Wednesday, June 8, 2016

Portable Antennas

Portable antennas have always been a fascination of mine. As much as I would love to have a 100' tower and large yagi antenna above my shack I realize that is not realistic when it comes to mobile or portable HF operations. It is true that field day each year there are those who drag a portable tower system on a trailer with a monster array to place on top. This is great if you have a team of people to help and a place to erect the tower.

A few years back I was attending a field day event when a friend arrived with his crank-up tower loaded and mounted on a twin-axle trailer. At the start of the event he lowered the trailer stabilizers and began to assemble the antenna and mount it to the top of the tower. Next with his wench and a homade lift he brought the tower to a vertical position to allow the crank-up procedure. For the next 2 1/2 hours in 90 degree weather with 80%+ humidity he cranked away. Being prideful and desiring the the badge of self-accomplishment he refused any help. When the tower was fully erected he connected the coax to the antenna switch system and walked to a shade tree where he spent the next three hours recovering from his accomplishment. Six hours into the event he was finally able to enjoy his efforts. Needless to say the antenna and tower system produced some great results but was it worth the cost?

If I am looking at carrying my portable HF system and an antenna with me when I attend a field day event, go on vacation, or when I need to get out of dodge, then the trailer, tower, and monster antenna setup is not practical. I need a small system that I can throw in a backpack or hard case and hit the road. I really like my Yaesu FT-991 which offers HF, VHF, and UHF bands. Therefore I need a practical solution to go along with me. 

First let's talk about the HF side of the fence. This is usually the most difficult item to select or build in a portable configuration. Antennas are compromises in the best of situations. We do not live in a vacuum and our locations are always influenced by our surroundings. Not knowing what band will be usable we desire an antenna that covers multiple bands while at the same time we need something we can easily carry, assemble, erect, and tune. With those qualifications our field of commercially available antennas has drastically narrowed.

Outside of the good old fashioned wire dipole, there are a few out there. The ones that come to mind for quick setup and operation are the Buddipole, Buddistick, and the Super Antenna (MP1DX). Even though these antennas have the same goal in design, they each have different characteristics. The Buddipole operates in a dipole fashion. You erect a vertical pole and the attach two radiators to a T-connector. Depending on your location you may need a guy wire system to stabilize the setup. Your radiator setup determines band. Changing bands requires a little effort in changing the radiator setup. People have reported surprisingly good results with this system. 

The Buddistick is more suited as a vertical antenna with a wire counter poise. It is designed for operation under 250 watts. This can be mounted on a tripod or clamped to a picnic table or rail. The vertical pole the antenna is mounted on can be raised surprisingly high. This antenna is very easy to setup and reports are positive to its use. 

The Super Antenna is also a vertical but has a higher power rating than does the Buddistick. The Super Antenna doesn't require radials but when added becomes a very interesting performer. Like the Buddistick it can be clamped to a table or mounted on a tripod. Changing the frequency is done by moving a tap on the loading coil. This antenna also receives good reviews. 

Many times we like having VHF along for the ride. If this is the case eliminate the Buddistick from the list. The other two are capable of operation in the VHF band. 

You may be asking why I did not include a discussion of the wire dipole in my list. It does a great job but has one major limitation - installation requirements. You have to tie the ends of the antenna to something at height. Some locations do not have trees or structures to accommodate this requirement (beach, etc.). Otherwise it would have floated to the top of my list. 

This topic like so many others has opinions that reside in both sides of the fence. I would love to hear what you think and what portable antenna you prefer.