Tag Archives: Mat-Tuner mAT-705Plus Review

Field Reports, News, Portable, POTA, QRP

POTA Field Report: A beautiful day for obnoxious QRM!

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A few weeks ago–on July 12, 2021–I popped by Lake James State Park to do a quick activation with the Icom IC-705. It had been a while since I’d used the ‘705 in the field and the little rig was begging to go outdoors.

Here’s the funny part: I completely forgot about that activation! Two days ago, while browsing my photo archive, I noticed the video I made of the activation and, of course, the memory came flooding back.

In my defense, it has been a crazy summer and the weeks/days seem to all blend together in my head.

Thing is, this activation was memorable for a bad reason: QRM (human-made radio noise). It was also memorable for some of the folks I worked on the air.

Lake James State Park (K-2739)

I arrived at Lake James and was a bit surprised to practically have the place to myself.

I found a picnic table with a view of the water, deployed my speaker wire antenna, and set up the IC-705. As with all of my activations, I was only running 5 watts.

I attached the speaker wire antenna’s BNC binding post adapter directly to the mAT-705 Plus ATU.

Gear:

Propagation was–you guessed it–forecast as very poor.

It felt that way when I hopped on 40 meters at first as the band was pretty quiet..

Still, I managed to log 5 contacts on 40 meters (two in SSB, three in CW) before moving up to 20 meters which served me well.

I worked a total of eight stations in nine minutes on 20 meters.

QRM

Check out the noise level on the waterfall display!

If you watch the video, you’ll hear how nasty the QRM was at times.

I keep forgetting that there’s a source of intermittent radio interference at the Lake James visitors center. The spot where I set up the station was only 25 meters or so from that building. I believe the center was responsible for the QRM I first experienced during the activation. Whatever the device is generating the QRM, it doesn’t last for long periods of time–it cycles.

The second batch of QRM was emanating from a small boat that pulled up to the dock in front of my site. It was nasty and completely wiped out the 20 meter band. When the owners turned off the boat and stepped onto the dock, the noise stopped completely. Later, when they got back into the boat, the noise started again. I have to assume it was something in their motor causing the QRM. I suspect they may have been using a DC trolling motor.

Memorable contacts

POTA activations often feel like a gathering of friends. I often see many of the same callsigns in my logs and it’s a lot of fun working them each time.

Also, it’s a lot of fun to work stations further afield. At Lake James, I was very pleased to work NK7L in Washington State, IK4IDF in Italy, and HA9RE in Hungary. My back of the envelope calculations tell me that I was pushing 1,000 miles per watt when I worked Elemer (HA9RE). To be clear, all of the work was done on his end as he has some world-class ears; just check out his QRZ page!

For some reason when I logged HA9RE, I copied VA4RE. I’m not sure why, but after packing up it hit me that I had logged him incorrectly (funny how brains work!). I reviewed the video on-site and confirmed it was indeed HA9RE.

Here’s my QSO Map:

I was also very pleased to finally work Dave Benson (K1SWL). He’s very well-known in QRP circles for his amazing Small Wonder Labs kits. Dave’s a great guy and, of course, loves playing radio in the field.

Video

Here’s my real-time, real-life, unedited video of the entire activation. Apologies in advance as I really needed a wind screen over my microphone that day–I had the mic and camera a little too close.

Loop next time!

The next time I hit Lake James, I plan to deploy a Chameleon loop antenna. I think it will have a significant impact on the QRM levels at that particular part of the park. Of course, I could easily move further away from the noise source (that’s the easiest solution) but I’d like to see how effectively a loop might mitigate the QRM. That and it’s been years since I last used a compact mag loop antenna in the field.

Thank you

Again, thank you for reading this report and thank you to those who are supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement–never feel an obligation to do so (especially if you’re investing in your first station, for example)–I really appreciate the support.

Here’s wishing you some outdoor radio fun in the near future!

Cheers & 73,

Thomas (K4SWL)

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Announcements, Antennas, New Products, News, Portable, QRP Radios, Reviews, Videos

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

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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.

Summary

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–?] 🙂

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