About
Ribbit is an OFDM modem specification for multi-media communication over radio created by the Open Research Institute. OFDM was developed for military communicaitons and Ribbit is one of the latest tools for off-grid disaster communications using this '4G' technology, but may also be used for citizen's band or amateur radio QSOs or any other communication need.
Ribbit is similar to the OFDM modem found in Codec2 as used in FreeDV and FreeDATA or the commercial/proprietary VARA modem, but unlike the Windows PC-based VARA modem, Ribbit is an open specification with true cross-platform and open-source implementations. This enables more inter-operable applications, and efficient operation on low power ARM-based devices like Androids, iPhones and the Raspberry Pi (where VARA can only be operated using unnecessarily complicated, slow and inefficient layers of emulation). Efficient use of energy is extremely important during disasters where it's scarcity may be an issue. Ribbit also suits QRP-friendly operation for mobile, Summit and Park radio ops.
Rattlegram is the recommended SMS application for Ribbit. Pictures can be sent and received using ShredPix and Assempix using the same Ribbit modem protocol. Compared to VARA, Ribbit offers better noise rejection and throughput while reducing complexity by working with simple acoustic coupling: over the air-gap between speaker and microphone. More experienced operators may still consider electrical interfaces to a radio using a patch cable and/or audio transformer, a simple 10k resistor or linear pot' is often all that is needed for a clean interface.
When sent using SSB instead of FM the spectral efficiency is comparable to FT8's working below -16dB SNR where voice contacts are no longer possible, and CW, PSK or MSK-based modes might be the other option. Ribbit is a next-generation acoustic (radio) modem that makes getting into digital modes easier than ever.
To get started download any application below for your phone, tablet or computer and join in the scheduled activity times or test at your leisure!
73's from Stuart ZL3TUX
https://www.ribbitradio.org
Applications
Ribbit: Web-app (online only)
- ribbit.nz/app (Christchurch, NZ hosted)
- badkangaroo.github.io (hosted overseas on GitHub)
- Github source code (for offline use or self-hosting)
Rattlegram: recommended SMS app (works offline)
- Google Play Store for Android
- App Store for iPhone
- GitHub source code
Assempix and Shredpix: for sending/receiving pictures (works offline)
rattlegram-cli: for hackers and nerds only
- GitHub source code
rattlegram-desktop: Cross platform (Windows, Mac & Linux) Python/Qt GUI
- Coming soon (WIP)
rattlegram-repeater: store-and-forward repeater Linux BASH script
- Coming soon (WIP)
ribbit-ip: Linux TUN driver (experimental, IPv6 only)
- GitHub source code
Band Plan
General Amateur Operator's Certificate (GAOC) required for the 'ham' bands.
Frequencies and channels are recommendations only, as there is currently no formalized Ribbit band-plan. Operators must comply with the New Zealand General User Radio License (GURL) at all times, in particular observing the EIRP limits noted below.
| Band | Channel (CB) | Frequency MHz | Mode | GAOC Required |
|---|---|---|---|---|
| 70cm | 20[5] | 432.320 | NFM | Yes |
| 2m | 21[5] | 144.210 | NFM | Yes |
| PRS | (22) | 476.950 | NFM | No[1] |
| PRS | (23) | 476.975 | NFM | No[1] |
| 11m | (24) | 27.235 | USB | No[2] |
| 30m | 25[5] | 10.140 | USB | Yes[3] |
| 60m | 26[5] | 5.354 | USB | Yes[4] |
| 20m | N/A | 14.070- 14.347 | USB | Yes |
| 40m | N/A | 7.030- 7.197 | USB | Yes |
| 80m | N/A | 3.550- 3.897 | USB | Yes |
- PRS 'telemetry' channels #22 and #23 - 5W EIRP maximum.
- 11m HF CB channels - 5W EIRP maximum.
- 30 dBW max EIRP.
- NZART 60m sub-license applies. 11.8 dBW max EIRP.
- Suggested channel number for radio programming only (not formalized or published in GURL band plans).
Please treat these as suggested calling channels only and QSY for longer discussions, as per standard radio ettiquete.
Schedule
Suggested activity times for QSOs and radio checks
The nets here are casual check-ins only with no formal script, just send out a PING, say hello and exchange a signal report to complete a Ribbit QSO!
| Band | Ribbit Channel | Schedule |
|---|---|---|
| 70cm | 20 | Sundays 7:15 PM |
| 2m | 21 | Sundays 7:30 PM |
| PRS | 22 & 23 | Mondays 8:00 PM |
| 11m | 24 | Sundays 4:00 PM |
| 30m | 25 | 09:30 PM first Sunday every month |
| 60m | 26 | 09:30 AM first Sunday every month |
- Refer to band plan above for channel information.
- All times are NZ local times.
- The 30m and 60m schedule is on the same activity day as the Alpine Fault Network and staggered to not clash with the AFN SSB schedule.
- Ribbit.NZ is an hobbyist/amateur radio project not associated with the AFN or AREC.
- Ribbit and Rattlegram does NOT replace official emergency communication services like 111, in a real emergency always dial 111 first.
Repeaters
no repeaters yet, please contact Stuart ZL3TUX if you can help with a site or operating one!