HF Radio

• Use 40M
• 1/4W into 2W amplifier
• Domino and RTTY 110 baud
• Spacenear.us compatibility: Yes for both Domino and RTTY
• Duty: Starts at top of minute, Domino, RTTY, RTTY
  • About 25s transmits for 20s
• Current: 200ma at TX, 75ma idle

HF telemetry data will be plotted on to the Spacenear.us map. To contribute you'll need a HF radio which can do SSB on 40m, an aerial, a computer running Windows/Linux/Mac OSX and some software: dl-fldigi. Dl-fldigi is an adapted version of the excellent soundcard decoding software fldigi, the modifications allow for telemetry strings to be detected, validated and uploaded to a central server where they are then plotted onto a map.

Currently the plan is for the transmitter to tx on 7.1035 MHz which means that you should tune to 7.102 Mhz on USB mode. The transmitter will alternate between RTTY and DominoEX - dl-fldigi can autoconfigure this for you, all you need to do is press the switch button on the right hand side of the interface.

• Grab the latest binary or source from github
• Unzip and install it
  • On Mac OSX open the dmg and copy dl-fldigi and dl-fldigiHAB to your Application folder
  • On Windows follow the installation wizard
• Open the dl-fldigiHAB version.
• Follow the wizard
  • Please enter your latitude and longitude (roughly) in a decimal format please DD.DDDD with +/- rather than NSEW e.g. 52.0000 -0.12345. This will plot your listening station on the map allowing propagation to be calculated.

• Select wb8elk2 from the payload list

• Once you've selected wb8elk2 you then need to click the autoconfigure button on the right hand side.

• Now tune the radio to find the telemetry, line up the red decode lines on the waterfall and the data should start to decode.
  • Green means that the string you received passed its checksum
  • Red means it failed
• To quickly change between modes there is a button below the autoconfigure button which will switch between RTTY and DominoEX to allow you to grab as much data as possible.

• Valid strings (green) will be uploaded to the server and will be plotted onto the Spacenear.us map

Guide and images adapted from the UKHAS wiki

Serial Format: 4800, 8, N, 1

Wait for “!” char from HF TX, then send serial command. Start command with $$, end with *

ASCII Hex Comma delimited 8-bit values.

• 8-bit value
• 8-bit value
• 8-bit value

Telemetry Data Example:
$$T,FF,0F,F0*

Command to Transmit Lat/Lon/Alt/Time Now:
$$P*

Set telemetry data rate high ( every 1 minutes ) :
$$H*

Set telemetry data rate medium: (every 10 minutes):
$$M*

Set telemetry data rate low ( every 1 hour ):
$$L*

DO NOT TRANSMIT ANYTHING FOR 2 minutes (Power draw constraint when sat txing):
$$X*