Fixed or Handheld VHF

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mr_bosun

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Using a 70 ft narrow boat that spasmodically (monthly) navigates The Thames (Brentford to Limehouse or vice versa), I am now required to have a VHF on board.

Cost wise there appears to be nothing to choose, although I appreciate fixed radios offer benefits in the areas of receiver sensitivity and transmitter power. Storage is a consideration and I notice that some handhelds have BNC connectors for the rubber duck aerials. Could I connect a proper aerial (something like a RIB Raider) to a collapsible mast (3 to 4 metres) and then to a handheld via the BNC connector (thus, hopefully providing better reception and transmission but an easily stored / removed solution)?

I could go for a fixed installation but unfortunately the light fingered brigade seems to find boats on non-residential moorings an attractive target (the latest loss be a tank full of diesel, and did it take a while to figure out why it wouldn’t start)!

Suggestions gratefully received.

Andy
 
Id go for a h/held and forget the extra aeriel. Someone is going to here you! Anyway, you ve got a mobile too, i assume
 
I use Handheld more than fixed ... and yes there is no reason why you can't use fixed aerial on the HH.

But for river use - you probably wont need that extra bit ... unless around tall numerous buildings etc. shadowing you.
Even then the power from the radio will be reduced by time it hit's aerial.... possibly.
 
Having used VHF in the area that you will be I offer the following:

A handheld will not be able to call London VTS from anywhere west of Putney, you will hear them them but thats it.

It may be possible with a handheld connected to an external antenna and 12v to do it. some handhelds put out 5watts when on DC power.

It is possible with fixed station.

I have a handheld that I use on the Thames but have just upgraded to a fixed radio in order that I can call London VTS from Teddington rather than use the phone.......

I got one of these
http://tinyurl.com/2btrwb

Julian
 
I was just going by the two that I have, both are 1w on batteries 5w on external power.

As for distance yes its pushing it for a simple setup I can ususlly hear London VTS from Teddington on the handheld and I have heard people I know working London VTS from Teddinton and Brentford on fixed sets hence my decision to change.

There are times when VHF carries far farther than you expect it to /forums/images/graemlins/blush.gif, on a band below marine I often used to work stations 1000km away, but that was from a hilltop with a large antenna system /forums/images/graemlins/cool.gif

Julian
 
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Many tx at 5W when on internal battery.



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they may say they do, but I have a few doubts. I think it is asking a lot of a NiCad battery pack to provide that sort of current.
 
[ QUOTE ]
[ QUOTE ]


Many tx at 5W when on internal battery.



[/ QUOTE ]
they may say they do, but I have a few doubts. I think it is asking a lot of a NiCad battery pack to provide that sort of current.

[/ QUOTE ]The current isn't a problem, its how long it will last at full power that is! Nicad Batteries have quite low internal resistance and will overheat and even catch on fire if they are shorted out.
 
[ QUOTE ]
Could I connect a proper aerial (something like a RIB Raider) to a collapsible mast (3 to 4 metres) and then to a handheld via the BNC connector (thus, hopefully providing better reception and transmission but an easily stored / removed solution)?

[/ QUOTE ]When I used a hand-held airband radio, we were told that the output was specifically conditioned to match the rubber duck. External aerials for use with hand-held transceivers had a choke or something in the cable. Without that it would work OK for reception, but not brilliantly for transmit. This type of rig was used quite a lot for glider or ballon chase cars, with a magmount aerial on the car roof and a hand-held transceiver.

The same may apply to marine band (airband is just a little lower frequency, but not a million miles off)
 
If nicking diesel is prevalent in your area mark the diesel filler as water and vice versa. dont forget yourself though.if someonr syphons off your freshwater supply in the dead of night you get the last laugh. /forums/images/graemlins/grin.gif
 
I would go for the handheld only. This then means that you comply with the rules. Whether the local VTS can hear you or you them would then be their problem - I think ! If it was a small RIB they would only use a small handheld.
 
Hi Folks,

Thanks for the advice and guidance.

Installed and tested solution is XM2000 hand held (picked because it is the only one which I could find that specifically said an external aerial could be fitted), TNC to SO259 adapter, Alinco Linear Amplifier (1 Watt in approximately 20 watts out, tweaked by local HAM geek to “stop harmonics”) and V-Tronix Rib Raider mounted on a three metre extending pole (three section adjustable camping tent pole).

Successful contact with London-VTS from the southern side of the river near the London Wetlands Centre.
 
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