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[aprssig] Easy Predicting GO-32 for the mobile!

Robert Bruninga bruninga at usna.edu
Fri Oct 12 23:33:05 UTC 2007


Looks like with the minimum elevation for Mobile reception of
GO-32 being 30 degrees, this translates to usable ground tracks
every 12 degrees of longitude which means we would need 5
tables, one for each of these cities:
SFO, SLC, Dallas, Chicago and Wash DC.  

These tables and timeswould not change except twice a year
switching to/from Daylight Savings time.  For example, here is
the WashingtonDC table (rounded to nearest 5 minutes).

Day1 Day2 Day3 Day4 Day5 Day6 Day7 Day8 Day9 Day1
---- ---- ---- ---- ---- ---- ---- ---- ---- ----
0930 0910 1025 1005 0940 0920 1040 1015 0950 0930
     1050                1055
2050 2030 2005 2125 2100 2040 2015 2135 2110 2050
     2210 2145                2155

Today is day 3.

If you lived south of DC, then your passes would be 5 minutes
later in the morning and 5 minutes earlier in the evening.  For
each table, the only info you need is what day you are on.  Then
you can count forward or backward in time to predict any passes.

Remembering that for uplinks, there is an additional pass 100
minutes before and after each of those shown as a single pass.

>> ELEVATION ANGLE:  ... is also easy to infer.  
>> The days with double passes are near 30
>> degrees each (barely detectible by the mobile).
>> The days midway between these lowest peak passes 
>> are the highest elevations (75 or more degrees).  
>>
>> Happy wilderness traveling!
>>
>> Bob, WB4APR





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