MFJ tuners really that bad?

Discussion in 'Amateur Radio Equipment Reviews' started by KF7WMM, Oct 19, 2013.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I've owned a few, and used a few others elsewhere and I think their high powered tuners are a bit overrated for power handling, but actually fine designs. They're well validated designs. The only issue is material selection and workmanship.

    Problems do occur, but it's the luck of the draw. They're not assembled by robots. If they were, they'd be better.:eek:

    I'm not fond of Palstar after having some of their stuff fail. The Ameritron ATR-30 is probably the "strongest" manual tuner out there, IMO. Never had one fail, even through a lot of abuse and squeaking power above the legal limit (accidentally, of couse!) several times.

    Also true that tuners aren't difficult to homebrew. Very easy, actually. The trick is finding the right components. The "box" isn't early homebrew tuners, even running a kilowatt, had no enclosures -- they were built on a sheet of plywood and worked fine. The "shielding" on a metal-cased tuner isn't so much to prevent radiation as to prevent the user receiving RF burns from touching stuff when he's transmitting.
  2. N4IAG

    N4IAG XML Subscriber QRZ Page

    I've been using the MFJ-993B for a while now and haven't had any issues other than the meter lamp burning out, which I replaced with an LED. This thing has spoiled me, it's nice to instantly tune anywhere with the touch of a button. 5/5 for me. :cool:
  3. KB1NXE

    KB1NXE Ham Member QRZ Page

    No, just a ham who doesn't know the rules....
  4. NO9E

    NO9E Ham Member QRZ Page

    Regarding 962C, it has a coil switch with one contact too close to a bolt. I put some glue around it and the tuner worked pretty well for some 15 years. With > 1 KW on lower bands there was a slow creep in SWR. Probably the coil warming.

    MFJ-998 did all of possible jokes. After adding some caps and especially after grounding to the amp, it started working very well.

    I had 945 and 989, and was not much excited.

    Ignacy, NO9E
  5. WA8JXM

    WA8JXM Ham Member QRZ Page

    Probably a good choice. I have an old MFJ-Versa tuner that I used for years. It worked without problems but I always wondered about it's efficiency. I bought a Palstar AT2K last year, very happy with it, well built. Oh, I also had an MFJ927(?) remote tuner. It died under warranty, took them 3+ months and badgering to return it. When they did, it didn't work. Poor buying choice on my part.

    I'd still like a remote tuner and am looking at the SGC-239, which is under $200. Yes, it requires a weather proof enclosure, but then the MFJ did too since the cover didn't fit in their box and cracked the corners.
  6. AA4HA

    AA4HA Ham Member QRZ Page

    I look at MFJ products as something better than homebrew. It gets all of those nagging mechanical details worked out so you are not drilling and bolting things together. You need to have a Zen-approach.

    The day it arrives you open it up, resolder all of the connections, check the wiring and tighten the screws. Usually it will be OK after that.

    Also that gives you that idea, "what if I add a doorknob capacitor "here"?".
  7. N2DOW

    N2DOW Ham Member QRZ Page

    As some have already stated, with MFJ it is not a design problem that usually occurs but the assembly process.
    It's not how it's built but who built it..
  8. K7MEM

    K7MEM Ham Member QRZ Page

    I like AA4HA's take on MFJ. I never thought of it quite that way. I like MFJ products because of the variety and low cost. And because of the even lower cost when the broken products turn up at ham fests.

    I picked up a MFJ-941D Tuner at a swap meed for $15. It was cheap because the SWR/Power meter didn't work. It turned out that it must have been over powered because the diodes were open and null trimmer was shorted. Plus small plastic cup that usually holds the internal balun was melted around the balun. But I fixed all that and, after a little calibration, it worked fine. Oddly enough, I tested the balun and it wasn't toast. Overall, it only cost two diodes and a small trimmer. One year later, for some unknown reason, one of the diodes again went bad. But that was easily fixed again. It took longer to disassemble the unit, than it did to actually fix the problem.

    Another time, I also purchased MFJ-16010ST "Super Tuner". It was a small tuner ( < 100 Watts) but it didn't work. I bought it for a few bucks and thought that I could use the parts for something. After inspection, I found that the common wire from the tapped coil had broken off. It was hidden nicely under the switch mechanism and difficult to see. It worked great after I fixed the wire. I used it for years until it got in a fight with some lightening. The lightening welded all the capacitor plates together and burned a hole though the case. But then, I didn't expect it to be lightening proof. I don't think they will take it back now.

    I also have a MFJ-259 antenna analyzers ($100), a old MFJ-842B memory keyer ($9), a MFJ-752C audio filter ($15), and probably a few other things that I have forgotten about. I bought them all used, and saved a little bit of money, so I can't complain.

    If you like tinkering with your equipment, MFJ is the way to go.
  9. NN4RH

    NN4RH Premium Subscriber QRZ Page

    I've had an MFJ-949E, MFJ-969, and a Palstar AT-500.

    The MFJ-969 was very dissappointing. The roller inductor the used in that thing was cheap out of round crap and contact was always intermittent in areas. Also I had to resolder the connections to the roller inductor and the coax connectors.

    The Palstar AT-500 was a very attractive "well built" tuner but did not have nearly the wide range of the MFJ-949E. Not even close. Plus with that Palstar is that you had to supply external power to even use it. There's a relay in the thing that has to be energized for it to tune on any band 80-6 meters. Without exgternal power, it would only work on 160 meters. Why in the world anyone would design it that way I don't know.

    I had that MFJ-949E for about 8 years. I wish I had kept it. It would tune just about anything from a dead short circuit to a railroad bridge.

    I also briefly had an SGC MAC200. Completely useless junk. Luckily HRO let me return it.

    The past couple years I've only had resonant antennas and only have needed a small tuning range which the autotuner in my FY950 easily covers.
  10. WA1FOK

    WA1FOK Ham Member QRZ Page

    I have a mfj 949e and had to replace the inductor switch because it was so flimsy and poorly designed. I would suggest building your own , it is not very difficult. Good Luck
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