"A balloon launched by an Illinois ham radio club might have been the balloon shot down over Canada recently by U.S. Air Force fighter jets.

?

The balloon was launched in October 2022 by the Northern Illinois Bottlecap Balloon Brigade and was on its seventh trip around the world when it disappeared from tracking about the same time an Air Force F-22 shot down a balloon over the Yukon Territory in Canada on Feb. 11. "

Like Julian, I've gone through many iterations on "man-portable" antennas. I was delighted to see that he is recommending the N9SAB OCFD antenna; I've been using his 40M version for a couple of years now and it's still my "go to" antenna for flexibility and portability. I couple it with my IC-705, LDG Z-100+ tuner, and a SOTABeams Carbon6 mast, and I'm good to go. I also 3D printed a guying ring that slips right over the mast, which helps a lot in windy situations. Total pack weight, including water/food, sits right at 6kg (13 pounds).?

?

About the only issues I've run into with this antenna is that a) it takes a lot of room, and b) to be truly multi-band, a tuner is required. To satisfy the latter, I have the LDG Z-100 Plus, which I see you also have, and I've found that if you don't use internal batteries and instead run it on the same battery as the radio, it saves a lot of weight.??

?

As far as deployment size, the long side of the dipole is around 26 meters (85 feet), which is tough to deploy in areas where space is limited, such as the top of certain peaks here in Colorado, where the summits can become quite crowded. It is possible to reduce the overall length to 20 meters, making the long side ~13M (~45 feet), but that cuts out 40 meter coverage and still takes a lot of room. I'm OK with that as I rarely operate on 40 meters, as all of my SOTA activations take place during daylight hours.

?

The other antenna I've been playing around with is a magnetic loop. I started with the Chameleon F-Loop 2.0, which performs fabulously, and while it's technically man-portable, by the time you add a tripod etc, it's not only bulky, but it pushes my pack weight to about 9kg (about 20 pounds). It's also not weatherproof, but then again, neither is my IC-705. The benefit of the mag loop is that it is crazy fast to deploy. Like 5 minutes or less. So now I'm thinking about picking up an Alexloop Hampack, which is a lot lighter than the Chameleon (and smaller), along with a small carbon fiber tripod. Still a lot heavier than the OCFD, but a lot easier to deploy. Last fall, while up on Mestaa'hehe, I successfully QSO'd with a guy in France using the Chameleon mag loop--5/5 signal report on 20 meter SSB and he was a very clear 5/9 on my end. Mag loops are like magic and they're super cool looking too!

?

Tony. K0mcw

NA0TC program coordinator?

?

The shunt inductance added by the hairpin match can be adjusted by changing its geometry. The general idea is to vary the length of the hairpin match to adjust the inductance. Shorter hairpins have more inductance than longer ones, and the relationship between length and inductance is proportional.

?

However, the precise relationship between the length and inductance of the hairpin match is complex and depends on a variety of factors, such as the wire diameter, the distance between the two legs of the hairpin, and the proximity to other conductive elements.

?

In practice, adjusting the hairpin match can be a trial-and-error process. You can start by using a fixed length hairpin match and adjust it until you achieve the desired SWR. If you find that you need to make larger adjustments, you can try making the hairpin match longer or shorter, or changing its geometry in other ways, such as changing the wire diameter or the distance between the legs.

?

If you're looking for a more precise method, you could consider building an adjustable hairpin match similar to the ones sold by DX Engineering. These types of hairpin matches allow you to adjust the inductance by changing the position of a slider along the length of the wire, making it easier to achieve the desired SWR.
---------