One of amateur radio’s many interests comes in portable operation, taking your radio to an out of the way place, usually a summit, and working the world using only what can be carried in. Often this means using the HF or shortwave bands, but the higher frequencies get a look-in as well. A smaller antenna is no less the challenge when it comes to designing one that can be carried though, and [Thomas Witherspoon] demonstrates this with a foldable loop antenna for the 2 metre band.
The antenna provides a reminder that the higher bands are nothing to be scared of in construction terms, it uses a BNC-to-4 mm socket adapter as its feedpoint, and makes the rectangular shape of the loop with pieces of fiberglass tube. The wire itself is flexible antenna wire, though we’re guessing almost any conductor could be used. The result is a basic but useful antenna that certainly packs down to a very small size, and we can see it would be a useful addition to any portable operator’s arsenal.
[David], DL1DN, is an Amateur Radio enthusiast with a penchant for low-power (QRP) portable operations. Recently he was out and about, and found that 10 m propagation was wide open. Not discouraged by having forgotten his antenna, he kludges up a makeshift one using a 20 cm length of aluminum foil (see video demonstration below the break). [David] wasn’t completely unprepared, as he did have the loading coil for his portable 20 m antenna, but was missing the telescoping whip. He calculated the whip length should be around 20 cm for 10 m operation, and crinkles up a sheet of foil the approximate length. He tunes it to length by rolling the tip to shorten the “whip” until he gets an SWR minimum.
Ham radio isn’t just one hobby. It is a bunch of hobbies ranging from chatting to building things, bouncing signals off the moon, and lots of things in between. Some of these specialties, such as supporting disaster relief or putting odd locations “on the air”, require portable operation. To encourage disaster readiness, hams participate in Field Days which is a type of contest that encourages simulated emergency conditions. So how do you erect an antenna when you just have a few hours to set up a temporary station? [KB9VBR] shows how he and his friend used a Chameleon Emcomm III portable HF antenna for Winter Field Day. You can see the video review, below.
Unlike some portable antennas, this one is almost 100 feet of wire (73 feet of radiator and a 25 foot counterpoise). The entire affair is meant to be put up and taken down repeatedly.