Tag Archives: mAT-705 review

Testing the updated and upgraded Mat-Tuner mAT-705Plus portable IC-705 antenna tuner

On Wednesday (December 16, 2020) I took delivery of the new Mat-Tuner mAT-705Plus ATU.

Mat-Tuner sent this updated and upgraded version of the mAT-705 ATU to me at no cost and asked that I give it a thorough evaluation in the field.

History of the mAT-705

If you’ve been following the story of this tuner, it was the first introduced in September 2020 and designed to pair directly with the Icom IC-705 transceiver. Note that Icom plans to introduce their own IC-705 antenna tuner (the AH-705) but it is not yet on the market at time of posting, so the mAT-705 has certainly had a market opening.

The original mAT-705 had a mechanical power switch on the front/faceplate.

I received the original mAT-705 ATU via Mat-Tuner US distributor, Vibroplex, around the same time I received my Icom IC-705 in early October. I took the original mAT-705 to the field and made a quick video demonstrating its ability to find matches from 160 to 6 meters. In short, it did a brilliant job.

A couple weeks later, however, I discovered that the original mAT-705 had some design shortcomings. I updated my review with this follow-up post.  In brief, the mAT-705 could deplete a 9V alkaline battery within a couple of days if you failed to turn off the tuner’s mechanical on/off switch.

Replacing the internal 9V battery was a complicated procedure requiring the user to carefully detach the front panel without losing the LED lenses that were prone to simply pop out. The 9V battery was mounted internally on the board with adhesive–obviously, not an ideal situation for an ATU that would require frequent battery replacement. Due to this, I simply could not recommend the original mAT-705–it was too pricey at $220 for an antenna tuner with so many design shortcomings. For full details, read this post.

Introducing the mAT-705Plus

Mat-Tuner was obviously listening to customer feedback, because within two months they introduced the upgraded and updated mAT-705Plus antenna tuner.

I love the USB-C charging port!

Here are the mAT-705 upgrades:

  • No mechanical on/off switch–power is internally managed
  • 9V battery replaced with 1000 mAh internal lithium cells
  • Batteries are internally charged via USB-C port
  • No longer necessary to open the enclosure/housing

Update: Using the mAT-705Plus with other transceivers

Since the new mAT-705Plus lacks a power switch to manually turn it on, I originally noted that I was unsure if it could be engaged via RF sensing when paired with other transceivers. I tried to no avail. Before posting this review, I sent an inquiry to Mat-Tuner about this. Here is their reply:

The power of the new version of the mAT-705Plus tuner is controlled by the KEY signal of the control cable. When KEY is high, the tuner is automatically turned on. The function of following the transmitter to automatically turn on and off is realized.

In addition, the mAT-705Plus tuner follows the ICOM tuner protocol. Like other ICOM tuners, you can manually start the tuning cycle by manually customizing the control cable, just like the AT-120 tuner.

After you solve the KEY signal to trigger the tuner to start and make a manual control cable, you can use it [the mAT-705Plus] for other non-ICOM brand transmitters.  But we do not recommend you to use it this way.

Because it is specially designed for the IC-705 transmitter, [it must be modified for use with] other transmitters, which many customers cannot do.

[Since] it uses a magnetic latching relay, after completing the tuning cycle, you can completely turn off the IC-705 transmitter power and connect the tuner to other transmitters.
The tuner will remain in the tuning state.

To clarify, I believe what the Mat-Tuner engineer meant is that if you tune an antenna with the IC-705, you can power the rig down, connect the mAT-705 to another transmitter and the mAT-705 will preserve the last tuner setting (the last match).

Let’s see the mAT-705Plus in action!

Yesterday, I took the mAT-705Plus to the field and paired it with my Chameleon Emcomm III Portable random wire antenna.

I made the following real-time no-edit video yesterday afternoon. Other than charging the mAT-705Plus batteries the night before, this video captures its first time being connected and used.

The Emcomm III Portable random wire antenna’s frequency range is 160-6 meters–the mAT-705Plus quickly found matches on every band.


At first blush, the mAT-705Plus looks like the ATU Mat-Tuner should have released on the first go: it’s portable, lightweight, fully automatic, rechargeable, and quickly finds matches across the HF spectrum.

Size comparison: mST-705Plus (left) Elecraft T1 (right)


We’ll see how well the power management works in real life. I plan to take it to the field over the next few months and carry a small USB battery pack to recharge the mAT-705Plus when the batteries are finally depleted. Hopefully, I won’t need to recharge it for a long time! The proof will be in the pudding!

Of course, I’ll also pair the mAT-705Plus with an assortment of antennas: random wires, verticals, delta loops, doublets, dipoles, and end-feds.

Stay tuned! [See what I did there? Rimshot anyone? Anyone–?] 🙂

Mat-Tuner authorized distributors:

MAT-TUNER mAT-705 woes

UPDATE: 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, I posted a review of the Mat-Tuner mAT-705 antenna tuner that is designed to pair with the new Icom IC-705 transceiver.

My initial assessment was very positive, but since then the shine has worn off. I’ll explain…

On Monday, I took the IC-705 and mAT-705 to the field for a little Parks On The Air (POTA) fun.

