"Sinclair" Style Wide Band Folded Dipole Antennas

Here are the intimate details on the construction of wideband folded dipole VHF and UHF antenna arrays of a style popularized in Canada by Sinclair Radio Labs. The design first originated in England in the late 40's and was first used by Sinclair in the 50's for their x10 series antenna arrays. They are still being manufactured by Sinclair and are the commercial antenna of choice in Canada. At least one (Comprod in Quebec) and possibly more competing manufacturers have copied the design.

This antenna style features:

• Wide Band coverage. The match is typlically better than 1.5:1 SWR over a 20% bandwidth (eg 138-174 MHz or 406-512 MHz). This allows many radio systems to be multicoupled on the same antenna.

• Totally enclosed feedline cable within the dipole. This makes the antenna more resistant to environmental stresses.

• Totally grounded design. This eliminates static built up on the elements and greatly reduces potential lightning damage.

VHF High Band Folded Dipole Design Details

Sinclair Antenna Models Based on This Design