23cm datatransceiver

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To make packetradio more ‘fun’ I designed in 1998 this 23cm transceiver with which it is very simple to get QRV on 38.4 kbps up to about 150kbps. Running TCP/IP a lot is possible: browsing, mail, news but also streaming audio or even video! All you need is a transceiver, a modem and an scc-card in a pc running linux or jnos. Or a megabit tnc described next. The transceiver is operational at quite some nodes and users in the Netherlands and abroad. It can handle datatraffic using a manchester modem but just as well WBFM audio. The NF is 3dB, and the output power is about 3W.

23cm data trx schematic diagramSince packet radio died (sic), the transceiver can get a new life as wideband audio transceiver. This allows even stereo transmissions. With proper tuning you can even use this transceiver for narrowband transmission, but of course this is not optimal.

23cm data trx top layer pcb

The stripline vco oscillates from 1100-1300 MHz and is phase locked with the cheap TSA5511. With a crystal of 3.2 MHz this allows a tuning step of 50kHz. Since the transceiver is designed as datatransceiver, no audio amplifier or mic-amp are included, but these can simply be added off board.

The printed circuit board is euro sized (10×16 cm). The board is double sided, with the top side left all copper.

23parts

 

 

 

 

Originally, the software in assmbler was developed for the Atmel 89C2051 chip.

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