Fishing rod for mobile whip

[VK3XL]

here are a few pix of my version of the center loaded vertical

20 meter loading coil installed

1378377852072.jpg (11.44 KiB) Viewed 1074 times

The antenna is 2.5meters long overall with the 20 meter coil installed.

I did try an open coil for 80 meters with a alligator clip to short out turns so that it could be multibanded, but found there was difficulty getting it to work on 40.

good luck with the project

[VK1UU]

Very tidy coils Mike

[VK3XL]

I used the Mobile.exe program to determine the ideal diameter of coil using a few fixed inputs like wire diameter and spacing. I used either 1mm or 1.25mm wire and spacing (or pitch) of 10 turns per inch which equals 2.5mm spacing.
Then searched around to find plasic tube or in the case of the 20 mm coil solid material close to the required diamener. Then back to the program to re calculate the coils with the actual diameter of the coil form.

The coils have a fibre glass rod thru the cernter for strength, but even so I dont use the 80 meter coil while mobile, there is just too much wind resistance.

Good luck with the build.

[VK1UU]

I am mostly interested in 20m mobile as a starting point so am not too fussed about building interchanegeable coils.

This makes construction a whole lot easier because I don't need the threaded ends on each coils. I will just use a single fibreglass rod (1 piece) and then mount the coil around it in the centre.

If i get interested in other bands, it would almost be easier to make an entire seperate antenna rather than making interchangeable coils.

We'll see