ENTECH ZM-2 ATU
My primary initial observation is that this ATU is somewhat faster and easier to tune than my tuna tunah ii. You just turn the two knobs for the strongest signal and switch to tune position and tweak, watching the LED for a null. The null of the LED is very deep and obvious whereas it is less deep or obvious on the tuna tunah ii, in my experience. It's three disadvantages are cost, about twice that of the Tuna Tunah ii, weight/size, at just over 7 oz. it is twice as heavy and somewhat larger, and is somewhat limited in what it can tune. You can read about my observations of the Tuna Tunah II on that page.
2018-08-14 I want to be impressed with this tuner but am struggling. Today, using my 35 ft wire antenna with 9:1 UNUN I was unable to tune up 20 and 40 meters with it. At the same time the tuna tunah ii tuned 40, 30 and 20 nicely. Is the 9:1 UNUN the problem with this tuner? It seemed to perform better when I was using a 4:1 balun.
2018-07-07 Today the EMTECH ZM-2 ZMATCH Antenna Tuning Unit (ATU) came in the mail. So after grabbing a quick lunch I headed to the back yard, put up my 35 ft wire antenna using the Wonderpole to support the far end and a patio chair to anchor the shock cord on the driven end. I connected the 15 ft counterpoise and 25 ft of RG174 coax to the ZM-2. Then I just turned the two knobs to get the loudest receive signal (noise in this case as the bands were not great at all). Finally, switching the ZM-2 to "TUNE" I keyed the FT-817nd and nulled the LED on the ZM-2. It took very little tuning on the 40, 30, 20, 17 and 15 meter bands to get a complete null on the LED SWR indicator. I did not find a good null on 80.
The few signals that were on 20 meters suffered from very deep, slow QSB but I did manage to answer K3WW's CQ from Pennsylvania who gave me a 539 report. He was 559.