Manager


Manager - NA4M
Manager Notes

Reviews For: MFJ-989C

Category: Antenna Tuners/Matching Networks

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : MFJ-989C
Reviews: 144MSRP: 360
Description:
Handles 1500 watts PEP SSB output power
Product is in production
More Info: http://www.mfjenterprises.com/products.php?prodid=MFJ-989C
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
001442.7
WD5KCA Rating: 2004-02-10
Mine is ok Time Owned: more than 12 months.
I see a lot of bad reports on this tuner. Mine has been working just fine for 6 years. I knocked it down a point because the meter is not very accurate.

The first thing I notice is that mine does not match the picture shown on here and on the MFJ advertising. The case is metal and everything is connected solid. Maybe I have an older version?

Mechanically it is ok. The knobs turn with reasonable effort and there are no glitches. I haven't tried to tune some extreme antenna system. I have used it only to tweak my inverted vee for increased bandwith. I occasionally run up to 1kW with no ill effects.
KB7UXE Rating: 2004-01-05
The Henery Ford of Amateur Radio Equipment Time Owned: more than 12 months.
And so it goes.....
In an attempt to lighten my dipole, I replaced my heavy duty home brew center insulator with a light weight budwig center insulator. I use an old SB220, mfj 989C, and icom 736. A short time after the center insulator swap I noticed the swr was, well, unstable. that is, durring a qso, it would change, also my tuner settings were really differnt, and my recieve was didn't werk so well either.. So I checked the coax with an ohm meter and found a direct short! OUCH! The coax ( RG8X ) and the budwig had melted creating a direct short!!!. DUHHH... Now I can't fault the bud wig, It is a wondeful light weight, medium power center insulator, it just wasn't ment to operate at 1.5kw. But I do believe no other tuner would have even servived operating much less even tune into a direct short on the end of about 200 feet of coax.
It did tune and handle the 1.5kw into a direct short for several hours with NO problems !! I just can't say enough on how durable this equipment is.
I just can't believe how some folks talk down mfj. ok, it may not have a fancy case, blinkin lights bells or whistles, but then I always liked functionality over frills. Everyone is entitled to their opinion. I must say this event has made a MFJ believer out of me! Again, 1.5kw into a direct short with NO problems. do the math.
I view MFJ as the Henery Ford of amateur radio equipment, low cost and reliable.
Thank you MFJ.
VE4SR Rating: 2003-11-25
It works, but ..... Time Owned: more than 12 months.
I have had this tuner for about three years. I purchased it new, and right away I had to resolder a couple of loose connections. The noisy roller inductor bothered me and I thought it was a defect, but apparently they are all noisy. I also had to change the sensor circuit board which quit working for some reason. It seems to work fairly well now, but I do have concerns about just how long it will last. If I had to do it again, I would likely buy a Palstar tuner rather than this one.
VR2AX Rating: 2003-11-02
Good within its design limitations Time Owned: more than 12 months.
Bought mine from HRO in San Diego while on holiday in 1996. Initial reaction when I ran my new ETO 91B into it to tune a vertical on 160 was not at all good, very disappointing actually. However this is a design issue with this and generically similar tuners and the Nye Viking tuner which uses a pi network design (not the N4XM tuner however - see March 1997 QST for a comparative review). I found quality of construction and components to be ok. The problem is the T match design in the 989C just will not tune everyday antennas efficiently on 160/80 with high power because the 240 pf capacitors are too low value. Putting wide spaced air variable capacitors with a rating of 4.5 kv (not 6 kv as claimed by MFJ) is no good when the capacitors have insufficient capacitance. The voltage across the 240 pf caps when 'tuning' a simple 50 ohm resistive dummy load on 160 would be 2.5 kv rms at 1500 watts. The coil would be drawing 10 amps and wasting 350 watts of power at a Q of 50. Imagine the effect of a load other than 50 ohm especially low impedance capacitative loads. At least 500 pf and preferably 600 pf is needed for each capacitor otherwise the result will always be arcing at US legal limit and excessive current and loss in the coil on 160/80. Increasing the capacitance to 600 pf as in N4XM's design lowers the voltage and current to levels where the T match tunes with acceptable loss and no drama. I have however found MFJ's customer service to be second to none. I dropped my unit off the table onto its rorary inductor handle and wrote off the coil and ceramic standoffs a few months after carrying it home form CA. Despite telling MFJ what I had done they treated it as a warranty repair case and sent me a new inductor and standoffs which I installed. I just paid the carriage from Hong Kong to MFJ and they paid the return shipment. MFJ have deservedly suffered for grossly overstating the spec of this tuner. I do not regard it as at all suitable for 160/80 for the above reason. On 10 it is also inefficient because the coil is too close to the metal enclosure which lowers the Q and increases losses. For 1500 watts pep I believe it is a reasonable amp for 40 to 15/18 metres. Under no circumstances should 3 kw pep be put into it on any band.
KB3JZG Rating: 2003-10-14
Dont do it Time Owned: 3 to 6 months.
