Field Day Antenna Selection Guide
last updated 25 May 2022
I’m currently writing this page specifically for Field Day antennas, but it may be useful for a lot of different applications. I’ll make a more generic version later.
There are a lot of different ways to approach Field Day, depending on one’s personal preferences. Some see it as a serious contest, some as a social event, it may be an excuse to spend time outdoors, and, for some of us, it is an opportunity to experiment with antennas. Similarly, there is a lot of variation in the station set-up philosophy: some will carefully plan their antennas and station layout in advance, some will take their favorite antenna and figure out a way to put it up in the field, and others will find a convenient site, then worry about what antenna they can put up out of the materials at hand. (And some of us will set up antennas for 5 stations and still have the back of the car crammed with wire, rope, and feedline, just in case someone wants to try something different this year.)
The purpose of this page is to provide a guide for possible antennas to use in different situations. This guide is by no means complete or definitive, but I hope at least it helps readers to consider some different alternatives, or to choose between two different options (even if it is to say that the two antennas will work about the same, so the choice can be made on other criteria.)
For Field Day, or any other antenna installation, there are a lot of factors to consider when choosing an antenna. For myself, some of the important ones are:
- light weight
- flexible, easy to work with
- adaptable to different situations / antennas
- good performance for QRP operation
- suitable radiation pattern for the expected distance and direction of contacts
In many cases these affect the way the antennas is constructed, rather than the electrical design of the antenna itself. Sometimes the specific site may impose strict limitations on size, supports, or how much you can carry on your back while hiking to it.
I strongly recommend, when evaluating these antennas for your own use, that you have a standard antenna, such as a dipole, to compare them against, especially if they are complicated or expensive. I’ve come up with lots of designs that, while they may be cute or clever, aren’t really enough better than a simple dipole to justify the added effort, space, or complexity.
And if you already have your favorite antenna that works well enough for you, go ahead and use it. Unless it is particularly inefficient, or in marginal conditions (such as running QRP SSB from KH6 or KL7), even a mediocre antenna can still make plenty of contacts.
Field Day antenna assignments
Many Field Day sites run two or more transmitters operating at the same time. The HF bands used are 80m, 40m, 20m, 15m, and 10m. (160m and the VHF/UHF and higher bands are also available). On each band, different modes (voice, CW, and digital) can be used. The question often comes up, what is the best way to divide the bands and modes among the stations.
One approach is to assign one transmitter to each mode. This requires, then, that each transmitter have antennas for all the HF bands that will be used: more effort for the antenna installation crew, and more potential for interference from other stations on the same band. However, it permits all the stations to operate on the optimum band at any time, and each station can be optimized for a particular mode.
Another approach is to assign specific bands to each station, with a monoband antenna for each. For example, one station might have 80m, 20m, and 10m, while a second uses 40m and 15m, with each using whatever mode the operator chooses. Then you may end up with stations on adjacent bands, or on harmonic frequencies, but not on the same band at the same time, and only one antenna per band is required across all stations. Less interference, fewer antennas to install, and often at least two bands are open at the same time.
Often we end up with a hybrid: the voice and digital stations are close enough together, they can share antennas however they want to, while the GOTA (beginners) and CW stations have their own antennas at a bit of a distance, and can do whatever they want to.
You’d think this isn’t an issue for a single-operator station, but there still may be question of using a single multiband antenna, or separate monobanders. That will depend on the space and time available to set up, and how much antennas need to be optimized for specific bands or paths. And sometimes a single operator may want to have different antennas for the same band to compare them, or for covering different directions.
It is a good idea to have this decided in advance (even if there is only one operator) as it affects the antenna installations and choice of supports when setting up.
Some clubs will insist on monoband antennas to reduce the radiation and/or pickup of noise by/from other transmitters. This doesn’t always provide sufficient isolation, however: if a radio is transmitting phase noise, then solve it at the source (often by using a different transmitter) rather than relying on the antennas as filters. Band pass filters can also be useful, as long as you remember to switch them when you change bands. If you do need to reduce coupling between antennas to eliminate receiver overload, then placing antennas as far apart as possible, installing antennas at right angles, and using different polarizations may help.
Dimensions for several of these antennas are included it the FIELD DAY WIRE LENGTH TABLE.
Finally, we get to the meat of the article.
In this section I’ll give a specific situation, then give links to various antennas to consider for it. There will be a lot of duplication, of course, because some antennas can be used in many different situations.
These are worth considering for most applications.
single antenna for multiple bands
- multiple dipoles on a common feedpoint
- original fan dipole (wideband)
- trap dipole
- link dipole
- doublet (including G5RV / ZS6BKW and others)
- off-center-fed dipole (OCFD)
- end-fed half-wave (EFHW)
- horizontal loop
- end-fed random wire (including non-resonant verticals)
- trap vertical
- alternative feed bobtail curtain
- quarter wave vertical
- trap vertical
- tuned vertical
- dual-frequency vertical
- inverted vee
- delta or diamond loop (switchable polarization)
- double loop
- bisquare loop
- OCFD / EFHW inverted vee
- hanging ground plane / J-pole
- hex beam
- aluminum yagi
- single support wire yagi
- single support wire quad
- sloping quagi
single support with top spreader
- dipole / doublet
- delta / rectangle loops
- wire yagi
- wire delta loop quad
- bobtail curtain / half square
- 80m biconical dipole
- inverted L
- horizontal loop
- vee beam / rhombic
- coil-loaded dipole
- dual-band dipole
- 50 ohm delta / rectangular loop
- vertical (various sorts, including random length)
- “delta loop 40m mini”
high gain antennas
low angle radiation
- sloping long wire with reflector / director
- bobtail curtain
- vertically polarized delta loop
To cover much or all of the 3.5 – 4 MHz band in Region 2