I do my best to shake up each field activation I perform. Even if in some small way.
While it would be way more efficient to deploy the same radio and antenna combination at each park and summit I visit, I get a thrill out of trying different radio and antenna combinations.
I should add that I’m fully aware how fortunate I am to have a lot of radios and even more antennas to pair in various combinations. I keep reminding myself that building and buying radios and antennas is still cheaper than restoring a 1940s era Willys CJ-2A.
Recently, a reader reached out and asked my opinion about the Chameleon Tactical Delta Loop (CHA TDL) antenna. I think the TDL is a brilliant antenna system, actually, and the one I recommend the most from Chameleon because of its versatility.
Not only can it be deployed as a multi-band vertical delta loop but it has all of the parts needed to be an MPAS Lite vertical as well, save the counterpoise.
The CHA TDL comes with a 25 foot wire that connects the two 17′ whips into a loop configuration, but the clamps on the end of that wire can’t connect to the ground lug on the MPAS ground spike terminal as-is. That said, you could easily make a short connector cable or connection point that would allow the CHA TDL wire to clamp to the ground spike terminal. Else, of course, you could cut a dedicated 25′ counterpoise from pretty much any wire you might have around the shack.
You can buy the same counterpoise used with the MPAS Lite package, but it’s more affordable just to build your own since there’s no magic in the counterpoise. And, FYI, configured as the delta loop, there’s no need for a separate counterpoise; only if you configure it as a vertical.
This same reader also has an Icom IC-705 and an mAT-705 Plus antenna tuner. He was curious how well that combo might work with the CHA TDL. I knew that the combo would work well, but I thought, “why not try it?”
I realized that it has been ages since I last deployed the CHA TDL in the field.
Zebulon B. Vance Birthplace (K-6856)
Tuesday, February 28, 2023, was a gorgeous day weather-wise, although it was a bit gusty at times.
I arrived at K-6856 and decided to film the full set-up of the CHA-TDL.
For an antenna with a fairly large profile when deployed, it’s actually very compact, albeit a bit heavy (mainly due to the weight of the solid stainless ground spike and TDL hub). That said, I did take this same CHA TDL setup on an 11 mile round-trip SOTA hike once and didn’t find it too heavy.
This Saturday (Jan 30, 2021), I had a small window of opportunity to perform a Parks On The Air (POTA) activation. My park options were limited because I needed to stay near my home and a store where I was scheduled to do a curbside pickup.
The only viable option–since time was a factor–was my reliable quick hit park.
The Blue Ridge Parkway (K-3378)
I plotted a quick trip to the Blue Ridge Parkway Folk Art Center which is centrally-located and, this time of year, there are few visitors.
But what radio take? It had been a couple of weeks since I used the IC-705 in the field, so I decided to take it and rely only on its supplied BP-272 battery pack.
My buddy Mike (K8RAT) had warned me only a few minutes before my departure that propagation was pretty much in the dumps. I’d also read numerous posts from QRPers trying to participate in the Winter Field Day event and finding conditions quite challenging.
Saturday was the sort of day that I should’ve deployed a resonant wire antenna and made the most of my meager five watts thus collect my required 10 contacts in short order.
And that’s exactly what I didn’tdo.
You see, a really bad idea popped into my head that morning: I had a hankering to pair the IC-705 with my Elecraft AX1 super compact vertical antenna.
This made absolutely no sense.
I tried to get the idea out of my head, but the idea won. I suppose, at the end of the day, I’m not about taking the easy path (and I’m obviously a glutton for punishment).
I was also very curious if the mAT-705 Plus external ATU could tune the AX1 on 40 meters. More on that later…
I arrived on site a few minutes before noon. Setup was fast–that’s the big positive about using the AX1.
Normally, I deploy the AX1 antenna with my KX2 or KX3 and simply attach it to the BNC connector on the side of the transceiver. The AX1 Bipod gives the antenna acceptable stability during operation.
The IC-705 also has a side-mounted BNC connector, but it’s much higher than that of the KX3 or KX2. I’m not entirely sure I could manipulate the Bipod legs to support the antenna without modification.
