[MRCA] Backpack GPS system

[Eric Walker]

Ray,

Those are different mapping reference datums and should have absolutely no impact on the units ability to receive signals and triangulate its position, only on how it translates its position in three dimensional space to latitude and longitude to match existing surveyed maps.

The default standard for quite some time has been WGS-84 but you may have some old paper topo maps that were done under NAD-27. Look at the bottom of your topos and it should tell you which datum was used.

Do a search for "GPS datum" and you fill find plenty to read.

-Eric

N3XW

On Tuesday, October 7th, 2025 at 9:43 PM, Ray Fantini via MRCA <mrca at mailman.qth.net> wrote:

> if you have been following the saga of the Magnavox first generation GPS system you know that upon powering up the system it prompts what format or system do you want to use and gives you some forty different choices to select from. It appears to me that they are databases but not one hundred percent on that. also suspect that you were able to use the same system for several systems at that time and although it has what looks to be a L band antenna and preamp or down converter i wonder if the appropriate database had to be used to work with the L1C/A code set?
>
> So here is the list of available options:
>
> ADINDAN      01      LOCAL ASTRO      20
> ARC 1950 02      LUZON   21
> AUSTRALIAN GEOD    03     MERCHICH 22
> BUKIT RIMPAH 04      MONT JONG LOWE 23
> CAMP AREA ASTRO    05     NIGERIA 24
> DJAKARTA   06      CONUS NAD-27 25
> EUROPEAN 07     ALASKA NAD-27 26
> GEOD DATUM 1949 08      MAUI 27
> GHANA   09     OAHU 28
> GUAM 1963 10     KAUAI 29
> G. SEGRRA 11     O.S.G.B. 1936 30
> G. SERINDUNG 12      QURNOQ 31
> HEART NORTH 13      S. LEONE 1960 32
> HJORSEY1955 14      PROV. SAD-1956 33
> HU-TZU-SHAN      15     CORREGO ALEGRE 34
> INDIAN 16      CAMPO INCHAUSPE 35
> IRELAND 1965 17      CHAU ASTRO 36
> KERTAU 18      YACARE   37
> LIBERIA 1964 19      TRANAARIVE OBSY 38
> TIMBALAI 39       TOKYO 40
> VOIROL 41       INDIAN SPECIAL 42
> LUZON SPECIAL 43      TOKYO SPECIAL 44
> WGS-84 SPECIAL 45      WGS-84 46
> WGS-72 47       ARDEC-87 48
>
> Ray F/KA3EKH
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20251008/05d57c0f/attachment-0001.html>