HF Considerations

The world of HF is quite different from that of VHF or UHF in several ways. The ham who has a newly acquired general class license or is new to HF needs to make decisions about which transceiver to buy, which antenna to build or buy, which band or bands to operate on, which power supply to buy, whether a tuner is needed, and

If the choice is to spend less money ($200 to $400) and purchase an older transceiver equipped with "glow in the dark" tubes, then one must be concerned with whether the radio is in good working order. As when buying a used car, be sure that it is given a "test drive" and thorough check-out before laying down the cash. One advantage of using a tube-type transceiver is that it has a built-in tuner (pi-network), which is not the case with most modern transceivers. Another consideration is that the older transceivers may not cover the WARC bands (30, 17, and 12 meters). Also, most of the older transceivers do not have digital frequency readouts, and it is more difficult to dial in the exact frequency of another station (most HF operators nowadays zero in on an even numbered frequency such as 14.210.000, rather than 14.210.45 for example). It also takes much longer to tune a tube-type transceiver, with more knobs to adjust, switches to set, etc. Be especially careful to make sure that an older radio is capable of operating on SSB, and not just AM or CW. Some of the older radios were only transmitters, requiriing a separate receiver to operate with. Often an older transceiver is sold without a power supply, and the buyer will need to purchase a power supply capable of supplying the proper power and having the appropreate connector to mate with the transceiver.

New HF transceivers typically cost in the range of $800 to $3000 or more. With this extra cost come many bells and whistles not found on the older radios. Decisions must be made about the need for an internal antenna tuner, a scope feature, digital signal processing, speech processing, filtering, and other features.

A very important aspect of the decision process is which antenna to use (there are no "rubber ducks" on HF radios !!). First, one should take into account the condition of the sunspot cycle. Which bands will be "open" for the next year or more? At the low end of the sunspot cycle the best bands will generally be 80m, 40m, and 20m. Under this condition it would seem reasonable to use an antenna capable of operating on one or more of these bands. Why put up an antenna which works best on 10m when the band is only "open" an hour or two every two weeks? And the 40m band is shared with foreign broadcast stations using millions of watts of poweer, so hams more often tend to use the 80m or 20m bands.

An important choice to consider is whether it is more important to work stations in foreign countries or within the US. Another factor is the time of day that you will be able to get on the air. Is it sufficient to work DX only on weekends when you are off work? The 80m and 40m bands are suitable for contacts within the US, and the 20m band is more useful for DX contacts outside of the US as well as more distant contacts within the US. The 80m band is a good prospect for early mornings until about 9am and evenings from about 4pm until late at night. The 40m band is "open" about the same hours, but it is often difficult to find space to operate between foreign broadcast stations. The 20m band is often "open" during the day, especially in the mornings. Stations from different parts of the globe are heard at different times on the 20m band, with openings to Australia, New Zealand and Japan often occurring in the evenings near "prime time." ARRL members can get forecasts indicating the probability of reaching specific areas at various times of day.

Antennas for the 80m and 40m bands are usually long wires such as the G5RV antenna, or dipoles, because of the length of wire needed to resonate on those bands. An important consideration is the amount of space available to hang the antenna. Are trees available on each end of the property, such that a slingshot or bow can be used to get an antenna anchored high into the trees? A wire antenna does not have to be in a straight line. Is space so limited, or are restrictions so tight that only a "hidden" antenna can be used? An antenna in the attic or under the eaves will never work as well as one out in the open and away from other objects such as trees or buildings. A wire antenna that is low to the ground (under 20 feet for example) may work well for contacts within the state, but may be poor for DX contacts and east coast contacts.

If an importance is placed on being able to operate on more than one band the answer may be to use a multiband vertical antenna or a G5RV or similar horizontal antenna. The multiband horizontal antennas require the use of an antenna tuner, often even though there may be an internal antenna tuner in the transceiver. At any rate, such all band antennas will generally not provide better reception or transmission than a dipole antenna designed for use on a single band.

Antennas for the 20m band often include a dipole, vertical, loop, or a beam. By far the best is the beam. Loop antennas such as a delta loop or a quad loop will generally perform better than a dipole or vertical antenna. A cubical quad (reflector and driven element on a boom) performs better than a 3-element beam at low elevations around 30 feet. The beam is better at its designed height of nearly 60 feet elevation. Beams or cubical quads need to be rotated toward the station to be worked, and a tower is usually used for support of such antennas.

In times of high sunspot activity when the sunspot cycle is at its height almost any antenna will be suitable for making contacts around the world, but we need to be prepared for the less perfect conditions.

A good antenna is the most important factor in making reliable contacts with amateur radio. It should be clear that the following questions need to be considered when deciding on which antenna to use:

1. How much space is available?
2. How high can the antenna be located?
3. Is DX, close range operation such as statewide nets, or both desired?
4. How will the sunspot cycle, monthly and daily cycles affect reception?
5. What time of day is available for operation?
6. What expenditures can be made for antenna, transmission line, balun, etc?
7. What are the engineering needs to erect an antenna that will withstand all weather conditions for years to come?

A great series of articles on antennas by a renown expert on the subject can be found at the website http://www.cebik.com/gup/groundup.html .