Antennas for travel: MP-1
The four antennas I'll be discussing in these next few days are:
We'll start with the MP-1. This was one of the first small antennas I bought and I picked it up on a lark from Ham Radio Outlet in New Hampshire while browsing around (which is probably why Sandy gets nervous when I start browsing at HRO!). The antenna is pretty simple: it consists of a mount, a small rod, a clever coil assembly, and a collapsible whip. The coil consists of two parts: one with the wire coil and a second sleeve that slips up and down on the coil to change the tap. Tuning the antenna means sliding the sleeve until you get a good match.
The antenna is a shorted vertical so it does need a set of radials. I've added some nice lengths of wires with quick-connect connectors on them for this purpose. The whole kit weighs very little and the longest piece is about a foot long. This makes it easy to pack and carry.
How does it perform? Rather than give my testimony or do a lot of mathematics here talking about efficiency and dBs, I'm going to point to a web site that provides a great set of comparisons for a whole slew of antennas. The HFpack web site has a couple of Shootout reports that directly compare the performance of various antennas using a "reference" antenna such as a 1/4 wave vertical or a full-size dipole. The Vertical Antenna Shootout Results show the standard MP-1 antenna to be about 2 dB down from the reference antenna. That's pretty good given that we've drastically shrunk the size and weight of it!
The MP-1 is an excellent antenna for operating off of a hotel balcony. As I said, it is small, light, and easy to assemble and tune. The other reason why I like this antenna is that it uses standard 3/8-inch by 24 threads for its pieces so you can mix-and-match other antenna parts to further improve the antenna's performance. Adding a longer whip, for example, would help. So would substituting a longer rod between the coil and mount. I made both substitutions on my Hawaii trip and the antenna performed very well. Because of the successes I've had with this antenna, it is now packed with my big (50 pound) Pelican trunk and always travels with that rig.
Your first DXpedition need not be elaborate. You might consider just bringing a small HF radio and one of these antennas on your next business trip. If you can get to the hotel balcony, you can use an antenna like this one to make HF contacts. That sure beats HBO!
Tomorrow I'll talk about another shortened vertical: the Buddistick. Until then, 73!