That and the AX1 needs an ATU to match 40 meters (where I planned to spend most of the activation). Since the IC-705 doesn’t have an internal ATU, mounting it to the side of the transceiver really wasn’t an option.
I employed my AX1 tripod mount for the first time. On the way out the door, I grabbed an old (heavy) tripod my father-in-law gave me some time ago and knew it would easily accommodate the super lightweight AX1.
On The Air
I first tried using the Mat-Tuner mAT-705 Plus ATU to tune the AX1 on 40 meters.
No go.
I tried both the phone and CW portions of the 40 meter band, but the mAT-705 Plus simply couldn’t find a match. SWR was north of 7:1 – 9:1.
Instead of grabbing the Chameleon MPAS Lite or 2.0 from the car, I decided instead to see if the Elecraft T1 ATU could tune 40 meters.
It did.
In short, I logged my ten contacts to have a valid activation, but it was slow-going. All but two of my contacts were on 40 meters CW. The last two logged were on 20 meters CW.
It was a challenge, but I really enjoyed it! And, frankly, considering the propagation, 5 watts of power only using the IC-705 battery pack, and the inherent inefficiencies using a loaded compact vertical antenna and ATU? I was impressed.
Here’s a QSOmap of my 10 contacts:
I bet my effective radiated power was closer to 2-3 watts.
Typically, the AX1 antenna acts almost like an NVIS antenna on 40 meters, but Saturday it favored Mid-Atlantic and the states of IN, OH, and PA. Normally, I would expect more of a showing from the states surrounding North Carolina.
My last two contacts on 20 meters were with KE5XV in Texas and KB0VXN in Minnesota. Not a bad hop!
It took longer to collect my ten contacts than I had hoped and I ran nearly 25 minutes late to my curbside appointment. I’m a punctual guy, but there was no way I was leaving without my ten! 🙂
Here’s a video of the entire activation. Hint: it’s the perfect remedy for insomnia:
Next time I try to pair the IC-705 with the AX1 antenna, I think I’ll try adding a couple more ground radials and see if the mAT-705 Plus can more easily find a match.
One thing I know for sure: the T1 is a brilliant little ATU. While the mAT-705 Plus was never designed to do this sort of match, it’s comforting to know the T1 can.
I’m very curious if anyone else has paired the Elecraft AX1 with the Icom IC-705 or other QRP transceivers. If so, what was your experience? Please comment!
I’ve received no less than three inquiries this weekend from readers who are seeking advice about purchasing a portable external ATU to pair with their Icom IC-705 transceiver.
Fortunately, there are few options on the market and I believe there is no “right” one because choices are really based on operator preferences.
I’ll do my best to sum up my thoughts below based on the three ATUs I regularly employ and what we know so far about the AH-705 ATU from Icom.
Keep in mind this list will not include some excellent options from LDG, MFJ, and other companies simply because I haven’t used them in the field. Please feel free to add your comments if you have experience with other good options.
Mat-Tuner mAT-705 Plus
The Mat-Tuner mAT-705 Plus is the first external ATU on the market that directly pairs with the Icom IC-705 via a control cable.
The latest iteration–the mAT-705 Plus–is the ATU I can recommend.
Be careful if purchasing an mAT-705 used as you’ll want to make sure you’re getting the Plus version. The Plus version has a USB-C charging port on the front panel (seen in the photo above)–the original mAT-705 does not (it uses replaceable 9V cells).
Pros:
Perfectly pairs with the IC-705 for full CAT control
Wide tuning range
Tuning is fast and relatively quiet
Numerous memories making repeat matching rapid
Internal rechargeable battery
Rugged chassis
Cons:
Cannot be paired with other radios without modification (not recommended by the manufacturer)
At $220 US, it’s not the cheapest option
Because the IC-705 relies on CAT control for operation, if you leave the control cable at home or on a park bench, you will not be able to operate the ATU. (Pro)Fortunately, the CAT cable is a simple 3 conductor 1/8″ stereo patch cable.
Summary: If you’re looking for an ATU to take full advantage of IC-705 CAT control, the mAT-705 Plus is a great option. The only significant disadvantage of this ATU is the fact that it only pairs with the IC-705 (or possibly other Icom transceivers with similar CAT control). In other words, you can’t pair it with other QRP transceivers you might own.
