VHF Radio aerial position - impact on effective distance

[KenMcCulloch]

Salty John has offered me a great price on one of these

http://www.saltyjohn.co.uk/metzmantavhfantennaaerial.htm

Dylan

PS - does wave height make any difference - perhaps you should add it

3m is about right I reckon

We put one of John's antennae up our mast when we refitted a year ago. It's about 14m above the waterline. In the great glen we could hear the lock operators' handhelds from 30miles away in some cases. Excellent piece of equipment.

 

[dylanwinter]

Salty John, who knows a fair bit about aerials said the following

"Antenna height versus range. Communicating with a coastguard station or a ship with antennas at 100′ above sea level your theoretical range is 16 nm for an antenna 10′ above sea level and 20 nm if you put it at 40′ above sea level.
The higher the better is the way to go, all other things being equal, but practicalities and cost can effect your decision so it’s important to know what you are losing or gaining, in this case about 4 nm range."

One of the advantages of using the gantry is that should we get dismasted then I will still have an aerial

http://www.saltyjohn.co.uk/metzmantavhfantennaaerial.htm

and dismasting is probably quite high up my list of possible mishaps

darn it is hard to balance risks

if you overdo the risk avoidance then you end up never going to sea

D

 

[LittleSister]

darn it is hard to balance risks

if you overdo the risk avoidance then you end up never going to sea

D

Probably the biggest risk is a lot of swearing trying to get cables in (or out) of the mast!

As others have said, the theoretical distance in open sea is less of an issue than getting a signal through when you are screened by headlands, islands, etc., and boats and other 'clutter' when you are in/near harbour.

 

[Pete7]

Dylan, which ever position you choose, don't skimp on the cable. It could be the difference between being clearly heard at maximum range or just a load of noise. Salty john does a nice line in RG8x cables and I have a 20m length to fit if the wind ever stops blowing and I have enough nerve to clime the mast again.

Pete

 

[KellysEye]

There was a significant noise but Tenerife Radio was good readable. So the 25 Watt of VHF power are suficiant for a distance of 130 miles.

Coast stations have much more powerful radios than yachts. We found on a good day our VHF radio was good for 25 miles if there was a clear line of site.

 

[chinita]

I have a Metz supplied by salty john. Mounted on my pushpit as I intend going through the French canals with the mast down.

Connected to my classic danish sailor compact with a proper speaker and telephone handset it is the dogs bollax.

 

[rob2]

I keep hearing Frenchmen in the Solent.

I've seen a lot of Frenchmen in the Solent - but my eyesight is carp!

Rob.