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Reviews Categories | Antenna Tuners/Matching Networks | MFJ-994 Help

Reviews Summary for MFJ-994
MFJ-994 Reviews: 29 Average rating: 3.3/5 MSRP: $Price: $359.95
Description: The MFJ-994 600 Watt IntelliTuner automatic antenna tuner
Product is in production.
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K8DXX Rating: 2/5 Jan 19, 2018 09:45 Send this review to a friend
Does NOT Work Like My MFJ 939I  Time owned: 0 to 3 months
Well, sorry to say, I have to revise my initially glowing review. My 994B did start out working like the MFJ 939I 100 watt auto tuner. Then, it appeared to develop a relay problem. On my 40 meter antenna where the typical unmatched SWR was 2.5:1 (too high for my ALS 600 amp), the unit would try to tune (activate the clattering relays) and achieve the same 2.5:1 SWR. Perhaps 1 time out of 20, it would make 1 clunk and achieve 1:1. Repeating the tuning process would revert to the 2.5:1. I did perform the "relay test" as documented but could not get conclusive results.

Using this same antenna, ground, etc. my IC 7300's internal matcher consistently achieves 1:1. My external MFJ 939I also does the same. I've talked to MFJ people before and they've been consistently helpful. The guy I reached today seemed impatient. So, it's going back to HRO for a refund.
KD7XL Rating: 3/5 May 23, 2016 13:31 Send this review to a friend
Technically good. Bad user interface.  Time owned: 0 to 3 months
After using the MFJ-729 tuner with my Icom IC-7000, I bought this tuner to handle the 600W from a new Ameritron ALS-600 amp. Like the 729, the tuner does a good job of matching my antennas on 80-10 meters. However, I did have some problems getting it to work. I've noticed several reviews noting problems that seemed to indicate a defective tuner. I suspect many of these issues were caused by the bad user interface on the 994B.

Note that I bought the MFJ interface cable that connects to the IC-7000. If there is a interface cable for your rig, I recommend getting it.

The first problem I had wasn't with the tuner itself, but the interaction between it and the IC-7000. If the tuner power button is not depressed when the radio powers up, the radio will not sense that a tuner is attached. Result: The radio will not go into tune mode. Other radios may work the same way. Be sure the power button is depressed on the tuner before you power on the transceiver.

The tuner suffers from several usability issues: Poor user feedback, too many confusing modes, and a manual that is vague, confusing, and at times contradictory. The biggest problem is that there is no visual indication that shows whether the tuner is active or in standby. Would you buy a car that gave no feedback as to whether or not it is in gear? This is the main reason I gave the tuner just a 3 rating. A simple LED indicator would solve this problem.

I had to wade through the confusing manual to get the tuner set to a mode that works for me. If you have a similar setup these settings should work:
1. Power button always depressed
2. Auto button always depressed. It's counter intuitive, but takes it out of Auto mode so it only starts tuning when I press the Tune button. I don't want the tuner to be tuning just because I start transmitting, and especially not when the amp. is turned on.

3. I avoid "Sticky-tune" (Where did they come up with this?) for the same reason as above. By default, this mode is disabled, but if you accidentally hold down the Tune button for more than 2.5 seconds, it will be on. If the tuner starts tuning when you transmit, cycle the tuner power on the tuner. This will turn StickyTune off (unless you changed the power-on default by holding down the Tune button for 8 sec. Do that again to change the default.)

4. To start a tune, I press the Tuner button on the radio. This puts the radio in tune mode and starts the tuner tuning. This is the best way to initiate a tune, because it avoids the possibility of holding down the tuner Tune button too long (2.5 sec) and enabling StickTune.

5. To bypass the tuner, I tap the Tune button on the tuner (Tap = press < .5 sec.)

6. Since the tuner doesn't show its state, if I don't remember if it's in or out, I have to press a button from step 4 or 5 for the state I want it to be in.

These steps may help others work around some of the issues with this otherwise good tuner.

WB4HRH Rating: 0/5 Nov 3, 2014 17:54 Send this review to a friend
Miswired cable damages IC9100  Time owned: 0 to 3 months
I purchased a MFJ 994B two weeks ago and an MFJ 5124I interface cable for my new IC9100. The cable was wired completely opposite and blew out my IC9100. I replaced the internal 5 amp fuse and the IC9100 came back up. But, the voltage from the IC9100 tuner connection is now 8 volts and will not power the tuner.
MFJ sent a replacement cable but will not cover the repair of the new IC9100. (hundreds of $)

If I run an external power supply the 994B will work.

