VHF radio

[Paul]

Along with my brother I have owned a small RIB (Avon searider 4.0m) for 3 years. We tend to do solo trips of around 30-60 miles (in good weather) either up the east coast from Tynemouth or on the West Coast of Scotland travelling up to 5 miles offshore. We have a handheld VHF (ICOM M1Euro V) along with other safety equipment (liferaft, flares, drysuits, lifejackets, 101MHz EPIRB, auxillary 3 hp engine). Firstly, if we were to get into trouble would a handheld radio reliably summon help and secondly is this asking too much of the boat?

[Allan]

A handheld VHF radio does not have a huge range for two main reasons 1, it has low transmitting power, your radio is 5 watts (compared to 25 watts for a fixed set). 2, Antenna height, the higher the better- not easy to achieve height in a RIB.

Despite these shortcomings a VHF is a very important safety tool, you may not succeed in contacting the Coastguard directly, but may be able to contact another boat in the area which would be able to instigate a Mayday Relay on your behalf. The biggest benefit will be in aiding your rescuers to locate you when they come into reasonable proximity with you.

A small boat is not easy to find in anything approaching bad conditions, a few years back I was filming a rescue exercise which we had arranged with the Royal Navy (helicopter) and the RNLI (52 foot Arun class lifeboat) (All use of flares and smoke etc. had been cleared with the Coastguard and they were notified upon completion of the rescue exercise).

Weather was moderate Force 5 gusting 6 occasionally and 1 to 1.5 metre swell. Our target was a medium sized liferaft (8 man) with the normal orange canopy with retro-reflective strips, and a 4 metre RIB is not very much bigger as a target and not often likely to have large areas of dayglow orange and retro-reflective strips!

The liferaft crew were using both hand held orange smoke and big floating orange smoke flares, we knew where they were but despite this, finding them visually was frighteningly hard. As soon as they replied to our VHF calls, the Direction Finding (DF) equipment on the Lifeboat pointed us in exactly the right direction. Each transmission received on the lifeboat enabled it to continuously correct its course, its just like providing a motorway directly to your position!

I believe that not all Search and Rescue helicopters are equipped with DF equipment sensitive to marine VHF freqencies but they do have DF for 101MHz EPIRBS (101 MHz was originally an aviation search frequency) so your combination is a very good one.

If possible it would be good to have a spare power pack or batteries for the VHF as part of the panic bag contents as its usefulness is so good, not to mention the re-assurance you will get from being able to speak to the lifeboat as it speeds to the rescue.

It is not possible to give an unqualified positive answer to your question about handhelds reliably summoning help but it will certainly make a dramatic improvement in your chances of a rescue being completed successfully!

[Paul]

Thanks Allan for your detailed reply. Do you think I should get a fixed set as well or would that be overkill?

[Allan]

A fixed set would be a possibility, but the major problem in terms of signal propogation is the lack of antenna height, this has a bigger effect than raw power.

If your main concern is attracting attention, a fixed set may offer little or no improvement in range because of the lack of height of the antenna so perhaps you could consider boosting the contents of the flares pack with some nice big red rockets. The important thing is to get noticed and you already have an EPIRB which will be a big help, so rockets and smokes will help your rescuers locate you.

As I mentioned in the previous post, it is quite frightening how hard it is to locate a small boat so everything you can do to help in that department has to be worthy of consideration.

[Paul]

Thanks again- I'll forget the fixed set and use the money to get the rockets as suggested

[jools]

When your next out why not try a "radio check" to the coastguard. I'm sure they won't mind and it will give you peace of mind to know that your hand-held works.

Remember the coastguard have lots of repeater stations along the coast so when you hear that crackling broadcast on your VHF its probably from a sailing boat miles out to sea - that the coastguard can pick up OK.

So if your fairly near the coast I would think you would be OK - and as Allen said in a Mayday situation if a vessel heard your transmission and did not hear a reply from the coastguard then they should send a "Mayday Relay" of your message to the coastguard.

[Michael]

I would recommend that you go for a fixed VHF as well as the handheld. A DSC model linked to a GPS will give you significant additional capabilities.

[Allan]

Mea Culpa, I should have been more accurate in proof reading my post! It has just occurred to me that little EPIRBS are designed to operate on 121.5MHz not 101!

If you are particularly worried about reliably being able to raise the alarm in an emergency situation then an EPIRB which operates in the 406MHz band is the very best bet.

Once correctly registered, it will provide a set of information to the most appropriate MRCC (Maritime Rescue Coordination Centre) as follows:
(a) ship name;
(b) MMSI; (Mobile Maritime Service Identity)
(c) radio call sign;
(d) EPIRB identification code (if applicable) and its homing frequency;
(e) country where the ship is registered;
(f) brief description of ship, including its type, gross tonnage, ship superstructure, deck colours and identifying marks;
(g) name, address, telephone and (if applicable) telefax number of emergency contact person ashore;
(h) alternative 24-hour emergency telephone number (alternative contact ashore);
(i) capacity of ship for carrying persons on board (passengers and crew);
(j) radio installations carried on board the ship and survival craft;
(k) type and number of survival craft; and
(l) date of last modification of registered particulars.

Being a satellite based system, it will locate you to within 3 miles on the first pass and to within 1 mile within 3 passes. It is an internationally recognised format that will be supported for the foreseeable future (unlike 121.5MHz and Ch16 on VHF)

In terms of cost, it would be similar to a DSC enabled VHF set (approx £400), it has its own power supply and it floats. If you are unlucky enough to sink your boat, a fixed set will go down with it!

Cruising in company is a great asset in terms of safety and if you don't have any regular friends to cruise with, joining an organisation such as B.I.B.O.A. (if you don't already belong) or a post to the august members who contribute here, may help you meet folks with similar interests.

