Satgen72  Dove a simple but fascinating satellite  by GM4IHJ 14 Aug 90

For the past week the Brasilian microsatellite DOVE , Oscar 17, has been
sending telemetry and packet information. To receive it, all you do, is
tune your terrestrial packet receiver to 145.825MHz. Keep your ordinary
packet, audio and squelch settings, and use almost any 2m aerial.

Dove orbits go past UK at about 100 minute intervals between 0830ut and
0120ut ( BST 0930 to 0220 next day ). Rough times of UK passes (all utc)
Dove UK Acquisition Times UTC + or - 5 minutes during August 90
 14   15   16   17   18   19   20   21   22   23   24   25   26   27   28
0020 0836 0110 0038 0008 0825 0055 0025 0841 0114 0042 0013 0829 0100 0030
0903 1014 0810 0919 0852 1003 0935 0908 0841 0814 0924 0856 1008 0940 0912
1042 1154 0947 1059 1030 1142 1115 1047 1019 0951 1103 1035 1147 1120 1051
1222 1334 1126 1238 1211 1322 1254 1227 1159 1131 1243 1215 1327 1259 1232
1402 1503 1306 1418 1350 1502 1434 1406 1339 1311 1423 1335 1506 1439 1411
1541 1651 1447 1557 1529 1640 1603 1545 1518 1450 1602 1534 1645 1618 1550
1718 1827 1624 1734 1707 1816 1750 1723 1656 1629 1738 1712 1820 1754 1727
1854 2003 1800 1909 1842 1952 1925 1858 1832 1805 1914 1847 1956 1930 1903
2030 2141 1936 2046 2018 2129 2102 2035 2008 1941 2051 2023 2134 2106 2039
2209 2322 2113 2225 2157 2310 2242 2214 2146 2118 2230 2202 2315 2247 2218
2351      2253      2339           2356 2327 2259      2344           0000
Part of a typical Dove telemetry download is :- DOVE-1>TLM: 00:59 01:5A
02:8E 03:35 04:5C 05:59 06:6E 07:4A 08:70 09:6A 0A:A5 and on to 38:C8
These are not ordinary numbers. They are hexadecimal. The 1st of each pair
is the telemetry box address, the 2nd is its contents Eg 0A:A5 means that
box hex 0A reports the actual volts on the 5v bus. To work out this actual
volts , take contents hex A5 =165 , and feed this into the decode formula
for this box , Volts = Contents times B (where B= .0305) =165 x .0305
= 5.0325 volts.

In the same blocks of tlm ,boxes 26 hex to 2A hex change in 45 seconds
from 26:70 27:01 28:4D 29:01 2A:03 to 26:01 27:44 28:66 29:01 2A:01
Taking box 26, it changes contents from 70 hex= 112 to 01 hex =1. Put this
in its decode formula and we see that Solar array on the -X face of the
satellite has changed current produced from +.22275 to -.0149 amps. If you
check the other boxes you will see the +X array feeding box 27 has gone
up, while the rest have stayed much the same. In fact these boxes tell you
exactly how the satellite is spinning in relation to the Sun. You can
check this by noticing that they all go to low contents values when the
satellite goes into earth shadow.

If you are interested this satgen will be followed this week by a bulletin
reporting all the Dove telemetry box numbers, their contents and their
correction formulas. In addition future satgens will give more details as
to how Dove can be used for a wide range of interesting space experiments.
Hopefully Dove is now clear of computer crashes that put it out of action
for the last 5 months. In the next few weeks controllers will upload the
computer generated voice software so that it can " talk " these same
telemetry boxes so you will not need packet to download the telemetry. It
will also be "talking" peace messages uploaded from schools all over the
world. NOTE.  Dove will be off during uploads. 73 de John GM4IHJ@GB7MAC