Tag Archives: ATUs

Antenna Tuners, Antennas, Field Reports, How To, Kits, News, POTA, QRP

How to tune: Pairing the Emtech ZM-2 manual ATU with the Mountain Topper MTR-4B on the Blue Ridge Parkway

21 Comments

You’ve no doubt heard me brag about the Emtech ZM-2 ATU in previous field reports. I think it’s an accessory every field operator should have.

The ZM-2 is a very capable manual transmatch/ATU and is also one of the more affordable tuners on the market. It’s available as both a kit and a fully-assembled unit. Both well under $100.

I do believe the “manual” part of the ZM-2 scares off some and it really shouldn’t. We are used to simply pressing a button these days and allowing our automatic ATUs to do all of the matching work for us.

Manual ATUs do require some amount of skill, but truth is, the learning curve is very modest and intuitive.

Manual ATUs require no power source in order to operate–you adjust the L and C values by hand–thus there’s never a worry about the ATU’s battery being depleted. They also are easy to manipulate outside the ham bands because they require no RF in order to read the SWR–you simply make adjustments to the L and C until you hear the noise peak.   This is why many shortwave broadcast listeners love the ZM-2 so much. It’ll match most any antenna you hook up to it!

I also argue that everyone should have a portable ATU even if you operate resonant antennas. Think of an ATU as a First Aid Kit for your antenna: if the deployment is less than ideal, or if you damage it in the field, an ATU can help you find an impedance match your radio can live with. ATUs have saved several of my activations.

Mountain Topper MTR-4B V2

I’ve also mentioned that I’ve had an MTR-4B on loan from a very kind and generous reader for most of the year. He was in no particular hurry for me to send it back to him, but I wrote him in early November and said, “I’m doing one more activation with this little rig, then I’m shipping it to its rightful owner!”

He had a request, and it was a good one:

I think it would be a good little twist to the usual YouTube if you paired a random wire with the ZM-2 and the MTR-4B…showing how to tune the ZM-2 with a Mountain Topper…

I really liked this idea, so I made plans to to hit the Blue Ridge Parkway nearby and give it a go.

The first time I tried this in the field, I paired the MTR-4B with one of my Sony amplified speakers because the MTR-4B 1.) has no internal speaker and 2.) has no volume control. During the video, however, I realized that there simply wasn’t enough audio amplification so that the viewer would be able to hear a noise peak as I manually tuned the ATU. I decided to scratch that video and just do the activation on my own. I really wanted to show how the tuning process worked in the video.

I went back to the field the next week–on November 10, 2022–with my Sony in-line digital recorder knowing it would be much easier to hear how the L/C changes affected the band noise. Continue reading How to tune: Pairing the Emtech ZM-2 manual ATU with the Mountain Topper MTR-4B on the Blue Ridge Parkway →

Accessories, Antenna Tuners, Antennas, News, QRP

Joshua’s ATU-10 review update after new firmware upgrades

2 Comments

Many thanks to Joshua (KO4AWH) who shares the following update to his previous guest review of the ATU-10 automatic antenna tuner:

Update on the ATU-10: new firmware released

by Joshua (KO4AWH)

The short story is that David N7DDC has a Firmware update with a new tuning algorithm that seems to fix the previously seen failure to find a decent match. As noted earlier in comparison with the Elecraft T1, the ATU-10 still does not necessarily get as close a match to 1:1 SWR but it now does indeed find a good match making this tuner my go to for use with my IC-705.

Not previously mentioned, the ATU-10 is also designed to work with the IC-705 for tuning commands when connected with a TRS 3.5mm cable, not just as an auto tuner when given a signal. And, in practice it works just as it should. I actually took the IC-705 and the ATU-10 and worked a SOTA/POTA with the beta version of this new firmware. I ran a 35’ wire and it worked great allowing me to work 40m, 20m, 15m and 6m for a total of 26 contacts. As a followup to my previous testing with the prior firmware 1.4, below are my results with the current new 1.5 firmware.

Testing on August 20th, 2022

The only difference from the original testing is the 31.5’ radiator was replaced with a 35’ and I did not tune and record results with the T1.

