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Reviews Categories | Antenna Tuners | MFJ-974H Balance Line Tuner Help


Reviews Summary for MFJ-974H Balance Line Tuner
MFJ-974H Balance Line Tuner Reviews: 28 Average rating: 4.0/5 MSRP: $190
Description: The MFJ-974H is a fully balanced true balanced line antenna tuner. It gives you superb current balance throughout its very wide matching and frequency range.
Product is in production.
More info: http://www.mfjenterprises.com/products.php?prodid=MFJ-974H
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W6IZK Rating: 5/5 Jul 31, 2008 22:56 Send this review to a friend
Works great, so far  Time owned: 0 to 3 months
Just received MFJ-974HB tuner, as most other reviewers have mentioned, had to tighten the coupling shaft inside the case to the inductor switch. Inside of case was clean, solder joints looked ok, tightened allen screw and put the cover back on.

Have an old Johnson 250 Watt Matchbox, it failed miserably to tune a 125 foot dipole fed with 100 feet of 450 ladder line. Could not obtain a good match on 20 meters in particular, 75 was the only band that came close to 1:1 VSWR.

Replaced match box with MFJ unit and happy to report it tunes fine on all three bands including 20 meters. Very easy to tune, the suggested settings chart are nowhere close to what I wound up using but you have to start somewhere.

From my experience, would say the unit lives up to its specs just fine and is a good value for the money. Could have spent 3 times as much for a Palstar which I'm sure is better built but I balked at spending more for a tuner than my rig.
 
N6VL Rating: 4/5 May 10, 2008 12:19 Send this review to a friend
Good, but could be better!  Time owned: more than 12 months
I've had the 974H for several years now. It is is one of two tuners in regular use. I use it mostly for the upper HF bands. There is a review of balanced tuners in September, 2004 QST. There I noticed the efficiency is good if the impedance is not too low. The 974H is used for a 44 foot dipole (a Cebik favorite) for 30 through 10 meters. I also have a delta loop, used for 80 & 40 meters, which has a very low impedance on 80 meters. The QST review showed a dismal 41% power loss on 80 meters with a 6.25 ohm impedance. I use a venerable 275 watt Johnson Matchbox (modified) for the loop, to prevent excessive losses.

That said, I think the 974H fills a definite niche in my shack. It is easy to use, once I log the settings for each band/frequency. It is a departure from the tuners that use a balun on the output. I don't get RF in the shack with the 974H, like I do with an autotuner with a current balun on the output. Balanced feeders are great for those who take to the time to properly install them. But they require tuners like the 974H or Matchbox for best operation.

I gave the 974H a 4 because of the above mentioned losses at lower impedances. Perhaps the larger 976 would be better, with its large roller inductor rather than a tapped coil. It is nearly useless on 160 meters, where even a 1:1 load consumes 1/4 the power. Some of the earlier reviews have underrated the 974H. It almost merits a 5.

I don't think the lack of a coax bypass is a hindrance. It is meant for balanced fed antennas, which always require a tuner. The lack of a bypass is comparing apples and oranges.

The ideal balanced tuner would use linked coupling, rather than a balanced T network. I wish someone would market a modern upgrade to the Johnson Matchbox, with true linked coupling, and a wider impedance range, with the WARC bands included. That would require dual differential capacitors and be quite expensive these days. Until then the Johnson Matchboxes will have to do.
 
KA4DPO Rating: 3/5 Nov 18, 2007 18:55 Send this review to a friend
Not bad but certainly not a Johnson Matchbox  Time owned: more than 12 months
I got this tuner about 3 years ago and have never been able to tune a balanced load with it. I tried it on several dipoles fed with 450 ohm ladder line and couldn't get a match on any band. I have been able to tune a 17 meter coax fed antenna with it with the jumper in place and also an end fed wire antenna for 20 meters. My Johnson Matchbox tunes any balance antenna I connect it to without any problems so MFJ's claim of this being the successor to the Matchbox falls short. Not a badly built little tuner, it just doesn't perform as advertised and it certainly doesn't do what the Matchbox can. If you can find a Johnson Matchbox in reasonable condition buy it and keep it.
 
