How do I make an emergency vhf aerial?

[Guest]

That's it - I know you need coax cable and copper tube, but the dimensions.........?
Anybody know?

Brendan

 

[Guest]

First take 1.65 metres of thick wire, copper tube or any other good conductor stiff enough to hold its shape in a straight line.

Cut it in half.

Connect one half to the inner of the coax from the transceiver, the other half to the outer.

This will give you a half wave dipole fed in the centre

Hoist it as high as possible so that it hangs down vertically with the half connected to the inner of the coax at the top. And away you go.

If you are short of coax, connect twisted twin lead between the antenna and the transceiver - not ideal but will work at a pinch.

If I could draw a picture it would be easier but I hope you get the idea.

 

[Guest]

There was an article in PBO about six months agao which described exactly this.

 

[Guest]

Re: There is an easier way.

Take a length of coax cable. Connect one end to the VHF set through a suitable connector. At the other end of the coax strip the outer plastic cover off for a length of 825mm. Push the mesh from the end back towards the 825mm point, This will expand its diameter.
pick the inner through the mesh at the 825mm piont. When all of the insulated centre core is extracted fully from the mesh you effectively have a dipole antenna, with the feed point at the 825mm point. Stretch out the mesh and check that both the external insulated core are both 825mm long, cut down to length if necessary and tape the split point together. Connect a tiewrap to both ends and hoist the antenna vertical, clear if the mast, with the tip of the insulated inner to the top and the free end of the braid to the bottom. It will perform better if the coax is led horizontal for a minimum distance of 825mm. It sounds quite long winded but all that is required is a length of coax, two tiewraps and a haliard to hoist it with.

 

[Guest]

Re: There is an easier way.

Thanks, all.

Brendan

 

[Guest]

Re: There is an easier way.

the easest way is to pay about £20 to a chandler and what you get is a damn site easier to stow!....Its about the size if a parachute flare!