ARRL

QRP: More Than a State of Mind

 

Looking for a new challenge? Try reducing power and adopting a few new operating habits.

By Bradley Wells, KR7L

Low-power operation, or QRP, has enjoyed a surge in popularity in recent years. Why? Mostly it's the challenge of working stations the "hard way," be it during contests or everyday operation, and the great satisfaction that comes from making contacts that the "big guns" make. Most low-power ops will agree that the motivation for QRP is the same as for chasing DX -- but the rewards are inversely proportional to the amount of power used.

In this article, we'll take a look at the exciting world of QRP, discuss some equipment that's available and talk about ways of improving your chances of success with low-power operation. One word of caution to the reader, though: QRP can be habit-forming.

The definition of QRP, recognized by most amateur organizations, is 10-W input, or 5-W measured output. Five watts may not sound like much to those who consider 200 W low power, but the difference is not as great as you may think. Under actual conditions, 5 W will have little effect on your ability to work DX. The difference between QRP and, say, 200 or 2000 W is only 3 or 5 S units. Also, QRP exemplifies the spirit of the Rules -- specifically 97.67(b), which states that " . . amateur stations shall use the minimum amount of transmitter power necessary to carry out the desired communications."

Choosing an Antenna

A major failing of both experienced and novice QRPers is the antenna system. Unfortunately, most hams think low power equates with poor antennas. Many QRP operators seem to delight in using their rig with a 50-foot piece of wire thrown out the nearest window.

The basic rule of QRP antennas is that nothing beats a beam; and nothing beats a beam on a tall tower. Put up the best beam/tower combination you can afford. A good 3-element beam and 40foot tower will put you on a more-than-equal footing with those running 200 W to a vertical.

A good full-size dipole is the next best choice. On 20, 15 and 10 meters, a high dipole exhibits directivity, so place it broad-side to the desired direction of radiation.

Related to the dipole, and almost as easy to construct, is the single-quad loop. This antenna is more directive, has wide bandwidth and can exhibit up to 2-dB gain over a dipole.

The poorest choice for the QRPer is the vertical antenna. The vertical suffers two defects when compared to a dipole. It is highly susceptible to man-made QRN, notably power-line noise. For a vertical to have the same radiation efficiency of a dipole, a good radial system is required. Amateurs lacking space for beams or dipoles might consider the Cushcraft R-3 tuned vertical, which requires no radials and approaches the efficiency of a half-wave dipole.

Do not skimp on the coax. Use the best grade of RG-8 you can afford. We are not interested in power capability, but in achieving the lowest attenuation possible. The ham with an amplifier will not miss a couple of watts heating his coax as much as the QRPer running 5 W will. For portable operation, RG-8X may be used where its light weight and ease of handling offset the increase in attenuation. Make all connections clean and weatherproof. Strive for the highest possible efficiency in both feed line and the antenna.

Operating Tips

One may wonder how a DX station can hear a 5-W signal when megawatts are coming at him. But hear it he does, and more often than not the experienced QRP operator will get through those pileups to snag the rare DX station. To do this, however, the operator requires some knowledge of tactics used by successful stations.

First, and most important, listen before using your key or mic. Is he working stations by call area or at random? Is he picking up tailenders? Is he listening high or low, and how wide is the split? All of these things can only be learned by listening. Spend five, even 10 minutes on your receiver before you begin to transmit.

Second, invest in a memory keyer. You're going to send your call a number of times, and it's much easier to do so by pushing a button instead of wearing out

your wrist. Send your call at a slightly slower speed than the DX station is transmitting.

Third, on phone, use standard phonetics. The ham on the other end doesn't have time to figure out cute call signs, and will ignore you. In addition, use some form of speech processing to boost your average power, but don't overdo it. Too much is far worse than too little.

Fourth, time your calls. This is most important for QRP operators. Don't try to be first to hit the keyer or PTT switch. Normally, everyone will send their calls all at once, pause, then try again. When you hear that pause, slip your call in just once. That's all you have time for. Do this correctly, and you may get through on the third or fourth call.

Finally, know when to quit. Everyone has days when the propagation is wrong or Lady Luck is against you. Believe it or not, the world will not end if you fail to work the DX in that pileup.

Rx for Success

With only 5 W, there is no way you're going to blast an opening into a crowded band. You don't have an "afterburner" to kick in under heavy QRM conditions, or the power to make your own propagation. So, you need a change in operating style.

The first habit you will break, and soon forget, is calling "CQ." In fact, "CQ" and "CQ DX" will just about disappear from your vocabulary and keyer. With full legal power, a "CQ" in any direction will get you contacts. QRP will never bring the same results. For those unwilling to change this operating habit, the kiss of death is on their QRP career.

There are several ways to increase your chances of success. First, have a good beam antenna. Second, sign your call with /QRP. This may cause stations to call you out of curiosity. The idea is to let everyone know, up front, why you're not 40 dB over S 9. However, most hams will not answer a weak "CQ" unless your call begins with something like S79, VKO or T32.

The single-most-effective QRP operating technique is search-and-pounce. Search-and-pounce is simply tuning carefully through each band until you find a station to work. Most of the stations you work will be calling "CQ, " or you will nail them as they finish a QSO.

