South Midlands Communications Group

Radiating Masts

SMC carry a stock range of components which enables a simple tubular steel or tubular aluminium mast to be converted to a radiating mast for the 200kHz to 28MHz MF and HF bands. (Spot frequency or tunable with appropriate antenna matching unit).

Any of the masts described in our data sheets PA2 or TS series may be converted making a very versatile range of omni directional antennas from 6-30 metres in height, in 2", 3" or 31/2" diameters. For the lower frequencies (or where mast height is a consideration) a capacity hat arrangement may be included in the design for more efficient operation.

The SMC PA2 series of portable aluminium masts are particularly suited to transportable, portable or permanent use with the appropriate fittings, and the TS series masts are normally for permanent Installation.

Specifications

Frequency range 200kHz - 28MHz to design frequency or capacity
Bandwidth Normally tuneable by antenna matching unit
Polarisation Vertical
Radiator pattern H plane Omni-directional
Input impedance Normally in the range 2 - 10 ohm but 50 ohm for 1/4 wave height
Power handling Up to 30kw

 

Height 6 - 30 metres, 3 " or 3112 " diameter
Stays HT galvanised steel wire or to customers requirements, to 120' or 90' in plan
Stay insert insulators Ceramic loop stay or egg type and number to design height and power rating
Base insulator 35/65kv wet/dry flashover fitted lighting spark gap arrestor, dependent upon power rating
Capacity hat Normally included in stays or can be supplied separately in cadmium copper
Feed point Stainless steel
All other fittings Galvanised steel
Capacity 450 - 1500 PFD dependant upon height and capacity hat design
Input impedance 2 - 10 ohm, 50 ohm for 1/4 wave height

 

Height 4 - 18 rnetres
Mast diameter 5Omm nominal
Stays Normally 6mm diameter, pre-stretched polyester or galvanised steel with insulator inserts for permanent sites. Also available in Parafil, Keviar or Philistran
Base insulator 15/30kv wet/dry flashover ceramic fitted lighting spark gap arrestor
Capacity hat Included in top stay, hard drawn copper elements
   bordered to mast sections
HF feed point Stainless steel
Capacity 120 - 420 PFD
Input impedance 2 - 10 ohm, 50 ohm for 114 wave height

 

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