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Reviews Categories | Antenna Tuners/Matching Networks | S.E.M. Transmatch Help

Reviews Summary for S.E.M. Transmatch
S.E.M. Transmatch Reviews: 12 Average rating: 4.6/5 MSRP: $(missing—add MSRP)
Description: HF Antenna Tuner
Product is in production.
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MM1EWA Rating: 1/5 Dec 8, 2015 12:03 Send this review to a friend
Pretty poor  Time owned: more than 12 months
Sorry to kill the party, but while I'd like to like these tuners they are simply unable to tune anything more than a slight mis-match.
After buying one and it failing to perform as expected on a number of antennas I figured I had lemon and picked up another, sadly its the same.

The tuner fails to perform when put up against KW-107 tuners or even a Leader Lac-895, on various wire antennas, infact the internal tuner of the radio does a better job than these dogs.
The inductor looks very mickey mouse, and the 160 meter 'add-on' inductor takes the biscuit.

The tuner simply lacks the ability to handle any serious mismatch.
As I said, I wanted to like these tuners, but in all honesty save your money and get a KW-107 these SEM things are rubbish I'm sorry to say.

I suspect I'd have better results with these tuners if I ran a couple of hundred meters of waterlogged TV grade coax to my antenna.

Michael - MM1EWA
G4VEC Rating: 5/5 Oct 24, 2014 08:39 Send this review to a friend
Very Good Quality Components.  Time owned: 0 to 3 months
Obtained this TranZmatch via eBay about a month ago.Yes, it is a great performer,and appears to be more or less hand assembled,good quality parts as mentioned by most other postings. I have another 'dark horse' ATU also hand assembled, LAR Omni-Match, made in Leeds UK, and as with the SEM, 'production' ceased early 1980's (I think) Back to the SEM TranZmatch, I am puzzled as to why some state that the power handling should be kept to no more than 100 watts, another has stated 50 watts. It seems that no mention is made on the ATU, or instruction sheets as to the max rated power handling. My rig has power output of 100 watts and have loaded this ATU at this power on all bands with no sign of any problems (full size G5RV) The capacitors and coils and all components look as though they could handle considerably more power,my LAR Omni-Match is not as such high quality, but is rated at 200 watts. Of course if one is using a SEM version with a dummy load I doubt if it would be rated at more than 100-watts.....? 73 Mike
M0LSX Rating: 5/5 Nov 21, 2013 21:10 Send this review to a friend
A great buy  Time owned: more than 12 months
I wanted one of these & the reality has matched my expectations..It is used at home & on Special Event Stations & will tune almost anything. Even a patch lead & SWR meter on 10 & 20 meters (Don't ask.)
I have had my SEM for at least 10 years now, it has top band & ezi tune fitted, but I do not normally use either.
I have other tuners both manual & auto, including a KW ezi match & a Nevada TM-1000, but nothing has been used as much as the SEM.
The only down side to these ATU's is the fact that they do not handle more than 100 watts...And if buying one, look inside the case, as if they are over loaded they flash over.
The price for these is getting silly, but they are a great ATU..
G4VVQ Rating: 4/5 Mar 8, 2013 01:38 Send this review to a friend
Good HF Tuner  Time owned: 0 to 3 months
Hi Fred in uk, I have just acquired one of these S.E.M Transmatch units, it was of course second hand, made in the Isle of Man, when I got it, it would only tune on 40 and 60 mts, took cover off, found there was a connection broken off the big capacitor, due to loose screws and too much twiddling, soldered it back on the pcb, it was better but still wouldn't tune on 80 mts, then I noticed when I turned the tuning knob right round the capacitor plates were not going right in, so I loosened the grub screw and realigned the capacitor, all works ok now, it will tune balanced, unbalanced and long wire no problem, I use it with a 115 ft doublet, if you use unbalanced antenna or long wire you need to earth one of the balanced terminals, the one nearest the earth post. Drawbacks...mine has no by-pass switch, power is limited to 100 watts from 10 to 80 and 10 watts on 160. Mine has an ezitune function which needs a 12 volt dc supply to phono socket on the back, optional, the schimatic seems impossible to get hold of, so I have created one and put it on my qrz page...happy tuning, Fred g4vvq.
MI3LVZ Rating: 5/5 Mar 12, 2009 13:33 Send this review to a friend
Superb!  Time owned: more than 12 months
My SEM is the basic model but still a great tuner, once you find the resonant point on the band your working, write down your findings for next time and away your go. Will tune a table leg, great job.
M3PMY Rating: 5/5 Sep 25, 2008 06:31 Send this review to a friend
Super, Lovely, smashing  Time owned: 0 to 3 months
I managed to buy my Tranzmatch from ebay, it has the 160+80-10 switch, the tuner has no other bells or whistles, but what a performer! it can fool my 897 that a 50ohms match is possible on 80-10m on a 450 ladder line fed 66ft doublet, no meters no mess, just tune her in, write down the tuner and coupling settings for the next time you visit the band of choice, now i can tune it quicker than some auto tuners!!

