Redundant Digital File Transfer (RDFT)
RDFT is an amateur radio digital mode used to transmit files invented by Barry Sanderson, KB9VAK. Uses DPSKDifferential Phase-Shift Keying.
RDFT was designed for radio amateurs to send files, primarily pictures, known as Digital SSTV, although it was not very popular. Now it is used almost exclusively by the Cuban Number Station (HM01).
Original applications for coding, modulating, demodulating and decoding, which use DSP techniques to work with PC soundcard, were written by Barry Sanderson, KB9VAK. The only GUI application (which utilizes applications written by KB9VAK) known to copy the files (but not necessarily decrypt them) is DIGTRX made by Roland Zurmely, PY4ZBZ.
This software has been long abandoned for other modes and has been replaced by HamDRM and other similar digital SSTV software.
Cuban Number Station
The only station known to utilize RDFT is the infamous Cuban Numbers Stations (Enigma designation HM01). HM01 transmits both a synthesized voice signal as well as the RDFT file transfer mode. Files are sent in .TXT format but are encrypted. This station is known to use the broadcast facilities - via a feeder or other unknown means - of Radio Habana.
- Hobby Level Software
DIGTRX was developed by Roland Zurmely PY4ZBZ, a Brazilian Ham Radio operator. This software was originally intended for use in amateur radio for Digital SSTV, but is also able to send images and other computer files using the computer's sound card.
|RDFT Intro||RDFT EOTEnd of Transmission|
Cuban Numbers Station
- Shortwave Radio HM01 Cuban Numbers Station 9240 Khz (YouTube link)
- Amateur RDFT Example (Mislabeled as WINDRM OFDM)
- Cuban HM01 Numbers Station, 17480 kHz 12/10/13
- I-56578 "The Cuban Lady" HM01
- RadioScanner.RU DIGTRX
- Cuban Numbers Station in HM01 Mode
- The title is a mis-translation from Portuguese. HM01 is not a mode - it is an Enigma designator.
- Cuban Voice/Data Hybrid HM01
- Numbers Stations.com HM01
- Numbers and Oddities Recordings
- You can find HM01 and its ancestor station SK01 recordings at the bottom left of this page
- Priyom.org - HM01