ARES Radio Considerations
During public service events or emergencies you could easily need to connect your radio to someone else’s power supply or someone else may need to connect their radio to your power supply. To facilitate this inter connectivity a standard for power connectors is necessary.
The recommended connector is the Anderson Powerpole 30A (APP-30A). The ARRL approved the change to the APP-30A in June of 2000.
This connector is gender non specific but when assembled per recommendation cannot have the positive and negative polarity reversed. The recommended configuration is shown here. This connector is rated at 30 amps and is recommended for higher power applications but will work very nicely for lower power situations as well.
In a size comparison between the previous recommended RS/Molex and APP-30A there is about .020″ difference between the two connectors with the APP-30A being the smaller. Or more simply, they are virtually the same size but due to the difference in appearance, the APP-30A looks smaller than .020″ would indicate.
The Anderson Powerpole 30A connector is not as readily available as the Molex connector. Thus your group may want to consider purchasing bulk quantities for its members. This will also reduce the cost per connector. One supplier charges $1.00 per connector, plus shipping, in quantities of ten but also charges seventy five cents per connector, delivered in quantities of 200.
The manufacturer (with a list of – distributors – ) is at http://www.andersonpower.com/distributors/US/
(I have had good luck with www.powerwerx.com – W0IPL)
It is recommended that you equip your radios, power supplies and batteries with these connectors. Since not everyone will use these connectors it would be very helpful for you make adaptor cords (patch cords) made with these connectors and other types. Connections you may want to have available are:
- large auto-type battery clips
- cigarette lighter plugs
- any other connectors that your group has in abundance.
Knowing your Equipment
Nothing is more embarrassing during an event than to have to ask someone else to show you how to operate your own equipment. To avoid that situation you should:
- Make sure YOU can set up the radio on any frequency/mode the radio will operate on.
- Insure you know how to set, turn on and turn off the sub audible tone encoder for VHF/UHF.
- For VHF/UHF radios – make sure you can operate “reverse pair” if the radio is not “rock bound”, in case the repeater IS down and someone else is “rock bound” or doesn’t know how to fully operate their radio.
- Does your radio have the ability to lock on or out a frequency? Insure you know how to activate or deactivate that function.
- Try all configurations of power source, transceiver, antenna, fuses, and patch cords you have.
Make a card with tune-up procedures and operating precautions.
- Photocopy key pages from the operating manual and place in an envelope attached to each radio. Include enough information so another ham can use your radios without further instructions.
- Label pre-programmed memory channels by name and frequency. Preferably on the radio or in a plastic pouch attached to the radio.
When you maintain equipment in standby or “on the shelf” waiting for a callout the equipment may not be used for months. It’s easy to overlook routine maintenance you should perform regularly. You should keep in mind:
- NiCd batteries self discharge at approximately one percent (1%) of their capacity per day. If you leave them on the shelf for over three months they can go to zero charge or be in such a poor state that individual cells in the battery pack may reverse polarity, thereby ruining the pack. The best way to avoid problems is to use EVERY battery pack you have every month. One complete discharge/charge cycle WILL keep the battery pack healthy well beyond “normal” life span.
- “Button” cells used for memory backup in programmable radios can go dead in three to five years. Replace them when it’s convenient for you, not when it’s too late.
- Connectors, switches, and potentiometers can develop corrosion from disuse, especially if dissimilar metals are present. Operate, unplug/replug, and clean them regularly.
- Pre-installed antennas at served agency locations and vehicles can be damaged and detuned. Check them monthly for changes and physical damage.
- Printer ribbons and ink cartridges dry out from disuse. Develop a stock rotation plan so spares don’t get too old.
- Dry cell batteries, flares, first aid supplies, fuels, food and water all have shelf lives. Develop a stock rotation plan for the ones you have.
Portable Antennas and Generators
Of all possible portable antennas, the type that will be easiest to transport, store and put up is the wire antenna. These antennas can be made in various configurations based on the frequency range to be covered. For VHF/UHF the “J-pole” antenna, made from 300 ohm TV type twin lead, will produce gain over a quarter wave yet store in a very small space. For HF the mono band or multi-band dipole will be very effective.
- One of the most effective “local coverage” H.F. Antennas is the NVIS or Near Vertical Incident SkyWave. This is a half wave dipole mounted less than 1/8 wave (at the highest operating frequency) above the ground. Excellent results are obtained with the antenna at ten to fifteen feet above the ground. This antenna is most effective on 40 and 75 Meters.
- When you put up H.F. antennas, you must consider the potential impact of the antenna on people and equipment in the area. Or more simply you must have sufficient poles, rope, anchor weights, boundary marking tape and such to put the antenna far enough up to not be a hazard to people or equipment in the area.
- An effective NVIS antenna for 40 and 75 meters can be made from a 1:1 balun and two lengths of wire (62′ for 75 and 34′ for 40) per side. Add to that a four inch separator at the ends of the 40 meter elements an end insulator at the ends of the 75 meter elements and you are complete.
- Another configuration that shows promise is to take two mono-band mobile antennas and mount them base to base with one being the driven element and the other being the ground side. Care must be exercised in tuning this configuration that the elements remain the same length. In testing this configuration we found that this antenna delivered a signal from one to two “S” units less than the full sized dipole. The ones I used are available at HRO. Antennas are Ironhorse IHF75′s and IHF40′s (two each) and the Ironhorse IH-DAK-AD adapter. Total cost (tax and all) for four antennas and the mounting bracket is $117.96.
- Many times you will be in situations where the 1/4 wave antenna will not be as effective as necessary. During those times a three to five element Yagi antenna will be very helpful.
- Keep the antenna at least one full wave (at the operating frequency) away from conducting surfaces if at all possible.
- Keep coax runs as short as possible.
- Use the lowest loss coax you can.
There are several safety considerations to keep in mind when using portable generators. Some of the primary are:
- Insure you have the best possible ground line hooked up to the generator ground post BEFORE you start the generator.
- Check the engine oil level before you start the generator and each time you need to refuel.
- Refuel the generator when it is cool if at all possible.
- Store the extra fuel away from the generator.
- Remember, even the smallest generator has enough voltage-current to kill you. Take extreme caution with this equipment.
- Use only three wire extension cords to bring power to the operating area.
- Insure the extension cord has the required capacity for the projected load. Do NOT put multiple cords together to get the length you need (the wire gage used in virtually all extension cords is the minimum allowable for that length/load – thus if you connect two fifty foot cords to get 100 feet, they will have less capacity than a 100 foot cord).