QRP Field Tuners: Emtech ZM-2 vs. the ATU-10

[@w2aew]

I built my ZM-2 about 17 years ago, still works great. That little autotuner looks really cool - thanks for the demo and link.

[@davidjohnson497]

Thanks for this. Two more potential downsides of the ATU-10 (and any autotuner): 1. more complex than a manual tuner (active components like transistors or ICs), so could be more likely to fail in the long term 2. depends on design (probably including software algorithms) for minimizing SWR and displaying correct value of SWR Maybe these 2 points have been overcome in the design of the ATU-10, but I do know they have been a factor in my rejecting the use of autotuners in the past. Some autotuners are known to have trouble tuning to low value of SWR as compared to some manual tuners, when used with same antenna. That said, the ATU-10 may be my first autotuner in the future! Really appreciate this video, very thorough and good demo. Keep up the good work! 72

[@betterbprepared]

Great comparison on these two QRP tuners. I purchased the ATU-10 several months ago after some correspondence with you and I love it. it is a very small, light weight tuner that works well and easily fits into my go bag.

[@harleyreaper5146]

I love my ATU 10. My nephew recently broke the charging on mine. So I'll be buying another one.

[@MyHamRadioJourney]

Thank you for this video. Also, thanks for giving us a link to buy the correct tuner with the links. This auto-tuner will go very well with my QMX. Thanks again. 73s

[@EvanK2EJT]

You're welcome!

[@KYFriedHam]

Love my ZM-2. It was a super fun kit build and really fun to use. There are only 2 things I don't like...In bright sunlight, the variance in the LED is hard to see, and because it's so light, it tends to tip over all the time because the cables come out of the top.

[@EvanK2EJT]

Both absolutely spot on! It's definitely not perfect.....but it's hard to argue with how well it works for what it costs.

[@bmh67wa]

I've been on the fence about getting the ATU-10. I didn't even think about checking Amazon. I think I'll be getting one from there. It says it has the current firmware and the seller is legit. It will be just what I need for my Xiegu G106. Thanks for the link!

[@EvanK2EJT]

No problem. Yeah, it works great. No regrets at all.

[@chevnut712]

I have both of these. I always go with the auto tuner first, just cause its easier and quicker. You're right, the battery lasts forever. Good video. I look forward to working you sometime. I'm upstate NY as well, just outside Amsterdam. John WA2OUZ

[@EvanK2EJT]

I'm sure I'll catch you on 40m some day!

[@Swamp-Fox]

Great Review. I have a ZM-2 and have my eye on the ATU-10. I agree....I need both! 73, Patrick KF4LMZ

[@thequarantinecatholic]

Love ABR, nice little QRP radio!

[@Kinetic79]

Great video as always. One interesting thing about the Z-match design is that it provides some additional bandpass filtering that the ATU-10 and basically most auto tuners will not ... this can help with receiver overload (e.g., in the presence of an AM station), and it can also help reduce transmit harmonics if you're operating a radio with a less than ideal filtering -- or you're running a radio with good filtering on a band that the filters weren't fine tuned for (e.g., 30m on a QMX 10m-20m high-band kit). I have a digital modes radio from crkits (orig design by Barb -- I think wb2cba), and at my home qth it is significantly more performant on 20m ft8 receive through a z-match than it is through a T-design.

[@EvanK2EJT]

That never occurred to me, but that's definitely an additional plus for the Z match tuner!

[@stevet7522]

Great video and excellent choice in pencil.

[@EvanK2EJT]

Thanks 😁

[@brianve7jyd943]

LOL- the string and the toilet is priceless - but owning a G90 - ur rite -- i have the ZM-2 and its touchy but works good - but i think ill get the ATU-10 aswell thanks for the vid Evan - 73 VE7JYD

[@dugbohamradio]

Both these ATUs are great. The issue I have with the QMX is I have the SWR protection enabled at 3 and both the ATU- 10 and ZM-2 during tuning would enabled the SWR protection on the QMX and stop all TX capabilities. Fix is to disable the SWR protection.

[@EvanK2EJT]

The ZM-2 shouldn't.......The radio should see 1:1 with the switch in "tune" mode.

[@dugbohamradio]

@@EvanK2EJT I’ll check again to see if the idiot factor was enabled 😆

[@dugbohamradio]

@@EvanK2EJT thanks for doing the video . Yeah full idiot factor kicked in. Just tested the ZM-2 and works absolutely fine .

[@EvanK2EJT]

@@dugbohamradio LOL I was gonna say......I've never seen anything but 1:1 with it in Tune mode. Glad you got it working!