Conclusion on the ATU-10

I now feel very comfortable recommending this ATU. newdiytech.com has a great price and the build quality seems just fine. With the new algorithm update, a good match is found. The ATU-10 works great stand alone and also works fully automatically when used with a IC-705. This configuration means you can put the ATU at the antenna feed point and run a control cable back to the IC-705 and have a 50 ohm across the coax to help minimize loss, making for a nice portable setup with great band hopping flexibility.

Of course, if interested, I sell a protection cover for the ATU-10 just as I do for the T1.

If your curiosity is strong, here is some testing I did for David as he was updating the Algorithm now used in firmware 1.5.

UPDATE August 3rd 2022:

David Fainitski N7DDC has released a test firmware with a new tuning Algorithm with some promising initial results. A quick test on each band in the table has been added to reflect the new algorithm. This is not a firmware update yet but I suspect it will be soon. Results are great as tested. I hope to see this in a new FW soon.

August 6th, 2022

A second test firmware from David Fainitski N7DDC with the ability to increase or decrease the L and C manually allowed me to verify if a better match could be made. Turns out in a few cases it could. After testing again with a Tufteln 9:1 T80-2X2 on a 41ft sloping radiator I was able to achieve much better results than with the current version 1.4. In two cases I was able to find a better match manually. I realized later that if I were to tune a second time the ATU-10 would find the same, better match, on its own. Again, not a full firmware update, i.e. you have to flash back to 1.4 if you want to be able to turn off the turner.

(Click to enlarge.)

August 7th, 2022

Another test firmware David asked me to check. This version seemed more likely to find the best match. I did have the ATU go to L0, C0 twice but then find a match on a second try. This happened once on 40m and once on 10m. Almost like it faulted but there was some switching/clicking involved before stopping, it just landed at a 3:1 or higher with 0 for L and C. A second tune however straightened it out. I did not record those two cases. Below are the results. I was able to find a slightly better match twice but I am sure one would never notice the difference during normal use. The improvement both times was within the error of SWR across the three device measurements.

(Click to enlarge.)
Accessories, Antenna Tuners, Antennas, News, Reviews

Joshua tests the ATU-10 portable automatic antenna tuner

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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 newdiytech.com, 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. Continue reading Joshua tests the ATU-10 portable automatic antenna tuner →

Antenna Tuners, News, Reviews

Barry’ review of the ATU-10 QRP Antenna Tuner

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Many thanks to Barry (KU3X) for sharing the following guest post originally posted on his website:

ATU-10 from Banggood.com

by Barry (KU3X)

There are times I find myself in need of an ATU. One example is when I use my half wave end fed 40. I can not always erect this antenna in the clear. I did purchase the LDG Z100 Plus 705 with interfacing cable. The unit does as advertised but I am not impressed with its performance. My biggest complaint is, when interfaced and the IC-705 tells the LDG to tune and it does not know the antenna is matched and resonant, the LDG adds capacitance and inductance which actually raises the SWR. It’s too dumb to go into bypass. I resolved this by not using the interface cable. Now I only tell the LDG to tune where needed. Most of the time I turn the LDG off by toggling between bypass and tune using the button of the front of the unit.

Size matters to me and the LDG ATU is too big. Another downside is it uses SO-239 connectors instead of BNC connectors. Everything I have relating to QRP operating uses all BNC connectors, including my home brew two position antenna switch. I do want to get my hands on an Elecraft T1 ATU but Elecraft can’t get the parts from the manufactures to make them. So the hunt was on for a small ATU with internal batteries and BNC’s instead of the dreaded SO-239 connectors. Here is what I came up with.

I ordered the above pictured ATU-10 from Banggood.com. I have also seen them posted on Amazon.com. They can be found on eBay as well. I did not provide a link for ebay because some ebay adds are dated. There is a very good demo posted on YouTube. Here is an overview of the ATU-10 [PDF].

My ATU-10 arrived 11 June 2022. Here are my findings:

The package contained an Allen wrench and a USB cable for charging the battery as well as for updating the firmware. The package DID NOT include the interface cable for the Icom 705 nor did it included any paperwork…….no manual! My battery showed about half charged and firmware version 1.4 was installed. If you forget to charge the battery and go on site with a dead battery, you can supply power to the ATU-10 via the USB charging cable. You may have to give it a few minutes for the batteries to take a little charge, but from that point on just leave keep the ATU-10 connected to the USB cable.

