How "clear" should VHF reception be at sea?

BrAinZ · 08 July 2009, 22:17

I've been listening in to VHF occasionally near the coast on a handheld (Standard Horizon), where I often can't pick up weaker signals so sometimes only hear one side of the conversation.

I assumed that when I bought my new RIB with a "proper" VHF setup (Icom 411) reception would be as clear as a very clear bell type type thing.

Quite surprised that things are still quite crackly, and not nearly as clear as I thought things would be.
So far, I've only been between Cowes - Needles sort of area.

So just what type of quality reception is the norm?

willk · 08 July 2009, 23:36

Tricky. I think if you're getting some good clear RX from local traffic, then your setup is working ok. More distant traffic can sound very crackly and faint. Bear in mind that on Duplex channels, eg. CG working channels, you can only hear one side of the conversation - the CG.

In short, if your squelch is set properly and you get no clear reception at all - ever, then you have a problem.

alystra · 09 July 2009, 00:32

Depends what you mean by clarity. It's never going to sound like Radio 4 in your car, but you should be able to understand what's said (if it's in a language you know).

You'll often hear only one side of the conversation because one sending station is out of range or shadowed by hills etc., or the tx is on a duplex channel (ie the tx and rx frequencies are different. This was great for telephone calls, but since that service stopped the CG took over the channels for general working.)

My recently purchased SH hand held is every bit as clear as my main Raymarine set, and that's good. I've never experienced 'crackling' on VHF. I wonder if you have interference from the engine? Does the crackling remain if the engine is not running?

Erin · 09 July 2009, 12:05

If you've done your VHF course, you'll know about duplex channels already!

Cookee · 09 July 2009, 13:36

Also coastguard stations have enormous ariels and repeaters, so it is quite likely you won't hear the other half. You shouldn't listen to other peoples conversations and certainly not from land ..............

Steve_B · 09 July 2009, 14:03

Listening from land is OK, Transmitting from land a No No!

BrAinZ · 09 July 2009, 20:35

Quote:

Originally Posted by Erin

If you've done your VHF course, you'll know about duplex channels already!

I'm doing the VHF course as "home study" before I take the exam. And YES, I totally understand that it's illegal to TX until I take the test, so I won't.

As for not listening to other peoples conversations.... That's a silly statement... What does everyone do, cover their ears when anyone transmits?

We've only just got the rib, so will test it again and compare engine running with engine off.

Thanks for all the advice so far!

chewy · 09 July 2009, 23:21

Quote:

Originally Posted by Cookee

Also coastguard stations have enormous ariels and repeaters, so it is quite likely you won't hear the other half. You shouldn't listen to other peoples conversations and certainly not from land ..............

I've got a scanner for listening to a few VHF channels, can't see a problem in listening to what other people are saying.

Cookee · 10 July 2009, 08:37

Quote:

Originally Posted by chewy

I've got a scanner for listening to a few VHF channels, can't see a problem in listening to what other people are saying.

Maybe I'm wrong, but I'm sure when I took my first VHF test (It was after the morse days

) they told me it was technically illegal to eavesdrop.

MarkWildey · 10 July 2009, 09:02

Cookee is correct that the CG have massive aerials, whereas you, and everyone else, has some mass produced poorly made ariel that is almost mounted at sea level, plus you transmit at <25 watts ( signal loss in the cable,poor connections ). Tow your boat up to a cliff and mount a half or full wave length ariel then you'll be the master of the airwaves until your arrested!

Sometimes the atmospheric conditions create a "lift" that allows signals to bounce around and much better reception/transmission distances are possible.

Steve_B · 10 July 2009, 09:12

Scanners are readily available for virtually all radio channels, which include LW/MW/VHF/UHF and beyond. These cover both aviation and marine frequencies. It is not illegal to listen to the vast majority of these frequencies.
But if you purchase a radio that has the ability to transmit, then it is the responsibility of the person making the purchase to ensure that appropriate licence is obtained before using the transmit function.

In aviation, there are times when we have to be very careful of what and how we pass or request info to aircrew, as we know that there will always be numerous "spotters" listening in. Fortunately we now have the ability to "talk" to aircrews without the need of a radio in certain circumstances.

DJL · 10 July 2009, 09:30

Quote:

Originally Posted by 250kts

Scanners are readily available for virtually all radio channels, which include LW/MW/VHF/UHF and beyond. These cover both aviation and marine frequencies. It is not illegal to listen to the vast majority of these frequencies.
But if you purchase a radio that has the ability to transmit, then it is the responsibility of the person making the purchase to ensure that appropriate licence is obtained before using the transmit function.

