Courtesy Jim HadlockK7WA operating portable from the Pacific shore in British Columbia.
Planning is important for portable operation to be a success. If you are going to be vehicle-based, you can haul considerably more gear. Will your power source be a battery, the vehicle battery, commercial AC, AC from an inverter connected to a battery, or an AC generator? How about operating tables or tent?
Fabric camp chairs can be awfully uncomfortable for operating a radio on a table — try them out. Before setting out, set up in your backyard and take the station for a spin so you can see what works and what doesn’t. The author operated from Emerald Island, North Carolina during a July contest and managed to bring a fan along, too!
Operating from a campground on Emerald Island, NC.If you’re going to be hauling your gear, treat it like a backpacking trip. Start by assigning yourself a total weight budget. Get creative with antennas and accessories to maximize your options for the radio and power. Some amazingly small and lightweight radios are available. These radios aren’t always the easiest to operate, however.
If you’re just starting, you may want to pass up a minimal radio in favor of one that’s easier to operate and has more features until you know more about operating. When you have more experience, you’ll know what features you can do without. Practice setting up and using the gear at home so you’re not trying to learn how it works while swatting mosquitos!
When you are just starting, concentrate on one or two bands. On HF, the 14, 17, and 21 MHz bands are favorites with low-power and portable operators. These bands are active for a large portion of the day, and the antennas are small enough to carry easily. If you like evening operating, 7 MHz and 10 MHz are best. Picking one band from each group is a good beginning strategy.
On VHF, 50 MHz and 144 MHz operation from high spots is common. Plenty of operators are available, particularly during weekend contests, and those bands often feature interesting propagation.
Portable antennas for ham radios
At VHF and UHF, portable antennas are very small, lightweight, and easy to pack and carry. Even for the 6 meter band, a three-element Yagi or 2-element quad can be quickly disassembled and carried in a gym bag. On higher-frequency bands, longer, higher-gain antennas are practical, as well. Two or three sections of a painter pole or telescoping tubing are sufficient to hold the antenna with a minimum of guying. Three light-duty ropes and some tent pegs are sufficient to hold up most antennas and masts.At HF, however, the larger antennas are more difficult to deal with. You can try a lightweight wire antenna if you can find a way to support it well above the ground. Trees or lightweight fiberglass masts are your best choices. Vertical antennas need a sturdy base, often a set of guy ropes, and usually a set of wires to make a ground screen.
A more convenient choice may be the portable antennas designed exactly for this type of operation. The Buddipole designs are well-known and easy to set up. Each of the horizontal sections is adjustable so you can create a dipole for the 40 through 2 meters bands. Turned vertically, the TW vertical dipole can be adjusted to cover several bands. Both the Buddipole and TW designs are supported by a tripod which makes them easy to support, even in the wind.
Small, portable antennas are a compromise, trading performance for convenience. If you can put up a higher, longer antenna, do so. You’ll find the performance to be much better.
Portable power for ham radios
In the first image above, K7WA is using a lead-acid storage battery to power his 100-watt transceiver. This certainly enables him to put out a strong signal but it’s not a practical choice for carry-able stations! What other options are out there?- Lead-acid storage: Large and heavy but these batteries can supply a lot of power. When fully charged, they can run a QRP transceiver for an entire weekend.
- Lead-acid gel-cells: Available in a wide range of sizes, these are still heavy but smaller than car or tractor batteries; can be trickle-charged.
- Li-ion: Multi-cell battery packs are fairly lightweight and can be charged quickly; good for QRP operations; must have a Li-ion charger.
- Li-iron-phosphate (LFP): Better performance than Li-ion and constant voltage output, but expensive; must have an LFP charger.
- Solar panels: Bulky at the size needed to run a radio directly; can be combined with a battery pack and charger; combination panel-charger-battery units available.
When you’re not using an AC-powered supply, you need to use equipment that can operate from a wide range of voltages. Batteries discharge or a cloud can shade a solar panel. Most 100-watt transceivers need to be supplied with 13.8 V plus-or-minus a couple of volts. Low-power QRP radios are more tolerant but you still need to keep the input voltage above the specified minimum. When power supply voltage drops to the minimum, the radio may begin operating erratically or transmit a poor-quality signal.
Portable operations of ham radios on Field Day
The annual ARRL Field Day is one of ham radio’s largest events. Held on the fourth full weekend of June, more than 50,000 hams from around North America are involved in some years. Clubs, informal groups, and individuals are all involved in this annual exercise.
Members of the St Charles Amateur Radio Club (KOØA) during the Field Day night shift.If you’re going to be operating with more than one radio being active at a time, take along some band-pass filters to keep Radio A from interfering with Radio B. Suffering through local interference all weekend is stressful and makes it darned hard to have a good time. Try to keep the antennas for each radio far apart and don’t point them at each other.
Whether just using 100-watt transceivers or adding amplifiers, having “RF in the shack” can be a real problem. Make sure you bring some ferrite RFI suppressors, follow good cabling practices, and pay attention to bonding of the equipment and computer.
Assuming you’re using AC power, don’t scrimp on AC safety. Be sure the generator is protected by a GFCI (Ground-fault Circuit Interrupter) outlet or build your own (kits for outdoor GFCI outlets are available in the electrical department of home improvement stores). Check the ground and neutral wiring of extension cords and power strips. Even without rain, equipment may still get damp, so be sure you have good grounds at the station and at the generator.
Because Field Day tends to attract larger antennas, don’t get sloppy about putting them up. “Walking up” a tower or mast with an HF antenna attached can be perilous — keep the center of gravity between the lifters and the base of the tower, which should be securely held down. Don’t let anyone climb a poorly guyed tower! Watch out for power lines and other hazards — remember that you’re not familiar with the area.
Protect yourself and visitors by clearly marking feed lines and power cables, antenna wires, guy wires and stakes, fuel cans, batteries, and other safety hazards. Assign one member of the team to be a “safety captain.” Keep vehicles away from the stations and antenna systems. And watch the weather — rain, wind, and lightning can appear quickly.