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Reviews Categories | Antenna Tuners | MFJ-998RT Remote Auto Tuner, 1.5 kW, 1.8-30 MHz Help


Reviews Summary for MFJ-998RT Remote Auto Tuner, 1.5 kW, 1.8-30 MHz
MFJ-998RT Remote Auto Tuner, 1.5 kW, 1.8-30 MHz Reviews: 25 Average rating: 3.0/5 MSRP: $769.95
Description: An MFJ HF tuner (160 M-10 M), capable of 1.5 kW of power SSB and CW. It is an external tuner and can be installed at the base of the antenna, which yields better results than with the tuner in the shack. It goes well with the Ameritron amps: ALS-1300, AL-80B, AL-82, AL-1200 and AL-1500 legal limit amplifiers. It weighs 9.5 lbs and has an ABS plastic cabinet and stainless steel metal chassis. It measures 13.75x6.75x17.5". Matches instantly impedances from 12-1600 ohms and includes 20,000 virtual antenna memories. Has one coaxial antenna and a binding post for end-fed long-wire antennas. Upgrade firmware via a serial port. Includes a one year warranty.
Product is in production.
More info: http://www.mfjenterprises.com/Product.php?productid=MFJ-998RT
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KN2M Rating: 4/5 Feb 2, 2014 18:39 Send this review to a friend
Based on what I read, I am surprised I haven't had problems  Time owned: 0 to 3 months
I have a single antenna application on 160m for this tuner. My IAC bazooka inverted L worked very well with resonance around 1825 kHz without this but I had trouble operating around 1860 kHz and upwards without climbing VSWR and an unhappy amplifier. When setting it up, my friend waited outside at the unit and watched the response while I put 10w to start the tuner every 15 kHz. In some cases, he was able to tune a bit better than the microprocessor but not by much. Now the amp has no more than 50w reflected from 1800 to 1875 kHz with 1500w output. In general, the tuner seemed happier at frequencies lower than resonance versus higher as represented by lower VSWR and better match over a wider range. All in all, I am well pleased as I had up to 200w at times without the tuner at higher frequencies. I have never used a tuner before in 5 decades of ham radio because typically rely on meticulous design, engineering and construction to achieve best match. I hope it lasts as it seems to be just what I needed to expand the capabilities of my antenna system. Sorry, I can't go along with the majority opinion here that does not favor this device. I don't know how a tuner gets a great rating but for now it certainly operates properly and has enhanced my transmit capabilities.
 
NY6C Rating: 4/5 Oct 1, 2013 14:44 Send this review to a friend
It works - I would definitely recommend  Time owned: 0 to 3 months
This tuner works and it works well. Note that you should test this in the shack AND READ THE MANUAL CAREFULLY. This isn't really a 'plug and play' tuner. You can get the most benefit from the tuner by setting up the tune memory locations. Many times when tuning a new antenna the SWR will get close - but you can manually tweak the tuning a bit to get it even lower. Then save this setting in memory. Once you do this on all of the bands in question you can just leave it alone and it will do its thing. I would give this a '5' rating if there was a way to control some of the switches remotely. You need to configure things when you first get it by taking the cover off - not a big deal but remote control of those internal switches would be awesome.

I have this tuner at the feed point of a 32' vertical (using a 40' fiberglass spider beam pole). This works well on 40M and is also a 5/8 wave vertical on 17M - great for DX. Would I buy this tuner again? Yes.

-Greg NY6C
 
G3SZU Rating: 0/5 Sep 15, 2013 12:34 Send this review to a friend
Part 2 of my report from early 2012  Time owned: more than 12 months
I installed my *first* 998RT in early 2012 and in a previous review on this site, declared that the "jury was still out"...well, the jury's in and has delivered its verdict: Guilty! I recommend that you do NOT buy this tuner. Here's why:

I had two doublets that I fed to the 998RT with 400 watts via a 1:1 balun. The doublets were switched by an external relay box. Measurements with a VNA told me that on all frequencies from 80m thru 10m, impedances at the antenna socket were *well within* the MFJ spec for both antennas. Unfortunately, no-one told the 998RT and it decided to burn out a couple of relays and made a nice big hole in the circuit board and burnt out several tracks.