The needed interface cable is nothing more than a stereo audio cable with 1/8″ male plugs on both ends. But, the ATU works without the interface cable, it’s just not controllable from the radio. As for the matching, I can say it works as good as or as bad as my LDG Z-100 Plus. Where ever the LDG provided a match, so did the ATU-10. On 80 meters where the LDG did not do so well, neither did the ATU-10.

I first tried the ATU-10 without the interface cable. I just sent a carrier from the radio and the tuner went into the tune mode. It’s that simple. It takes anywhere from 2 to 5 seconds to find a reasonable match.

To use the ATU-10 with the interface cable, there is the setup procedure. Hook up all of the cables, including the interface cable to the IC-705. Now turn the ATU-10 on. Once booted, turn on the IC-705. Go into the, “Function” screen and tap the, “tuner” icon. You are ready to go. You do not have to change modes to have the ATU-10 go into the tune mode. In any mode on the radio, like SSB, just key the mic and the tuner will tune. Give it a second or two and you are ready to go. Change bands and key the mic, same results. I lost communication between the radio and the ATU-10 when I went to 80 meters. I have no idea why? I just turned the radio off, then back on and everything was reset…ready to go.

When I received my ATU-10, I noticed all of the hardware was not that tight. I retightened each nut and Allen screw.

User group for the ATU-10 and the ATU-100.

Pros:

  • Size…the ATU-10 is small enough to carry in your shirt pocket ( 5″ x 2-3/4″ x 1″ )
  • Antenna connections… BNC. All of my cables used when I set up portable use BNC connectors.
  • Power source ….the ATU-10 has two internal rechargeable batteries so no external power source is needed. Since the ATU-10 uses latching relays, the only power that is needed is for the display. The display has a time out timer and the ATU will turn off after 30 minutes on non use. The ATU will last you for months on end before needing to be recharged.
  • Display… the display shows SWR, power out and the state of charge for the internal batteries. It also shows what firmware is installed. The display will fall asleep after 5 minutes of non use. If power is applied, the display will wake up. The entire ATU will turn off after 30 minutes of non use.
  • Bypass mode (simply turn the ATU-10 off)
  • Construction…..the ATU-10 is built inside of a solid metal enclosure.

Cons:

  • Loss of communication….more than once communication was lost between the radio and the tuner. Easy fix by turning the radio off and then back on but this is very inconvenient.
  • No manual…..not even a little sheet of paper showing the specs. Whatever you need to know can be found on this site: ATU-10 info at GitHub.

Final notes:

For the price, it think this is a great buy. It does exactly what I want it to do and provides a reasonable match to make the radio happy. You can use the ATU-10 with any radio at power level of 10 watts or less. It’s a perfect size for backpackers. I don’t think the interfacing between the radio and the ATU-10 is all that importable. I myself choose not to use the interface cable. Since the tuner will go into a tune mode if the SWR is too high, that’s all that is really needed.

Antenna Tuners, Antennas, News

Norm recommends the MFJ-212 Matchmaker for effortless tuning

4 Comments

Many thanks to Norm (VE3WNS & M0CEL) who writes:

Hi Thomas,

[…]At my condo QTH in downtown Toronto I’ve been using a balcony tripod mounted MFJ 1886 along with my Icom 7300. I heard about the MFJ-212 Matchmaker and decided to try it out. It worked brilliantly. What it does is put out a signal in the form of hash and you can see the resonant point moving along the band scope on the radio as you tune the antenna. Once the hash is centered you are on frequency without ever transmitting.

I’m back at my QTH in Manchester where I have a pretty respectable station, you can see both on QRZ. Anyway, your videos are responsible in a large part for getting me interested in POTA so I’ve purchased an ICOM 705 and a Chameleon F Loop 3.0. I decided to purchase another MFJ 212 Matchmaker and again, it works brilliantly. No transmitting required as the antenna can be tuned visually on the 705 band scope. The 212 can be powered externally or, as in my case, I’m using the 9 volt battery option. I figure the battery will last for ages.

[…]I have to say the MFJ Matchmaker has made working with a hi Q loop a pleasure, especially one that tunes as smoothly and finely as the Chameleon F Loop.