Unbelievable !!!!!

My new ALS600 also has a defective design that shorts the reflective power indicator. No help from MFJ either. See my review and others in the past few weeks.

I can send pictures of these issues if you like. This is not a company you want to do business with.

WB0WQS Rating: 2/5 Nov 16, 2013 16:42 Send this review to a friend
Bad Experience mirrored  Time owned: 0 to 3 months
WOW. Where do I start. I bought the MFJ-994B the same day I bought a new ALS-600S amplifier. A rep from MFJ recommended that the MFJ-994B was the perfect tuner for my situation. When I got home for the un-boxing, my first warning flag was that the front of the Tuner says "600 watts PEP SSB and 300 watts CW" The Manual specifications rate the tuner for 600 watts PEP SSB/600 watts /500 watts constant carrier. What is up with that? Short story is.. the tuner tunes my 135 ft inverted L antenna fed with ladder line to a 4:1 balun and short run of coax to the shack. It did fine with 100 watts to about 300 W. Anything above 300 watts put the tuner in "protected" mode. Which bypasses and protects the tuner (good) but triggers the fault on the ALS-600s (the protection circuit bypasses the tuner so the amp is suddenly seeing high SWR). Every band, every time. Very, very frustrating. To reset the protection circuit, I would have to shut the tuner off and turn it back on. It acted like the tuner was locked up and the only way I could reset it, was to power off, power on. Now, some of you are thinking, that I have RF going crazy, running mayhem all over the shack. But upon replacing the tuner with two different auto tuners for comparison purposes, the antenna tunes fine up to full power of the ALS600S specs. Right now I have replaced the MFJ with a LDG-600 proII, which is working great in the same environment. I also will point out, that the dealer I bought it from, gave me a full refund.. so I am not bitter and I don't have an axe to grind. But I saw some reviews on this tuner that mirrored my experiences exactly. Hopefully I just got a lemon and this is not typical of the MFJ Product. Hope this helps.
GD1MIP Rating: 4/5 Nov 22, 2012 13:33 Send this review to a friend
Works well but quality control seems to be a problem  Time owned: 0 to 3 months
My MFJ994B was purchased new on 29/09/2012 at the Newark (UK) show. I also bought the MFJ993RC remote panel to go with it.

On unpacking I noted the case finish was quite poor with sharp edges and a blemished paint finish as if it had been 'touched up'.

I applied 13.8 volts to the unit with the supplied power lead as per the guide and .... nothing, no lights not a thing happened. Then a second later a bad burning smell and a nice little puff of smoke from the rear by the serial type connector.

As it's not the most expensive item available I could live with the finish, but it is a new item and I expected it to at least work.

I had to post it back to the UK dealer and this cost me 12.50(sterling). The dealer was not good in their communications but eventually I got a replacement new item. They refused to pay my postal costs. So I was now at least 12.50 poorer.

My new unit was still factory sealed when it arrived.
Worryingly a small piece of alloy 'swarf' fell from inside it on unpacking. It looked like debris from a screw hole. A point for quality control as this could have caused problems? A good shake and clean out were needed to ensure nothing else was in there.

Thankfully this one works. It will easily tune a 100 foot doublet on 160 - 6m. It is installed at the base of the doublet, (50 foot twin feeder to AMU and then 60 foot H100 coax to rig) The remote unit works a treat and has a red and green LED as an SWR 'meter' I made up a remote lead to match the coax length and this works fine at this length. I am now happy with the unit.

The bad taste is still in my mouth though. I was without a unit for a while and it cost me money in postage etc to get a working unit. The UK dealer was not good. They only did the minimum.

MFJ in the US however kept in contact with me and promised a result. They delivered and even covered my costs direct from the US.
A big positive here is this customer care from MFJ. They really did go out of their way.

Pity about the UK dealer who left me out of pocket.

If I buy MFJ again I will insist the dealer shows it working before I purchase it.

