VHF cable Charriot you around?

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HG02 said..
Im looking at RG213/U is that the heavy duty cable? would this be a good choice?

I bought it any way its heavy duty ,just have to locate some fittings and solder the ends. Just slides behing the main mast sail track so no movment what so ever.
with two runs of Tycab double insulated 3mm for my nav lights.

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Charriot said..
hi HG
excellent cable for VHF and UHF, very low looses.
3 mm for LED Nav lights is a bit overkill , but nothing wrong to have less resistance.

thanks Charriot just had some spare 3 mm so thought Id use it
just having problems finding fittings to suit the RG213

Already fitted the cable under the mast sail track its the end fittings jaycar dont stock them

Also is there rocket science as to aerial resistance
That is matching up suitable parts

A couple of PL259 is what you need HG:
www.jaycar.com.au/uhf-pl259-plug-suits-rg8u/p/PP0682

Ask for the RG213U fittings at whitworths. They stock them too.
wayne

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Lazzarae said..

HG02 said..
............ its the end fittings jaycar dont stock them

I got mine there & I'm running RG213 from mast to VHF radio. I put a joiner at the base of the mast.

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Lazzarae said..

HG02 said..
............ its the end fittings jaycar dont stock them

I got mine there & I'm running RG213 from mast to VHF radio. I put a joiner at the base of the mast.

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Lazzarae said..

HG02 said..
............ its the end fittings jaycar dont stock them

I got mine there & I'm running RG213 from mast to VHF radio. I put a joiner at the base of the mast.

There is one step of rocket science regarding the antenna ..... RG213 is indeed OK for the connection. You might have heard the reference to 50 ohm regarding your radio and the cable. It also applied to the antenna.

Basically the radio needs to be 50 ohm to drive the 50 ohm cable and the antenna needs to be 50 ohm to work with the cable. (Work decently that is).

This is the rocket science bit .... the antenna needs to be the right length for the 156MHz marine VHF radio signal. A common antenna size is "1/4 wave". Yours might be. To work out the length of a "1/4" wave use formula length(metres)=74.5/f. Where f is frequency. So a "1/4" wave 156MHz marine antenna needs to be 74.5/156 metres long, ie 0.477m.

if the antenna is too long (physically) or too short (physically) it wont be 50 ohms it might be 65 or 140 or whatever. Because the exact "ohms" of the antenna is unknown and a bit unpredictable theres a tool called "SWR meter" than radio hams and professional radio people use to trim the antenna to the right size exactly. (Called tuning). If you could borrow beg or steal one of those and a person who can use it you can use it to get your antenna working great. We are talking losing 90% of your signal if the antenna is wrongly tuned.

I found this video on Youtube of tuning a CB radio antenna. VHF for boats is the same idea.