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.

24 thoughts on “MAT-TUNER mAT-705 woes”

    1. It’s not the turning it off and on. It’s the battery drain. A reader just contacted me and said he accidentally left his on and two days later the battery was dead. Using it in the shack would be an exercise in discipline to remember to switch it on, tune, play radio, then switch it back off else, it’s time to get out the Allen wrench and go through the process of replacing it and re-inserting the LED illuminators without harming the back connections to the board. Trust me, it is actually as you say, a burden. 🙂

  1. Very valid point to consider Unfortunately,I just took possession of mine as I read your article. I would have reconsidered, if I have known those little details.
    Thank you,

  2. Hi Thomas
    the lack of an auto power down function does appear to be a shortfall. The LDG Z817 has this function and it works well. Four ‘AA’ batteries easily last a year at which time they are replaced in accordance with LDG’s recommendations. The unit has to disassembled to do this but it is a simple task.
    Thank you for your writeups of the 705, they make great reading.
    Mark VK2XMB

  3. Even before I got the unit I had already planned to replace the 9V battery with a rechargeable type, added a charge controller, a barrel port which charges the battery and powers the unit at the same time from 12v – simple mods that fit with my operating setup – solar/LiFePo unit I built.

    should I have had to do them – of course not – but hey – what piece of equipment is perfectly designed so that it satisfies 100% of the users in very situation 100% or the time.

    1. Actually, if you did a mod like this, you’d have a great ATU. The whole issue is the fragility of the process to replace the 9V battery. That mod could solve that.

  4. I agree with what one user said…. You mean you have to remember to turn it off? Come on. I turn all my radios and tuners off after I’m done with them. Should the battery be mounted with tape? No. Should the end plate be attached with the BNC coax? probably not. Sliding a board into a slot to hold it in place in the case is how the QCX radio works with the Bamatech case. Happens. If it works, and it seems to based on reviews, I think the cost is more of an issue than remembering to turn it off.

    1. I hear ya. As a reviewer, I try to provide my honest assessment. Sounds like remembering to turn off the power isn’t an issue for you, so I’d encourage you to check out the mAT-705.

      Check out my comment reply here for more detail about why I mention the battery replacement process.


  5. It seems that the ciriticism of the MAT-705 started when the reviewer made the error of leaving the device turned on and then the other problems he encountered made him more and more critical of the device.

    If he is critical of finding adhesive tape holding the battery in place, considering the price, he is also going to find grave dissapointment if he opens up an iPhone too in that case. As for the PCB “floating around in the case” – it’s not, as he said, it goes into a groove, so it is secured in place when the case is reassembled.

    It’s a shame, as for a device that matches a radio to an antenna it appears that it does a very good job.

    It wouldn’t take much effort to add a flying lead into the MAT-705 with two sets of PowerPole connectors and the job would be done. Or failing that, slap yourself with a wet fish if you forget to turn the thing off.

    Incidentally, they are a lot cheaper directly from China.


    1. Ha ha!

      Indeed the mAT-705 does a brilliant job matching antennas.

      I’m guessing you haven’t used this ATU, though, Trystan? All of the portable ATUs I’ve ever used automatically turn themselves off after matching an antenna. It’s what I consider good design when using portable power.

      I’m willing to bet that you might even find it frustrating if you forgot to turn off the mAT-705 switch then two days later hit the field to activate a summit and discover the ATU is dead. You’d then need to dig out the Allen wrench and *carefully* remove the board. Even placement of the battery back on the sticky pad is crucial. Here’s the process per Mat-Tuner:

      My Elecraft T1 ATU? A 9V battery will run it for *months.* The power is only on while tuning. And replacing the 9V battery is a matter of opening the slide door on the back and replacing it. Takes me 10 seconds maybe?

      I’m guessing you’re probably not the sort of person that would forget to turn off the switch, but if you do, you’ve got a little operation to perform.

