The ECS/VHFH mobile antenna is a ground independent, half wave, helical, end fed design ideally suited for use where no metal groundplane exists, or where the groundplane is not of sufficient area to allow a normal quarter wave whip to be mounted.
Factory tuned for 151.3 MHz with 2.1 dBi gain and standing approximately 360 mm tall, this highly flexible helical whip is just one-third the size of a stainless steel whip for the same frequency.
The delrin, copper, stainless steel and brass construction provides an extremely robust and durable antenna capable of surviving the harshest of conditions and treatment. 4 metres of RG58 stranded cable exits through the antenna base. An SMA male connector is fitted to the cable.
Mounting is to any bracket with a 10 mm hole using the stainless steel nut and washer on the base ferrule. Typical mounting positions are to a truck mirror, vehicle gutter, guard or boot.
It is important to have the antenna as far away from other antennas or metallic objects as possible to avoid distortion of the omnidirectional pattern and interference. At least 350 mm side clearance is desireable, preferably more. The antenna must be vertical for best performance, not mounted at an angle. Route the cable carefully via the shortest possible route. Ensure that the cable is not stretched excessively and there are no sharp kinks. Use cable ties, but do not pull so tight as to crush the cable. A damaged feeder cable is a cause of high VSWR and reduced performance.