Top Band vertical

G3LIQ / G4ERZ Top Band Vertical 50Ohm Coax feed. Info by G4SEF (Corrected by G4XFC)

The original publication by G4SEF had a mistake in wire size quoting 1.2 AWG which is over 7mm instead of 1.2mm magnetic wire, which fits into the length of the designed loading coil.

For practical and economical purposes I recalculated the loading coil with 16 AWG (1.25mm) magnetic wire. Calculation on the original publication meant that over 52mtrs of wire was needed for the loading coil which meant you had to purchase a 1Kg roll to wind the coil as their is approx 92mtrs of wire to the Kg (40mtrs of unused 16AWG wire in the shack).

Calculations based on the original loading coil with a length of 22″ and dia of 1.32″ using 1.2mm wire produced an inductance of 373 micro henry’s with 446 turns which meant a length of wire 52mtrs long. I calculated the loading coil based on using .5KG of (approx 45mtrs of 1,25mm wire) which is 400 turns on the same diameter and the length of the coil is 500mm with a calculated inductance of 353 micro henry’s.

Doing an internet search, I discovered a supplier in Ripon that sells .5kg reels of 1.25mm magnetic wire for £9.46 plus delivery and discounts for bulk buys if a group get together to buy it at the same time. www.wires.co.uk

The original publication can be found here with more information on the short vertical.