When I fitted a new antenna, I could easily pick up signals from ports that were out of line of sight 10 miles away. Out at sea I’ve not been out of range of the Coastguards station which has an antenna high up. Signals from other boats are only limited by their antenna’s height above water for line of sight.

Are you planning an adventure or having problems?

 

Thanks for your reply,, it was just that I call s good friend 2 miles away and we struggle to speak , I have 3 metre antennas which must must in total 14ft up , I guess it must be an issue the other end possibly.

 

1. Have you checked the antenna connections?
2. Is your antenna vertical, if it's raked back in the "Boy Racer" position the range will be greatly reduced.

 

Also make sure you transmit at 25W and not 1W.

 

Hey Paul,
I've never had an issue picking you up between 3mile and the Oysterledge (approx 5miles). Who was the other boat- could they be the ones struggling to transmit/receive?

@gowerpower may have a point regarding the frequency your transmitting on; I rarely ever change to 25w as my set turns to 1w when I press 16... I've never really noticed how far away we can communicate with other boats, but in some weather conditions it seems to cut the distance right down - maybe next time we're both out we can test how far we can communicate via VHF.

 

My set default transmission power is 1W unless press hi-lo button so if you have a memory like mine it’s all too easy to forget to push hi-lo button before transmission....

 

Are you sure? Mine automatically defaults to 25w when I change to 16.

 

As a rule of thumb, assume 1W per mile with line of sight. VHF does not go round corners or bend around the Earth. Because of that the aerial height determines effective range. This shows the distance for a high mast on a shore station (from the RYA course book and www.boat-angling.co.uk).

The horizon is 3 miles away from a person with an eye height of 2 metres so if your antennae was 2 metres above water level you could in theory reach another boat with similar antennae 6 miles away if you were transmitting at least 6 watts of power.

 

Hey Paul,
I've never had an issue picking you up between 3mile and the Oysterledge (approx 5miles). Who was the other boat- could they be the ones struggling to transmit/receive?

@gowerpower may have a point regarding the frequency your transmitting on; I rarely ever change to 25w as my set turns to 1w when I press 16... I've never really noticed how far away we can communicate with other boats, but in some weather conditions it seems to cut the distance right down - maybe next time we're both out we can test how far we can communicate via VHF.

On my last outing my friend was struggling to talk with me I would guess the problem would be his side , I've also had channel 18 on to listen how busy tawe lock is as I would rather fish another hour than hold in the river and I noticed out deep off the swigg I can't hear tawe lock ?

 

I've also had channel 18 on to listen how busy tawe lock is as I would rather fish another hour than hold in the river and I noticed out deep off the swigg I can't hear tawe lock ?

I often communicate with tawe lock on 18 from out wide off mumbles head, saved my ass a few times when running late or checking on lock master decision closures. Definitely worth testing next time your out.

 

I struggle to speak with my local marine rescue station even less than 1km from their base when it's in clear site yet I can talk with other rescue bases 80km away on a good day. This simply doesn't make any sense to me, also when the local base isn't manned the land base switches over to repeater stations which means we then communicate with Sydney base 360km away.

 

As a rule of thumb, assume 1W per mile with line of sight. VHF does not go round corners or bend around the Earth. Because of that the aerial height determines effective range. This shows the distance for a high mast on a shore station (from the RYA course book and www.boat-angling.co.uk).

The horizon is 3 miles away from a person with an eye height of 2 metres so if your antennae was 2 metres above water level you could in theory reach another boat with similar antennae 6 miles away if you were transmitting at least 6 watts of power.

Radio waves can be bent, distorted, by atmospherics, high pressure and very low pressure can do weird things to your signal.

 

I never thought to check weather my vhf switches from 25w to 1w when i change channel how stupid am i but it seems im not alone will be sure to check when the boat goes back in the water ,thanks for enlightening this idiot .

 

I struggle to speak with my local marine rescue station even less than 1km from their base when it's in clear site yet I can talk with other rescue bases 80km away on a good day. This simply doesn't make any sense to me, also when the local base isn't manned the land base switches over to repeater stations which means we then communicate with Sydney base 360km away.

That could be a function of their antenna gain which focuses the radio energy into a narrower band and as the emanating radiation energy is in a teardrop shape for single pole antennae if it is mounted higher than you are at short range you may be in a shadow area.
I looked for a good example to show radiation patterns but google failed me. The following on a keep it simple basis was the best I could find. However it may explain what is happening with you and indeed the OP if he has a high gain antenna and the boats were rolling in a swell.

https://www.westmarine.com/WestAdvisor/Selecting-a-VHF-Antenna

edit

and

 

I drive a few different boats, all of which struggle with our local rescue station. I've brought this up with them and believe they have issuess due to not removing old cables from the loft space of the radio station.

 

My set automatically switches to 25w when I select ch 16.

 

You need someone with a Marine frequency Power/VSWR meter, to check your radio's output and your antenna. If you weren't so far away I'd check it for you.