Monthly Archives: February 2019

Blog

Flying season has begun

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Today we started a new season with our RC models on the airfield. Days are now longer and the Sun provides more energy to the off-grid system which is powered by one standard sized solar panel.

Nominal peak power (Pmax):   225 W
Maximum power voltage (Vmp): 30.2 V
Maxium power current (Imp):  7.44 A
Open circuit voltage (Voc):  36.6 V
Short circuit current (Isc): 8.06 A

For storing captured energy we use Panasonic LC-XB12100P battery with a capacity around 100 Ah and some spare car batteries with the capacity around 55 Ah, thus total capacity is 200+ Ah.

Last year the MPPT tracer 1210a provided 127 kWh and today it juiced the battery to 13.8 V which is considered fully charged.

Blog

Maidenhead Locator System

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Have you ever wondered how the so-called QTH Locator or WW locator is calculated and what is behind it?

Many HAMs and radioamateurs use it but ask them where their locator came from and not many can tell you. There are plenty of web based applications which overlay Google maps with a locator grid and many of them provide a calculator for conversion from other geographic coordinates to Maidenhead Locator System.

clear all;
close all;
clc;

m = mobiledev();
m.Logging = 1;
pause(2)

lat = 50.2727514;
lon = 14.2518494;

alphabet = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','R','S'];

locator = [];
len = 4;

lon = lon + 180;
lat = lat + 90;

lon = lon / 20;
lat = lat / 10;

for i = 1:len
    
    lon_tmp = floor(lon);
    lat_tmp = floor(lat);
    
    if mod(i,2) == 0
        
        locator = [locator int2str(lon_tmp) int2str(lat_tmp)];
        lon = (lon - lon_tmp) * 24;
        lat = (lat - lat_tmp) * 24;
        
    else
        
        locator = [locator alphabet(lon_tmp+1) alphabet(lat_tmp+1)];
        lon = (lon - lon_tmp) * 10;
        lat = (lat - lat_tmp) * 10;
        
    end
end

locator

Corresponding output:

locator =

    'JO70DG05'

And the most amazing aspect is executing .m files on your iPhone. The disadvantage is that an internet connection is necessary for computing via the application.