Last month, I received a comment and question from Gordon (KO4AYC) here on QRPer.com:
“I am curious if anyone has used the AX1 with the AXE1 40 meter extender and tuned this antenna for 40 meters using the Emtech ZM-2 tuner?”
For the life of me, I couldn’t remember if I’d tried this combo before.
The ZM-2 ATU is a simple manual antenna tuner that you can purchase either as a fun-to-build kit or fully assembled and tested.
I’ve owned my ZM-2 for many years, and I believe every QRP field operator should have one. They do a brilliant job of matching random wire antennas and taking your resonant antenna to a non-resonant band. Being a manual ATU, they require no power source. If you’d like to read a quick tutorial on tuning the ZM-2, read this previous post.
I figured the easiest way to answer Gordon’s question was to give it a go!
The AX1 does require a counterpoise, so before hitting the field, I did check to make sure there was continuity between the shield of the ZM-2’s BNC connector and the black binding post when the ZM-2 was switched to “GND” for coax antennas. Fortunately, there was! I loved this idea because it meant that no matter the radio, I knew I’d have an easy connection to ground for the AX1 counterpoise.
Blue Ridge Parkway (K-3378)
On Wednesday, February 21, 2024, I grabbed the ZM-2, AX1, and AXE 40M coil (since Gordon specifically asked about 40M) along with my Yaesu FT-818ND. It was time to see just how effectively the ZM-2 might match the AX1.
I store my AX1 in this Maxpedition pouch (see link in gear section below).
Upon arrival, I began setting up the station.
Even though it was approaching 2:00 PM locally, I wanted to see if the ZM-2 would match the AX1 (with AXE coil) on 40 meters first. I didn’t expect a lot of activity on that band so early in the afternoon, but I figured I could hopefully work a couple of stations.
I attached the AX1 directly to the ZM-2 antenna port and deployed the whip and 40M counterpoise.
It was a bit gusty, and I quickly realized that the AX1 might topple over in the wind. To secure the antenna, I used the handle of my GR1 backpack. It was a semi-effective arrangement (actually, the handle sort of pulled the antenna toward the pack, which wasn’t ideal either–I eventually removed it).
In calm conditions, I wouldn’t worry about the antenna toppling over; the ZM-2 provides enough of a base that it’s stable. In the wind, though, you’ll definitely need to secure the ZM-2/AX1 combo to keep it from being blown over.
My plan was to start on 40 meters, then also hit 30, 20, and 17 meters. This would give me an opportunity to see if the ZM-2 could match the AX1 on multiple bands.
Side note: I can’t remember if I mentioned this in a previous field report, but one sad bit of news for me is that there’s a new source of QRM at the Folk Art Center. It’s likely coming from the VA medical complex next door, but it raised the noise floor to at least S5 on most bands. This will make it more difficult for me to work weak signals from this particular POTA site.
Then again? My buddy Alan (W2AEW) recently pointed out to me that compromised antennas like the AX1 don’t feel the effects of local QRM as a higher-gain antenna would. I’d been thinking the same thing.
Gear:
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I hopped on the air and started calling CQ POTA on the 40-meter band. I worked one station quickly (thanks, W5GDW) and then silence. I didn’t expect 40 meters to be active this time of day, but I didn’t think it would be completely dead either.
I checked the POTA spots page and discovered that the connection to the Reverse Beacon Network was down. Even though I scheduled the activation, the system hadn’t spotted me.
Once spotted, I worked three more stations in quick succession.
Many thanks to Matt (W6CSN) who shares the following post from his blog at W6CSN.Blog:
It Was Bound To Happen…
by Matt (W6CSN)
You’d be safe to guess that Mt. Davidson would have been my first SOTA activation seeing as it’s the closest SOTA summit to my home QTH. However, it actually took me a little while to get around to heading up W6/NC-423.
The trail begins near the corner of Dalewood and Lansdale.
Today was the day! I dropped my hiking buddy off at work at 8 AM then drove up Market Street, over Portola Drive and wound my way around Mt. Davidson, finding easy parking on Dalewood Way near Lansdale Ave.
The easy trail up Mt. Davidson.
From the trailhead near the bus stop, it a short and easy hike up to the activation zone. On this route you reach the east end of the summit, opposite the large cross, which is a well known landmark.
Except for the occasional exercise enthusiast, I had the place to myself this morning. Not wanting to lug the fiberglass mast up the hill, I deployed the Gabil Radio tripod and loading coil, using a 3 meter collapsible whip antenna. This is an easy setup and not too much of a compromise on 20 meters.