Get one! if you can.


GM0WEZ Rating: 5/5 Jan 19, 2008 16:13 Send this review to a friend
Quality Manx engineering  Time owned: 6 to 12 months
If you want a balanced tuner there are not many options - the Johnson Matchbox, the KW Eezeematch, and I think MFJ now offer a balanced tuner. There is also the SEM Tranzmatch, made on the Isle of Man, and widely available on British ebay.

Some of the SEM Tranzmatches have a dummy load, some have 160m coverage, some have the ezitune noise bridge circuit. Mine has all three. The most basic model seems to go for around 60, often more for the options.

It will tune end fed wires etc but it really shines when using balanced feeders to a doublet or loop. Tuning is quick and reproducible. It nearly always copes with 100watts - on a few settings it objects but these can be noted and avoided.

The direct setting bypasses the tuner. This is handy if you're tuning down to medium wave for broadcast stations, navtex, 500khz ham etc, as I find at these very low frequencies you get better results bypassing the tuner.

Ezitune needs 12v at 25mA (centre positive on mine) but isn't really worth having in my view.

Its quite big - bigger than the photos suggest at circa 8.5 x 4.5 inches. There is no integral meter.

The engineering is pretty good with a robust case and fairly well rated components.

The 'manual' (one sheet) is available on line at:

G6XCJ Rating: 5/5 Jan 19, 2008 14:55 Send this review to a friend
Excellent tuner!  Time owned: more than 12 months
Do not exceed 50w. This ATU is magic and yes you dont need the Ezitune(TM) just listen to what ur tuning in, go for the loudest signal. You are set to go. Bought mine in 1980s and it really is worth the 200quid paid for it.
EXG8JCF Rating: 5/5 Jan 19, 2008 14:41 Send this review to a friend
Excellent:Does the job  Time owned: 0 to 3 months
Hi, I've just acquired an SEM Tranzmatch ATU on eBay-don't why people sell them, 'cos they seem to be a unique piece of kit ! - anyway, I have the model with the EZiTune feature with an RCA Phono socket on the back marked DC, can anyone tell me what the wiring is for this skt, ie is centre +(positive), I assume 12V DC input ? Also, on the front panel it has a 3 way switch marked Direct, Tuner, Load. I assume that Direct means bypass the ATU ie connect the aerial directly to the output terminals, Tuner means go thru the Tranzmatch, but what does Load mean ? Any help would be very much appreciated. The model has the 160/80-10 switch on the front and only has XMIT and ANT PL259's on the back - I've seen some which also have SO259's for 160, ie 4 SO259.

Once again many thank in advance for any help.


(ex G8JCF - if you are interested in SDR's then please take a look at and the G8JCFSDR)

PS. I know this is more of a cry for help than a review, so if I've it got wrong please forgive my newbie ignorance
G7TOK Rating: 5/5 Jan 4, 2006 16:58 Send this review to a friend
Unsurpassed  Time owned: more than 12 months
This ATU is the dark horse of the amateur world.

It won't handle high power, stick to 100w and you'll be fine.

Examples vary some just have the two main controls, some have the 160m mod, some even have the "Ezitune" noise bridge circuit in,

mine has all three.

It will tune just about anything, no the antenna will not be any more efficient, but your silicon P.A. will be a lot happier.

None of that peaky T or L type nonsense, this turns my rather hap-hazard home-made OCF dipole into a broad-band antenna on every band, even 160m.
No MFJ, PALSTAR, CAPCO or what-have-you is going to do that.

Amazingly, it never really crossed the pond, so the colonials are almost totally unaware.
Yes, they've seen the odd Z type floating about, but nothing like this !
You don't even need a meter, you can tune your antenna by ear if you like, or just peer briefly at your S-meter and its done.

How much would Palstar or MFJ charge you for that eh ?

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