The thought of me playing with CW QRP is definitely unexpected. I'm not a very good CW (Morse Code) operator, operating mainly what I call DX CW. That's where you can transmit your call sign, and 599 TU. On the reception side, all you need to be able to do is recognize your own call sign. From time to time you need to deal with a few other common sequences, such as CFM or AGN. A considerate operator will also be able to follow split frequency instructions, such as UP 2. If you can't follow these instructions, or understand when your number or continent (NA, EU, etc...) is being called, you will not make the contact, and you will probably make a lot of enemies who want to call you a lid.
QRP is the term used to generally describe low power operation, with less than 5 watts of power on transmit. Over the last few years I've only added power, arriving firmly at the legal limit of 1500 watts. Coupled with decent antennas, this makes a lot of contacts much like the proverbial shooting fish in a barrel. Although there are complete commercial QRP radios, it is far more common that the radios are built from kits, or even totally scratch built. This adds a special and historic dimension to QRP operation. In days long ago, almost all amateur radio equipment was built by the hand of the operator. Now, the popular mass-marketed radios are packed with so many features and microprocessors that with few exceptions they are all commercially built. So, QRP activity is often the confluence of low power operation, radio design, and construction.
Why in the world would I want to get involved with QRP operation?
To improve my CW skills. I certainly won't be chasing DX pile-ups while running QRP, so it's necessary to be able to engage in a real conversation, even if it is the classic name, QTH (location), and weather report. Working with weak signals, which is often part of QRP operation, is a good way to build CW proficiency.
To go through the exercise of building the radio. I seem to find a reason to fire up the soldering iron about once or twice a week, but often times it's for building cables, which are not all that exciting. I'm planning on building a vector network analyzer based on surface mount technology, and I wanted to build something much simpler as a warm-up exercise. A QRP radio seemed about the right amount and type of work.
To use a radio I built along with an antenna I built. Although I'm getting ahead of myself, I plan on operating QRP on 40 meters. On this band I use my Hex Array, which is an antenna project that I've been working on for several years. Using a radio I built myself on a band where I built the antenna array maximizes the amount homebrew and homebuilt content. Then, I can transcend to the next level, and fabricate my own transistors from beach sand. Perhaps not.
To see what can be worked. I will be using a good antenna with my QRP radio, at least while at home. How many states and countries can I contact? How long will it take?
To try and figure out what others see in QRP. You know, there are many activities in life that appear to be uninteresting, until you jump in. Then, all of a sudden, you find something that interests you, and you have a new challenge. Like the saying goes, nothing ventured, nothing gained. I'm not getting any younger - are you?
The Internet contains a wealth of information on QRP radios and operation. Some of my favorites are:
eHam.net QRP Radio Product Reviews: The eham.net site maintains reviews of most all amateur radio products, including QRP radios. These pages are usually a great place to find out what others are saying about a product. The QRP page is a good place to see what's available, and what other hams think about them. eHam has a second page devoted to QRP accessories.
North American QRP CW Club: Dedicated to QRP operation, using strictly CW. The group encourages the use of CW, regardless of power level.
NORCAL QRP: Northern California QRP page. One of the early QRP groups.
The AC6V QRP Links Page: It's always a good idea to check out the links at AC6V.
Small Wonder Labs: The maker of my particular kit, the DSW-II for 40 meters.
K3WWP's Listing of QRP Rigs: A nice summary of what's available in radios.
There are many printed publications that present QRP radio designs, and QRP operating information. The ARRL bookstore has several books devoted to QRP. eBay usually has many listings related to QRP.
Another good source of QRP information is through the many clubs that exist to promote QRP.
As part of my experimentation with QRP, I have created the following web pages:
The Small Wonder Labs DSW-II Kit (40 Meters): Description of the kit building and testing process.
Ohm's Law for Dummy Loads: A quick look at a QRP power level dummy load.
After considering all of the alternatives and options, I decided to build the Small Wonder Labs DSW-II kit for 40 meters. This was my choice for several reasons.
The kit is a complete kit. I didn't want to fool around with partial kits, not even ones only missing an enclosure. I normally like to scrounge around for parts, but at this time, I needed to get back to the vector network analyzer project as soon as possible. I wanted to brush up on my soldering skills, not my parts procurement skills.
The DSW-II design has a maximum power output of 4 watts, near the upper end of the QRP range. I guess I'm still enough of a chicken about the whole lower power thing that heading down to 1 watt or less seems to be going too far. Perhaps as I get my feet wet in QRP, lowering the transmit power will add to the challenge.
My main reason for selecting this kit was because it operates across the whole band. Many QRP transmitters use crystal control, and are restricted to the crystal frequency, or a very narrow range around the crystal frequency. The DSW-II uses a microprocessor to drive a digital synthesizer chip, which is the basis of the transmit and receive operating frequency. This architecture allows the radio to tune the entire band, which seems like a very desirable feature, so that a clear frequency, or activity, as desired, can be found. This capability is referred to as frequency agility. Because there is a microprocessor in the transceiver, other useful features can be easily added, such as an electronic keyer. Many QRP operators use an external keyer, but one is not needed with the DSW-II, since it's built-in to the control microprocessor.
I picked the 40 meter band (as opposed to 20 meters, the other choice) because it's a popular QRP band, and my homebrew Hex Array antenna operates on 40 meters. This gives me a band where I will have constructed both the radio and the antenna. In some sense, 20 meters is almost too easy, due to the excellent propagation. I was recently (14.153 MHz, December 26, 2003, 20:52 Z) working my friend Lyle, ZS1UOK, located in Capetown, South Africa. For whatever reason, I turned off the amplifier, and started to reduce my power. Now this was on SSB mind you, not CW. When I got down to around 20 watts, Lyle could no longer hear me. But, Rick, VK2ZF, called in long-path from Australia, and told me that he could copy me without problem when I was running under 10 watts. This is a 14,000 mile distance, using SSB, and long-path. Propagation on 40 meters is usually more challenging, if for no other reason than the level of the background noise.
40 meters is also the band where I did most all of my operating when I first received my radio license back in 1969. My operation on 40 meters these days tends to be centered around chasing DX, and the QRP radio will give me a chance to enjoy the band again, and it's particular propagation characteristics.
I was also pleased to see all of the kit documentation on-line. This included the construction and alignment manual, as well as a troubleshooting manual with complete signal flow and theory of operation. This is becoming a popular trend on the Internet, and it seems to suggest that the provider has nothing to hide.
There are literally thousands of QRP radio designs. A transmitter can be built with as few as 2 to 3 transistors and a handful of surrounding components. The receivers are usually a little more complicated, but with various integrated circuit OP amps and mixers, the parts count still remains relatively low. The kit I bought cost $150 (USD) at the end of 2003. This is at the upper end of kit prices. It is certainly possible to build a QRP station for next to nothing, although you may need to shop carefully.
Another variation which is sometimes seen with QRP is the use of vacuum tubes. This is usually part of a nostalgia statement, where a few vacuum tubes can be combined to make a complete radio station. This was where most amateur radio operators started in the hobby, in the first few decades of the radio. You would have to build your own transmitter and receiver in order to get on the air. The transmitter power level was usually more than 5 watts, but not by much. There is something very compelling about the glow of a vacuum tube.
My QRP story will be an unfolding tale. At this point, at the end of 2003, my name is on the waiting list at Small Wonder Labs. I hope to receive my DSW-II kit for 40 meters in the next few weeks, and begin construction, which will be described on another page.
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