KD0BAI Rating: 4/5 Aug 29, 2007 20:31 Send this review to a friend
good light tuner  Time owned: 3 to 6 months
A good little antenna tuner that does what it is is supposed to do. I ran it barefoot and with amp up to nearly 300 watts and it did a great job. I purchased a up grade from PALSTAR ATIKP for more than twice the price so that i could run the amp up to power. I will use the 974H as a portable tuner and would recommend it for any barefoot or low power amp applications. Well packed and worked without missing a beat.
KD0BAI
 
K1YHR Rating: 4/5 Feb 17, 2007 21:02 Send this review to a friend
works fine  Time owned: more than 12 months
I purchased my MFJ-974H new from AES about 2 to 3 years ago. I was aware of some potential quality control problems, from reviews found here at eHam, but I wanted to put up a doublet antenna and feed it with 300 ohm twinlead. At that time, the alternative balanced line tuners were much more expensive. I resigned myself to doing some initial repair on the unit. When opening the shipping carton, I was disheartened when a black sheet metal screw hit the floor! I opened the unit, but saw nothing missing, broken, or misassembled. It has worked fine since then. The only problem is a slight drag in a certain part of the rotation of the Transmitter control. I would also say that this tuner is so light weight that it can be somewhat difficult to position it when one of the stiffer coaxes is used as an interconnect with the transmitter. Otherwise, I have been very pleased with it and I have not yet encountered any additional problems. I conclude that, even if you do have to perform some small repairs, the unit functions well and is reliable. -Dave K1YHR.
 
W4PM Rating: 5/5 Jul 7, 2006 13:23 Send this review to a friend
Very Nice Tuner  Time owned: 0 to 3 months
I received my MFJ-974HB two weeks ago. After reading some of the reviews here, the first thing I did was remove the top cover and checked out things inside. All was as it should be! My antenna is an extended double zepp for 40M (176 ft long) up 60 feet. The tuner tunes all bands 160 through 10 with ease. On 160, of course, I feed the antenna as a top loaded vertical wire against ground which is easily accomplished by pushing the new "coax/wire" button on the front panel. This grounds one side of the balanced T network making it an unbalanced tuner. It's very handy to have this switch up front so you don't have to place a jumper on the back. With the tapped inductor I can't get an exact 1:1 on all bands but it's never over 1.3:1 which is quite acceptable. I'm very pleased with the little MFJ-974HB but I'm afraid I need to sell it to help with the price of the MFJ-976 (the high power balanced tuner) because I recently purchased an amplifier and would like to be able to use it! It's too bad the 976 tuner will be bigger than my rig and a lot bigger than my amp. That's just the price you pay for more power.
 
VK7RL Rating: 5/5 Mar 6, 2006 18:10 Send this review to a friend
No Complaints Yet  Time owned: 0 to 3 months
Until recently it was not possible to buy a modestly priced tuner, with a TRUE balanced output, until MFJ announced their 974.
Since becoming licensed, 23 years ago, I have always used antennas fed via a classic link coupled tuner and tuned twin feeders.
I currently use a unit which was constructed when I worked in the aerospace industry. It was built to a professional standard using very high quality components and was thoroughly tested in development.
The link-coupled tuner is very flexible, can accommodate a very wide range of impedances and reactances, and, because it is possible to select the optimum LC ratio, is very efficient.
I read the QST review of the MFJ 974 with interest and noted the high losses, incurred at some lower frequencies and impedances and in particular the high loss on 40 and 20 metres with a non-reactive 50-ohm load!
Being attracted to the simple elegance of the balanced T-Match design (and aware of its flaws) I decided to purchase a MFJ unit and carry out a series of comparative measurements. These measurements would be conducted using simple test equipment, a “real” antenna system, resulting in some idea of its electrical performance ONLY.

1) Test Set-up: -

a) Yaesu FT 990 transceiver as a source
b) My link coupled unit (as a reference)
c) A MFJ-974HB tuner
d) A pair of RF thermocouple ammeters inserted in the feeders
e) A 68’ centre fed doublet antenna, fed via 42’ 300 ohm slotted feeder.


2) Test Procedure

a) Set transceiver for 100 watts CW output at test frequency.
b) Adjust link-coupled unit for Min VSWR at test frequency.
c) Record feeder current(s), balance and ATU settings
d) Substitute MFJ unit
e) Adjust MFJ unit for Min VSWR at test frequency
f) Record feeder current(s), balance and ATU settings
g) Repeat all above at next test frequency.

To ensure accuracy and repeatability the above tests were carried out a further TWO times.


3) Observations

An analysis of the data recorded showed that: -

a) both units exhibited VERY slight feeder imbalance at some frequencies – but so small as to be inconsequential.
b) The total feeder current, in the link coupled unit, was marginally higher at some frequencies than the MFJ unit, but only by a magnitude of 2% or so.
c) Max current coincided with Min VSWR on both units.
d) The MFJ’s VSWR/Power meter corresponded with the built-in FT990 meter.