KE5BM Rating: 3/5 Sep 29, 2012 08:07 Send this review to a friend
Good for <300w  Time owned: 6 to 12 months
All the tech specs and advertisements for this tuner show that it is capable of 600W. From the MFJ Catalog: "Like MFJ-993B but handles 600 Watts SSB/CW..." Note that it specifies 600w CW. However, on the chassis it specifies 600w PEP SSB/300w CW. This is Problem #1. I spent the $360 to get the ATU that would handle the power output of my AL-811. On the lower bands (80m-30m) it does a fair job of tuning the power. (Works flawlessly when only tuning the barefoot 100w configuration of my TS-2000) Once you get to 20 and up, however things go south quick.

On 20m, driving the amp with 10w input and <1.5:1 SWR the tuner goes into the self-protection mode. I cannot get better than 200W output before the protection circuit engages. The higher the frequency, the lower the power. By the time I get to 10m I cannot get the tuner to accept any more than 100w.

I would think, that if a tuner is advertised to be used specifically with the AL-811 line of amp that it would allow the full potential of that amp. However, even with a perfect match it will not allow full power through the tuner.

Overall, it works and it is easy to use and very quick to tune. It has made matches that no other tuner I have used in the past would make. BUT, it does not handle the power advertised.
KC5PGZ Rating: 3/5 Jul 8, 2011 20:28 Send this review to a friend
Had to work on it......  Time owned: 0 to 3 months
I had wanted an auto tuner for the shack for some time. I ran across a 994b on an auction site and snagged it for a fair price. It arrived in the original box, and in good shape.

After hooking it up, I noticed the forward power needle did not move, and the power switch was intermittent.... BTW, there is a warning in the manual about causing internal memory damage by powering on and off rapidly...and it was doing it on its own!!

I contemplated the usual, complaining and demanding my money back, contacting MFJ and hoping for the best (I have had good results in the past), or doing what I knew I should do! I took it apart. The wire that feeds the forward needle was not attached..never soldered. I inspected the power switch, and decided it was external or board related. I tighted the mounting screw below it and the problem was resolved.

Now that the unit was operational, my tests show that it works. Not as smoothly as I hoped, since it requires pressing the tune button more than once to get a match. It is not as forgiving as I had hoped on my wire antennas and often stops short of a match when coming back to an already matched frequency and antenna.

I have not hit it with more than 100 watts as yet, and probably won't until I am certain I understand its behavior better.

I didn't give much for it (<$180.00), so I guess I got what I payed for.

MFJ should offer the display on it that the 993 has, and they really need to eliminate their Quality Control problems, enough is enough.
VK6BN Rating: 1/5 Jan 10, 2011 15:52 Send this review to a friend
Show Stopping Glitch  Time owned: 0 to 3 months
My 993B is great, entirely satisfied with it but sometimes I need to run more power so I bought the 994B. The glitch is that sometimes the 994B starts to retune when I am using the amp (IC2KL). The amp protection kicks in as a result. An annoying show stopper for me. I thought maybe something was changing on the antenna but not so. I also checked that the amp wasnt being overdriven. 17m is a particularly bad band for this glitch but it happens on other bands too. The problem occurs with or without the IC746Pro - 994B interface cable. I am so fed up with this problem I have gone back to my 30 year old AT500 tuner. Disappointed with the 994B after my totally good experience with the 993B.
AA6TJ Rating: 1/5 Jun 14, 2010 20:07 Send this review to a friend
Disappointed  Time owned: 0 to 3 months
I purchased the MFJ-994 and the MFJ 5124 interface. I found that the tune button on my radio indicated an untunable antenna with the MFJ-994. I had been using a LDG AT200PRO, which had no problem with any of my antennas. Finally I reinstalled the AT200PRO and my radio tuned up with no SWR greater than 1.2 on any HF band. The cover on the case of the MFJ-994 was sharp, and the 5124 shipped without screws to hold it together. I am sending the MFJ products back, and I am purchasing a LDG AT1000PRO.
KH6AQ Rating: 4/5 Apr 29, 2010 02:20 Send this review to a friend
Does the job  Time owned: 0 to 3 months
This tuner works per the manual. It makes band changes with the ALS-600 amp fast and easy.

It finds a lower VSWR when tuned at 20 watts than when tuned at QRP levels. As the manual states, it will stop tuning once the SWR is 1.5:1 or less. If you want a lower SWR hit the TUNE button a second or third time. And the bouncing meter communications is clever.
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