the whole thing off
    for under $100, with some luck. And then, if it works like this one, it's a good deal, good unit that
    adds considerably to the functionality when used as I have - looking at the IF of a radio. (keep in mind this
    unit can tune up to 2Ghz - allegedly - so if you can pick off the IF, it will run off many radios, not
    just 455kc radios!)

    Oh, it's not going to fly as a stand alone radio, due to the BC band overload potential - but with filters, or a preselector
    it would probably be ok for casual SWL and other listening. I've yet to try it on FM or up on VHF/UHF.

    Anyhow, just a few somewhat random reports...


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