With all fairness to MFJ, ( not really ), I had bought this one slightly used, and its junk. I dont think you could ever expect to be at the same position twice by using the indicator for the roller inductor, without having to reset it every time you used it. The roller itself is very "noisy", meaning a very slight adjustment of the roller can make a huge difference in the value. Like some others said here before me, this thing isnt worth the money. This is the second MFJ tuner I have had, and it will be the last. The first was a 949D, which had the cheapest rotary switch made in it, and this unit didnt use much more expensive parts then that one had. I had expected to get something a little better then what I got for this price.
K8CKW Rating: 2003-09-21
Good and easily modified Time Owned: 0 to 3 months.
In all fairness to MFJ I find this tunner to be very well made. I had no problem with the construction. I installed a reduction drive for the tx cap for finer tunning control (6 to 1}. I also changed the roller inductor knob to a crank style knob that is much easier to use. It performs exactly as inditcated in qst. I run 210 watts into it with no problem. All my antena's are 3.4:1 swr or less. If you know what your doing the 989c should work fine. Tune up at lower power first and increase power as you get closer to a match. Avoid trying to match strange complex impedence. The load shoud be reasonably close to what you expect from a 'real' antena.
Good radio practice makes all the difference. I might replace the roller inductor with a heftier job from Tucker should I decide to use a kw or more. But for now it works just fine. For the price this is a fine tuner. The 3kw claim is for intermittent peak tx and an explanation of this is in the tuner's manual. I have no connection with MFJ or its affiliates.
KF7VZ Rating: 2003-08-27
owned one for several years, seems to work OK . Time Owned: more than 12 months.
I have owned a 989C for several years. Always worked for me just fine, even with my Ameritron AL-811H fired up (seldom)> I now use it for MARS operation all over the spectrum on HF.I do not like the "rubber belt" dial drive. The original lamp is still working. The quality is OK as I have no parts rolling around, and it has always worked OK for me. I understand the later ones have quality control problems, or none at all.
Remember your antenna and ground is the most crucial element in your station. This from an old timer, hi only 45 years on the air. 73 de KF7VZ
WA4JAF Rating: 2003-08-13
Can be good! Time Owned: more than 12 months.
I bought mine used (fried) for $100. I repaired it for a few bucks and about 3 or 4 hours of time well spent. First of all....DON'T buy a new one! If you have to have a new tuner, get something else. Here's what I did to make mine work...
Replace the insulating pieces that are part of the capacitor assemblies. The ones that were there from the factory were made of some kind of phenolic material, or maybe "rye-krisp" crackers. At any rate, they broke down under high-voltage and smoked. I used Delrin plastic but I am sure Plexiglass or Lexan would do the job. Use the old pieces as models to copy from (if they are still intact). I also replaced the stand-off insulators that go between the caps and the chassis. Now for the roller-inductor...
I polished the coil with a 3M Scotch-brite pad (green). Be sure to clean off the dust when finished..you can do this with alcohol and blow it off with compressed air or the aerosol duster spray. Apply a coating of NO-OXID grease to the coils. Dont goop it on too heavy, just enough to protect the surface. Do the same procedure to the roller-slide wheel. I now have a tuner that so-far works good and can handle 1200 watts or so without any problems. The design of this tuner (circuit-wise) on paper is good. The problem began when it was put into production using poorly chosen materials and Quality Control that is, in my opinion, poor at best.
Hope this helps those folks that are struggling with this piece of gear.
73 and best of luck to all.
Ken Pascal - WA4JAF.
EHAMMEMBER Rating: 2003-07-31
POOR-AWFUL Time Owned: 6 to 12 months.
Like the majority of reviewers, I too had major problems with the antenna tuner. MFJ’s description (specs) of the tuner is far, far from correct. I figure that’s why the majority of these reviews are negative. Take this to the bank, this is not a 3KW, 2KW, or even a 1.5KW tuner. It’s closer to a 500 Watt tuner.

In response to N1LYC (the real ham), I had the 989C MFJ tuner. It was junk. I shouldn’t have to begin working on the unit immediately. I had purchased the unit new. It was never my intention to pay $300+ for a kit. If this is what MFJ intends to do, they need to sell the unit as a kit in the beginning.

So, to the real hams, and the fake ones too, pass one this one.
W2DAP Rating: 2003-07-22
Purchase a real "tuner" like the XMatch Time Owned: more than 12 months.
I have an older 989C with a history.....High losses while matching impedances well within its rated range, meaning VSWRs of 4:1 or better...try it with 500 watts PEP on 160 and be prepared for a really HOT box! My lamp burned out early; the flimsy plastic shaft coupling the tune knob to the capacitor, split and is working again thanks to a load of silicone cement....I found a rubber band to replace the one which couples to the turns counter and snapped...No it is not resettable now, but hey, it wasn't before either! I run it as a backup these days with my AM gear at about 100 watts carrier and 2:1 VSWR or better, and it seems OK for the moment.