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-rev-c--s-up-down-amsat-iaru-link-model.xlsx) and
  3. the link budget for VHF to VIOLET, the uplink, and UHF to the Earth, the downlink (ccp-cnb-00045-rfc-rp-rev-b--vhf-up-uhf-down-amsat-iaru-link-model.xlsx).
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, approximately one orbit per day of the 15.7 orbits per day and
  • downloading data from the payload instruments, named GRIPS (GNSS Receiver for Ionosphonic and Position Studies) and SASI (Spectral Airglow Structure Imager), approximately 14.7 orbits per day of the 15.7 orbits per day.

The three planned amateur communication modes are:

  • an S band half-duplex record-and-playback mode (VIOLET will beacon on carrier frequency centred at 2405.40 MHz, followed by recording for 14 seconds, a 150 kHz wide spectrum, followed by a 1 second pause, followed by a half-duplex playing back of the 150 kHz wide recorded signal. 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, a carrier frequency at 145.910 MHz, demodulates the audio, in full-duplex mode, modulates the audio and transmits it on a UHF carrier frequency of 436.830 MHz,  as an analog narrowband FM signal.) and
  • a packet bulletin board (VIOLET receives AX.25 packets on VHF, a carrier frequency of 145.910 MHz, modulated at 9600 bits per second using frequency shift keying, followed by transmitting AX.25 packets on UHF, a carrier frequency of 436.830 MHz, modulated at 9600 bits per second using binary phase shift keying.).

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 12.3 dBiC for the signal to VIOLET and a UHF antenna with a gain of 15.5 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 1.8 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 2405.4 MHz, 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 62 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 and built. We anticipate that the call sign of VIOLET would be VE9VLT. Information at this page often changes as the project advances.

IARU frequency coordination

On March 9, 2021, we received a frequency coordination document from the International Amateur Radio Union (IARU) containing information which is paraphrased as:

  • VHF uplink, Earth to VIOLET, 145.910 MHz, emission designators
    • 12K5F3E (FM transponder) and
    • 12K5F1DBN (FSK 9600 bits/s, AX.25),
  • UHF downlink, VIOLET to Earth, 436.830 MHz, EIRP 26 dBm maximum, emission designators
    • 12K5F3E (FM transponder) and
    • 15K0G1DAN (BPSK 1200, 2400, 4800, 9600 bits/s, AX.25),
  • S band uplink, Earth to VIOLET, 2405.400 MHz, EIRP 33 dBW maximum, emission designators
    • 12K5F1DBN (FSK 9600 bits/s, AX.25) (This is to be added to the ITU RF application.),
    • 150KF1DBN (FSK, AX.25),
    • 150KX3X (record and playback),
    • 2M00G1DDN (QPSK),
    • 2M00G1DBN (BPSK),
    • 2M00G1DCN (BPSK error-control coded),
    • 2M00F1DFN (MSK) and
    • 150KF1DCN (AFSK error-control coded).
  • S band downlink, VIOLET to Earth, 2405.400 MHz, EIRP 33 dBm maximum, emission designators
    • 2M00G1DDN (QPSK),
    • 15K0G1DAN (BPSK 1200, 2400, 4800, 9600 bits/s, AX.25) (This is to be added to the ITU RF application),
    • 150KX3X (record and playback),
    • 2M00F1DFN (MSK),
    • 2M00G1DBN (BPSK) and
    • 2M00G1DCN (BPSK error-control coded).
  • with a telecommand station having the call sign VE9CNB,
  • having a deployment from the International Space Station (ISS), at a planned orbit,
    • apogee 410 km,
    • perigee 408 km,
    • orbit inclination 51.64 degrees and
    • orbital period of 92.68 minutes.

CubeSat NB ground station, earth station

At this time, the planned CubeSat NB ground station

with these antennas

  • VHF right circularly polarized 12.3 dBic Yagi-Uda antenna,
  • UHF right circularly polarized 15.5 dBic Yagi-Uda antenna and
  • S band right circularly polarized 30.0 dBic 1.8 m diameter dish

having radiation patterns distributed as this CubeSat NB document

Many details are available in our publicly available read-only link to our

miro board: CubeSat NB ground station.

Amateur radio activities at the University of New Brunswick

Some activities are documented at

This page was updated on January 15, 2023, by the CubeSat NB Team.