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Reviews For: MFJ-986

Category: Antenna Tuners/Matching Networks

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Review Summary For : MFJ-986
Reviews: 79MSRP: 330
Description:
Covers 1.8-30 MHz
Product is in production
More Info: http://www.mfjenterprises.com/products.php?prodid=MFJ-986
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00793.6
N2KEN Rating: 2003-12-07
Good, but needs maintenance Time Owned: 0 to 3 months.
MFJ-986 Differential-T Tuner

I purchased an older version of this tuner that is several years old, at a "bargain price". I've used the newer model as well, but prefer the look and feel of the older model. I use it with my Ameritron AL-811H amp and 2 element TGM hybrid mini-quad antenna. It does a very nice job fine-tuning for lowest SWR match on 10-20 meters. When handling a gross mismatch with this antenna on 40, 60, and 80 meters, the tuning bandwidth is very narrow. But, I'm usually able to achieve an exact 1:1 match. I haven't used it on 160 meters.

I like the tuner, however it has the "typical MFJ" mediocre quality control issues. Inside the tuner is substantially built (components appear and feel rugged). However, several of the solder joints and connections were haphazardly done. Soldering 101 should be on the MFJ employee training list! One of the SO-239 connectors had only a minimal dab of solder on the feed wire. Several other MFJ products, new and old, had similar poor solder joints that required attention. I re-soldered all connections prior to placing it into service. MFJ should seriously consider an ISO 9000 quality process!

The older version 986 has a different roller inductor coil construction than the newer model. I like the smoothness of the weighted knob and utility of the little spinner handle. The drive uses a small rubber belt that turns the roller assembly using small plastic pulleys. These features and coil construction that places the contact wheel external to the coil, gives the inductor a very smooth feel. Nice! I like this drive method much more than the flimsy, choppy, and stiff feel of the newer dimple-type spinner knob and nylon gears. Not nice! The capacitor knob is also weighted and gives a pleasing, smooth feel as well - unlike the newer units that feels toy-like and "cheap". Also, the antenna selector switch has a very sturdy, positive, and husky feel, which I like. The differential capacitor has an impressive, heavy-duty appearance with thick, sturdy plates and rigidly constructed support frame. The newer model's capacitor looks similar.

The single capacitor is easy to adjust, but really does not save any time compared to using the MFJ-989C or 969, which I've both used (I own two 969 tuners and they are just as easy to tune). A recent antenna tuner review in QST points-out that the efficiency on the lower bands of the single capacitor is significantly less than the dual capacitor designs. I haven't seen any practical effect in my shack. Tuning is quick and very intuitive, usually requiring two or three sequential tweaks of the inductor and capacitor until a perfect match is achieved. I did notice a few sporadic spots on various bands (17, 40, and 80 meters where an exact 1:1 match was not possible. Worst case is 1.3:1. I can live with this. The 969 with both transmitter and antenna capacitors has no trouble with 1:1 matching with any antenna I've used with it.

I also doubt the 986's ability to handle a full 1.5KW across every band. Labeling it a "3KW Roller Inductor Tuner" on the front panel is just plain absurd! I've experienced a few arcing situations with the roller inductor at just 700 watts PEP, about the maximum output of the AL-811H on SSB. This occurred on 17 meters and ironically the antenna SWR without the tuner in line was just 2.0:1. The arcing was from the center of the inductor coil to one or both of the top, long support bolts or roller inductor contact wheel support shaft. I found that the inductor contact wheel, support shaft, and mounting frame all needed cleaning, tightening, and slight bending to achieve consistent inductor wheel and support frame grounding contact. The RF grounding apparently deteriorated due to routine wear and tear. The tuning weak spots also improved (but, were not entirely eliminated) with this easy maintenance procedure. This seemed to solve the arcing problem before any damage was caused.

I would recommend being very cautious feeding moderate to higher power levels into this tuner without fully inspecting it (Do your own quality control). Ironically, I've frequently pushed my MFJ 969 tuner (rated at just 300 Watts) up to 600 watts PEP on 17 and 20 meters SSB without any signs of arcing. Maybe the newer inductor design resists arcing better.

