Like a lot of QRPers, I love a good challenge.
Maybe it’s just in the nature of those of us who love QRP.
We get a small thrill out of seeing what we can accomplish with less.
AX1 Doubts?
On the morning of February 7, 2022, I received an email from a subscriber in South Carolina who had placed an order for a new Elecraft KX2 and an AX1 antenna package. He picked this particular combination because he wanted the most simple and easy-to-set-up field radio system for impromptu CW POTA activations and a little random QRP fun.
He mentioned that, at his age, mobility is a bit of an issue and even though he knew a wire antenna would be more effective, deploying it while walking on uneven ground just wasn’t in the cards. The AX1 was a much more manageable and packable system. Plus, as he said, “I’m not going out to work DX. I just want to play and have fun.”
Only a week after placing his order, he was having buyer’s remorse which prompted his message.
He explained that he had exchanged emails with a friend in his radio club who told him he’d made a foolish mistake and that the AX1 was completely ineffective as an antenna and would only lead to disappointment. His friend said [direct quote here], “I owned [an AX1] for a month and was never able to make a single contact. It is really good at being a dummy load and nothing more! This thing shouldn’t be marketed as an antenna. It doesn’t work.”
I pointed out that I’ve used the AX1 numerous times in the field and have yet to be disappointed.
Before I used the AX1, I too, was very skeptical but after actually using it (instead of simply theorizing about it) I found it’s one of my most valuable antennas for a quick and fruitful activation. I pointed him to this playlist that includes all of my AX1 activations on YouTube. In all of these activation, I’ve limited myself to 5 watts as well even though the antenna can handle a full 10 or 15 watts from the KX2 or KX3.
I told him I’d been planning to pair the AX1 with my Mountain Topper MTR-3B and, it turned out, that very day a small window of opportunity opened in the afternoon. I told him we could both see how the AX1 might perform with three watts of power, especially since he’d planned to use 10 watts with his KX2.
As I’ve mentioned in the past, my motto is less theory, more practice!
We’d put the “dummy load theory” to the test!
N6ARA TinyPaddle Jack
This impromptu activation also provided me with a convenient excuse to use my new N6ARA TinyPaddle Jack!
I wrote about this new product from my buddy Ara (N6ARA) last month (click here for details).
The TinyPaddle Jack is the perfect size for my MTR-3B Ultra-Compact Field kit.
I was really looking forward to using them in a proper activation so this was a perfect fit: Tiny Radio + Tiny Antenna + TinyPaddle = QRP Fun!
Blue Ridge Parkway (K-3378)
This being a short activation on a day filled with errands, the logical site was the Blue Ridge Parkway Folk Art Center. In fact, on February 7, 2022, it was one of only a couple portions of the Blue Ridge Parkway that was even accessible; most sections were closed due to winter weather.
I was only able to squeeze in the activation because our weekly grocery pickup was delayed by an hour. One must take advantage of these openings!
Here’s the gear I brought along…
MTR-3B Ultra-Compact Field Kit:
- Tom Bihn Handy Little Thing (HLT) Size 2.
- A 5′ DC power cord. I also have a super short 9V alkaline battery connector (not pictured).
- Sennheiser earphones (not used)
- A PackTenna Mini 20M EFHW antenna (in kit, but not used for this activation)
- Koh-I-Noor .9 mm Mechanical Pencil
- Muji A6 Notepad
- N6ARA TinyPaddle & Jack
- The LNR Precision MTR-3B transceiver with a 3D-printed protective cover
- 20′ BNC to BNC RG-316 from PackTenna.
- 25 meters of Marlow KF1050 Excel 2mm Throwline, and an 8 oz Weaver throw weight (in kit, but not used here)
- A Bioenno 3 aH (9V) LiFePo Battery (Model BLF-0903W).
Other Gear:
- Elecraft AX1 packed in a Maxpedition Fatty Pouch
- Spec-Ops Brand T.H.E. Pack EDC
- Sony SRS-XB12 portable wireless speaker (no longer produced–eBay search)
- Camera: OSMO Action Camera
By the way, I included the full station set up in my activation video below.
Feed line and ATU placement best practices
Ideally–and especially in a setup like this where you’re running very low power into a compromised antenna–it’s best to use the shortest lengths of coaxial feed line as possible and also place the ATU at the antenna instead of the transceiver.