73

Thank you for sharing this, Norm and for the kind comments! I had no idea such a product existed. I love the concept, though–this could be especially useful tuning antennas like loops with high Q and thus narrow bandwidth. 

Click here to check out the MFJ-212 Matchmaker at MFJ ($149).

Update: A number of you have pointed out that the MFJ-212 is a noise bridge! I think it’s so cool that, in a sense, this accessory is even more useful when paired with a transceiver with spectrum display. Thanks for the comments!

Antenna Tuners, News, Portable, QRP

Richard recommends the Phoenix QRP Pocket Transmatch

10 Comments

Many thanks to Richard (M0RGM) who writes:

Hi Thomas,

Hope this email finds you well, and thanks for all the recent blog updates and videos.

Like many other QRP ops we sometimes need an ATU or matching unit. For a while I’ve been looking for a small compact unit for use with my QCX-mini, MTR-3B and TX-500. I was sorely tempted by the Emtech ZM2, but they are quite expensive over here in England, especially as I’m awaiting delivery of a Venus SW-3B!

After much research I stumbled on the Phoenix Transmatch sold by Kanga Products. Paul, the proprietor, sells quite a range of quality QRP goodies. Having purchased the assembled device (work gets in the way of construction these days), I can say that this is a really good lightweight model that suits my purposes fully. No, it doesn’t have the tuning range of the ZM2, but I rather hope my antennas are not too far out of resonance!

For size comparison, see the attached photo taken whilst playing in the sunshine….

For anyone interested, the web details can be found at https://www.kanga-products.co.uk/ourshop/cat_1750054-QRP-ATUs.html

I have no connection with Kanga other than being a satisfied customer!

Regards,

Richard M0RGM

Thank you for sharing this, Richard. I love the size of Phoenix Tranzmatch–I was not familiar with it. It would be a great additon to pretty much any field kit. I see you also have the N6ARA paddles–I think they’re great!

It also sounds like you, too, have a QRP radio addiction. I hope you realize there’s no cure, so don’t fight it! 🙂

Thanks again for sharing this, Richard. 

Antenna Tuners, Antennas, News, Portable, Portable Power, POTA, QRP, SOTA

“What battery, antenna, and ATU should I pair with the Discovery TX-500?”

25 Comments

Many thanks to Vitor Morais who asked the following question in the comments section of my YouTube video:

Hi,

Greetings from UK.
I recently learned that POTA [is now in the] UK so I am really looking forward to it.

I also recently put an order for [the Discovery TX-500] so I am really excited as well.

I would like to create a very compact setup pouch for field use to pair with this radio; one that I could take to summits or parks and also travel abroad.

What battery and antenna would recommend?

Would you recommend an ATU?

Or would you compromise to fewer bands or pack a secondary antenna?

I love to know your opinion.
Thanks

Great questions, Vitor! In truth, these sorts of questions are easy to ask but quite complicated to answer due of the insane number of options and possibilities available. It’s impossible to cover them all so I’ll try to give you some suggestions based on what I tend to use in the field. Continue reading “What battery, antenna, and ATU should I pair with the Discovery TX-500?” →

Antenna Tuners, Antennas, News, Videos

Hike and Talk: Non-Resonant vs. Resonant Antennas and should you buy an ATU?

27 Comments

I had a topic on the mind as I made my way back to the trailhead after a SOTA activation recently.

I get a lot of questions from readers and subscribers about resonant vs. non-resonant antennas and whether or not an ATU is a good or bad thing.

If you know me, you’ll know that I tend to lean towards qualitative research; meaning, I like to base my opinions on first-hand observations rather than laboratory or textbook explanations. Part of the reason is I’m not an engineer, so specifications and performance stats don’t influence me–I don’t understand them half the time–rather, I base my opinions on trying or field testing.

The proof is in the pudding, right?

So with the topic of antennas and ATUs on the brain, I decided to turn on the action camera and do an unscripted video on the trail as I hiked back to my car.

This video is essentially stream of consciousness: I won’t blame you if you skip it.

With that said, if you manage to stay awake for the whole video (congratulations in advance) I’m curious what your thoughts are so please consider leaving a kind comment!

Thank you & 73,

Thomas (K4SWL)

Antennas, News, POTA, QRP

Icom IC-705: Reviewing the Mat-Tuner mAT-705 in the field

8 Comments

UPDATE: My review of the mAT-705 ATU below is accurate as of its original posting. Since this review, however, I’ve discovered some design issues that prevent me from continuing to recommend it. Click here for details.

