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Old 03 January 2012, 19:10   #1
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Handheld radios

I'm re-radioing and given the recent upgrades and power increases am seriously considering a switch from a fixed+hand-held way of life to getting two hand-held devices. There will be 12V charging off secondary battery, obviously.

The idea being that there are a number (4) boats used and if I can take both handhelds onto each vessel every time, that may save me about 5K.

Furthest from coast would be ten miles for two hours. There is an arch on two of the boats.

One main question is, does any manufacturer offer a hook-up to an external aerial from a handheld that is worth it's while? Or is there a way of amplifying handhelds?
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Old 03 January 2012, 20:28   #2
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sorry I am a bit confused, how would you save 5000 when buying 4 fixed VHF radios (a decent brand i.e. ICOM) would only cost you less than 700?

or am I missing something?!

I have not seen any handheld radio being connected to an external antenna other than its own built it antenna. You can not and should never attempt to amplify the strength of a handhelf VHF radio; two reasons:

1. It is illegal. You are not allowed to transmit over 25W unless you have license.

2. It is dangerous for the user. Handhelf radios are normally operated close to your body so the top of the antenna on the VHF radio has the highest amount of power and it is very harmful if used close to brain. Similar effect of conventional radars on body; more or less, although VHF signals have different wavelength.

Most VHF radios operate between 2-5W, I have seen a 6W model recently, which I think is the max you are allowed as VHF.
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Old 04 January 2012, 02:56   #3
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A decent hand held can be twice the price of a fixed, I have a Standard Horizon DSC HH that outputs 6w and expect I could swap the antenna over but it would really struggle to get anyway near 10 miles, with interrupted light of sight I don't hear Solent Coastguard from Chichester harbour.
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Old 04 January 2012, 04:11   #4
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You can hook up a handheld to an external aerial, you just need the right plug on the end or an adaptor, PL259 to BNC for example, depends on the handheld.

You can also get amplifiers that will take you up to 25W.

Agreed though, what's the point? You can buy a decent fixed VHF for 150-200.
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Old 04 January 2012, 04:14   #5
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Quote:
Originally Posted by Vandad View Post
2. It is dangerous for the user. Handhelf radios are normally operated close to your body so the top of the antenna on the VHF radio has the highest amount of power and it is very harmful if used close to brain. Similar effect of conventional radars on body; more or less, although VHF signals have different wavelength.
Are you sure about that? My understanding is that Marine VHF signals even at fairly high power would not harm anyone. If there is some evidence then It would be worth sharing.

Energy in an electromagnetic wave is proportional to frequency. This is why you can stand next to a 2 meg long wave transmitter without issue, but a few watts of microwave can fry you.

Marine VHF is sort of in the middle.

Gary
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Old 04 January 2012, 04:36   #6
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You are not allowed to transmit over 25W unless you have license.
Quote:
Originally Posted by Vandad View Post
VHF radios operate between 2-5W, I have seen a 6W model recently, which I think is the max you are allowed as VHF.
You need a license to transmit at any power level up to 25W. Anything over 25W is illegal, whether you have a license or not.
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Old 04 January 2012, 05:41   #7
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You need a license to transmit at any power level up to 25W. Anything over 25W is illegal, whether you have a license or not.
Does that mean 6w is just a sensible limit for battery life with a normal duty cycle for handhelds or is part of the limiting factor the small ariels making it impractical to transmit at more than 6w on a handheld?
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Old 04 January 2012, 06:27   #8
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OK, so the idea was to have two handhelds and not four fixed plus one handheld, including fitting and re-aerialing.
Plugging into a fixed, and hence taller, antenna was an idea.
I am licenced.
Don't forget that there is a 12V power supply.
I was kicking this idea around simply because two of the boats are nearly permanently 200 miles apart. The thinking being that having the hardware with me in HH form is handier also from a security perspective.
Some handhelds come with external antenna plugs, thanks MARTINI......do you know which to steer for? I have a preference for ICOM but haven't started tyre kicking yet.
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Old 04 January 2012, 07:13   #9
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I know someone who wanted to do a similar thing with his amateur radio transceiver and he found a cradle which could be connected to a 12v supply and be placed on the back of the radio in the place of the battery. I'm not sure Icom do something similar because I know it says to turn the radio off when charging. maybe it is worth emailing some manufacturers or going to the Boat show and asking there if you can.

You can get connectors for anything on the internet, I've got mini-SMA to PL-259 to connect mine to external aerials. I would suggest a hand mic though because plugging the handheld in can make it awkward to use
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Old 04 January 2012, 10:01   #10
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i ran a hand held on a fixed airiel until last year since my base unit was stolen from my fishing boat around 1995,and i never got around to getting another base set ,granted i only ever went out about 6 miles or so using crab pots /long lines .
only thing that i was told by a proffesional radio engineer {guy who repaired and set up ship radios in the local port is that a bit of loss would occour through having an extra unf connecter and extra cable and best not to use it during a thunderstorm .
suppose biggest problem is a lot of newer sets dont have detachable airiels ,

Dont know if the regulations have been changed the maximum power that could legally be used in the uk was for normal marine vhf is or was ,

Hand held /transportable , 5 watts max ,
Fixed base station 25 watts ,

one advantage was the airel was mounted 12 foot up ontop of the wheelhouse/short mast rather than me stood up at 6ft above sealevel ,so i did gain a little .
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