[@davidryeburn6446]

@@EvanK2EJT It supplies a safe load, but not necessarily a 50 ohm load. If you look at the circuit you'll see that there is a bridge, two 50 ohm resistors in series to ground on the left side of the bridge and a single 50 ohm resistor in series with the load (as transformed by the tuner) to ground on the right side of the bridge. The indicator circuitry is across the bridge so that if the load becomes 50 ohms then the bridge is balanced and the indicator light goes out. Worst cases are if the load is open or shorted. A shorted load gives 100 ohms in parallel with 50 ohms, or 33.33 ohms so the SWR is 1.5. An open load gives 100 ohms so the SWR is 2.0. Anything else will give an SWR that cannot be any worse than 2.0 which should be safe for most transmitters. If you want even more protection you can build a Pi or T 50 ohm to 50 ohm pad out of three resistors to be placed between the transmitter and the ZM-2 while tuning. The more attenuation you build into the pad, the safer things will be (but the harder it will be to tell when you've come closest to a match). Of course you remove the pad after you get it tuned, just as you flip the switch on the ZM-2. Some people leave the ZM-2 switch in tune position even after completing the tuning, to go QRPp. If you get a perfect match, the resistive network in the ZM-2 will attenuate both transmitted and received signals 6 dB or 1 S unit. I wouldn't do that, because the rectifying diode and the LED might produce some (very weak) harmonics and to the extent that they made it through the tuner resonated on the fundamental, they'd get radiated. David VE7EZM

[@rjy8960]

I didn't know that the ZM-2 presents a 50R load to the radio when in tune. That would make me a LOT happier tuning an unknown antenna for use with my QDX. Food for thought. I also wanted to get an Electaft tuner for my TX-500 but in the UK they are rocking horse sh*t made from Unobtanium so settled with a MAT-10 which I'm quite happy with. Similar idea as the ATU-10 in that it has latching relays so charge a couple of times a year and you are good to go. The only problem is that you should use the charger that came with it - no easy option for charging in the field if you don't have the charger - it's a weird voltage I think. I REALLY fancy one of the FX-4CR. It looks a really good radio.

[@EvanK2EJT]

Yeah, the 50 ohm load is nice when you're worried about the delicate finals in some of these radios. It definitely gives you peace of mind. As for the FX4-CR....get one if you can. They're awesome 😁

[@P.SeanCoady]

Wishing the atu 10 would be OK with 25 watts, I'd be mounting it on top of the mast as a remote ATU.

[@EvanK2EJT]

It would definitely be cool if it could handle a little more power for sure!

[@KD9ZHF]

I orderd a T1 in January. I got it in February. Not so bad. T1 is currently in stock for $289.95 + Tax.

[@EvanK2EJT]

Wow! That's FAST. Eric K9VIC waited almost 13 months for his.

[@KD9ZHF]

@@EvanK2EJT We both got ours around the same time. I actually end up using my LDG z100plus more though, and it was so much cheaper.

[@KC2BKM]

I want the zm-2 for a back up in the bag.

[@EvanK2EJT]

It's a sweet little tuner!

[@ErikErkelens]

Elecraft must be running out of shortages, I had to wait only two weeks for the T1, but yes, it did cost a kidney. I have the 100w/non-latching sibling of the atu-10, the T1 definitely matches a wider range. Do you use the tuning cable with the 705?

[@EvanK2EJT]

Yeah, I use the cable with the 705, and it works well. Good to hear that they're working through the backlog of orders!

[@Majorme2]

Where did you get the short coaxial from the atu to the radio.

[@EvanK2EJT]

Amazon of course LOL: www.amazon.com/gp/product/B07TD1S1S8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

[@brianve7jyd943]

Evan u mentioned watch for authorised ATU-10 -- is the link you show one of those or how does a fella tell thanks

[@EvanK2EJT]

The link in the description is from a vendor that's on the approved list by DL2MAN for the (tr)uSDX. I figure if they're good enough to build a radio and have him authorize them, they can put together a tuner. It's honestly hard to know what you're getting with some of these things, but if you buy it from that Amazon link you should be good to go

[@brianve7jyd943]

@@EvanK2EJT i hear yea Sir - Much Obliged

[@470smith]

It is so easy to build an EFHW 40 meter no tune antenna. 49:1 unun 65’2.2” of wire. 40,20,15,10.

[@EvanK2EJT]

It is, however quite often an antenna you build and tune in one place is sometimes nowhere near resonant when you put it up somewhere else. I've built antennas that are 1.1:1 at home, and put them up in a different place with different ground conductivity, and the exact same antenna is 2.6:1. Another benefit of having a tuner is you can run a random wire and with a wire not much longer than a 40m EFHW you can work every band 80-6

[@470smith]

@@EvanK2EJT I have had that very problem and didn't realize it could the different ground conductivity. I never take a tuner and figured it was old batteries. The Xiegu G106 has no meters at all so I would cut the antenna at home and go. Radio, Battery and Antenna is all I would take. Thanks for the info! 73

[@downsouthsafaris6788]

The ZM-2 handles 20w I thought the ATU10 was only 10w that makes a compelling choice if you’re operating SSB with the FX4CR I’ve got the 10w Kanga products transmatch - similar but not it’s equal and 1/3rd the price

[@EvanK2EJT]

The ZM-2 will handle 15w. The ATU 10 says 10w, but I've used it up to 16w with no problem. Over that it yells at you and tells you it's over voltage. I'd say it's a wash either way.

[@SCTaylorTX]

Forgot the Zm-2 can tune a doublet also!

[@EvanK2EJT]

Yes it can!

[@skepticalmechanic]

CW IS NOT HARD! 😊