      If I owned the mAT-705, I’d probably modify it so that I could attach an external 9V battery so I wouldn’t have to re-solder the BNC. It wouldn’t be elegant, but it would give the ATU better longevity because frequent battery replacements will eventually lead to re-soldering the BNCs to the board. I’d prefer attaching Powerpoles, but I’m not sure what the voltage range of the mAT-705 is. It uses a 9V battery and most of my batteries produce something north of 12V.

      I’ve opened up iPhones and replaced both batteries and screens. You’re right: most of those batteries are held on with adhesive. But how often does that battery need to be replaced? My iPhone is 4 years old and still has decent battery capacity. Next year I’ll probably crack it open and replace the pack, though.

      Part of what I do when I review a product is be honest about what I feel are its pros and cons. For the mAT-705, the pro is it matches antennas as well as other portable ATUs I’ve used–possibly even a little faster. The enclosure is also top shelf quality. The cons are that the internal design feels cheap even considering the direct from China $160 price point.

      It’s just poor design for the application. That’s how I see it, so that’s what I state. It’s what I would want to know when choosing a portable ATU for my IC-705.

      K4SWL / M0CYI

  6. Tom, the people who think you’re making a big deal out of the power switch will never buy that tuner for that very reason. Ham radio forums are full of those sorts.

    I for one appreciate your thorough reviews as do your other readers. I personally want to know more than superficial observations about products which is why I read both of your blogs and avoid many of the youtube guys. Your review of the Elecraft KX2 is why I bought that radio and I’ve never been more pleased with a purchase.

    Keep up the good work. No need to defend being a thorough reviewer. You’re a dying breed and I for one truly appreciate your work. Just dropped you some coffee fund money via paypal by the way.


  7. Thomas,

    Instead of adding an external 9v battery, put a 78L09 (it’s a 3 pin 9V linear regulator) in the MAT-705 then it could share the same power as your rig.

    If you wanted pimp it up as an auto power-off (instead of slapping yourself around the face with a wet fish every time you forget to turn the power off), then you could do that with three components:

    An N-Channel MOSFET, a 10M resistor and a 100uF capacitor. That would power down the unit in 1.5 hours.

    An useful circuit to build as a stand-alone device too for lots of other applications if you’re concerned about leaving something turned on.

    Have fun!

  8. I viewed your video on this product, and saw later videos where you were using other tuners, after reading your review here and the update, that it was on loan it answered that question. Great review and update, i ordered one but just was a little apprehensive about it, i may cancel the order and get on the waiting list for the elecraft or see what the icom tuner is like until some issues can be addressed. Thanks for sharing your experience.

  9. Hi all. I also have one problem with this tuner, however in my case the second version mAT-705 mkII. After some (not very heavy) usage, the 3,5mm jack female connector broke. I have fixed it quite easily – re-soldered it back, however, the issue is that the connector is not fixed to the panel in any way, it’s held by the pins on the board only and thus when you connect/disconnect the jack cable, you put a stress on the soldering. Maybe my piece was crappy, who knows. If it happens again, I’ll put a screwing socket on the panel that would fix it and that’s what they originally should have put there…. for the price…

    Anyway, apart from that, this tuner is awesome, small, light, tunes not everything, but basically any antenna – I have a 21m wire that could be tuned for 80m even without any unun…

    The mkII version has a rechargable battery inside, USB port for charging, no power switch, it automatically powers down and if you run out of battery, you can plug in your powerbank the same way as you do with your phone…

    I have built this all into a “go-box”, with IC-705 and external battery, etc. However, I have realized that even if the tuner is off/bypassed, it does not like VHF signals going through. Unfortunately though, I have to open the go-box, reconnect the coax pigtails whenever I want to switch to VHF.

    UHF appears OK, but who knows.

    Anyway, after all, I can recommend this tuner.

  10. I bought this tuner new with my ic705 and worked great but it didn’t take long before I started having issues with the connectors, very weak solder, I reinforced them and thought I was good and today, second use after fixing same problems with just light handling. In worldly when give this tuner away. I’ll try to fix again and use my heart mfj long wire tuner instead.

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