DIAMOND SD-330 HF Mobile antenna 3-30 MHz
The Diamond SD-330 is a motor driven mobile antenna for shortwave, from 3 to 30MHz (Screwdriver Antenna). Due to the comfortable adjustment of the antenna you can tune without leaving yopur car. With the supplied 120cm radiator the antenna has a total length from 170cm (3.5MHz) to 185cm (@30MHz). With the optional radiator OPE-750 (77cm) the antenna has a length from 130 to 145cm. With this short radiator operation is possible from 7 to 52MHz.
The SD-330 has a bad PL connector and can be installed on any solid PL mount, for example our heavy PL base 20029, or the Diamond trunk lid clamp K-400 th cable set. With a parked car (not while driving) a smaller PL magnet base can be used as well, with the huge triple magnet base operation may be possible even while driving. As any mobile antenna the SD-330 requires the body of the car as counterpoise. If the grounding is not sufficient (especially on the low bands 80 and 40m) an additional magnet mat MAT-50 can help. If the antenna is used at home a suitable counterpoise system must be built with wires.
The SD-330 antenna is tuned with a supplied Up/Down control inside the car. The supply voltage (12V) is taken from the cigar lighter. The control cable between Up/Down control and antenna is 5m long. To change frequency you first tune the antenna to maximum noise on the receiver, then start transmitting with low power (10W) and tune for best SWR. With a goood counterpoise an SWR equal or better than 2:1 is possible. Tuning takes max. 50 seconds from 3 to 30MHz or 20 seconds from 7 to 30MHz. max power load 200W, weight 1.1kg.