While I can do a lot of back and forth the get the loading coil set just right for a good match, I find it easier just to get the coil close enough and touch it up with a tuner for a low SWR reading.
I sent a spot via Sotamāt and started calling CQ SOTA on 14.058 using the QCX-Mini. My first call was from JG0AWE from Nagano City, Japan. This was followed quickly by several more stateside calls and I was able to gather the four QSOs needed within a span of five minutes.
QCX-Mini on 20 meters.
I continued working stations and chasing some Summit-to-Summit contacts for another half hour. It was at that point I noticed that I failed to throw the switch to the “Operate” position on the ZM-2 tuner. This whole time I had been operating in “Tune” mode with the 50 ohm absorptive bridge in circuit! It was almost like using a dummy load for an antenna!
Oops! I left the ZM-2 in the “tune” position!
Later, at home, I measured this tuner configuration with this radio using an actual 50 ohm load instead of an antenna and found that I was most likely operating with an effective power to the antenna of only 300 milliwatts!
Despite this extremely low power I was able, using CW, to complete the activation with no difficulty. This is a testament to the effectiveness of the CW mode, and not so much this operators skill.
Sutro Tower and Twin Peaks to the North.
After logging 10 contacts, I called it quits, packed up the station and headed back down for some breakfast. Next time I’ll try to remember to set the switch correctly after tuning up, but I make no promises. I’m guessing pretty much everybody that has a ZM-2 has at one point or other forgot to switch into “operate” mode, It was bound to happen.
After posting my latest field reports using the Elecraft AX1 antenna, I’ve received a number of messages from new AX1 owners. All of the following have kindly allowed me to share them here with you.
AX1 Patio DXing
From Michael (K1ETA):
Thomas,
I am a subscriber and an avid follower. [L]ike you, I do a lot of portable ops with various antenna setups and radios. I was recently offered an AX1 and I was told it was basically a dummy load. Having seen your videos and proof of success I accepted it and I can’t say how much fun I have with it. Yesterday, I made 22 DX contacts throughout Europe in the ARRL World Wide CW contest from my patio in my back yard with 5 watts, the AX1 and my KX2.
I would never have tried that with the AX1 had I not seen your videos. You see it is even good enough for contests if you don’t try to compete with the big guns. Listen, search and call back the stations without pileups!
Many thank for all you do and for making me an AX1 believer.
72
Michael Kenney (K1ETA)
Pairing the AX2 and Emtech ZM-2
From Michael (N7CCD):
Hi Thomas,
I just finished your video comparing the AX1 and AX2 and thought you might appreciate a solution I came up with for making my travel more compact.
I purchased the AX2 during the February sale and found it pairs well with the ZM-2 ATU for my IC-705 (wow what a mouthful of acronyms. No wonder my wife and daughter call me a nerd…). I didn’t get the tripod adapter in the sale, but found the AX2 sits perfectly on the ZM-2 which acts as a very stable stand. There is some body capacitance when tuning, but not too much. I was even able to easily tune it on 17M. I need to try other higher bands sometime.
I set it up in our breakfast nook just for kicks and sent a few JS8 and FT8 transmissions to see where I was being heard (I’ll include a screenshot). Was able to successfully send an APRS text message, and I even made an SSB contact into a special event station in Nevada!
I found a hard sided case I can store the tuner and AX2 in, which also had enough room to put in a “speaker wire” antenna as an option. Why not?
I think this may replace the AlexLoop for air travel since it’s so compact and versatile.
Hope all is well on your side of the country!
Michael – N7CCD
P.S. +16 into Michigan!
AX1 DXing
From Kevin (KD8IE):
Hi Tom,
After video about the AX1 recently, I decided to order one and it came last week.
The weather’s been kind of chilly up here. As a matter of fact, it was 41 when I decided to go out and do an activation then at Cuyahoga Valley National Park.
Well, suffice to say I made contacts with the antenna a lot farther than I expected it would be. The bands were really long. First station I worked was in New Brunswick. The last two stations were Italy and Slovenia.
73,
KD8IE
Many thanks to all of you for sharing your experience and tips using the AX series antennas!
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.
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?”→
Lately, I’ve had quite the backlog of reviews and evaluations building up. Family life has been active–and it always comes first–but also I’ve a number of projects on the table (two kit builds, one repair, two antenna projects), four articles for various publications, two new transceivers (the TX-500 and now an X5105 on loan), and a number of family business projects. ‘Tis the season, I reckon.
