HT BACKUP POWER AND ACCESSORY UTILITY BOX
W4FMD
The composite utility box in the attached photos provides backup power for W4FMD’s dual-band HT with two 7AH sealed lead acid batteries. These batteries can power an HT directly, or can be used with one of the MAHA or similar chargers to recharge an HT’s battery packs. This is sufficient power to use a 5 watt HT for several days without access to AC power. Since it is unlikely that both batteries will fail at the same time, this insures there should be a minimum of one portable 7AH source available for emergency service.
One battery at a time can be used through a marine quality accessory plug located on the box lid. The cigarette lighter plug and receptacle have water resistant seals that permit safe operation in a wet environment. The batteries are in separate compartments formed by adding small wood baffles that are screwed to the sides of the box. With this modification, and the top closed, the batteries cannot shift position.
The batteries are recharged using a multi-stage 1.5 amp charger. The charger operates on 110 VAC, but can work with a small inverter from another 12 VDC source. This charger easily recharges each battery overnight. When not regularly used, the batteries are recharged once a month.
In addition to space for the batteries, the box has a separate compartment that is used to carry the HT’s external microphone, earphones, spare fuses, several feet of coax cable, and various tnc/bnc/N/PL259 adapters for connection to external antennas. Supplemental antennas (larger single band antennas for use when a simple rubber duck is insufficient for communications) are stored between the two battery compartments on top of the center baffle.
Not shown, but also carried in the box are the operating manuals for W4FMD’s HT and dual-band mobile transceiver. The manuals make it easy to use some of the less frequently used functions of both radios whenever necessary (e.g., cross-band repeater functions, tone access and signaling, non-standard repeater offsets, etc.).
Similar and larger utility boxes and connectors are currently available from marine supply stores such as West Marine and Boat U.S. They have stores in the immediate Washington D.C. area in Alexandria, Woodbridge and Annapolis. The equipment can also be ordered from them online. (The approximate dimensions of the box in the photos is 12x6x6.)