This is technically incorrect. Section 48 of the Wireless Telegraphy Act 2006 covers the offences.

It is illegal to listen to any licensed set of frequencies, marine and aviation are examples, without the correct license/authority. Scanners can only be used to listen to broadcast radio stations, CB radio etc - unless of course you have a license for other frequencies.

PeterM · 10 July 2009, 10:01

I'm with 250 on this one - I think it is the recording of conversation that can be classed as illegal - simply lietening to a public boradcast channel is not.

I have radios to receive & transmit on Air & Marine band sat in the garage(which could cause serious mayhem if I didn't know what I was doing !) and no-one ever asks to see you licence when you buy them ! I think its big ask to make anyone think its illegal to listen !

Considering there is no actual legal requirement for me to have a radio in my boat , or aircraft for that matter its a bit of non-started to try & make it illegal to just listen to a frequency.

Any way I'm sure have all registered our main sets & a ourhand helds properly & hold all the correct personal licences ?

Steve_B · 10 July 2009, 12:47

Section 48 is designed to procecute persons who use electronic equipment to access information which is not intended to be public. As both Marine & Aviation radios are broadcast messages or open, I cannot envisage any circumstance where this act could be used to bring a procecution. But then again, the anti-terror law could be used for anything ....

To Quote;-A person commits an offence if, otherwise than under the authority of a designated person—
(a)he uses wireless telegraphy apparatus with intent to obtain information as to the contents, sender or addressee of a message (whether sent by means of wireless telegraphy or not) of which neither he nor a person on whose behalf he is acting is an intended recipient, or
(b)he discloses information as to the contents, sender or addressee of such a message

As all our messages start with the addressee & includes who we are and the general content, therefore we could all be locked up everytime just for listening ......

When I make that Mayday call, I want the world and his wife to listen, take notes and help, whether they are licenced or not

chewy · 10 July 2009, 13:07

Quote:

Originally Posted by Cookee

Maybe I'm wrong, but I'm sure when I took my first VHF test (It was after the morse days

) they told me it was technically illegal to eavesdrop.

My scanner is for listening to the normal VHF channels plus channel 0 and 31. Gives me a head start on the rest of the crew if I hear the CG saying we're launching Staithes Lifeboat.

tim griffin · 10 July 2009, 19:24

Not sure if you have done your course Brainz but I have one running on the 26 th of July and as we are local to you .

Let me know if of interest .
Cheers Tim

willk · 11 July 2009, 10:38

I'm not sure what the legal situation in the UK is but when applying for my Short Range Certificate (VHF) certificate, I had to sign an official goverment "declaration that he/she will preserve the secrecy of correspondence". So basically, listen all you want, but keep yer beak shut about it later. Adherence to callsigns, not real names was another big issue in the training...

... so it always cracks me up when I file a TR under my callsign (ok, the rib's callsign) and the local CG responds, ending ...enjoy your trip/dive "willk"!

chewy · 11 July 2009, 17:42

Quote:

Originally Posted by willk

I'm not sure what the legal situation in the UK is but when applying for my Short Range Certificate (VHF) certificate, I had to sign an official goverment "declaration that he/she will preserve the secrecy of correspondence". So basically, listen all you want, but keep yer beak shut about it later. Adherence to callsigns, not real names was another big issue in the training...

... so it always cracks me up when I file a TR under my callsign (ok, the rib's callsign) and the local CG responds, ending ...enjoy your trip/dive "willk"!

I like it when the CG pass peoples mobile numbers over the radio for all to hear, granted its on zero but anyone can get a scanner and listen.

Today a mate found "something" on the beach, the CG wouldn't say what it was over the radio in case anyone was listening, good eh, they then went on to announce that the MOD's EOD section would take a look in the morning.... wonder what he could have found eh.
It had me in stitches when they were describing it as a foot long 4" wide and got slightly fatter in the middle. The MOD wanted pictures of it, told my mate I get sent emails with similar items in if they want me to forward em on?

DJL · 12 July 2009, 09:46

Quote:

Originally Posted by 250kts

Section 48 is designed to procecute persons who use electronic equipment to access information which is not intended to be public. As both Marine & Aviation radios are broadcast messages or open, I cannot envisage any circumstance where this act could be used to bring a prosecution.

"which is not intended to be public". And there lies the answer. Marine and aviation bands are not 'public' - they are licensed bands. Until you hold an SRC and have a ships/transportable license you are not licensed to listen or transmit - hence under Section 48 you would be using "electronic equipment to access information which is not intended to be public"

Its exactly the same with 'private' channels like Channel 0 - you have to be licensed or authorised to use a particular frequency.