Normally, I’d be in Dayton, Ohio right now enjoying a weekend of fellowship and Hamvention/FDIM insanity, but all that was cancelled this year due to the pandemic.
I’ve had a number of projects that sort of force me indoors, but I haven’t felt like doing them. Spring in the mountains of western North Carolina is truly a thing to enjoy (save the allergies)–and it’s an incredible distraction.
On Saturday afternoon, May 8, 2021, my whole family wanted a little outdoor distraction time, so we hopped in the car and drove to a nearby spot in Pisgah National Forest.
The drive takes nearly 50 minutes even though the actual site isn’t even 5 miles from the QTH as the crow flies. The weather was beautiful, but a front was moving through bringing strong wind gusts.
I had planned to set up my activation next to our car along the forest service road, but to shelter myself from some of the winds, I decided instead to set up next to the nearby creek, down the hill a bit.
This particular site is actually located in both Pisgah National Forest and Pisgah Game Land–they overlap, which makes this a Parks On The Air “Two-Fer”.
While setting up next to a creek makes for a beautiful little activation spot, it also adds a lot of extra background noise. Normally, I would have used some in-ear earphones with the TX-500 for sound isolation, but (after twenty minutes on the air and against my better judgement) I decided to make an activation video at this site, so used the speaker/mic instead.
I’ve activated this site numerous times in the past and while it has tall trees and loads of spots to set up, it’s also in a pretty deep ravine, surrounded by tall ridge lines. While this is less a problem with HF as it would certainly be for line-of-site frequencies, history has proven that it makes for a challenging activation.
I deployed my new PackTenna 9:1 UNUN random wire antenna as a vertical. I’m glad I chose the PackTenna because it’s such a low-profile antenna, I knew it would be less affected by the strong wind gusts.
I also decided to employ my Emtech ZM-2 manual antenna tuner during this activation. Why? Because I had never used it with the PackTenna before. So why not?
On The Air
I hopped on 40 meters and started calling CQ. Thankfully, the Reverse Beacon Network found me and the POTA website automatically created a spot from the RBN information.
I worked four stations in four minutes! This was a much better start than I’d ever had at this site before.
Then, nothing…
About 20 minutes passed as I called CQ on 40 meters. This was going to be a challenging activation after all.
I decided to move up to the 30 meter band. I thought there might be some value in showing how to tune the ZM-2, so I started recording one of my real-time, real-life activation videos knowing that the audio might not be ideal with the rushing creek.
On 30 meters, I was able to pick up three more contacts in fairly short order, giving me a total of seven contacts. Only three more needed to validate my activation!
At least 20 minutes had passed since I was on 40 meters, so I decided to hop back down there hoping some new hunters might be monitoring the POTA spots.
Sure enough, I was able to add five more contacts in ten minutes!
My 12th contact is on the back of this log sheet: KF4YEY in FL.
I likely spent a total of one hour on the air. By the time it was over, my wife and daughters were ready to hit the road again: temps had dropped pretty quickly in that one hour time frame and the gusts were strong enough my wife was concerned it could knock some branches loose. (I was less concerned because I always check a site for widow-makers and power lines before setting up.
With such a simple radio kit, packing up was very quick.
This was my second activation with the new TX-500. I really do love this radio.
A number of folks noted in my last TX-500 video that there was an audio pop present as I keyed the radio either with my paddles or with the built-in memory keyer. I had never noticed this before, but I think I know why it’s happening. In my videos, I crank the speaker/mic volume up all the way so the audio can be heard. When I do this, the T/R relay audio pop/recovery is quite noticeable.
I think I may slow the relay recovery to something like 400ms so the audio doesn’t try recovering between characters. The TX-500 isn’t capable of full break-in QSK anyway, so there’s really no need for a 100ms recovery. I’ll also share this feedback with the engineers at lab599 as I suspect this can be sorted out in firmware. In the shack, it’s not an issue because audio levels are in the normal range, but in the field when the audio is cranked up, it’s pronounced. This also would not be an issue if using earphones, of course.
I do love this TX-500 and am very happy I’ve officially purchased it from lab599 and added it to my transceiver arsenal! Now to give it a name and make it official…
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).
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!
Icom uses this photo to demonstrate one of the ways the AH-705 ATU can be mounted for remote operation.