Even knowing this, I somehow ignored both of those best practices!
I’m so used to directly pairing my AX1 on the side of radios like the KX2, KX3, and X6100–radios with built-in ATUs–I didn’t think to bring a short feed line to connect the AX1 to the T1 ATU. I grabbed my gear at the last minute as I left the QTH that day and simply forgot.
Fortunately, my MTR-3B field kit contains a BNC to BNC RG-316 feed line, but it’s far from short. In fact, it’s 20 feet long! And it’s RG-316 which is lossier than heavier coax. You see, I carry a longish length of RG-316 in the MTR-3B kit because I like giving my EFHW antennas a bit of extra counterpoise (via the coax shield) when I deploy them. I’m willing to absorb a bit of line loss to gain the extra counterpoise. In my head, that makes sense (disclaimer: this is merely a gut feeling and not based on science or even science-fiction).
Since I only had a 20′ length of RG-316, that’s what I used.
Fortunately, I keep a 2 foot RG-316 BNC to BNC jumper in the pouch where I store my Elecraft T1 ATU.
Also, without realizing it at the time, I actually made the AX1/MTR-3B system even less efficient by placing the T1 antenna tuner at the radio end of the feed line instead of at the antenna end. Doh!
As I rewatched this video I realized why I made that mistake. I rolled out the 20′ of RG-316, connected it to the antenna, then connected the other end directly to the MTR-3B. When I pulled out the T1 ATU kit and saw the 2′ section of RG-316, I felt pretty silly having forgotten it, and simply connected the antenna line to the ATU and the short jumper to the MTR-3B. This is what I’d normally do with a random wire antenna. It was a bit of muscle memory working against me.
Post activation, it hit me what I had done.
But, hey! RF must go somewhere, right?
So I’m willing to bet I’m one of the few POTA activators that day using an AX1 antenna with 3 watts of power, coursing through a full 22 feet of RG-316.
Could I have made this field kit any less efficient? (Don’t answer that.)
On The Air
I had not scheduled this activation in advance, so I spotted myself via the POTA spots page on-site.
I started calling CQ POTA and began working stations in fairly short order despite all of the inefficiencies I’d built into this particular kit!
Within 16 minutes, I had already logged the 10 stations necessary for a valid POTA activation on 20 meters.
For fun (and since I had a few extra minutes) I added the 40 meter extension and 40 meter counterpoise to the AX1 and called CQ a bit longer. I managed to work one more station (good ole’ WB1LLY in Georgia)!
Forty meters was very quite and although I’m sure I could have logged a few more stations, I ran out of time. I was happy to add one 40 meter contact in this brief activation!
Here’s my log sheet from K-3378 (NC):
QSO Map
So here’s what 3 watts into the AX1 with 22′ of RG-316 feed line can still do!
Activation video
Of course, I made a real-time, real life video of the entire activation including setup. As always, my videos are commercial-free.
Click here to view on YouTube.
Is the AX1 a dummy load?
Based on all of my previous activations using the AX1, and this one in particular, I conclude that the Elecraft AX1 is a horrible dummy load.
Turns out, it’s a very capable POTA/WWFF/SOTA field antenna, though!
Despite my best efforts to undermine the AX1’s performance by 1.) only using 2.5 to 3 watts of power, 2.) using 22′ combined feet of RG-316 coax, and 3.) placing the ATU at the transceiver instead of the antenna base, the AX1 still managed to validate this activation in 16 minutes on the air. Those are great stats!
This little pairing also managed to accomplish about 400 miles/650 km per watt during this activation.
Thank you!
Thanks for joining me on this quick activation!
I’d 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 certainly not a requirement as my content will always be free, I really appreciate the support.
I hope you get a chance to play radio in the coming days. As it warms up here in North America, I’m noticing an uptick in POTA activations. It’s so difficult to stay indoors in front of a computer when it’s beautiful outside. In fact, hitting the field and activating a park is what I’m going to do as soon as I press the “publish” button on this post. I just need to decide what antenna and radio to use.
Again, thank you for joining me and have a wonderful week, friends!
72,
Thomas (K4SWL)
No comments:
Post a Comment