The Elecraft T1 has been on the market for at least 16 years and is one of the most popular portable antenna tuners on the market.
Elecraft offers the T1 in kit form ($159.95) and factory assembled/tested ($189.95).
The Elecraft T1 has a CAT control port that has been used with the FT-817 in the past. Elecraft recently announced that they will also produce an IC-705 CAT cable that will allow full pairing with the IC-705 transceiver (much like the mAT-705 Plus above).Â
To be clear, though, the T1 doesn’t need a control cable to function: simply press the TUNEe button for one second, then key your transceiver.
Pros:
Very wide tuning range
Soon it will have an IC-705 CAT connection cable option
Uses common 9V battery that is easy to replace in the field. (Con) Not internally-rechargeable like the mAT-705 Plus.
One of the most compact automatic ATUs on the market
Pairs with any 0.5-W to 20-W transceiver covering the 160-6 meter bands
FT-817 Remote-Control Option
Cons:
Front panel buttons need protection while in your pack to prevent accidental pressing that will deplete the battery. I 3D-printed this simple cover that works brilliantly.
Not weather-proof
Summary: The Elecraft T1 is my personal favorite. Since the T1 pairs with any QRP transceiver, I love the flexibility. The T1 has also been on the market for ages and is a solid, safe choice–we know longevity is benchmark. I’ve never been in a situation where the T1 couldn’t find a reasonable match.
I will certainly test the new IC-705 control cable option when it is released in the near future–stay tuned.
The AH-705 is Icom’s custom ATU designed to perfectly pair with the Icom IC-705 via control cable. If you want an all-Icom setup, this is it.
Pricing in US dollars is TBD at time of posting, but the announced retail price is $350 .
Pros:
Perfectly pairs with the IC-705
Wide tuning range
2-way power sources using alkaline batteries (2 x AA cells) or external 13.8 V DC
IP54 dust-protection and water resistance construction
Could (potentially–?) be permanently mounted outdoors at the antenna feed point as a dedicated remote tuner
Cons:
In terms of overall size, the AH-705 appears to be the largest of the portable ATUs mentioned here
It doesn’t appear AA batteries can be recharged internally
The AH-705 may (we don’t know yet) only work with the IC-705 and possibly similar Icom models
The maximum power handling of the AH-705 is 10 watts–if you use other transceivers (if that is even possible) you would have to be extremely careful with power settings.
The AH-705 is pricey if the actual retail price ends up being near the projected $350 mark. Hopefully, it’ll be much less than this.
Like the mAT-705 Plus, the AH-705 will require a control cable for operation. (Pro) Of course this means it pairs perfectly with the IC-705 and can follow frequency changes without RF sensing.
Summary: Keep in mind, I have not tested the AH-705 yet, so this is only based on announced specifications.
The strongest selling point for the AH-705? Since the AH-705 is designed to be dust and weather resistant, it could be mounted at the antenna feed point. At home, perhaps it could act like an externally-mounted, remotely-controlled antenna tuner. I’m not sure what the maximum length of the control cable could be, but Icom Japan even lists a 16 foot control cable as an accessory. Of course, you would still need to follow Icom’s guidance about protecting the antenna, transmitter and control cable connection points.
The biggest negative to me is the size. Just check out how large it is compared to the IC-705 in this video. It’s still very portable, but the other ATU options above are much smaller.
Still: if the AH-705 is great at matching antennas and the price ends up falling below the $300 point, I’m sure it’ll be a very popular ATU.
Another option often overlooked are portable manual antenna tuners. I’m a big fan of the Emtech ZM-2 which is offered both in kit ($62.50) and factory assembled/tested form ($87.50).
It is a manual tuner, so requires manual input to find a match. While it’s not as easy as push-button tuning, it isn’t complicated either.
Here’s my routine:
I set the top right switch to “GROUND” if using coax feed line and “LINK” if using a balanced line.
