ARRL

Why QRP?

Why QRP?

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

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.

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.

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 visit the website where you can download a sample copy of QRP Quarterly in PDF format. 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 7030 or 14060 kHz - popular QRP hangouts.