[aprssig] proposal for APRStt grid loc. Σχετ: 60 Grid Square............

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Sat Feb 14 15:57:06 CST 2015


Pardon my literalness, but if you say "Row 1st, Col 2nd", then for KM 
I'd go to row K up the right side and column M across the bottom and get 
520 whereas your example says it's 502 which seems to be column K and row M?

More than one example would make it more clear for those of us that need 
to see what you're talking about.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

On 2/14/2015 7:33 AM, George Vastianos wrote:
> Hello Bob
>
> IMO in APRStt the conversion between grid and numbers should be very 
> easy in a way that no calculation algorithm will be needed by the user 
> and only a small printed table will be enough. In this way with a 
> small printed paper in the pocket and the low cost HT anyone could 
> define his position in the APRS system (of course if he knows his 
> position and if there is APRStt infrastructure in his area...)
>
> In the attached file (PNG picture) you can find my proposal for a 
> simple conversion table
>
> the result is that you add a group of 3 number-digits for each 2 
> letters of the grid
>
> eg. KM = 502, KM17 = 50217, KM17uw = 50217902, KM17uw48 = 5021790248
>
> based on the fact that my proposal uses only the 0-9 digits and not 
> the *,#,A-D this makes it compatible with the APRStt format.
>
> The conversion table was designed in a way that the conversion from 
> the number to ascii will be very easy (even for 8-bit 
> microcontrollers) and will not require usage of memory lookup tables.
>
> Below is a sample code (in basic style) that will convert the 3-digit 
> number into the Grid Square letter characters (e.g. for i=502 then 
> Chr(C1) becomes "K" and Chr(C2) becomes "M")
>
> ----------------------------
>
> 'example I=536 will print "NQ"
>
> Dim I, X, CO1, CO2, C1, C2 As Integer
> I = 536
> If (I >= 100 And I < 340) Then
>     CO1 = 10: CO2 = 65
> ElseIf (I >= 400 And I < 640) Then
>     CO1 = 40: CO2 = 75
> ElseIf (I >= 700 And I < 940) Then
>     CO1 = 70: CO2 = 85
> End If
> X = Int(I / 10)
> C1 = 65 + X - CO1
> If C1 < 65 Or C1 > 88 Then End 'ERROR i is outside limits
> C2 = I - X * 10 + CO2
> If C2 < 65 Or C2 > 88 Then End 'ERROR i is outside limits
> MsgBox Chr(C1) & Chr(C2)
>
> --------------------------
>
> In the above sample code the C1 and C2 are integers that contain the 
> ASCII value of the 2 characters..... This proposal is not only for the 
> satellite app but for the APRStt in general.
>
> 73
>
> sv8gxc
>
> P.S. The limit of 40KB in aprssig list....really sucks! i tried 3 
> times to send the same email until it fits in limits. SORRY in case 
> you received multiple times the same message (e.g. amsat-bb)
>
>
>
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> http://www.tapr.org/mailman/listinfo/aprssig

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