Many thanks to Bruce (W0MBT) who writes:
Hey Thomas,
After many years of inactivity, the combo of this blog, the IC-705, and Covid shutting down all the other fun things I like to do has finally got me somewhat active again. I agree with you that [the Icom AH-705] seems pretty large and expensive for a portable tuner, given the available alternatives. To me, the most interesting possible application is in a semi-permanent outdoor installation.
Currently, my setup is an EmTech ZM-2 installed in a watertight toolbox on my fifth floor balcony, grounded into the metal siding of my building, with a stealth radiating wire tossed onto a conveniently-located tree. It seems to get out pretty well, but QSYing across bands is a pain, and not really practical when it’s raining, which happens a lot in Seattle. I could replace that whole setup with an AH-705 stuck to the siding with double-sided tape.
My questions (and I realize you won’t yet have answers) are:
* How long will it run on AAs? This will determine whether I need to run 12V out to my balcony.
* What’s the maximum control cable run? In my current apartment layout, I’m looking at about 25′.
Bruce
W0MBT
Hi, Bruce,
First of all, I’m so glad to hear you’ve gotten back on the air and honored to hear this blog might have contributed to that a bit! Based on your current setup, it’s obvious that you’ll go out of your way to play radio. Anyone who’s willing to manually adjust a remote ATU each time they wish to hop around the band is dedicated to their radio play!
Since the AH-705 hasn’t been released yet at time of posting, I really know nothing about the AH-705 other than what I’ve read in the specs. I’m not sure how long a control cable could be nor how long AA batteries would last. We won’t know this until the AH-705 is tested.
If I were in your shoes, though, I wouldn’t wait on the AH-705.
I can think of at least two other options I consider to be better choices for a permanently-mounted remote antenna tuners:
1.) Assemble a remote tuner box
So at my QTH, like yours, I rely on an external, remotely controlled ATU. My shack is located on the first floor of my house. There’s a carport with a metal roof behind my shack. Since we designed and built this house. we installed conduit in the walls so that I could run cable from my shack to an antenna switching and tuning point mounted outside.
It’s built around an LDG Z11 Pro which is not marketed as a remote ATU. The Z11 Pro is mounted in a (rather ugly but effective) weather-proof box a friend gave me–I think the box was originally used in a remote sensing application. It actually has some penetration points on the side I was able to use.
In 2011, when I installed this ATU, I found an old sealed lead acid battery to power the Z11 Pro knowing the Z11 actually requires very little in terms of power. I had planned to bring the battery indoors and occasionally recharge it, but I also happened to have a 5 watt solar panel and Micro M+ charge controller, so I put them to use charging the remote ATU battery.
From inside my shack, I bypass all internal ATUs in my transceivers and only use my remote Z11 Pro.
The Z11 Pro is RF-Sensing, so as I move across the band, it automatically finds matches and keeps the SWR well within an acceptable range (I monitor it indoors with an SWR and Power meter, of course).
This entire system costs less than the $350 projected cost of the AH-705 and doesn’t require a control cable. The best part is it can be used with *any* radio and can handle 125 watts.
I used the Z11 Pro because I already owned it, but there are less expensive, smaller LDG tuners that could be used. You wouldn’t need to have solar charging as you could simply replace an external battery from time to time. These tuners are super efficient–so efficient, the sealed lead acid battery I installed in 2011 was nearly dead back then, yet it has provided enough voltage via my small PV panel to reliably power the Z11 Pro over 10 years of seasonal temperature swings.
But there’s still an easier and possibly cheaper solution.
2.) Buy a proper remote ATU
When I originally built my remote tuning system, there were really no affordable options commercially available. I believe SGC and Icom had remote tuners but they were very pricey.
The RT100 costs $250 US and is designed to be used outdoors permanently-mounted. You need no outdoor power source because the ATU is powered from a Bias T 12V source via the same coax cable between your transceiver and the ATU. Makes for a neat, tidy package outdoors.
Again, this ATU–unlike the AH-705–can handle up to 125 watts and work with any transceiver in your shack.
Indeed, I’ve been thinking about grabbing an RT100 for use with another outdoor antenna I plan to build!
Also check out the MFJ-926B for $330 US. If you’re like me, you may never operate north of 10-20 watts, but some may appreciate the 200 watt power handling of the MFJ.
Summary
To get back to your original question, I suppose what I’m trying to say here is the Icom AH-705 is a portable antenna tuner that can be put into service as a remote antenna tuner. It can do both jobs.