UPDATE 2: Mat-Tuner released the latest updated and upgraded version of the mAT-705 in December 2020. It’s called the mAT-705Plus. Click here to read my initial review of the mAT-705Plus. Note that the following article pertains to the original mAT-705 which is no no longer being produced, but still available for sale (at time of posting) both new and used.

Last week, Vibroplex sent me their new Mat-Tuner mAT-705 external ATU on loan to evaluate with my recently acquired Icom IC-705.

Here’s some info about the mAT-705 from Vibroplex’s product page:

The new mAT-705 antenna tuner is designed specifically for use with the new Icom IC-705 QRP transceiver. Connect the mAT-705 directly to the TUNER jack on the IC-705 with the included cable and control the antenna tuner directly from the front panel of the radio or use RF-sensing to actuate the tuner when changing bands. 1.8-54 MHz, 5-1500 ohms matching range, 16000 user memories recalling previous used settings internal to the tuner when returning to an earlier used frequency.

The tuner is powered by an internal standard 9 volt alkaline battery. Power saving technology inside the tuner allows the use of the unit for months without replacement. No battery power is consumed by the unit when powered off.

Yesterday, I stopped by South Mountains State Game Land (K-6952) to give the mAT-705 some field time. Up to this point, I had not used the tuner other than tuning to the 80 and 40 meter bands from home (mainly to make sure it worked before hitting the field).

To really give the mAT-705 a workout, I deployed my CHA Emcomm III Portable random wire antenna. The Emcomm III is the only field antenna in my arsenal that covers 160 meters – 6 meters–an exceptionally wide frequency range.

What I like about this particular POTA site is the open parking area which allows me to configure the Emcomm III a number of ways.

The Emcomm III, being a wire antenna, is incredibly stealthy. Since you can’t see it in the photo above, I’ve marked up the configuration below (click to enlarge):

I’m guessing the apex of the antenna was easily 45′ high.

Activating

I started my activation on the 80 meter band.

After working a few stations on 80 meters, I decided to test the mAT-Tuner over a fairly wide frequency range before calling CQ on the 40 meter band.

Here’s a short video:

POTA Hunters: look for me on the 160 meter band this fall and winter! I’m so impressed how well it matched the Emcomm III on 160.

 

Indeed, I am very pleased with how quickly and efficiently the mAT-705 found matches on every band I tested.

In terms of form factor, the mAT-705 is quite compact, but a little longer in length than I had anticipated. Honestly, though, there’s nothing here to complain about.

The enclosure/chassis is incredibly strong. I’m willing to bet you could accidentally drive over it with your car and it would survive in tact.

The mAT is powered by an alkaline 9V battery. Vibroplex expects that this battery will last for months under normal use.

Note that there is a specific procedure for replacing the battery in order to protect the LED “illuminators” that are press-fit to the board.:

  1. Remove the case by removing the 4 rear 2mm allen screws.
  2. Turn the tuner upside down and shake it a little to get the PCB to slide out of the case enough to grab.
  3. Carefully grasp the PCB sides and slide the board out slowly.

Update: I’ve followed the procedure above and still had an issue with the illuminators falling out. They really need to be secured better. I was able to re-insert them and close the ATU, but when you open the mAT-705 to change the battery, be in a space where you can capture both of them if they fall out.

Any mAT-705 negatives?

Not really, but I do feel the price is a little steep at $219.95–but then again the mAT-705 seems to do the job and do it well. I have to assume the TBA Icom AH-705 ATU will cost at least as much. I’m okay with paying at the top end of the market if I’m getting a quality product and this certainly seems like one.

I like the fact that the mAT-705 integrates perfectly with the IC-705 via the control cable and that I don’t have to worry about protecting it at all in my backpack. It’ll also take the IC-705 through the entire HF spectrum and even up to 6 meters.

 

I plan to continue using the mAT-705 for a while and even test it on severely non-resonant antennas just to see how far I can push it for a match.

Stay tuned! (See what I did there–?)

Many thanks to Vibroplex, again, for lending me this mAT-705 for review and evaluation.

Click here to check out the mAT-705 at Vibroplex.