Standard Horizon and AIS VHF splitter

chippysmith

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I think I have settled for the Standard Horizon CP-300. I also want to upgrade to a DSC fixed VHF, within the spec of the CP-300 it mentions DSC polling. Can anyone explain this for me please.

Also... To connect an AIS to existing VHF aerial, it would appear you need a splitter probably equalling the price of the AIS engine.. have I interpreted this correctly or am i missing something.
 

AliM

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I think you either need a VHF splitter or another aerial. The other aerial mounted on the pushpit is ~£25, or about £40 for a mast-mounted one. Having a spare aerial in case of the rig coming down, or the cable getting damaged sounds good to me, and it's cheaper than the splitter. I asked the same questions of Malthouse and that what he told me - that's why I know!
 

aluijten

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I've got the CP300 just installed. Great piece of kit. Although the C-MAP stuff is not as good value for money as the Navionics.

For AIS I put up an additional aerial on the pushpit (more precise on the radar-pole next to the pushpit) it sits approx 2.5 metres above the waterline and only on inland waterways I managed to 'see' ships approx 8 miles away.
The VHF splitter is a tricky device. As it needs a power supply to operate any failure to this might become expensive for your AIS receiver when you pump 25 watts of RF energy into it during VHF usage.
In short, the 2nd aerial is a good idea, it cheaper but generally more work and you might not like the aesthetic part as well.
VHF polling, as I have understood it means when you request a position report via your DSC-VHF from a 'buddy' (someone you know and have his MMSI number) and you actually receive the report back, the plotter will indicate the position on the chart. The same happens when you receive a distress call made via DSC.
Basically this means you do not need to manually copy the Lat/Long from the VHF display and look them up yourself on the chart.
To be able to use this your VHF must be capable of sending the relevant NMEA messages to the plotter. Not all VHF sets do this. I'm using a Icom set that claims it will do this. I haven't seen it working (just finished the installation), although I did wire up the required connections.

Hope this helps,

Arno
 

Seagreen

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I've just got -but not yet installed a CP300 and the standard horizon quest VHF. I'm going for the single aerial with splitter option as the mast channel won't take 2 cables and I don't want a classic yacht's masthead turning into an xmas tree. I'll report back when its all up and running.

Malthouse seems to be the guy to talk to about all this.
 

fireball

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I've heard of an antenna installation in a wet locker that still manages to get a good range on the AIS ... ours will be fitted to the pushpit, but with the adapter I can always swap it with the mast head.
Personally I'd rather not go for the splitter - we've been hit by lightning once resulting in a total loss of antenna - had we had the AIS fitted at that time I could've just plugged the VHF into the spare antenna ....
 

Talbot

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a second VHF aerial is a much better bet than a VHF splitter:

It is less than half the cost
It does not halve the power transmitted (Most splitters have a 3 db loss, unless you buy a more expensive powered one which may reduce losses to 1db).
It provides a ready installed emergency aerial.

Personally recommend the 1.1m whip from JGTech.
 
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