The UK supplier was going to repair it...I asked them not to - how can you repair a big hole in the circuit board satisfactorily? I asked them instead to provide me with a new replacement as it was still under guarantee, which they kindly did, albeit an early model. This new one lasted a few months before *three* relays fried. Fortunately, no circuit board tracks were destroyed....

It is costly to ring the US from the UK but I rang MFJ Customer Services in the US to tell them what had happened and seek advice. I made it clear that I wasn't after a refund. I simply asked them for the range of *complex* impedances it would tune....to cut a long story short, they wouldn't tell me and treated me like an idiot and a nuisance despite the fact that I'm a qualified engineer. Charming.

In spite of being stone-walled by MFJ, I ordered three new relays from a UK supplier and installed them in place of the fried ones. Upon inspection, the old relays had experienced tremendous heat on the springs and contacts, presumably due to excess current.

In the month before I had to return abroad (August), the unit performed reasonably alright, but I had difficulty getting it to retune when changing bands. I have yet to give it a thorough testing and won't be able to until November.

My configuration is: doublet fed into tuner via balun. Chassis is connected to a good earth. Fed back to TX with 50 ohm 213 coax. I am now using one doublet.

When I bought mine, the total cost including P&P was the equivalent 1200USD.

 
K5AX Rating: 0/5 Sep 15, 2013 09:06 Send this review to a friend
Mine Had problems  Time owned: months
I am a Marine Service Engineer dealing with automatic antenna tuners regularly on ships, i.e. SGC, SEA, Raytheon, Skanti, Thrane& Thrane etc, So I am not a novice autotuner user.
I just bought a new 998RT. Read the instruction manual ahead of time so I knew about the tune power levels etc, and it looked like a good unit.
When I got it, I opened it and did the self test, and it passed. But when I applied 10 - 20 W, I got the QRO?. I looked closely and saw that the input lead (3 caps in parallel) was cleanly cut (like with good sharp dikes). I resoldered it, and it tuned fine on a dummy load.
I connected it to my 110-foot wire and it tuned at 10 -20W but would start tuning again when 100W was applied. So I cut off 10 feet of the wire (you need a wire length that presents a good impedance range for the frequencies you use), for an even 100 Feet. Then it seemed stable. Would not start retuning again at 100W. So I applied my amplifier (SB220 at 500W RF) and I saw my Reflected power go through the roof!. The 80M band section inside fried. Hopefully this was only an abberration to otherwise find quality equipment.
 
JF1QBV Rating: 5/5 Sep 11, 2013 20:21 Send this review to a friend
Works and Excellent !   Time owned: 0 to 3 months
The unit has been working flawlessly carrying up to 1500W PEP with various types
of aerials, including a random wire and a magnetic loop. The unit is well-built,
featuring a couple of types of input terminal: for a coaxial fed and for a single
wire and grounding, employing robust ABS and stainless steel coverage.
Another feature is a self-testing function built-in. I recommend this unit !
(Also, thanks to Diana - N5TWI for the excellent service !)
 
W5JO Rating: 4/5 Aug 30, 2013 08:16 Send this review to a friend
Would recommend again  Time owned: more than 12 months
After owning and using this tuner with everything from 5 watts to 1500 PEP I still like it. It has performed flawlessly and tunes my antennas properly

Remember that if your antennas complex impedance is out of the range of the tuner it won't work but in my case everything is cut and installed to provide the proper operational ranges so the tuner works as advertised. The unit will match all bands using my 1/4 wave inverted L for 160 meters except 80 which is out of the match range specified by manufacturer specifications.

Keep in mind you are dealing with a computer. If, for some reason, the memory is scrambled by a power flash or surge, it will cause problems. If you protect it as best possible from surges and isolate it from lightning then you should not experience major trouble. I have a relay that grounds my antenna system between it and the antenna connector of the tuner and thus far I have not had a disastrous lightning strike induced problem. Also I live in a rural area where power flashes and surges are common and proper protection on the power source of the tuner has prevented component failures but it will lose memory and it sometimes won't tune. So I pull the cover and do a reset and it starts right off.

