Note
The HD-1481 replaced the SA-1480, but for a brief time these two products were on the market together.
Like the SA-1480, the HD-1481 is a device for the remote switching of antennas sharing a common feedline to the shack. In the SA-1480, switching signals were sent via an eight wire cable—a system that made it all but bullet proof. The HD-1481 routes switching signals via the RF coaxial cable. While this is convenient insofar as no addition cable is required, it is far more susceptible to damage from lightning, static, and SWR.
Heath cautions that an SWR higher than about 3:1 (even momentarily) can damage the control unit. Switching is accomplished with a pair of relays and a polarity reversing scheme using four silicon diodes, two in the control box and two more in the remote unit.
The HD-1481 can select up to four antennas. The switch will handle up to 2000 watts PEP.
Note: when the power switch on the control unit is off, the antenna connected to coaxial connector J1 (antenna number 1 on the control box) is automatically selected.
Caution: Do not switch antennas while RF power is being applied to the remote coax switch.
Frequency range: 1.8 to 54 MHz
Loss at 54 MHz: < 0.2 db
VSWR: 1.15:1 or less below 30 MHz
Impedance: 50 to 75Ω
Power handling capacity: 2000 watts PEP
Temperature range: –40 F to +177 F
Number of ports: 4
Power requirements: 120 VAC, 7.5 watts
Size/Weight:
control unit 5.5 wide x 2.5 high x 7 deep; 2 lbs
remote: 7.5 high x 8.5 wide x 4.5 high; 1.5 lbs
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.