I'm sorry that this has strayed from the original VHF question but I hope it rounds out the safety aspect.

[Paul]

Sorry- my mistake, I meant to put 121 Mhz. Am I right in thinking that these particular EPIRBS are not too good at alerting rescue services (except when you don't want them too !!!) but as you said are good for pinpointing the distressed vessel once the alarm has been raised.
The 406Mhz EPIRBS that I have looked at all seem to sell for £800. Which models that sell for £400 as I would seriously consider one at this price. My worry about DSC/VHF is that I have heard reports that they are not reliable on RIBS as even the "waterproof ones" can fail due to water ingress. Is this true?
PS Thanks for the helpful comments so far

[Allan]

I saw a Kannad 406S recently for £365 +VAT the normal being £399 and a Tron 45 S for £465 +VAT. I'm sure that a quick look in something like Practical Boat Owner would turn up a few more.

There are international standards for "waterproof" and would be surprised if a "waterproof" set were to fail if installed correctly. On the Icom site they have brief descriptions of water resistance tests http://www.icomuk.co.uk/ Perhaps the sets that failed were only water resistant or splash proof?

[Garygee]

While I agree that antenna height is a very important factor in increasing range, antenna type is also vital.
On a handheld the typical antenna type is a helica. These can be typical -3 to -6 dBi gain.
A fixed antenna is typicaly +3dBi gain.

A good compromise which I use is a handheld with a fixed antenna. If you look at the figures you will see why

5 Watt handheld with -3dBi helical = 2.5W ERP (effective radiated power). On top of this the helical being close to your head etc is often at a poor angle (should be vertical) and detuned bey things around it.

5 Watt handheld with +3dBi antenna = 10W ERP

This gain is also on receive !!.

There are antennas available with upto 6 dBi gain. While these look good they have a very low angle of radiation which means that on a RIB which may be pitching a lot the angle of the antenna may chamge so much that the receiving antenna goes in and out of the beam so apperaing to fade in and out of contact.
These antennas are good on big boats but not for RIB's

Of course the best answer is a fixed VHF at 25W = 50W ERP and a handheld as a backup.
It may be that you carry a fixed antenna which in case of poor signal and need you attach to your hand held and hold above your head. If anyone has tried that you would be amazed how much better it is than a helical on a handheld.

[nigelt]

I have an Icom IC-M1 Euro handheld and would be very interested in linking it to a fixed antenna but am not sure it is possible. If not, what handhelds are you taking about which can be attached to a fixed antenna?

Nigel

[Alan Mckewan]

I havent tried it with the M1 Euro, but I have regularly used both a Navico and an older Maxcom through the masthead aerial on a yacht. You simply take off the rubber duck and fit a BNC-to-PL259 adapter (available from Maplin etc.) and then plug on the VHF PL259 plug. On a yacht it makes a massive difference becuase of the mast height, but I dont think the difference will be so great on the RIB. I have also done the opposite - after breaking off several fixed VHF aerials on one of the club rescue boats I resorted to fitting a PL259-to-BNC adapter on the back of a fixed Navico VHF set installed in the console, then fitted a rubber duck straight onto the back of the fixed set. The rubber duck sticks out straight into the middle of the console. The reception is not as good (understandably as the SWR on the rubber duck is probably crap) but at least the somewhat careless rescue crews cant break it off!

[Garygee]

Hi

I use a Swiftech M198, quite old now and big but has a standard BNC mounted antenna.

With regard to use on yachts yes you will get a very big difference as your getting a good antenna AND height. But the test I have done show that a call that is totally unreadable on the hand held helical can be fine on the fixed antenna.
The other minus you have on a yacht is the long cable run has quite some loss while the cable lenghth on a RIB is often short. This wont give the difference advantage of the height but helps .

Regards Gary

[sea rabbit]

Originally posted by nigelt
I have an Icom IC-M1 Euro handheld and would be very interested in linking it to a fixed antenna but am not sure it is possible. If not, what handhelds are you taking about which can be attached to a fixed antenna?

Nigel

I have an Icom M21 handheld and contacted them about adding an external antenna: I was told that an adaptor was available (principally for test purposes) that converted the antenna socket to a BNC (I think). You need to make sure that you fix the correct type of antenna, and I'm still researching this. The bottom line seems to be that whilst antennas will improve both Tx and Rx on a handheld, you then have to worry about trailing leads and ensuring that you maintain a good connection; then if you find yourself in the water - you won't have your radio available in its designed state. It's down to the right tool for the job really, though goodness knows how I would fit a fixed set and it's power supply into my boat! Good Luck

[nigelt]

Thanks Sea Rabbit. Almost a year since I posted that!!

I have however just bought a fixed Icom M401 last weekend so am not worried about the handheld and will use it as back up only from now on.

Nigel

[dmoore]

On the hand-held vs Fixed set issue, I use a hand held but have connected an external aerial on the top of my frame to aid proporgation. I cant proove this is better but it seem logical that the better aerial and about 1.5M extra height would make better use of the 5W power. I also use the 12V off the boat supply to make sure I get the full 5W. All I need now is a waterproof fist mike and I will have a detachable fixed rig!!!

[Jelly]

Nigel
For refference you need a SMA male to probbably BNC female or SO259 ( female PL259) to hook up an Icom M1e
Jelly

[thewavehumper]

OK guys I need to know some stuff now

SMA is that the portable antenna connector
what does SMA stand for
BNC (British Naval Connector) has a bayonet firtting, where does that go,
Most of the fixed antenna's I have seen have a UHF plug on the end of them is that what a PL 259 is

I snapped two aerials in one day on the first leg od the Round Ireland Challenge, and could have done with an adaptor at the time. But I guess it serves me right for buying a silly boat