Joshua tests the ATU-10 portable automatic antenna tuner

ATU-10 with TufteIn protection case

Many thanks to Joshua (KO4AWH) who shares the following guest post:

UPDATE: Please check out Joshua’s most recent review after updating the ATU-10 with new firmware. The results have improved dramatically.

ATU-10 Random Wire Testing

by Joshua (KO4AWH)

I had a bit of time to do some field tests and I recently acquired an ATU-10. So I jumped right in and did some ATU-10 Random Wire Testing. The testing was completed with a Tufteln 9:1 QRP Antenna configured with an elevated feed point sloper and a counterpoise hanging straight down. The coax feed was RG316 17′ with the ATU at the radio with a short jumper. Several different radiator lengths are used as mentioned below. The ATU-10 was sourced from, price was $120.24 shipped to me in GA USA, Ordered June 25, delivered July 8th.

A quick list of ATU-10 Features:

  • 0.91″ OLED Display that shows Power, SWR and internal battery remaining.
  • USB-C Rechargeable LiPo 1.7Ah
  • Grounding Lug
  • Bypass Mode (When I set to this mode however it would tune anyways)
  • Latching Relays (No power needed to keep in position. Hold tune with ATU off)
  • Input port for communication with IC705 (and potentially others)
  • 7 Inductors, 7 capacitors
    • (Elecraft QRP)
      • C array, pF 10, 20, 39, 82, 160, 330, 660
      • L array, uH 0.05, 0.11, 0.22, 0.45, 0.95, 1.9, 3.8
    • ATU-10
      • C array, pF 22, 47, 100, 220, 470, 1000, 2220
      • L array, uH 0.1, 0.22, 0.45, 1.0, 2.2, 4.5, 10.0
  • USB-C firmware update (ATU shows up as a drive, simply copy the new firmware file to the device and it will automatically update)
  • Weight 232g (8.1oz)
    • Tufteln Case adds 23g (.8oz) for a Total of 255g (8.9oz)
    • Compared to the T1 with cover for a total weight of 187g (6.5oz)

SWR measured with a RigExpert RigStick 320, Lab599 Discovery TX-500 and the ATU-10

The test process was to first check the SWR on the antenna with no tuner. SWR values recorded from the TX500 and RigExpert Stick 320. Values recorded in the 2 columns under the “No Tuner” section. This was completed for each of the Bands listed in the table rows (see below). SWR values were the lowest in the band range for all recorded numbers.

The second test was with the ATU-10 tuned. I tuned the antenna with the ATU-10 from the tune function on the TX500 (to produce a tone at about 3w) and recorded the value on the ATU-10 and the TX500. When a SWR over 1.5 was achieved I would give several more tries to get the ATU-10 to tune. I then disconnected the radio and checked the SWR with the RigExpert 320 through the ATU-10. These three values are recorded in the “ATU-10 Tuned” columns.

The third test was the same as the previous but after tuning with the Elecraft T1.

These tests were then completed with the same setup with only a different radiator length. See the table name in each for the length. 31.5’ 41’ and 85’ were all used. Sorry, I did not 80m but probably should have.

Test Conclusions

I will keep this brief as the data is self explanatory. The ATU-10 is not a great tuner. Maybe it is just the one I got? The Elecraft T1 is excellent (not the intention of this testing but of course no surprise on the results). The ATU-10 I received from was not DOA. It reads power level, shows an SWR level, Charges, clicks the internal relays etc. but it just doesn’t do a good job tuning the antenna. I will have to do some further testing and research on the device and see where this goes.

Other thoughts

Yes, a brief conclusion for sure. I am not very familiar with this ATU and to be honest I didn’t have very high expectations. The display with power and SWR reading was very attractive for me as well as the opportunity to offer another protection cover like I made for the T1.

One reason I chose was that they are one of the very few approved vendors for the (tr)uSDX and I have seen several times there they appear to have great customer support.

Did I mention the T1 is great? Currently they have shipping time from Elecraft listed as TBD due to chip shortages, I believe.

There is both a “Relay-Test” and “Manual-Test” file from the GitHub Repo by David Fainitski. You can load these firmware hex files and step through the L and C circuits. In a not so scientific manner, I watched Inductance and Capacitance through the open tuner and did in fact see changes with each step and hear clicks as well which at least tells me the relays are functioning. There is some discussion on the page as well, honestly much of which I have not yet read.

That page is for the original ATU-100 as well as the ATU-10. One commenter believes the cap values should be updated for better agility to match the network. You can see this in the Features section above when comparing the T1 and ATU-10.

It also sounds like David is planning to work on updating the tuning algorithm. The community work on this ATU and so many other areas of HAM radio is such a great thing to see!

Joshua KO4AWH Tufteln Antennas

For those still Interested an ATU-10 case:

19 thoughts on “Joshua tests the ATU-10 portable automatic antenna tuner”

  1. Read my thoughts on QRPer.Net under the ATU-10 posts. I did get it to work with a G5RV and with a 9:1 transformer but I wanted it to match my 28.5 random wire which I use a lot with a LDG Z100Plus. Thanks for the numbers.

    I got mine from Amazon and it was easy to return.

    1. Thanks for the info. I will hang onto mine for now. Funny you mention Amazon. I called my Father after conducting the test as i know he was looking to purchase. He canceled his Amazon order and I think ordered a ZM-2. I do believe either a firmware update to change the tuning algorithm and or a swap out of the capacitors and inductors can make this tuner work well and as I mentioned already I appreciate the additional features this ATU brings.