To me, though, it makes more sense to split these two applications: install a permanent remote ATU–that works with any transceiver–and also invest in a quality portable ATU for field work.
What are the major drawbacks of the AH-705 compared with a proper, dedicated remote ATU?
You’ll need to change AA batteries in the AH-705 on occasion or design a 12V source that can easily be recharged.
The AH-705 may (we don’t know yet) only work with the IC-705 and possibly similar Icom models. The LDG and MFJ ATU models above work with any radio.
The maximum power handling of the AH-705 is 10 watts–if you use other transceivers (if that is even possible) you’ll have to be extremely careful of your power settings, else fry the AH-705.
The AH-705 is pricey if the actual retail price ends up being near the projected $350 mark. Hopefully, it’ll be less than this.
The AH-705 will require a control cable. The options above are RF-sensing and do not.
My advice?
Build or buy a permanent remote tuner and hit the parks and summits with the ZM-2!
Since you already have the Emtech ZM-2, you’ve got a fabulous manual portable ATU. I use my ZM-2 in the field all the time (see photo above). Some folks prefer an automatic tuner for ease of use, but I’m guessing at this point, you’re an expert ZM-2 “tuner upper!”
Later, if you want to add an automatic portable ATU to your field kit, consider the Elecraft T1, the Icom AH-705, or an LDG model.
Readers, feel free to comment with your suggestions as well. I’m sure there are a number of options I haven’t considered!
While visiting my parents this week in the Piedmont of North Carolina, I took some time Monday afternoon to take the new Icom IC-705 to field and activate Lake Norman State Park (K-2740) for the Parks On The Air (POTA) program.
So far, most of my time with the IC-705 has been in CW mode but a number of my readers have been asking about SSB operation and performance.
My goal for this park activation was to give the IC-705 a proper shake-out on SSB.
Set-up
The activation was very much impromptu–I only decided I could fit it into my day an hour before my start time. In addition, while it wasn’t raining per se, there was a very heavy mist/fog that, at times, felt like a light sprinkle/drizzle.
I packed and planned on using my IC-705, mAT-705 external ATU, and Vibroplex End-Fedz EFT-MTR wire antenna.
I had an issue with the mAT-705 ATU (read more here), so opted for my trusty and incredibly capable Emtech ZM-2.
I did begin the activation in CW and quickly racked up a dozen or more contacts in short order after spotting myself. One of the great things about Lake Norman State Park is it’s one of the few locations I activate these days with proper cell phone coverage for mobile internet so that I can update my own activation spots on the POTA site.
I also moved up to 20 meters and switched over to my recently (re)acquired Elecraft KX1 (FYI, I named her “Ruby” so no way will I sell her again).
I quickly snagged two states (Iowa and Kansas) with 1 watt of power from the KX1’s internal AA cells, then 20 meters fell silent, so I moved to 30 meters to work a few more stations.
SSB on 40 meters
I then moved to the 40 meter band and decided to record a quick video after spotting myself on 7197 kHz. I wasn’t expecting such a productive mini pile-up.
As you can tell from the video, I had my hands full trying to hold my phone/camera, log, and manage the hand mic. Note, too, I prefer not hooking up the speaker portion of the microphone because audio from the IC-705 internal speaker is far superior:
I operated SSB for a good 30 or so minutes and was busy with contacts thanks to all of those excellent POTA hunters.
IC-705 Voice Memory Keyer
Before packing up, I remembered that my buddy Dave had asked me to make a video showing how I use the IC-705’s voice memory keyer, so I moved up to 20 meters (which you’ll see was pretty much dead) and recorded this.
Doh! I had the SSB position in LSB instead of USB! Thanks to one of my YouTube viewers who noticed this. I had been tinkering with mode settings earlier while evaluating the rig. No worries, though, this was more a demo of the memory keyer–check out SSB operation in the video above.
I was actually very relieved 20 meters was dead because I’m terrible at managing a camera, a tablet, and a microphone all at once!
The Icom IC-705 is an SSB champ
Photo taken at South Mountain Game Land last week.
Despite the fact that I was using the default microphone settings and had not even touched the TX EQ or compression, I received no less than three unsolicited compliments about my audio during this activation. That is probably a personal record.
No doubt, the IC-705 is a very capable rig for QRP SSB where audio quality is essential.
On top of that, the eight voice keyer memories are incredibly useful when activating a park, a summit, or even running a contest where you could truly automate your exchanges.
Have you been using the IC-705 in the field? What are your thoughts? Do you have any questions? Please feel free to comment!
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