Old antenna installation? Might be time to replace!

[vitalspark]

I had my doubts about my boat's existing VHF antenna set up with its original 10 year old RG58 coax cable and a 300mm or so short whip antenna.

I checked the output power at the antenna which gave only 11 watts (for 20 watts input at the VHF transmitter) and an SWR of 4.25. Definitely not good, and I believe potentially damaging to my radio.

I've now swapped the RG58 coax for RG213 and installed a half wavelength whip (about 900mm long). The difference is significant. Output power has risen to around 17 watts and SWR has dropped to 1.3. Result It has to be said though that RG213 is not the most flexible cable to work with.

Simplifying the above figures, before the upgrade my total power loss was 45% and this has now dropped to around 15%.

Maybe not such a big deal if you only boat where there are plenty of other vessels around but they're a bit thin on the ground in my neck of the woods.

Now just have to install AIS to stop the local speedsters from T-boning me! You know who you are

[Phil and Jane]

They are pretty good figures. I supply and fit this stuff in the course of my work. On some boats you’ll never get above 15 or 16 watts just because of the loss on the cable.

My wife and I also boat in the same waters as you in our rib for four weeks of the year so having a top-notch transmission system is vital.

At our sailing club I fitted all five ribs (that have VHF sets) with new Antennas new cable, connectors and tested them all with a meter. The sets in theory should all achieve 25 watts but the highest output is 22 watts with the rest ranging down to 12 watts.
What I do at the sailing club is leave a good length of spare cable coiled in the console then each spring take off the PL259 connector on the A frame end, renew it and feed the cable through to snip off the last 40mm then put on the new connector. Even using amalgamating tape doesn’t stop the corrosion at that end, gradually seeping in throughout the year.

[vitalspark]

I've enough spare at each end to replace the plugs 2 or 3 times so I'll bear that in mind. Gold plugs and taped up too. The RG213 coax is pretty awkward to solder in the confines of the console but doable.

Maybe see you around if you're up here. I'm based out of Miavaig.

[Pete7]

RG 213 is really good but as mentioned difficult to bend or solder, not that you should bend coax tightly. For short runs say on a rib, RG8 would be sufficient. Indeed the losses even with a mast aren't significant. We have a 20m run

By far the worst are the cheap kits in the chandlers with RG58 and poor connectors. Please don't buy these. Good quality antennas and coax won't give you any greater range, but the quality of the transmission at range will be improved so you can be heard more clearly, your choice.

Sadly Salty John who supplied Metz antenna's and good quality coax has retired. If anyone knows of another good UK supplier for coax it would be worth naming them.

Pete

[vitalspark]

Originally Posted by Pete7

Sadly Salty John who supplied Metz antenna's and good quality coax has retired. If anyone knows of another good UK supplier for coax it would be worth naming them.

Pete

For the gold plugs and 9m RG213 coax, I used:

https://moonrakeronline.com

Definitely no complaints with the quality of products or service

[GuyC]

Originally Posted by Pete7

Sadly Salty John who supplied Metz antenna's and good quality coax has retired. If anyone knows of another good UK supplier for coax it would be worth naming them.

Was there not some chap on here that took on the supply of Metz stuff - Phil and Jane.

Apologies - I see they've already responded.

If you need something bringing up at Easter, please drop me a PM.

[Pete7]

We are okay for a while as I bought 20m of RG8x off Salty John and fitted a new Metz antenna at the same time.

Pete

[GuyC]

Originally Posted by Pete7

We are okay for a while as I bought 20m of RG8x off Salty John and fitted a new Metz antenna at the same time.

Pete

Sorry Pete - it was aimed at vitalspark.