Category Archives: FAQ

Frequently Asked Questions

HF decoding

Picospace HF payloads send telemetry data using standard JT9 packets.

WSJT-X software has been modified to allow upload of JT9 telemetry from balloons to SNUS (spacenear.us) website.

The software can be downloaded here:

Tested version 1.5.0-devel:

Windows Installer
Source file

Beta version 1.6.0-devel:

Windows Installer
Source file

Note: 1.6.0-devel can also decode WSPR

The modified software adds two options on the main page:

* Telemetry: selecting this will allow packets to be uploaded to to server
* Location: selecting this will send your grid square to be displayed on SNUS map

NewImage

Some important parameters for the software setup:

* The frequencies will need to be set to the standard WSPR dial frequencies:

30m: 10.138700Mhz
20m: 14.095600Mhz

This will put WSRP in the standard 1400Hz-1600Hz audio band, and JT9 at somewhere outside of the WSPR segment, typically at 800Hz/1000Hz/1200Hz/1800Hz, depending on flights. Please see flight announcement for the JT9 offset.

This allow simultaneous tracking of multiple balloons at the same time.

Please note the software will decode multiple payloads automatically with no special settings, ie. if the setup can decode one payload it will decode multiple payloads. You just need to have the correct dial frequency and time synchronisation.

From PS-57, only 30m band will be used unless specified otherwise.

* See the WSJT-X manual here for setup details.
* Mode should be JT9. The “JT9 AND JT65” mode expects the different signals are in different parts of the audio bandwidth and is not recommended.
* Add your grid square in the settings for the “Location” option to work
* Enable Location and Telemetry options to allow upload of your grid square and telemetry data.
* WSPR/JT9 start transmitting at the beginning of the scheduled minute, so the computer will need to have the time synced to a time server on the internet.

The software behaves like a standard WSJT-X version otherwise, and can be used for standard QSOs. If the software is not tracking a PICOSPACE balloon, please turn off the Telemetry option to avoid uploading unnecessary data to the servers.

The positions of the balloons are displayed on SNUS tracking page spacenear.us which can be accessed through the Tracking shortcut at the top of this web page.

A big thank you to the UKHAS guys for making SNUS available to the HAB community.

TX time and frequency schedule (minute in the hour and TX band).
Each of the following timeslots has two minutes of WSPR transmission, and followed by 2 x one minute JT transmissions.

0 30m // Mandatory JT9 and WSPR, two per hour
10 30m // Optional JT9 and WSPR – Only when battery is charged
20 30m // Optional JT9 and WSPR – Only when battery is charged
30 30m // Mandatory JT9 and WSPR, two per hour
40 30m // optional JT9 and WSPR – Only when battery is charged
50 30m // Optional JT9 and WSPR – Only when battery is charged

Two instances of WSJTX software can be run at the same time, by specifying the -r option on the command line. It is recommended that one instance is used to decode WSPR and perform band-hopping if CAT is used, and one to decode JT9.

C:\WSJT\wsjtx\bin\wsjtx -r WSPR

Only for Multi-band payloads

Versions from 1.6.0-devel will also add an option, “PS hopping” on the WSPR page to map the band-hopping sequence to Picospace payload TX schedule.

This is to cater for the multi-band payloads, which is no longer required from PS-57 as only payloads will transmit only on one frequency, 30m unless specified otherwise.


0 30m // Mandatory JT9 and WSPR, two per hour
10 20m // Optional JT9 and WSPR – Only when battery is charged
20 30m // Optional JT9 and WSPR – Only when battery is charged
30 20m // Mandatory JT9 and WSPR, two per hour
40 30m // optional JT9 and WSPR – Only when battery is charged
50 20m // Optional JT9 and WSPR – Only when battery is charged

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When this option is enabled, the bands lower than 30m will be mapped to 30m, and the bands higher than 20m will be mapped to 20m.

The “Band Hopping” option needs to be selected as well.

The bands should be selected as shown here:
NewImage

This will allow the 20m and 30m bands to be cycled through in 10 minute intervals.