  2. Great article, thanks.

    I had thought of getting the ATU10, but already have the T1. Now glad I passed on the ATU10.

    73, ron, n9ee

    1. Ron I too have considered the ATU 10 but have had my T1 since way more than a decade. Tested the ATU10 that a friend of mine purchased and in my Humble Opinion the T1 outshines the 10. Maybe if Elecraft gets the T1 back into production I’ll buy a spare!!!! 72, Alex, K5UNY

  3. I’ve considered an ATU 10 in the past, but decided against it as I read reviews here and there. A T1 would be nice though price is out of my range for now. My ZM2 works well for me when needed when I use it with my UBitx v6 and/or QCX-Mini 20m into either a hamstick or a sivertip vertical.

    One of these days I’ll actually use my EFHW I have….

    Thanks for your thoughts and thanks Thomas for the platform.


  4. Nice study Joshua. I have a T1 and will stick with it. Wanted to comment however on the No Tuner data. I’m a bit concerned about the TX-500 SWR readings, especially with the 85 foot radiator. Assuming the RigExpert is the true value, the TX-500 is too often is telling me the SWR is under 2 when it is not. This could potentially result in damage to the radio. I understand that the TX-500 may not be as accurate as the RigExpert, but would have hoped to see they would both agree when the SWR is over 2.

    1. Mark, you bring up an excellent point. I really like my TX500 and use it quite a bit having purchased it in August last year when I got my general. I have always felt that the SWR reading was a bit generous, reading a bit lower than assumed actual. I had not heard that mentioned until you did and I have not seen any studies showing the same which was part of why I wanted to record its readings during this test. With that said, I don’t believe I have ever seen it read more than, say .2 lower SWR than a reading on another device such as the Stick 230 or my NanoVNA so I haven’t worried too much about it. Maybe that will be my next test when I get a chance to “go play radio”. I don’t know that there is a way to adjust its reading either. I don’t know if that is even a typical adjustment on radios today but if it is it wouldn’t surprise me if the Lab599 group added it in their frequent firmware updates if the interest was there.

  5. I ordered my Elecraft T1A in December 2021, and received it on July 12, 2022. Yes, they are behind. I’m glad I waited and didn’t cancel it. It’s a GREAT tiny tuner for my IC-705 and Lab599 TX-500. Couldn’t be happier with the T1A!

    1. Great question Frank ON6UU

      I was using the TX500 “TONE” function which is just over 4 watts at a 1:1 SWR. I found this to drop to about 3 watts with a 3:1 SWR. I did not redo the test above but I did setup several checks with the TX500 in AM and a power output showing around 1 watt. It did seem the ATU-10 would not tune if under 1 watt but if at or over 1 watt it would function the same as with the 3-4 watts from the TX500 sending its “TONE”. As for a difference in the ability of the ATU-10 to tune with the 1w signal, there was no difference noted. With several quick checks the ATU-10 failed to make a match, landing around a 3:1 SWR, similar to the results above, while the Elecraft T1 still found a match at 1.2:1 or lower.

    2. I now regularly use the ATU-10 with my IC-705 with SDR-Control on an Ipad. I use 10% power on the 705 to tune the ATU, so i would assume it is close if not right at 1W during tune and always works great.


  6. I had similar results with my ATU-10 unit (purchased from supplied by Malahit). It was so disappointing that I switched to the ZM-2. I hope the T1 will be back in production soon.

  7. Seeing the capacitance and inductance values listed for both tuners I suspected the best match would rarely be at a low swr reading. Inserting a lower value and shuffling the rest along would probably fix it, at the cost of the performance on lower bands. Including 80m would have been a good idea as it would work better there where the lowest capacitor value is half as important as on 40m.

  8. Interesting review. Mine fits my needs. But I’m using all resonant antennas. I only need it for the edge of the 40 meter band when I set up portable.
    As for the bypass, yes….it does have a bypass.
    Tap the button on the front of the AT-10 and make sure it says, “Reset.” Now the relays are set for bypass. Next, depress and hold the button until the AT-10 turns off. It is now fully in bypass and the RF will just go straight through. So if you have a high or low SWR on the antenna, that’s what the radio will see.

    I have no doubt the T1 is a better ATU, but it cost almost three times as much. I pain 89 dollars for mine from Banggood.

    Barry, KU3X

  9. Just a rough calculation in simulation: you hook up the tuner right behind the rig, 17ft cable, + 1:9 UnUn + 41ft radiator + radial. In fact – you are match your rig to the setup of [cable+UnUn+radiator]. A tuner does not ‘tune’ an antenna, it will match the 50 ohms of the rig to the ‘other side’, labeled ‘antenna’. That setup will have ~ 26% loss of power due to reflections. (3% in tuner, 18% in cable and 5% in the UnUn). The ‘good’ SWR you are seeing is just between the rig and the tuner, still a quarter of your power is lost. The tuner belongs to the base of the antenna, without an UnUn etc.
    73’s de OE1MWW

    1. Great comments, spot on. Considerations I rarely see mentioned. For this consideration, I really like the ATU-10 with the IC-705 for field use. Just like the AH-705, if you use a long 3.5mm TRS cable, the ATU can be placed at the antenna to minimize this loss. For field use i plant to use a 20ft cable, likely with some choking, and place the ATU at the antenna feed point. Be sure to check out the update to this post found here:

      Thanks for mentioning!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.