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.

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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• Yaesu FT-818ND
• WINDCAMP 3000mAh LIPO battery for FT-818/817
• WINDCAMP Anderson PowerPole Adapter for FT817/818
• Portable Zero FT-817 Side Rails and Bail
• Emtech ZM-2
• Elecraft AX1 packed in a Maxpedition Fatty Pouch
• VK3IL Pressure Paddle V2
• GraphGear 0.9mm 1000 Automatic Drafting Pencil
• Rite In The Rain Top Spiral Notebook
• GoRuck GR1 USA pack
• Camera: DJI OSMO 4 action camera with Sensyne Phone Tripod

On The Air

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.

I didn’t hang around on 40 meters.

Next, I moved to the 30-meter band where I was able to find a match and add four more contacts to the logs.

I suspected that 20 meters would be my most productive band, but decided to hit 17 meters first, again, just to see how easily the ZM-2 might match the AX1. It wasn’t difficult at all to get a match.

I logged four more contacts on 17 meters, bringing my total logged up to 12.

Finally, I QSYed to the 20-meter band and easily found a nice match via the ZM-2.

No doubt, 20 meters was the most productive band that fine Wednesday afternoon.

I logged an additional 15 stations in 15 minutes before calling QRT! Woot!

QSO Map

Here’s what this five-watt activation looked like when plotted out on a QSO Map. Each line is colored to represent the band used in the contact (40M green, 30M orange, 20M blue, and 17M purple). Note that N7CCD wasn’t at his QTH in WA, but activating a park in PA:

Activation Video

Here’s my real-time, real-life video of the entire activation.  As with all of my videos, I don’t edit out any parts of the on-air activation time. In addition, I have monetization turned off on YouTube, although that doesn’t stop them from inserting ads before and after my videos.

Note that Patreon supporters can watch and even download this video 100% ad-free through Vimeo on my Patreon page:

Click here to view on YouTube.

ZM-2 + AX1–?

So, Gordon, I can safely say that, yes, the ZM-2 pairs nicely with the AX1 and AXE combo.

Since the ZM-2 maintains a connection to the ground post even when it’s switched to a coax input, this means that you can connect the AX1 counterpoise to the ZM-2 if your rig doesn’t have a convenient grounding point.

Since antennas like the AX1 have a high Q, and are affected by topography and body capacitance, you won’t be able to reliably position the L and C controls to the same positions each time. That’s okay, though, because the ZM-2 is fairly easy to tune.

You don’t need a perfect SWR–I’d be happy with anything under 2:1.

Do think about a way to secure the ZM-2 so that when the AX1 is attached it doesn’t topple over in the wind. The ZM-2 is super lightweight, so adding a (non-conductive/dielectric) weight on it, or using a bungee cord, will sort that out in short order!

Thank you

Thank you for joining me during this activation!
I hope you enjoyed the field report and my activation video as much as I enjoyed creating them!

Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon, and the Coffee Fund. While not a requirement, as my content will always be free, I really appreciate the support.

As I mentioned before, the Patreon platform connected to Vimeo makes it possible for me to share videos that are not only 100% ad-free but also downloadable for offline viewing. The Vimeo account also serves as a third backup for my video files.
Thanks for spending part of your day with me!

Cheers & 72,

Thomas (K4SWL)