If you want to buy one off the shelf rather than rolling your own try
a search on "Watson WSJ-430". Here's one supplier:

http://www.wsplc.com/acatalog/Watson_VHF_UHF_Antennas.html

As for connecting the coax to the antenna, this page has a helpful diagram:

http://www.hamuniverse.com/slimjim.html

No, it's not a short circuit due to the magic of RF weirdness.

Cheers,
Zik VK3MHZ

On 4/14/07, Jinx <joecolquitt@clear.net.nz> wrote:
> I'm going to try the Slim Jim method (pipe or 300ohm), suggested
> by the list a little while ago, to see if it extends the range of a 433MHz
> data transmitter. Present range is about 100m+ with a 1/2 wave
> heavy-gauge copper wire
>
> http://www.hamuniverse.com/slimjim.html
>
> http://www.hamuniverse.com/2meter300ohmslimjim.html
>
> On those pages it shows both conductors of coaxial connecting to the
> Slim Jim. I understand that the core would be connected to the aerial,
> but where does the braid fit in ?
>
> The transmitter I use has an antenna output, which would be the core
> of the coax. Does the braid connect to the transmitter ground or what ?
> It seems to me that would just short the transmitter output. Do the
> radios this is intended for differ to what I'm thinking of ?
>
> 433MHz is about 69cm. Any suggestions re comparison to 2m ?
>
> TIA
>
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