24CM WALK-ABOUT HAT AERIAL

By G8MNY

This is a modified skeleton Alford slot a antenna with gain of 6dB or so, but still small enough to be mounted on a hat. An unusual feature, is the "short circuit ends" of the slot, that have been neatly folded inside the end loops to keep the size down.

Parts:- 2
1.4 M of 1.5 mm Copper Wire
1 M of Solder.
2 M of UR43 Coax.
1 UR43 coax plug.
1 Drinks Bottle (Ray dome)
.5"x2"dia Expanded Polystyrene
1 Hard Hat
12" of Tin Foil (if no tin hat)
1 idiot to wear it!

The aerial is simple to construct, even if fiddly with the small Balun & matching stubs. Tuning up should just be a matter of bend adjustments to alter the gap.

Line the hat with tin foil, to reduce any chance of becoming a HOT HEAD. Cut a drinks bottle with suitable tabs to fix onto thy hat, to form raydome. This is required as doorways tend to completely wipe out the aerial when one doesn't duck!

Although I had had lots of comments at to what it looks like, (even from police at shows) the performance of this aerial has been very good. From low lying ground level with 1 watt of Colour ATV & sound pictures have been Rx at P2 over 3 miles.

From RSGB VHF Convention at Sandown Race course, in the building on the 1st floor, GB3HV at High Wycombe gave a P3 Colour report over a distance of 25 Miles. Pictures from it were being Rx by the HCATV group on the BATC stand at the rally.

73 de John G8MNY

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