Set the added capacitance switch “ADD” to “0”
Set the TUNE/OPERATE switch to OPERATE
I set both capacitors to middle positions (6 on the scale)
Tune to AM or SSB and listen to the noise floor as I tune the variable capacitors to maximize the noise level. I typically start with the left capacitor, maximize it, then maximize the right capacitor
If the antenna is particularly challenging, I might add 250 or 500PF via the ADD switch
Set the TUNE/OPERATE switch to TUNE
In CW mode, I key down and make fine tuning adjustments with the variable capacitors to make the red tuning LED turn off (high SWR makes the red LED illuminate)
Set the TUNE/OPERATE switch to OPERATE and hop on the air! (Often, I’ll double-check the SWR on my transceiver).
This sounds complicated, but once you’ve done it even two or three times, it becomes routine. I’ve yet to find a wire antenna the ZM-2 can’t match–it’s a very capable tuner.
Pros:
The most affordable option listed here
Very wide matching range
Portable and very lightweight
Requires no batteries for operation
Mechanically simple
Reliable
Cons:
Although not complicated, there is a small learning curve involved
Each time you change bands, you will need to manually re-tune the ZM-2
Not as fast and hassle-free as an automatic ATU
Not weather-proof
Summary: I carry the ZM-2 with me even if I plan to use an automatic portable antenna tuner. If my auto ATU loses power for some reason, the ZM-2 will always rescue me. Plus, it’s just as capable of making tough matches as the ATUs above.
I also love using the ZM-2 to match antennas for shortwave broadcast listening outside the ham bands.
Even if you buy an automatic ATU, I would still encourage you to buy a ZM-2 as a backup. It’s affordable, reliable, and very handy.
As I mentioned above, these choices are just a small selection of what’s actually available on the market. Please share your favorite portable ATUs and experience by leaving a comment!
Yesterday, I started the day hoping I might fit in one afternoon activation at a local park. In the morning, however, my schedule opened up and I found I actually had a window of about six hours to play radio!
Instead of hitting a local park, I considered driving to parks I’d been planning to activate for months.
I may have mentioned before that, earlier this year, I created a spreadsheet where I listed of all of the parks I planned to activate in 2020.
From earlier this year–many of the parks listed as “rare” are much less so now!
Each park entry had the park name, POTA designator, priority (high/medium/low), difficulty level for access, and a link to the geo coordinates of where I could park and possibly hike to the site. I spent hours putting that list together as finding park access–especially for game lands–isn’t always easy.
Yesterday morning, I looked at that sheet and decided to knock two, or possibly three off the list.
I had already plotted the park run, driving to Perkins State Game Land (K-6935) near Mocksville, then to the NC Transportation Museum State Historic Site (K-6847) in Spencer, and finally Second Creek Game Land (K-6950) in Mt Ulla.
The circuit required about three hours of driving. Here’s the map: When I plan an activation run, I factor in the travel time, add ten minutes extra if it’s my first time at the site (assuming I’ll need to find a spot to operate) and then assume at least one hour to deploy my gear, work at least ten stations, and pack up.
Using this formula, I’d need to allow three hours for driving, plus an additional three hours of operating time, plus a few minutes to sort out an operating spot at Perkins Game Land. That would total six hours and some change.
Knowing things don’t always go to plan, I decided I’d quickly omit the NC Transportation museum if I was running behind after the Perkins activation. In fact, I felt like the NC Transportation Museum might be out of reach, so I didn’t even schedule the activation on the POTA site.
Perkins State Game Land (K-6935)
I arrived at K-6935 a little before noon (EST).
Since this is the week after Christmas, I had a hunch game lands could be quite busy with folks trying out their new hunting gear and I was correct. I passed by the first small parking area and it was packed with vehicles, so I drove on to the second parking area I identified via Google Maps satellite view.
The second parking area was also busy, but was larger. There was just enough room for my car to park between two trucks.
I donned my blaze orange vest–a necessity at any game land–and walked outside to asses the site. In short? It was a tough one. There were no easy trees to use for antenna support and I simply didn’t have the space. I knew folks would walk through the area where I set up my antenna so a wire antenna would have acted a lot like a spider’s web.
I pulled out my trust Chameleon MPAS Lite vertical antenna and deployed it next to the car. I rolled out the counterpoise into the woods paralleling a footpath so no one would trip on it.
Since I had no room to set up outside, I operated from the backseat of my car–it was actually very comfortable.
