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Gilligan Gilligan is offline
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First recorded activity by BoatBanter: Aug 2006
Posts: 1,049
Default Cheap navigation system


"Dave" wrote in message
...
On Tue, 10 Oct 2006 19:31:00 -0600, "Gilligan"
said:

It's
extremely unlikely that taking a second set of outputs from the GPS to the
radio, duplicating the connection that was there when the GPS was
installed
initially, is gonna be problematic.


That's a 25 watt VHF radio transmitter? Is the RF ground at the SO-239
antenna connector the same as the signal ground for the NMEA-0183? 25 watts
into a 50 ohm antenna is 50 volts RMS, let's say the VSWR is 2:1 on the band
edge you'll have 280 volts peak to peak on the coax. Let me know how well it
works during and after you transmit a few times.

Does your radio ground go to a ground plate? Is it tied to the other grounds
on your boat? Do the ground currents between the radio and GPS flow through
the notebook or is it a floating node? Is the 12V power adaptor ground the
same as the RS232 ground? Are the units individually fused or do they share
the same power wire/ckt?

Since you are a lawyer what does "extremely unlikely" mean under Murphy's
Law?

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