VHF Range

[Tony]

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

[chewy]

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!

[PeterM]

Originally Posted by Tony

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 ........

[Tony]

Originally Posted by chewy

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.

[codprawn]

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???

[Rogue Wave]

if it works close to another boat I'd suggest bad cable connection

[Zubenelgenubi]

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.

[willk]

Originally Posted by Tony

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.

[jyasaki]

Originally Posted by Zubenelgenubi

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

[Brian Dinsley]

Originally Posted by Tony

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.

[Mollers]

BIN THE RIB RAIDER!!! I had one, I was getting nothing. I swapped it for a Shakespear 1.5m GRP,perfect now.