T&T: Connecting new GPS with older Raytheon radar

[Peter Bennett]

Thursday, December 11, 2008, 4:33:55 PM, Bob wrote:

<snippage>

BM> "The R40 is programmed to accept data from the Loran in the NMEA 1082 
BM> and NMEA 1083 formats . . . The NMEA 1083 data standard will, in most 
BM> cases, provide Lat/Long, TD course and speed data for the radar display
BM> . . .The connection to the R50 Display Unit is made with a common BNC 
BM> connector. RG 58 A/U Coax cable of any length may be used to complete 
BM> the interconnection to the Loran C. A two wire, shielded cable may be 
BM> used in place of the RG 58 coax if necessary. . . ."

That should be NMEA-0183, I expect.

BM> Two questions come to mind:

BM> (1) Is the  NMEA 1083 sentence format from a GPS now the same as it was
BM> back in 1989 from a Loran C when this unit was made? (I realize the data
BM> stream may contain more information now than it did in 1989, but are 
BM> GLL, GTD, VTG and BWC sentences now the same as they were back in 1989?)

Yes - NMEA occasionally adds new sentences but I think most things
will still work.  If your GPS has a choice of NMEA versions, you may
need to use the earlier version.

BM> (2) Can any decent-sized wiring be used other than shielded cable as 
BM> long as I can attach a BNC connector at the display unit end? (The NMEA
BM> data from the GPS comes from an 18 or 20 guage wire, and I'd prefer to
BM> just run a little heavier wire and end it with a BNC connector if that
BM> were possible.)

I usually use #22 wire, but any size should be fine - it is just a
signal, no significant current required. (I thing the wiring from my
Garmin GPS17 antenna/receiver is only #28).

BM> I'd appreciate any thoughts you might have regarding this lash-up.




-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca