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Additional information on this subject and related topics can be found in back issues of QST and the following:
The ARRL has an extensive catalog of books and materials related to Amateur Radio.
From April 1984 QST, p 52:
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 10meter 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 February 1990 QST, p. 43
Low-power operation is more popular than ever before. Why not join in the fun?
By Kenny A. Chaffin, WBOE
2942 South Wabash Circle Denver, CO 80231
Why would anyone except a masochist want to operate with less than 5 W output? What possible attraction could there be? Perhaps it's for the same reason anyone would operate an amateur station in this age of global telephone systems and satellite TV.
Maybe it's for the challenge of doing something a little different. Maybe it's for the thrill. But I can tell you, there's nothing quite like having a QSO with a Japanese, Russian, or rare DX station while running less power than a kid's nightlight!
The QRP Q signal was created to mean "Shall I reduce power?" but has since been adopted by the enthusiasts of low-power operation as their banner. QRP has come to mean 5 W or less output for CW, or 10 W PEP output or less for SSB. Most amateur organizations and contests embrace these as the official QRP limits.
Many of the same amateur activities that take place in the rest of Amateur Radio's domain are alive and well within the QRP community. These activities include constructing home-brew equipment, operating QRP stations, experimenting, DX chasing, and contesting.
You Can Build It
The QRP arena is one of the few places where the average home-brewer still can make a decent showing. In this age of multistage, integrated circuit, super-sophisticated all-mode transceivers, QRP operation stands out as a home-brewer's dream. How many hams can hope to duplicate the operation of the latest HF transceiver on their workbench? Probably none. If, however, we change the rules by restricting the power output, it is certainly possible for nearly anyone with the ability to obtain a ham license to build a 5W transmitter.
QRP transmitting equipment is simple and physically small. The same can't always be said for the receiver, however. A QRP receiver must do the same job as any other receiver, while usually in a smaller box. It is certainly possible to build an adequate QRP receiver by using minimal circuitry and integrated circuits-but it's not easy to duplicate a top-of-the-line commercial receiver in a matchbox.
If you are interested in home-brewing, but haven't actually done much, I would suggest the QRP transmitters as a good first project. QRP transmitters usually consist of a few transistors, and for HF work, the layout is not particularly critical. Probably the toughest part is finding or building the coils and chokes. Even the coils are not a big deal once you've wound a few. Schematics and kits are readily available. They make it easy to get started. After you've put together a kit or two, it'll be a piece of cake to move on to "bigger and better" projects.
If you do start with a QRP transmitter, you can simplify the circuit even further by opting for crystal control. It may not be as restrictive as you think. A fair amount of QRP operation takes place on dedicated QRP frequencies-making it easy to pick the crystal you need. By adding a trimmer capacitor across the crystal you can "pull" the resonant frequency slightly to the lower side of the crystal frequency (This is, in effect, a simple VXO circuit.) The crystal can be pulled from about 3 kHz on 80 meters to 10 kHz on 15 meters, depending on the crystal type and other factors.
