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 Previous: ARRL Education & Technology Program Schools Get Best Buy Te@ch Grants | ![Next (later) Story](/images/sty-up.gif "Iowa Ham Club Designated "Point of Light," Gets Paul Harvey On-Air Mention"){kind=small} Next: Iowa Ham Club Designated "Point of Light," Gets Paul Harvey On-Air Mention |
By Anthony A. Luscre, K8ZT
Contributing Editor
March 16, 2004
Minimalist methods QRPers can use to package and interconnect radios, keyers, antennas and accessories
 An assortment of mint tins just wait to house a QRP project. [Photo by author] |
A first-time reader of many QRP mailing lists may wonder if Altoids is a major manufacturer of low-power radio equipment. Of course, many QRPers not only want low-power radios but small-size radios too. Altoids containers and similar tins have been used to contain many small radios and accessories.
Other common containers often put to the task
of packaging radio gear, accessories and adapters include 35-mm film canisters,
medicine bottles, plastic food storage containers, lunch boxes, VHS tape cases,
old external modem cases and even food packaging.
 Quick and easy adapter utilizing a film canister. [Photo by author] |
Because I frequently make up new cables and/or adapters for the various QRP radios that pass through my shack, I have developed a quick and inexpensive technique using plastic film canisters. One example is an adapter that allows connecting a 1/4-inch plug from my key into the 1/8-inch (3.5 mm) jack on the radio.
I start by creating a hole for the 1/4-inch jack in the lid of the container starting with an awl or knife, then using a hand ream. Then I puncture the proper size hole in the bottom of the container to allow a wire to pass through. After cutting the wire to the desired length, I place the 1/4-inch jack in a pan vise, solder the wire to the terminals (I do this before mounting the jack to avoid melting the plastic canister).
Knot the wire pigtail near the jack to physically secure it, pass the remaining length of wire through the canister hole and solder a 1/8-inch plug to the end. Finally, mount the 1/4-inch jack on the canister lid using the panel nut and snap the lid onto the canister. Doing this takes less time than it did for me to write it down.
You can vary this technique to produce 8-pin
microphone adapters that let you use a single microphone with radios having differing
pinouts (don't forget to label your adapters). Other possible accessories
include Y adapters and in-line volume controls. Such adapters can also contain components--dropping
resistors, potentiometers, capacitors--you name it.
 Keyer interface in small plastic component case. [Photo by author] |
To construct the keying interface that goes from my computer to my radio, I used the small plastic package that had contained one of the optocouplers used in the circuit. I used a sharp X-Acto knife to cut the D-shaped hole for a 9-pin serial jack. Two small holes on either side of the hole allow mounting/offset bolts to hold the jack in place. The offset bolts then provide a means to connect the serial cable from the computer to the keying adapter. The pins on the jack support my point-to-point wired interface.
I then connected wire to the output of the interface, tied my strain-relief knot and passed the other end of the wire through a small hole on the opposite side of the case. A 1/8-inch plug soldered onto the end of the wire goes to the radio's key jack. After snapping shut the lid of the plastic case, I used a black marker to label my project for future reference. In less than a half-hour, I was up and running in the CQ World Wide DX Contest using my interface and contesting software.
Although I use it with WriteLog,
an interface like this should work with other popular contesting and logging
software, including TR Log
and CT. The optocoupler isolates your
computer's serial port from voltage surges from the radio.
 Empty VHS tape case houses Ten-Tec regenerative receiver kit. [Photo by author] |
 The nibbler is a handy tool to cut rectangular holes in light metal [Photo by author] |
A VCR tape case makes a very inexpensive radio case that easily snaps open to work on the circuit or to replace batteries, then snaps securely shut and even looks good on your bookshelf.
As for tools, a set of sharp knives, round punches and a hand reamer are the only ones you'll usually need to work with soft plastic cases. For harder, more brittle plastic, careful use of drill bits, a heated knife or a Dremel tool work well.
For metal cases--such as those Altoids tins--drill
bits and an inexpensive hand nibbler let you cut round and square holes. If you
have ever been frustrated trying to drill round holes in soft or thin metal, I
have two tricks for you. Placing a piece of scrap wood behind the metal before
drilling into it allows the bit to pierce the metal cleanly, without distorting
it.
 Unibit step drill bit lets you create nice round holes in a variety of materials in a variety of sizes. If you have ever tried to drill a round hole in thin aluminum, you will love this tool! The only better way to make such holes is with much more expensive chassis punches (and you would need one for each size hole.) |
Unfortunately, unless it's cut to size, the wood tends to move. One trick is to fill your tin with water and place it in your freezer until solid. Then, using a center punch to guide the drill bit placement, drill through the metal and ice, which will prevents the metal from distorting. You might also try a unibit--or step bit--instead of a standard twist-drill bit.
Antenna Feed Lines
An ideal antenna feed line for QRPers would be low loss, low cost and easy to use. If you're taking your QRP gear to the field, it also should be small and lightweight. QRPers have six basic types of feed line available, each with its own advantages and drawbacks.
 Lightweight coax can lighten load when backpacking [Cable X-perts] |
*Although I have yet to try it, I received an interesting press release for a new specialized coaxial cable targeted at QRPers in the field. Produced by Cable X-Perts it's touted as "a new line of lightweight cable assemblies for back packing, QRP, vehicle installation, and limited space applications." Its manufacturer says longer lengths weigh less than one pound with connectors attached! Connectors can be snapped and unsnapped for quick installations with a variety of adapters.
Reader Feedback and Author Comments
The AZ ScQRPions have available a new brass paddle keyer kit. It's designed by Jerry Haigwood, W5JH, "to be small and portable but without sacrifice in quality or feel." At $25, you may not want to miss this one.
I received some unexpected e-mails from hams who had recently read my article "Choosing Your Ideal Vanity Call Sign" that I wrote in 2001 before I took over the QRP column. The original article ran on the ARRL Web site, but the most current version is available on my Web site.
A companion spreadsheet you can download helps you to compare the call signs you are contemplating. I think a good call sign can almost have the effect of adding a dB or two to your QRP signal--especially if it is a rare DX call sign!
Editor's note: Anthony Luscre, K8ZT, an ARRL member, lives in Stow, Ohio. He has
worked in the field of medical microbiology for 18 years and is now a
technology and computer coordinator for a local school district. Luscre is an
avid QRP operator having earned DXCC, WAS and WAC using no more that 5 W
output. Readers are invited to contact the author via e-mail, k8zt@arrl.net
or visit his Web
site.
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