Work the station with a moderate-to-loud signal. Since the sensitivity of most QRP receivers outstrips the effective range of their transmitter, a signal that is very weak may be impossible to work. Propagation is a reciprocal thing, and if the station on the other end is S 1 running a kilowatt, imagine what 5 W will sound like. Actually, there will be no sound at all - you simply will not be heard. This condition is more prevalent on 80 and 40 meters, where antennas and propagation tend to work against the QRPer.

If you become involved in a marginal contact, don't prolong it. The other operator did you a favor by coming back and will not get much enjoyment out of the QSO if you're only 3 3 9 at his end. The place to tell him all about your rig, antenna and the weather is on your QSL card.

A fact of QRP life, and one of its more frustrating aspects, is that you are going to get stomped on occasionally - whether it's deliberate bad manners, carelessness or simply that the station firing up on frequency can't hear you. Sometimes, you can operate through the QRM, but generally it's the end of the QSO.

For those of you who chase DX (and who doesn't?), listening on the local DX repeater is a good way to expand your search-and-pounce technique. If you do spot a bit of DX, work him first, then announce his frequency over the repeater. Do it the other way around and you may find yourself hip-deep in "big gun" stations.

Another prime requirement for being able to work DX (or anyone else) on a consistent basis is at least a working knowledge of propagation. All of the major amateur publications have monthly propagation charts. They use different formats, so different interpretive techniques are applicable to each. All of these charts are prepared several months in advance of publication; you should be able to update their information to make allowance for current conditions. There are two ways to do this. One is to monitor the WWV propagation forecast at 18 minutes after each hour. These recordings provide real-time information to update your monthly charts. A second method is to subscribe to one of the DX bulletins. Printed on a weekly or biweekly basis, all are excellent indicators of relatively current propagation conditions.

The three bands providing the bulk of activity for QRP are 20, 15 and 10 meters. When the 10 meter band is open, there is little difference between 5 and 500 W. It can exhibit rapid shifts in propagation, however, which can be disconcerting to even experienced hams. Twenty meters is the most consistent band, providing openings to some part of the world day and night.

Forty and 80 meters are less consistent producers because of their more-seasonal nature and higher levels of QRN and QRM. Both tend to be winter bands, but can produce results any time of year. The best DX time is 30 minutes before and after local sunrise or sunset. Also, the 30-meter band is excellent for QRPers. Its propagation lies midway between 20 and 40 meters, and only limited-power (250 W) operation is permitted.

Most QRP CW operation is around 40-60 kHz up from the bottom edge of any band. Most phone operation tends to be in the Advanced and Extra Class subbands. Stay out of the Novice segments; beginners have enough problems without the added difficulty of having to copy less than S 9 signals.

The QRP Contester

For many, contesting is just one interesting facet of Amateur Radio. For others, contests are Amateur Radio. Non-contesters and contesters alike may view operating a contest with a QRP rig as the ultimate insanity. Actually, the reverse is true. Most of us don't have the megabucks required to put together a top-drawer, big-gun, killer-type contest station. However, most hams can afford a first-class QRP station. Since QRP rigs are relatively inexpensive, you can afford to invest more in antennas -- a deciding factor in contesting.

Many contests have a separate single-operator, all-band QRP category. Thus, you need only compete against other QRP operators. However, winning still requires maximum doses of perseverance and a large amount of skill.

Contesting effectively with QRP requires the application of several important techniques. At the beginning of the contest, work the strongest stations. Then, work the progressively weaker stations. In addition, don't waste too much time calling any one station. If he hasn't come back to you by the fourth call, move on. You can work him later when the pileup is reduced. An exception to this would be near the end of the contest when that DX station represents a new multiplier.

Instead of tuning up and down the band, start at the high end and work stations as you go to the low end. When you hit the bottom edge, quickly tune up to the top and start down again. This will maximize your time on all portions of the band. Those proficient with a search-and-pounce technique will have a QSO rate almost equal to most stations calling "CQ. " Also, new stations will appear and disappear with great rapidity, so don't worry about working the band dry.

Another rule for the QRPer is to work the MUF (maximum usable frequency). Work the highest frequency that is open in the area you want to cover, based on WWV or other propagation information. Operating at or close to the MUF reduces path loss and maximizes your 5-W signal.

In a DX contest, know the areas that are easiest to work, and concentrate on those at the start of the contest. Work the more difficult areas during the last 24 hours. For example: Generally, Japan, Oceania and Europe can be worked from the West Coast on 20 meters in the morning. For the QRPer, however, it is more productive to work Japan and Oceania Saturday morning and Europe Sunday morning. By the last day, Europeans will have worked out much of the Eastern seaboard and will respond more quickly to a call from the West Coast.

In any contest, but more particularly in a DX contest, establish some type of game plan. Spend some time consulting propagation charts, and write up a time-versus-frequency plan for your own use. Decide which areas you will cover at what times and the best band for each combination. This plan should be used as a guide for each hour of operation. The most productive directions will be based on your experience and an examination of previous contest scores.

Next to your log, the most important record to keep is the dupe sheet. Duplicating contacts means wasted effort, lost points and less-productive operating time. Since, as a QRP station, you will be operating 99% of the time in a search-and-pounce mode, your dupe sheet must be as current as your contest log. There are as many different dupe sheets as there are contests, so use one that fits your needs.

Finally, keep the proper perspective and attitude before, during and after the contest. Above all, don't worry about the big-gun station down the block. You're not competing against him, only against other QRPers

From April 1984 QST, p 52: