QRP
Ham radio is about having fun and learning stuff. QRP, or low power operation, opens the door to some unique kinds of fun and learning.
A few words for the sake of readers that don’t yet relate well to dB: dB, or deciBel, is a way of expressing power ratios. 3 dB is double or half the power, 6 dB is quadruple or a fourth, 10 dB is 10X or 1/10, and 20 dB is 100X or 1/100, while 30 dB is 1000X or 1/1000. The natural response of our ears and radio receivers conforms with thinking in dB rather than simple ratios. Also 30 dB$ is 1000 X $1, and a great way of expressing the cost of your new ham equipment to your SO. “It was only +32 dB$.” sounds so much better than $1600.
Just an hour before writing this, I had a nice three-way SSB conversation on 18 MHz with a station in Texas and another in California, while running 10 watts. I got very good signal reports from both stations. Surprised? Think through the arithmetic for a moment. 10 watts is 10 dB down from a 100 watt radio. If a 100 watt station is being received at S9, and an S unit is 6 dB, then reducing the power to 10 watts should bring the signal down to between S7 and S8. That’s still a very copyable signal.
So what is the advantage that you get in return for running QRP? For one thing, the equipment and battery become far smaller. A complete 5-10 watt station, with antenna, tuner, and battery, will fit in a backpack. So you get portability. For another, the equipment, particularly homebrew, may turn out to be far less expensive, letting you play the game of “how much fun can you have for how little money”.
Back in the day, W7ZOI was probably the most notable QRPer, and a prolific QST contributor. (See Solid State Design for the Radio Amateur.) He was into backpacking in the wilds of Oregon. When you’re backpacking, ounces count so his solution was a tiny 2 watt CW rig, which added very little to the weight he had to carry. Compared with a 100 watt transmitter, his signal was down only by 2.8 S units, a little better than S6, so he was still able to make abundant contacts from remote areas.
Not to be outdone, I built a 4 watt 40 meter CW transmitter and receiver that cost only $25 plus parts out of my junk box. It’s bigger, and 3 dB up from W7ZOI’s rig. That’s only half an S unit, so it’s actually a small difference. But backpacking wasn’t my thing. Instead, I liked to volunteer to go to camp with the Scouts. I’d get the younglings off to their activities and merit badge classes, flop an antenna across a tree branch, put out the battery and solar cells, and have some fun. From Michigan, on 40 meters, I had plenty of stateside contacts, plus one from Mexico late one afternoon.
FT8 is a boon to the QRP operator. It will solidly copy signals that you can’t even detect with your ears. At the 5 watt level, I’ve snagged a few DX contacts using that mode. It’s a lot more exciting when that happens on QRP. A small, used laptop or a Raspberry Pi is ample for handling the computing chores, if you are willing to give up the freedom and simplicity of CW.
For more information, see QRPARCI.org. Also note, if you want to have fun on QRP, a good antenna is essential.
73 for now,
Denton
W7DB