Reply
 
Thread Tools Search this Thread
 
Old 19 August 2009, 04:55   #1
Member
 
Tony's Avatar
 
Country: UK - Channel Islands
Town: Guernsey
Boat name: Monkey Nutz
Make: Cougar R8 Sport
Length: 8m +
Engine: 350Sci Verado
Join Date: Aug 2006
Posts: 931
VHF Range

Hi Just wondered what the range was on a VHF Radio. I found myself out of range on Channel 6 on Sunday. I was only a mile from the shore. I wondered if the thing was working properly.

Thanks
Tony
__________________

__________________
Tony is offline   Reply With Quote
Old 19 August 2009, 05:09   #2
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
Doesn't sound too good, is it fixed or handheld? What power was it set on?
The weather affects it alot too. I've been on a gas platform in Morecambe Bay before and heard Humber CG before, also I've been at the Lifeboat Station and heard Forth CG before!
__________________

__________________
chewy is offline   Reply With Quote
Old 19 August 2009, 06:18   #3
Member
 
Country: UK - England
Town: Dorset & Hants
Boat name: Streaker/Orange
Make: Avon/Ribcraft
Length: 4m +
Engine: 50Yam/25 Mariner
Join Date: Apr 2007
Posts: 5,551
Quote:
Originally Posted by Tony View Post
I wondered if the thing was working properly.

Thanks
Tony
I'd say no - something is not right . Is the aerial still attached ? Prob the first & easiest check to make ........
__________________
PeterM is offline   Reply With Quote
Old 19 August 2009, 07:00   #4
Member
 
Tony's Avatar
 
Country: UK - Channel Islands
Town: Guernsey
Boat name: Monkey Nutz
Make: Cougar R8 Sport
Length: 8m +
Engine: 350Sci Verado
Join Date: Aug 2006
Posts: 931
Quote:
Originally Posted by chewy View Post
Doesn't sound too good, is it fixed or handheld? What power was it set on?
The weather affects it alot too. I've been on a gas platform in Morecambe Bay before and heard Humber CG before, also I've been at the Lifeboat Station and heard Forth CG before!
Its a freshly installed Icom fixed with a rib raider aerial.it was a bright day.
__________________
Tony is offline   Reply With Quote
Old 19 August 2009, 08:27   #5
Member
 
Country: UK - Wales
Town: swansea
Boat name: Too Blue
Make: BLANK
Length: 8m +
Engine: Suzuki DT225
Join Date: Mar 2004
Posts: 12,791
TX - RX or both?

Either a dodgy aerial or a dodgy unit but it could have been down to something local like interference or even jamming - try it again before ripping everything apart.

Maybe it's that new outboard???
__________________
codprawn is offline   Reply With Quote
Old 19 August 2009, 09:47   #6
Member
 
Country: UK - Wales
Town: Southampton
Boat name: DynaMoHumm/ SRV/deja
Make: Avon8.4, 5.4 & 4.777
Length: 8m +
Engine: Cat3126 Yam 90 &70
MMSI: 42
Join Date: Dec 2003
Posts: 6,556
if it works close to another boat I'd suggest bad cable connection
__________________
Here it comes again, I don't stand a chance
Soul possession, Got me in a trance
Pullin' me back to you - Deja Voodoo
Rogue Wave is offline   Reply With Quote
Old 19 August 2009, 10:02   #7
Member
 
Country: Ireland
Town: Ireland
Make: Lodestar 3.4
Length: 3m +
Engine: Yamaha 15hp 2 stroke
Join Date: Aug 2009
Posts: 166
There are many factors which can affect your range.
VHF operates on "line of sight" & should work up to a range of about 60 nautical miles on 25W assuming the height of the anntennae if sufficient. Beyond this range there will be some degradation.
Your theoretical range to the horizon is 2.21 x the square root of your height of eye (ie the annteanna) above the horizon in meters, your answer will be nautical miles.
So for example & the sake of simplicity if your height of anntenna is 9m, your theoretical range will be 2.21 x 3m = 6.63 miles. If another station has the same height of eye both stations can communicate at a distance of 2 x 6.63 miles.
This is a simplified rule of thumb, other factors among others which will affect your range are atmospherics.
__________________
Zubenelgenubi is offline   Reply With Quote
Old 19 August 2009, 10:05   #8
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Make: Redbay Boats
Length: 9m +
Engine: 370hp
Join Date: Feb 2008
Posts: 12,928
RIBase
Quote:
Originally Posted by Tony View Post
Hi Just wondered what the range was on a VHF Radio. I found myself out of range on Channel 6 on Sunday. I was only a mile from the shore. I wondered if the thing was working properly.

Thanks
Tony
Tony,

I've had range issues too .

Is the mile you refer to Line of Sight? If so, your kit is faulty. Even with a Rib Fader antenna, you should still get reasonable comms at one mile, LoS. Check that the set was on High, and showing a TX inducator, not ANT, signifying a connection fault or short? I've had a totally disconnected antenna (fresh from installation too) and had quite good long range RX and local TX - it took a few days out to twig it . Can't have done the set any good.

Finally, I'd make a point of systematically testing the rig over increasing ranges.
__________________
willk is offline   Reply With Quote
Old 19 August 2009, 11:42   #9
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Quote:
Originally Posted by Zubenelgenubi View Post
Your theoretical range to the horizon is 2.21 x the square root of your height of eye (ie the annteanna) above the horizon in meters, your answer will be nautical miles.
Remember that the top of the antenna generally is *not* where the radiation elements are. Usually a ways down the mast (on Shakespeare antenna's, you can cut at least a foot off the length of the antenna.)

jky
__________________
jyasaki is offline   Reply With Quote
Old 19 August 2009, 14:17   #10
Member
 
Country: UK - England
Town: Durham
Boat name: Hati Hati
Make: Humber Destroyer
Length: 6m +
Engine: Suzuki DF175
MMSI: 235064194
Join Date: Apr 2007
Posts: 53
VHF transmission problem.

Quote:
Originally Posted by Tony View Post
Its a freshly installed Icom fixed with a rib raider aerial.it was a bright day.
Tony,

Check out my postings on this forum. I had similar problems for more than 12 months. Sent my Icom 411 back to Icom twice, replaced my coaxial cable twice and replaced the VTronix Rib Raider Twice. I was pulling my hair out.

I finally contacted Shakespeare at Fleetwood. They bought out VTronix antennas about 1 year ago. They were very helpful and told me to disconnect the PL259 plug from the back of the radio and using a multimeter, test the resistance accross the centre plug and the outer screen. Should read a resistance value of 10,000 ohms. I found the antenna to be open circuit. I then connected the original antenna to the coaxial and found it to be short circuit.

I called Shakespeare (Product Support Dept, You'll find their number on the web) and told them what I'd found and they sent me two new, tested replacement units. I am extremely pleased and relieved to say that I now have a VHF that not only works, but performs very well!!

Incidentally, prior to fixing this issue, I tested the transmission from my boat VHF using a hand held set. The boat VHF seemed OK, but when I got out to sea and tried to contact the coast guard, the lack of antenna meant I wasn't transmitting. Presumably, I was transmitting a weak signal via my coaxial cable which the hand held could pick up, but transmissions over distance were useless.
__________________

__________________
Brian Dinsley is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 18:15.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.