Confessions of an Inveterate Milliwatter People like to overcome challenges; it's part of our nature. I lack the physical skills to be a mountain climber, so I have instead chosen to challenge the fickle layers of the ionosphere with a transmitter that runs milliwatts. It's my way of riding the knife-edge of what can be done. Like many hams, I started chasing DX With 100 watts. I was content with this until a friend loaned me an HW-7. The meager 6 W didn't work very well with an indoor apartment antenna, but it gave me quite a thrill to work a few common European countries. I finally managed to move to the country, where I had enough acreage to grow a better antenna crop. I also built a crystal-controlled transmitter that used a 74S00 logic Chip as the oscillator and final amplifier, producing 250 milliwatts. A few local states were quickly put in the log. I smiled every time I told the station I was working that My final was a NAND gate! A few hundred miles seemed to be the limit until the 1984 CW Sweepstakes weekend. I had never paid much attention to contests, so I was not prepared for the bedlam I found when I turned on my radios that Saturday afternoon. A loud W4 was calling CQ on 40 meters, and with no expectation of actually being heard, I sent my call sign once. What's this? He's working me! Uh, let's see, I first got my ticket in, uh, '64 -- that will do. By the time the contest was over, I had worked 24 states with 250 milliwatts. Those big-gun contesters sure have good earsl Three years later, I had them all. My hand was literally shaking as I waiting for the band to improve enough to work a KU in the CQ WW contest. Last year, my milliwatt quest continuing, I modified an HW-8 to run 10 milliwatts output. I had quite an adventure during the '88 CW Sweepstakes, netting 56 QSOs with 31 ARRL sections. The 18-hour operation boiled down to 347,200 points per watt! The 1989 CW SS gave me state number twenty-nine. A couple of DX contests later, eight DXCC countries were in the log. All contacts were made Via an 80-meter dipole fed with open-wire ladder line. It's a high-tech effort. I use a computer to predict expected signal levels to those elusive western states. By all indications, WAS with 10 milliwafts can be done! If any operators west of the Mississippi want to test their station's weak-signal capabilities, I would appreciate a sked!-Ed Hare, KA1CV, ARRL Lab Engineer. |
Antennas
Once you have a working transmitter, you'll need a suitable antenna. Which brings us to the question: What kind of antennas do QRP stations use? You may think that following the lead of low-power, simple transmitter and receivers, QRP antennas should be small and simple. This is definitely not the case. A QRP antenna system should be as efficient as possible. Many transmission lines attentuate the signal considerably before it reaches the antenna. If you have 5 W of RF output and a poor feed line, you could end up with only a couple of watts at the antenna! You should approach your QRP feed line as if it were being used for UHF or satellite work. You want to get as much power to the antenna as possible. Using a lossy feed line at kW power levels is tolerable; at QRP levels, however, the loss of every milliwatt becomes more critical.
The antenna itself is also important. For best results you need the best antenna you can put up -- it's as simple as that -- a high-gain Yagi if possible, up high and clear. It's just as though you were chasing the farthest DX. My antenna is a vertical, which is probably one of the worst choices. But it's the best I can do considering aesthetics, ordinances, and neighborly relations. Even with my vertical I've worked Japan and many Soviet stations using only 5 W output.
Books and Clubs
A couple of reference books you may want to pick up are, The Joy of QRP by Adrian Weiss, WORSP, and QRP Notebook by Doug DeMaw, W 1 FB. The former is more operations oriented and the latter is almost entirely construction projects. There is also a monthly column on QRP written by Michael Bryce, WB8VGE, that runs in 73. Another monthly QRP column appears in World Radio.
Occasional QRP articles, such as this one, appear in various Amateur Radio magazines. Several QRP clubs are available for those interested. QRP Amateur Radio Club International is one of the biggest, and publishes QRP Quarterly. For information about QRP ARCI and a sample copy of QRP Quarterly, write to Joe Sullivan, WA I WLU, 267 Sutton Street, North Andover, MA 01845. The Michigan QRP Club encourages low-power operation with its newsletter, The Five Watter. And if you're interested in British-style QRPing, you can join the G-QRP club [G-land QRPing is strongly associated with home-brewing QRP gear.]
Operating Skills Required
If you want to hone your operating skills, QRP is for you. With only a few watts of signal to work with, it becomes mandatory to perfect your operating technique if you are going to work through that DX pileup. QRP is the radio equivalent of brain over brawn.
But isn't a 1-W signal lost in the shuffle of more powerful stations? It's not as lost as you may think. A 1-W signal is only a little more than three S-units weaker than a 100-W signal. So, if your 100-W signal is S-9, your 1-W signal will be about S-6. And that's plenty of signal!
For QRP operation, you must be able to find DX stations, be aware of when and for how long bands will be open and have a crisp and clear setup on both CW and SSB. You must be able to quickly assimilate a DX operator's technique.
One of the primary skills QRP operation strengthens is patience. With QRP power levels you have to wait for the right moment and make your move. This means you must be alert and listening rather than transmitting. You have to be familiar with the bands, operating procedures of DX stations and other QRP operators. All this takes a bit of patience, practice and listening.
How Do I Do It?