If you have tuning problems, follow the reset procedure and it should work fine. The manual has several test procedures listed so, if you have trouble, follow them. My experience with MFJ customer service has been very good by email. They are very willing to help you isolate problems and give suggestions as to what you can do to fix the problem. I recommend the unit.
 
TF3ARI Rating: 5/5 May 21, 2013 09:29 Send this review to a friend
1 month old and still 100%  Time owned: 0 to 3 months
Little add to my old review.
Tuner is now over 1 month old, I use him with up to 1 Kw daily and down to 1.840 Mhz from 6 meter and tuner still working 100%.
As many hams say he works only 1 to 5 days so there are good tuners out there or used as manual explain it should be or MFJ have fix there problems with it.
73
TF3ARI
 
DL4CW Rating: 1/5 Jan 27, 2013 02:02 Send this review to a friend
forget it!  Time owned: 6 to 12 months
Part 3 of the story, or how it all ended. In brief: After the device had failed for the third time I finally demanded a complete refund, which was granted by the dealer without any further inquiry...

The tuner was meant to replace a 100W autotuner (which btw did its job flawlessly for over 8 years at the feedingpoint of a 33ft vertical in my backyard). I replaced it with the MFJ just to be able to run legal limit power.

The first time it failed after 2 months with the same symptoms as described by LA5HE. Since it still was covered by warranty, I had sent it back to the dealer and it was returned to me after 6 weeks, a chip of the divider chain as well as the PIC chip had been replaced.

After successfully testing the device I put it back into place where it lasted - I couldn't believe it - JUST FOR FOUR DAYS - before it showed the same symptoms again. I again had to return it to the dealer. The PIC chip was gone once more, this repair took another 7 weeks.

After that it worked for about 4 months when I first noticed that the SWR would suddenly run bad on certain bands when increasing tx power beyond 25-30 watts. Leaky caps in the LC network this time? Anyway, it's history.
 
RK3TD Rating: 4/5 Jan 10, 2013 20:56 Send this review to a friend
Good, but not great  Time owned: 0 to 3 months
By paying attention to the previous reviews, I first carefully examined the new product. The funny thing is that the PL-connector MFJ-4117 missing one screw and nut jumped inside device. Restoring the MFJ-4117, I opened the main unit and looked him in the presence of poor quality soldering or other mechanical problems. All appeared normal. I did not change the default settings.
I use a device with an GP. Antenna height of about 7 meters (24 feet). The antenna has a few radials also up to 7 meters. The device is ideal works in the frequency range from 7MHz to 25MHz.
At 28MHz tuner refuses to find a normal SWR. It works more than 20 seconds, and in the end - a mismatched antenna on 10 meters. This seemed strange to me. However I found a way out of this situation: device has good matching on frequency 28.7-28.8. In the CW TX (28.0XX) station of this matching is enough.
Few words about 3.5MHz: Yes, it works, but the effectiveness of 7-meter GP is very low. So talking about the normal long distance QSO on this band is not necessary.
In general, the device I'm satisfied. But given the weaknesses identified during the first examination, and work on 10m, can not put the highest rating.
 
W7DAU Rating: 1/5 Dec 3, 2012 12:08 Send this review to a friend
Call it the Gambler  Time owned: more than 12 months
I have had the unit for about a year and a half. I would not recommend it to anyone for purchase. I call it The Gambler because sometimes it works and sometimes it doesn't. I am using a 43 ft. vertical over an excellent radial system and Andrew LDF4 for the transmission line. And a ICOM 7000. Using this vertical it requires using some kind of antenna tuner so I depend on this unit. When I change bands, 75, 40, 30, 20 meters I always have to turn it off, let set for a few seconds, and sometimes it will tune. Often I have to do this multiple times to get it to tune. This is the reason I call it The Gambler, you never know the outcome. When it does work the VSWR can be anywhere between 1.7 and 4.0. I am not at all satisfied with the unit. Right now I live in the city and am going to set up my ICOM tuner at the base of the tuner. Will have to run control line but it will work every time. MFJ is loosing it when it comes to reliability. This is the second piece of equipment I have purchased from them that was inoperative.
 
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