TAPR PSK Modem -------------- (Kit has been discontinued) The TAPR PSK modem kit is designed for use with FUJI/OSCAR 12, the Microsats and JAS-1B as well as linear satellite transponder operation through OSCARs 10 and 13. In addition, it is suitable for weak-signal work on terrestrial HF and VHF paths. The PSK modem has been tested with Kenwood, ICOM, and Yaesu radios. The kit consists of three (3) printed circuit boards and all parts to populate them. It also includes cabling, connectors, LEDs, bargraph displays and switches to complete the modem. It does not include a case or power supply (it runs on 11-16 VDC). A case is available separately. Construction requires a fine-tip soldering iron, a steady hand, two or three quiet evenings, and access to a calibrated oscilloscope. A function generator or calibrated audio tone source and a Digital Volt Meter are useful, but not mandatory. A front panel switch bypasses the PSK modem and restores normal operation to the TNC, including radio connections. Front panel indicators include a LOCK LED (indicating lock to an incoming signal), signal strength bargraph and center tuning moving-dot display. Manchester (for satellites), as well as normal PSK transmit modes, are available at the flip of a front panel switch. Doppler correction polarity (and defeat) is also switch selectable. The TAPR PSK modem requires transmit data and a x16 or x32 clock from the TNC; it supplies RX data, RX clock and DCD to the TNC. Any TNC-1/clone (Heathkit HD-4040, AEA PKT-1) or TNC-2/clone (AEA PK-80, GLB TNC-2A, PacComm TNC-200, MFJ 1270/1274/1278) will interface with no problems. The PK-232 will interface easily to the PSK modem with the use of TAPR's modem disconnect kit. Other units may interface but have not been reported to TAPR. Units with software HDLC may not interface (GLB PK-1 series, Kantronics KPC- series and KAM for example). The TAPR PSK modem utilizes a Costas loop demodulator which has a 3 to 8 dB better performance than designs which limit the signal at the input stage. It has been extensively tested and optimized for 1200 bps operation. Other speeds are possible with changes to the input filters, but these changes are untested and undocumented. Note: The PSK modem is not designed for recovery of the 400 bps non-HDLC telemetry transmissions from OSCARs 10 and 13. These transmissions are not compatible with standard packet TNCs. ========================================================================== Tucson Amateur Packet Radio Corp. 8987-309 E Tanque Verde Rd #337 * Tucson, Az * 85749-9399 Phone: (817) 383-0000 * Fax: (817) 566-2544 TAPR is a Non-Profit R & D Corporation ==========================================================================