Deciphering Downlink Message Headers
At times a user must look at the raw data sent from the satellite to see if things are working
properly. The first part of the message is very important to understand as it may help identify
problems at a site. Below is an actual message sent from a site.
163708DE08078181NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
Let’s break this down to understand it better.
The first 8 characters are the transmitter ID or DCP address. They are shown in bold below.
163708DE
08078181NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
The next two bytes are the year. In this case the 08 is for 2008.
163708DE
08
078181NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
The next 3 bytes are the Julian day. In this case 078 is March 18 , on a leap year.
th
163708DE08
078
181NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
The next 6 bytes is the time the transmission was received. This should be within the assigned
time window. In this transmission it was at 18 hours, 49 minutes and 03 seconds.
163708DE08078
184903
G51+1NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
The next byte indicates if the transmission was received properly; the G indicates Good. Other
possibilities are P for parity errors and ? for unknown errors.
163708DE08078184903
G
51+1NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
The next two bytes show the signal strength of the signal received at the satellite. In this case it
is 51 which is quite good. Numbers in the high forties are also good; lower forties is fair and 35
or less is surprising to see the transmission making it to the satellite.
163708DE08078184903G
51
+1NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
The next two bytes indicate if there is any frequency drift. A plus 0 is ideal indicating no drift.
In this case the +1 indicates a positive drift of 50 Hz from the center frequency. For each count,
1, 2, 3 etc it refers to 50 Hz per count of drift. A drift of 1 or 2 positive or negative is common.
163708DE08078184903G51
+1
NN021EUB00023BCT@DZ@DY@Dc@Db@Dm@Dxj
System 5000
Outputs 6-33
TM
Содержание WaterLog Series
Страница 1: ...Model System 5000TM Owner s Manual Revision 1 4 2...
Страница 2: ......
Страница 8: ......
Страница 24: ...2 10 Hardware Overview System 5000TM...
Страница 58: ...5 14 Inputs System 5000TM...
Страница 128: ...10 14 System Setup General Setup System 5000TM...
Страница 144: ...12 6 System Setup Inputs Outputs System 5000TM...
Страница 168: ...14 4 Maintenance and Troubleshooting System 5000TM...
Страница 170: ...A 2 System 5000 Specifications System 5000TM...
Страница 172: ...B 2 Pressure Sensor Option Module Specifications System 5000TM...
Страница 174: ...C 2 Analog Digital Option Module Specifications System 5000TM...