G4PVB Amateur Radio St Albans
Sky Hook Antenna: Every Amateur Radio enthusiast should equip themselves with the resources to operate their station in an emergency. Here's a VE3VDC - L D BLAKE inspired idea for a quick build vertical sky hook antenna (tree, loft or curtain rail near window etc.) that can be constructed with just a length of RG58C/U coax.
143 ÷ frequency in MHz gives dimension in metres for both legs extended. For a 2 m antenna (145 MHz mid band) 143 ÷ 145 = 0·986 ÷ 2 means you trim the inner to 0·49 m and the folded back coax shield also to 0·49 m which doubles as a choke balun. I've only used it at 5 Watts maximum.
Coil for easy transportation in your pocket. Folding the coax shield back looks neat & tidy on the diagram I found it near impossible so use a small screwdriver blade to tease a hole in the shield where the two legs part and ease the inner through it. Lay the shield along the cable sheath and wrap it up in aluminium baking foil then wrap it all up again in white insulating tape.
Use a pigtail lead to ease the strain where the feeder connects to the handie. Inner conductor crimped to M6 4 mm terminal ring (yellow shroud) painted with white Tippex. Hanging from a curtain rail, with kite string, behind a white net curtain it is almost invisible from outside so optimum stealthy. 50 Ω match across the band atrocious. If you require impeccable SWR this antenna's not for you. Something primitive to keep in your Go Bag. One day it just might save your life.
Contacted Mark M0WZD Watford: "I've never heard of that type before. You're doing amazingly well with that antenna hanging from a curtain rail and just a handie coming from St Albans... I give you strength five." 73, G4PVB/Bob p.s. There are three types of antenna: The one you used to have, the one you have now and the one you're going to have in the future. The design and image are public domain so feel free to copy them and give them out as you wish.
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