Emtech ZM2 QRP antenna tuning unit kit


Emtech ZM2 ZM-2 QRP ATUInitial Impressions
On opening up the kit when it arrived from the USA I was disappointed at how cheap and nasty it looked. The front panel itself is a predrilled aluminium sheet to which you must fix the printed paper covering. The box it fits in has a lack lustre look to it too. Together with the handful of components it really doesn’t look worth the money. Maybe I had a jaundiced view because I was stung for import charges on top of the purchase price.

The Build
I laminated the front panel rather than using varnish as recommended in the instructions – that was mostly because I have a laminator and had no clear varnish.
There is no circuit board supplied. Everything is simply self supporting on the wiring from those components which screw to the front panel. The instructions recommended using a piece of styrofoam to cushion the toroid but none was supplied and I had none so mine remains entirely self supporting. I guess if it breaks I’ll just have to repair it which should be quite easy as the circuit is simple.
Overall the instructions were good and putting it together pretty simple – an hour or two should be ample time for most people.

In Operation
So far my review has been pretty negative. This is the point where that changes. In use this little tuner is an absolute dream. I bought it to partner my Yaesu FT817ND QRP rig for use on holidays into less than perfect antennas and for that it works amazingly well. The procedure is simplicity itself after connecting up your station…

Select your desired operating frequency.
Twiddle caps for maximum received noise – one seems to be coarse and the other fine tunes so this is easy.
Switch the ZM2 to tune.
Transmit a carrier – 5w seems ideal.
Twiddle the caps again while observing the little LED – when it goes out or is least bright you are tuned.
Switch the ZM2 to operate.

… and that’s it. The whole process should certainly take less than a minute and will normally be a lot less. Checking with an SWR meter after tuning confirmed every match I tested to be 1.5:1 or better and that was using just about any random piece of wire I cared to throw at the ZM2. Naturally that doesn’t mean that a paperclip will make an effective HF antenna but I reckon a ZM2 would make a good fist of loading one up. I see no reason why any sensible doublet or long wire and earth couldn’t be used with the ATU effectively.

A cheap and cheerful bit of kit that almost certainly isn’t worth the asking price for the parts but more than pays for itself in terms of effectiveness. If you want a small QRP ATU you won’t go far wrong with one of these.


  2 Responses to “Emtech ZM2 QRP antenna tuning unit kit”

  1. Nice looking unit. I would like to build me one for my qrp home brewed from just a picture of the top and bottom board (it was carefully marked, so thankfull, it is 1.5 watts on 40 meters. I wonder if you just might have a photo of your little kit’s innerds? since I have the schematic I just need the layout.

    Best building to you my friend,

    Vessen Magee KF5DE

  2. Hi,

    I’m not home for a couple of weeks and don’t have it with me but will try to add a photo soon. As I mentioned in the text there is no circuit board and it is all self supporting off the front panel components.


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