4) Conclusion

The MFJ unit performed very well, when compared with the link-coupled unit, and overall there was really very little difference in their electrical performance.
I found this quite surprising because of the inherent additional theoretical loss in T-Match tuners, particularly when using a tapped inductor. However any losses incurred will depend very much on the RX values looking into the combined antenna feeder system.
The antenna system used for the test, coincidentally, happened to be one of those with a flat-top/feeder length that (as pointed out by MFJ in their manual) presents more reasonable RX loads to the tuner across a frequency range of 7 to 28 MHz.
MFJ also make the point that, with this type of tuner, the antenna should be a ½ wave at the lowest frequency of operation. Trying to load a 40M ½ wave antenna on 80M (with a T-Match tuner) can be a recipe for disaster! They do not like working into very low impedances.
It would be interesting to see these tests repeated at 160 and 80 metres using a 240’ doublet at a reasonable height above ground.
On the basis of its electrical performance and ease of use, when compared to the link-coupled unit, I give the MFJ tuner a score of 5.

5) Further Information

There is some very good free software available which allows you to model both doublet antennas and T-Match tuners.
The antenna software allows you to change all the parameters including antenna length, feeder length, wire size, feeder velocity factor etc. and calculates the RX data at the shack end of the feeder.
This data can then be inserted into the T-Match tuner program, which manipulates the LC values to obtain a match. RX Data and tuner LC values can also be manually changed giving you a very good insight into tuner efficiency.
The programs are:

1) Dipole3.exe
2) T_Tuner.exe

They are available from the website of G4FGQ http://www.btinternet.com/~g4fgq.regp/index.html
Who is to be congratulated for these (and plenty of other) programs he has written.





 
KA9CAR Rating: 4/5 Dec 16, 2005 11:53 Send this review to a friend
Good so far  Time owned: 0 to 3 months
12/15/2005 I purchased the tuner used on Ebay, from a ham that claimed he never hooked it up. (I believe him, see below). I do not know the vintage of this unit, but it is NOT the B version currently in production. It is a keeper, I am happy with it.

I started by opening the unit to see what it looked like, and make sure it was in good condition. I discovered that the knob for the antenna adjustment was turning, but the capcitors were not moving. I determined that the knob had no set screw in it, and since when I installed a screw, it pushed chips out of the hole, I assume it never had a set screw.

With the knobs both working, I unhooked my (modified to cover wider ranges) Johnson Matchbox from my 90 foot dipole fed with 450 ohm line, and put the MFJ in its place. For comparison, a 60 meter half wave dipole would be 87 feet.

I found that I could tune up from 160 through 10. The manual tells you NOT to tune a dipole shorter than a half wave due to the risk of arcing, but I had no trouble with 100 Watts on 160 and 80. It was a "peaky" on the bands where the dipole is less than a half wave, but no more so than the Johnson.

Satisfied that the tuner was working, I put my Johnson back in line, and moved the MFJ to its intended task of tuning a horizontal loop.

I estimate the loop is 275 feet long. It is strung through trees with out insulators, but it is insulated wire. Hieght varies from 15 to 30 feet. It is fed with 300 ohm T.V. line.

The 974H easily tuned 160, and all bands up to 17. I have not tried higher bands yet, but I have no reason to expect a problem.

So far I am happy with the Tuner. It is easier to use than my modified (5 knobs to tune) Matchbox to cover the same antennas. Settings were easy to repeat. I did not run any direct A/B comparisons. I was able to get the match under 1.2 under all conditions I tested.

The cross needle SWR reads SLIGHTLY higher SWR than my Autek WM-1. The forward meters agree on forward power. The difference in the SWR readings is not significant.

It is about time some one produced a reasonably priced balanced tuner, seeing as Johnson quit making them over 40 years ago!

KA9CAR
 
K1CT Rating: 4/5 Aug 8, 2005 19:09 Send this review to a friend
Good  Time owned: 0 to 3 months
Purchased MFJ974H from HRO today. Like others I found the power meter floating inside the 974H upon unpacking. Opened the 974H up to secure the meter and accomplished that easily with a #1 Philips. While inside I found that one power meter solder terminal was rubbing on a plastic gear for the transmitter capacitor bank - bent the terminal over and problem solved. Saw that the capacitors in each bank are about 10 degrees out of alignment (i.e. when one is fully meshed it's mate is about 10 degrees unmeshed). And what's this a scratch in the paint on the left side of my new tuner? The components are of good quality. The design appears to be good. Electronic assembly could use a bit more QC. My recommendation to MFJ is: make items like this available in a kit option so the owner can assemble it with the pride of ownership that he/she desires. I now proceed to actually try it out on my 87.5' on a side dipole ... I'm looking forward to trying out 160 meters (which my Nye-Viking Matchbox didn't offer).
 
KC5NWS Rating: 4/5 Jul 22, 2005 12:41 Send this review to a friend
a good tuner  Time owned: 0 to 3 months
Always wanted a balanced tuner so when mfj came out with the 974 i picked one up. Put up a 100 foot dipole fed with ladder line, built some thru the wall connectors out of threaded rod , nuts and bolts and i was on the air.Works fine, all bands are close to 1:1 or 1:1.No problems. I like it. w5wlb
 
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