ARRL HB 92 CHP 28 FIG. 16 ,91 CHP28 FIG.28
Description: This board provides a method to sample the RF and indicates the FWD and REV SWR. The circuitry also provides circuitry for chopped or unchopped video signal for a scope or monitor. The circuitry consists of a 7812 regulator, a 4066 IC and a three transistor video amplifier with 75 ohm output impedance.
Description: This project adds the following capability to the Ramsey Transceiver: Remote control via computer serial port, CTCSS encoding, DTMF encoding, 200 memory channels, user notes per channel, and memory scanning. The computer interface board interfaces to one of the diode selected channels maintaining the remaining 11 diode programmed channels. Contact the author for the computer program. ICs required: 80C51, MAX232, and PCD3312.
Description: The project provides the interface between the radio and a computer serial port to receive SSTV, Facsimile, and APT. The core software package enabling the computer to display the received signals was written by Ederhard Backeshoff, DK8JV. Other JVFAX software that redefines the computer serial port to 4 bit parallel data will also work with this interface. The circuits consist of a four stage low pass filter to remove the 2400 audio subcarrier leaving the DC level corresponding to the envelope of the video that is converted to 4 bit digital data via the ADC0820. IC's required are (2) LF347, 7812,7912, 78L05, ADC0820, 1498, 74LS14, 74LS158, and 1488.
Description: This adapter is used to receive audio APT imagery signals and store the picture in a GIF file using JVFAX 7.0 or TGA file using JVFAX7.1. Devices required: ADC0820, 74LS244, 4046, 4013, and LM3900.
QST Jan 94
Comment: NR1C reports that his club built
this as a club project. He indicated that those that completed the
project ended up with a functional SSTV system that worked nicely on
2 meters and HF.
Description: This is a HF audio to computer sound card interface for decoding PSK signals, uses OP27 OPAMP, (2) 2N2222 transistors.
Description: This is a replacement project for the old TCM3105 Baycom and Poormans style packet modems. The board will also do Bell 202 v.23 with the MX604 IC. A mini kit is also available consisting of PC Board,Crystal, 74HC04 and the MX614 IC. The circuit consists of MX614, (3) 2N2222, 74HC04, 78L05 and a 3.58 crystal.
QST Nov 00
Description: the article lists a number of sites that one can down load computer software to use with the modem. The project uses 2n2222, a programmed 16F877-20P, 622256 32K RAM, MAX23CPE, MX614, and 78L05.
QST Nov 00
Description: The circuit uses 2n2222, TL082 OPAMP, several diodes, and two RS audio transformers.
Description: This monitors the activity on a phone line and has a level output to a voltmeter, audio output, and LED activity indicator. Circuit uses four 1N4006's, LM386, and two 2N3904 transistors.
ARRL HB 00 Fig 22.80
Description: The circuit uses a MAX232, a 7417 and a 78M05 for Rx and Tx audio and PTT interface into the computer serial port. See http://www.plicht.de/ekki/civ/civtoc.html for more details. Board, MAX232, 7417 and 78M05 available.
ARRL HB 00 Fig 22.81
Description : The circuit uses a MAX232, (4) ps2501 opto-couplers, and a 78M05 for Rx and Tx audio and PTT interface into the computer serial port. See http://www.plicht.de/ekki/civ/civtoc.html for more details. Board, MAX232, (4) opto-couplers and 78M05 available for $14.00.