Okay, let's say you just want to operate QRP without building any special equipment. That's easy, just turn the power down on your 100-W transceiver. This requires a power meter or some other method of determining your output power. This adjustment is dependent on your rig, and may be as simple as reducing the RF output control or as complicated as retuning the transmitter for reduced output.
Here's a neat experiment that will introduce you to the realm of QRP operation in a gradual fashion: cut your maximum output in half and operate at that power level for a week or so, then cut it in half again. Continue cutting power until you're down to 5 W. I'm sure you'll be surprised, as I was, at how well you can communicate with reduced power. In many cases, the operator on the other end can't tell the difference. My Heath HW-5400 puts out about 100 W maximum, and now that I work QRP almost exclusively, I really have to have a special reason to crank it up to full power.
Commercial QRP Equipment
If for some reason you can't operate your rig at reduced output, there is commercial QRP equipment available. Heathkit has offered three different QRP transceivers. All operate CW exclusively and cover only that portion of the HF bands. The first was the HW-7. It put out a few watts and had a relatively unstable receiver. The redesigned and improved version turned into the HW-8; there are plenty of these still in use.
The QRP community really took the HW8 to heart and there are modifications galore available to spruce it up. Most of these have been collected in the Hotwater Handbook, available from Michael Bryce (he writes the QRP column for 73). This handbook has been recently revised and reprinted, and includes mods for both the HW-8 and the latest generation HW-9.
The culmination of Heath's QRP line is the HW-9. It features a vastly improved receiver and a bit healthier power output -- slightly more than 5 W on some bands. The HW-9 also covers the newer WARC HF bands and is the only QRP rig currently on the market. You'll have to find the others at swap meets or through the classifieds. Expect to pay up to $70 for an HW-7, $60-$100 for an HW-8, and $100-$200 for a used HW-9. (This last paragraph is no longer true, there are many commercial QRP rigs on the market today. -- Ed.)
The cream of the crop among QRP rigs is Ten-Tec's Argonaut series. The latest version (still long out of production) is the Argonaut 515. It's worth its weight in gold. The previously released 509 is almost as good and the 509's predecessor, the 505, is still hanging in there. These rigs operate both CW and SSB and are usually available at swap fests, through want ads, and from individuals. A 505 goes for $1004175, a 509 for $125-$200 and a 515 for $200-$300 or more, depending on the market. Most of these rigs are generally available, it's just a matter of whether you can afford, and find, a 515 or an HW-8.
A Few More Advantages
There are a couple of other advantages of QRP operations that aren't so obvious. Because you are operating with a minimal power output, your transmitter will probably last "forever." Your electric bill will be less -- especially if you stop using your 2-kW space heater. The other non-obvious advantage is that you won't overload the front end of your neighbor's television. It's a pretty rare occasion when operating with 5 W causes interference.
Contests and Awards
The bonus multipliers and points for QRP contest operation have gotten many hams hooked on QRP. Operating "QRP battery power" for Field Day gives a multiplier of five. You only have to make one contact for every five QRO QSOs.
QRP operation is becoming quite popular for many major contests. The following contests have QRP categories: November Sweepstakes, June and September VHF QSO Parties, January VHF Sweepstakes, and the ARRL International DX Contest, among others.
As far as awards, QRP ARCI offers a thousand-miles-per-watt award, available to anyone presenting evidence of a qualifying QSO. QRP ARCI also offers special QRP awards for WAS, WAC and DXCC. The other QRP clubs also offer versions of these, and other, QRP operating achievement awards.
What's Left
What do you do once you've completed QRP DXCC? How about milliwatting? Milliwatting is operating at less than 1 W output. Once you've perfected your QRP skills and equipment, this is the next challenge. Admittedly, there are few who strive for these ranks, but when it all works -WOW! I've recently seen a circuit for a half-watt crystal-controlled transmitter using a single 2N2222 transistor. I haven't tried it yet, but when I do, I can't wait to hear what the operator on the other end says when I tell him. Of course, at milliwatt levels your antenna and feed line become doubly critical. It seems strange to see a 1-inch-square, single-transistor transmitter connected to 3/4-inch hardline! But it's great fun.
So why not give QRP or milliwatt operation a try? You just might get hooked. See you on 7040 kHz-a popular QRP hangout.
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