blocking marine vhf?

vinnie13

Hi all,
Within the last few months in my local harbour(Wicklow) I have noticed that when I go up the river I can't make contact with the pier or coast guard always did have contact there.
Any ideas what could cause this?
It happens on all channels
It's not faulty equipment on my side,have checked with a friend's radio too.

martinsvi

what do you mean by getting a contact? A two way communication between yourself and pier or just receiving? does it work if you are closer to the harbour?

vinnie13

martinsvi wrote: »

what do you mean by getting a contact? A two way communication between yourself and pier or just receiving? does it work if you are closer to the harbour?

Making contact I mean transmitting and the other station can receive what I sat and vice versa.
It won't work either way I can't get them they can't get me.
The river is approx 100m from where comms brake.it works everywhere else.
Someone must have done somethingthats blocking out the transmission,there's nothing obvious in the way.

Xantia

Are you using a different aerial on board the boat?
Is it a metal wheelhouse or hull that might be blocking the signal?

vinnie13

Xantia wrote: »

Are you using a different aerial on board the boat?
Is it a metal wheelhouse or hull that might be blocking the signal?

Same aerial tried hand held and other base unit.
There has been no change to the boat and nothing that could interfere on my side it is something ashore of off another boat

Xantia

Maybe you should telephone the pier/coastguard just before you try and make contact with them.
Also it could be possible that they have fitted a directional antenna to face out to sea to get more coverage, not sure really its a 'situational problem'. Try ringing them and ask them to standby for a call.

martinsvi

yep, directional antenna was my thoughts exactly, maybe it has turned a bit in wind and they don't even know about it, although I thought they use vertical dipoles, it would be strange to use a yagi for this application. Maybe it is now lower than it used to be? Anyway, if it works when you are close by and doesn't work further away, it's probably their antenna that's not performing the way it used to

Xantia

Sounds right Martinsvi,
OP give them a ring when you are testing the VHF

vinnie13

I don't think they would use a directional aerial the cg do comms with the helo inland..have comms at start of river very clear to anywhere travel 50m up and all is gone pretty much have line of sight to wicklow head from where it looses..
So is their anything that teansmitts on the vhf band that could interfere or something that blocks all signals?

martinsvi

if there's a blocking interference, 50 meters (we are talking meters, right?) wouldn't make any difference on VHF

vinnie13

martinsvi wrote: »

if there's a blocking interference, 50 meters (we are talking meters, right?) wouldn't make any difference on VHF

yup 50m defo not much more if any,well smoething is blocking it out.was talking to a fisherman this morning and he noticed the same and cant figure it out either

martinsvi

ok this might be a complete long shot, but have you tried changing the frequency when you are away from the pier? Only by just a little bit, 5 Khz up and down. What I'm thinking - maybe the only reason you get through to the other station in close distance is because of splatter - an effect that weakens significantly as the distance increases.