VIOLET's radio-info website

Permanent web address

VIOLET's permanent web address is
https://www.unb.ca/cubesat-radio-info

which is re-directed to this page which radio amateurs and the public will use to access technical information regarding the radio interface and description of the protocols. That permanent web address will be documented with the Radio Amateurs of Canada (RAC); that address will also be sent to Innovation Science and Economic Development Canada (ISED), the International Amateur Radio Union (IARU) and the International Telecommunication Union (ITU).

Radio licensing

The application process for the IARU requires that supporting documents are available online.  CubeSat NB chooses to make those documents publicly available here.  Three documents are:

  1. the endorsement from the Radio Amateurs of Canada (RAC) (ccp-cnb-00042-prj-rp-b--rac-endorsement-application-form.pdf),
  2. the link budget for S band, 13 cm wavelength (ccp-cnb-00044-rfc-rp-b--s-up-down-amsat-iaru-link-model.xls), and
  3. the link budget for VHF to VIOLET, the uplink, and UHF to the Earth, the downlink (ccp-cnb-00045-rfc-rp-a--vhf-up-uhf-down-amsat-iaru-link-model.xls).
The link budgets were developed from Jan King's template, AMSAT-IARU_Link_Model_Rev2.5.5.xls, located at IARU spreadsheets.  The link budget documents indicate the proposed holder of the radio licence, even though the link budgets were developed by the team.

Radio amateurs communicating using VIOLET

CubeSat NB is developing VIOLET's schedule, which will be divided between:

  • having VIOLET aid mutual communication among worldwide amateur radio operators using three amateur communication modes, and
  • downloading data from the payload instruments, named GRIPS (GNSS Receiver for Ionosphonic and Position Studies) and SASI (Spectral Airglow Structure Imager).

The three planned amateur communication modes are:

  • an S band half-duplex playback mode (VIOLET will beacon in a 150 kHz allocated bandwidth in the 2433 MHz to 2438 MHz range, followed by recording for 14 seconds a 150 kHz wide spectrum allocation in the frequency band from 2403 MHz to 2408 MHz, followed by a 1 second pause, followed by a half-duplex playing back of the 150 kHz wide recorded signal in that allocated band in the range from 2433 MHz to 2438 MHz.  Any signal or mode sent by an amateur radio operator would be recorded and played back; analog narrowband FM could be used.  Furthermore, the recording would start at the top and bottom of the minute to allow FT8.),
  • an FM transponder (VIOLET receives an analog narrowband FM signal on VHF, demodulates the audio, and in full-duplex mode modulates the audio and transmits it on UHF as an analog narrowband FM signal.), and
  • a packet bulletin board (VIOLET receives AX.25 packets on VHF and transmits packets on UHF.).

The exact frequencies have not been assigned.  Our current link budget for S band, in the document linked above, has a 2.1 m diameter dish for communication with VIOLET, when 25 degrees above the horizon.  The ground station has a VHF antenna with a gain of 12.9 dBiC for the signal to VIOLET and a UHF antenna with a gain of 16.2 dBiC for the signal from VIOLET, when VIOLET is 10 degrees above the horizon.  The S band link budget is more constraining than the VHF and UHF link budgets.  This informaton is provided to allow worldwide radio amateurs to plan.  VIOLET's web address was announced to the amateur radio community and some feedback was received.  That feedback is shown here:

  • In S band, the use of narrowband signals by radio amateurs would improve the S band link budget and antennas with a gain less than a 2.1 m dish could be used.
  • The S band Doppler shift may be approximately calculated from the formula, fDoppler/fCarrier = vobject/c, where fCarrier is the carrier frequency, vobject is speed of VIOLET in orbit, c is the speed of light, and fDoppler is the Doppler shift experienced at the receiver on the ground.  Using 2.438 MHz as an example, even though the frequency has not been allocated, with VIOLET's orbital speed of 7.7 km/s which is the same as the International Space Station, fDoppler would be approximately as high as 63 kHz as VIOLET initially approaches the ground station.

On September 12, 2019, CubeSat NB decided to use amateur radio frequencies for VIOLET.  VIOLET is still being designed.  As of July 24, 2020, our best estimate of when VIOLET would be deployed from the International Space Station is in early 2022.  We anticipate that the call sign of VIOLET would be VE9VLT.

Amateur radio activities at the University of New Brunswick

Some activities are documented at

This page was updated on July 30, 2020, by the CubeSat NB Team.