I like the tuner, but would not fully recommend it to the inexperienced operator. If you decide on this model, consider the toy-like feel of both the newer inductor drive configuration and capacitor knob. If MFJ could create a tuner with the same smoothness and pleasing feel of the older 986 tuner and refine it to avoid the inductor arcing, this would be a 5. The MFJ-986 Differential-T Tuner is a good value if you find a cheap used one and like to tinker. If you can tolerate the newer (and displeasing) spinner knob feel, the redesigned inductor might require less attention and reduce the potential for arcing. 73, N2KEN.
VE6XL Rating: 2003-11-16
Could use a bit more quality.... Time Owned: more than 12 months.
I have used this tuner for several years. It requires a fair amount of maintenance to keep it going.

Recently I noticed the match jumps and it is difficult to obtain a solid match. I believe the roller inductor is its weakest point.
G0MGX Rating: 2003-09-29
Poor Quality Lets it Down Time Owned: more than 12 months.
Owned for just over 1 year - feet fall off regularly, meter came come loose from the front panel and most recently the shaft extension for the coax switch fell apart (where do you get a US hex key in the UK?!).

Tuner works fine, but would prefer that my £300 investment didn't need repairs in the shack quite so often!

Quality control clearly lacking in this and several MFJ products that I also own.
K8JS Rating: 2003-09-04
Older Version OK, Newer Version Not-So-Good Time Owned: more than 12 months.
I first bought a pre-owned, like-new, newer-type 986, the one with a movable grounding tab that contacts a section of the rollor inductor.
I found that this so-called "Resonance Killer" device limits the tuning range on 10 and 12 meters, and also caused intermittant tuning results for 10 and 12 meters.

later I sold it, and bought a pre-owned EARLIER version of 986 that did NOT have that stupid Resonance Killer built into it.
This earlier version seems to be built much better internally and tunes up my antennas very well, no strain-no-pain, all 9 Ham bands, from 10 thru 160.

I like that cross-needle SWR meter, which seems to function very well, and the turns counter dial seems to still be working OK after several years of usage.
WX8B Rating: 2003-05-15
Decent Low Cost Tuner Time Owned: more than 12 months.
I have had this tuner for about 10 years and it has tuned anything I have thrown at it without a problem with power up to 1 KW. I use it mostly with balanced feedline and it works great.

The SWR/PWR meter is fairly accurate. The biggest problem is the band that moves counter slips so that it needs to be reset from time to time.
KE4IZA Rating: 2003-05-14
Absolute Garbage Time Owned: 0 to 3 months.

I recieved my NEW MFJ-986 tuner today. What a piece of junk. Most of the case screws were loose and 3 were stripped out. There are 2 large screws on the bottom of the tuner that hold the tuning capacitor in place. Both were loose with the front screw half way out. To top it all off the tuner is dead. Does not feed a signal through. 5w in got me 0w out. Nothing on any selection. Steer clear of MFJ. Real trash.
WD4AWO Rating: 2003-05-10
Works great!!! Time Owned: more than 12 months.
Any problems with this simple easy-to-use tuner can be attributed to inexperienced operators. Accurate SWR/Wattmeter compared to a Bird 43.
AA8EK Rating: 2002-03-02
aood tuner for the money Time Owned: 0 to 3 months.
I bought this unit new in Ocotober of 2001, I got it at R and L Electronics for 284 dollars out the door. I have no complaints with the unit and it tunes everything I have thrown at it on all bands, 80 through 10 meters. But one of my buddys bought the same tuner from MFJ, he put 500 watts to it on CW, the thing popped and now the meter dosn't work on his. He doesn't like the tuner at all. I think it is good buy for the money. It just depends on who you talk to about it.
Steve
AA8EK
WD5BJQ Rating: 2002-02-09
Good Tuner up to 1KW Output Time Owned: 0 to 3 months.
I purchased one of these units on ebay. I paid $200.00 used, and it is the older model with the painted face plate. I am not sure if the model that is being sold today is any better/worse. I specifically wanted this one because I have a friend who told me it was better?? I see the newer ones now have Lexan. Very pleased with the unit on all bands, and very easy to use. If you intend to run more then 1KW CW, buy yourself a Ameritron ATR-30. I have a AL-1500 and an Alpha99 and it handles everything I have been able to put through it.
N7UQA Rating: 2001-08-17
Good tuner for near QRO power Time Owned: more than 12 months.
I have owned this tuner for nearly 10 years, in that time it has given good performace. I have run an SB220 at nearly 1KW through it with no problems even with very high mis-matches on 80 meters. This tuner is very easy to operate and will just about tune just about anything you attach to it. I did have one problem with the roller inductor input shaft breaking loose but it was a fairly easy fix. Even though it handels a KW on most bands I would recomend not to run more than 500 watts on 160 meters...