ping Larry - AIS unit

Hi Larry,

I need your advice again

I recently purchased a standalone Sitex AIS receiver - the little one
that has a small screen and which receives its GPS input by NMEA from
my Garmin.

It has a small externally mounted piezo alarm - no ID markings that is
simply too quiet to ensure that I am alerted or awakened if I drop off
to sleep. I would like to replace it with a louder piezo unit and am
of the vague understanding that as piezos draw little current that a
louder and larger one will not burn out or otherwise 'stuff up' the
AIS unit..

Is this correct?

I have emailed Sitex with this question and had as yet no response.

Also, at the moment I swap the masthead VHF aerial between the cockpit
located VHF radio and the AIS unit. In the absence of a proper VHF
splitter I reason that I won't need the AIS much in approaching ****ts
and if I need to talk to a ****p I have time to change over the
aerials.

As I have a chart table located VHF radio and the one in the cockpit I
have a proper A-B switch (rather like the old printer A-B switches but
more solid and metalic)  at the chart table for the aerials. I cannot
locate one of these any more.

The only AIS splitter that Defender had is one that is specific for a
Furono VHF radio and which cannot be easily adapted (by me at least)
for other brand use. At US$149 I sent it back as they said if it
didn't work to return it.

Do you know of anywhere I can purchase/make either a mechanical A-B
switch or an electronic automatic anntenna splitter?

Thanks and cheers
Peter

BTW, I may be visiting Charleston later this year on my way back to
Curacao as I am contemplating buying a Folbot and need to try a couple
of them out. It is also a reasonable excuse to visit the heart of the
South.