I pulled out the Elecraft KX3 and hooked it directly to the MPAS Lite–it easily tuned the antenna on both 40 meters, where I started, then later 20 meters.
I very quickly logged 13 stations on 40 and 20 meters.
While on the air, a number of other hunters discovered the parking area was nearly full–some turned around and left. I decided to cut the activation with 13 logged and skipped doing any SSB work. I accomplished what I set out to do here, was short on time, and I wasn’t actually using the game land for its intended purpose. Better to give others the parking space!
I quickly packed up and started the 30 minute drive to my next site.
NC Transportation Museum State Historic Site (K-6847)
The Cameleon MPAS Lite
I knew what to expect at the NC Transportation Museum because I’ve visited the museum in the past and, earlier this year, scoped out a spot to activate the park in their overflow parking area.
The museum is closed on Mondays. In general, I avoid activating parks and sites that are closed. I never want to give anyone at the park a bad impression of POTA activators.
In this case, however, the overflow parking area is wide open even when the park is closed and there was no one at the site. I felt very comfortable setting up the CHA MPAS Lite which is a pretty stealthy antenna. Indeed, as I was setting up, I’m guessing it was a museum employee that passed by in their car and waved–no doubt, POTA activators are a familiar site!
I set up my portable table behind the car under the hatchback so I took up the least amount of space.
I used the table primarily so I could shoot one of my real-time, real-life videos of a park activation. Readers have been asking for more of these and I’m happy to make them if they’re helpful to even one new ham.
In the end, I logged 13 stations and didn’t try to work more because I was still on track to activate one more park. I didn’t feel bad about only working 13 stations, because this site has been activated many times in the past–in other words, it wasn’t exactly rare.
Again, since I planned to make a video of the activation, I set up my portable table.
I decided en route to the site, that I’d use the Chameleon MPAS 2.0 vertical at Second Creek. Although I’ve used the more compact Chameleon MPAS Lite at a number of parks–including the two previous parks–I had a great spot to deploy the taller MPAS 2.0.
As with the MPAS Lite, deployment was very quick. the MPAS 2.0 vertical is made up of folding pole sections–much like tent poles. As with all Chameleon gear I’ve ever used, the quality is military grade. Full stop.
I started calling CQ on the 20 meter band in CW this time. Within a minute or so I logged my first contact, followed by five more.
I then moved to the 40 meter band and logged twelve more stations in twelve minutes.
I decided to then give SSB a go as well and logged two more stations for a total of twenty stations logged.
I would like to have stayed longer at Second Creek and even used the MPAS 2.0 on 80 meters, but frankly I was pushing my time limit to the edge.
All in all, it was a brilliant three park run!
These days, it’s difficult to pack more than three parks in my available time–in fact, I think this was the first three park run I’d done in months. During National Parks On The Air (NPOTA) in 2016, I’d been known to pack four or five parks in a day–it was so much fun.
Here’s my QSOmap for the day (click to enlarge):
Getting outside on such a beautiful day, driving through some picturesque rural parts of my home state, and playing radio? Yeah, that’s always going to be a formula for some amazing fun!
Many thanks to Stephen (KD4LYO) who recently commented that his new mAT-705Plus ATU had charging issues. Shortly after I posted my first test of the mAT-705Plus in the field, he noted:
So far, not so good for me. I received the unit earlier this week. I immediately pulled it out of the box and charged it. Once finished it sat on my desk the rest of the week until I tried it out today. It was completely dead. I just went to plug it in to charge and the red power light is flashing really quickly, I could have sworn it was solid previously when charging. We will see what happens.
Stephen then followed up. Turns out, the issue was very easy to resolve:
So they really improved the inside of the tuner.
MAT-Tuner replied and said the battery had likely popped loose. Here is a pic:
Click to enlarge.
Thanks for the feedback, Stephen! That is an easy fix. I bet your ATU was handled pretty “aggressively” en route to your home. ‘Tis the seasons and all of that!
You’re right, too, I do like the looks of that board inside the mAT-705Plus. A major improvement over the original mAT-705.
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.
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.
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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I do my best to shake up each field activation I perform. Even if in some small way.