The Par EndFedz EFT-MTR triband (40/30/20M) antenna

Enroute to the site, I thought it would be a good test for the mAT-705 to attempt to tune the excellent EFT-MTR antenna (which is resonant on 40, 30, and 20 meters) on all bands above 40 meters.

After arriving on site, I very quickly deployed the EFT-MTR antenna using my throw line. I then hooked the EFT-MTR up to the mAT-705 ATU and connected the ATU to the IC-705.

After turning on the IC-705, I opened the menu screen and tried to engage the mAT-705 ATU. Unfortunately, the ‘705 didn’t recognize the tuner. I double-checked to make sure the control cable to the mAT-705 was secure–it was. After some head-scratching, I realized I must have left the ATU’s mechanical power switch in the “on” position while using it a few days prior.

This evidently depleted the mAT-705’s internal 9V battery. What a bummer!

I bragged about the mAT-705 in a previous post because, frankly, it is a very capable ATU–quickly finding matches from 160 to 6 meters on my random wire field antenna and horizontal loop antenna at home. It also has an incredibly sturdy aluminum enclosure.  It’s a very capable ATU in terms of quickly and efficiently finding matches and, superficially smacks of superb build quality.


But if I’m being honest, my love affaire with the mAT-705 ended Monday due to a number of discoveries.

9 volt batteries

The mAT-705 next to the IC-705

According to Mat-Tuner’s product description, the mAT-705:

“[I]s 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.”

Turns out, they mean it saves power only with the mechanical power switch turned “off.”

This, in turn, means that the user must remember each time they use the mAT-705 to flip the mAT-705 mechanical switch off.  If left in the “on” position by accident, even with no connection to the IC-705 and while not in use, it will deplete a 9V cell in a matter of a few days.

This is a significant issue, in my opinion, and is compounded by a few other design choices:

Complicated battery removal

There is no “easy access” to the mAT-705 battery. The user must use a supplied (standard) Allen wrench and unscrew the rear panel from the chassis.

As we mentioned in our previous post, Mat-Tuner actually has a procedure for opening the case and replacing the 9V battery in order to prevent the LED illuminators from falling out. I followed this procedure to the letter, yet the illuminators still fell out. They simply aren’t secured properly and would be very easy to lose if replacing a battery in the field.

The LED illuminators

Once open, you discover that the 9V battery’s holder is a piece of double-sided tape. Seriously:

The mAT-705’s 9V battery holder

In addition, the ATU board essentially “floats” in the chassis secured in slide-in slots. The problem is the back panel–which you pull to remove the board–is only secured to the ATU board with three wired solder points.

Even when I lay the board down carefully, gravity will bend those BNC connections.

I can’t imagine this holding up with multiple battery replacements.

No external power port

Given that battery removal will take a user at least 5 minutes, I find it a little surprising that there’s no external power port.

It would be no problem at all for me, if the 9V battery died, to simply hook the mAT-705 up to my portable DC distribution panel like I can do with other external ATUs. But since this isn’t an option, you’re simply out of luck in the field. Better carry spare 9V batteries!

Where the lack of an external power port is really an issue, though, is for mAT-705 users in the shack. If the IC-705 becomes one of your main radios, you’ll have to be very disciplined to turn it on and off each time you use it, else you’re going to be replacing a lot of 9V cells.

Command connection to the IC-705 is basic

It seems to me that if you build an antenna tuner specifically to pair with a radio via a dedicated control cable, the tuner could potentially:

  • derive power from the transceiver
  • or at least be told by the transceiver to turn completely off when not actively in use. Especially since once a match is found, it’s locked into position even if the mAT-705 has no power.

The mAT-705 can’t do either.

Is it a good ATU? Yes. But inside it could be better.

As I said above, my original review stands in terms of the mAT-705’s ability to match antennas, I think it’s brilliant.

But I can no longer recommend the mAT-705 until some of these design shortcomings are addressed.

I’ve never owned a portable ATU that required so much discipline from the user in order to preserve the battery. I’ve also never owned one that was so fragile internally. Most portable ATUs *only* turn on when finding a match and then either “sleep” or turn off when not in use.

And portable ATUs like the Elecraft T1, for example? Even have a convenient battery compartment for easy removal. (And, oh yeah, the T1 will run ages on a 9V!)

The Elecraft T1 ATU 9V battery compartment

To add insult to injury, it’s one thing to discover that your mAT-705 ATU eats 9V batteries if left on but not in use, but it’s quite something else to discover your $220 ATU’s 9V battery is held in with a piece of double-sided sticky tape.

How long could this possibly function if you’re replacing batteries frequently in the field?

My hope is that Mat-Tuner will sort out this design and re-introduce the mAT-705 to the market. I’ve heard so many positive things about other Mat-Tuner models which is why I wanted to try one out with the IC-705.

Mat-Tuner ATUs are sold by respected retailers in the ham radio world (like Vibroplex, who loaned this model for review) so I expect they’ll address these concerns in the coming months. I’ll certainly post all updates here on QRPer.

Until then, I have to recommend skipping the $220 mAT-705 and instead purchasing the excellent ($160 kit/$190 assembled) Elecraft T1.