Unterschiede

Hier werden die Unterschiede zwischen zwei Versionen angezeigt.

--- projekte:3cmbeacon:start [2023/01/06 18:26] – thasti
+++ projekte:3cmbeacon:start [2023/01/06 18:30] – thasti
@@ Zeile 3: / Zeile 3: @@
 The goal of this project was building a 10 GHz beacon transmitter suitable for long-term unsupervised operation from commercially available integrated circuits. To make full use of the transmit power constraints in Germany, an output power of 1-2 W was targeted. Support for contemporary digital beacon transmission modes such as [[https://rudius.net/oz2m/ngnb/pi4.htm|PI-4]] was also a requirement for the design. Remote monitoring (telemetry) and control functionality was the third critical item on the feature list for a complete design.
-{{:projekte:3cmbeacon:pcb_v1_small.jpeg?400 |}} {{ :projekte:3cmbeacon:pcb_v2_small.jpeg?400|}}
 **Quick Pointers:**
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 ===== Architecture =====
+{{ :projekte:3cmbeacon:odu_tx_ref.jpg?500|Fully assembled transmitter PCB on temporary heat sink}}
 A simple block diagram of the beacon transmitter is shown in the figure below.
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 ===== RF Design =====
+{{ :projekte:3cmbeacon:pcb_v1_small.jpeg?425|}}\\
 One of the key design features that helps with driving down cost is working with a commercial four-layer FR4 stackup. These have become ubiquitous and cheap to use, so one supplier (JLCPCB from China) was chosen and their PCB process characterized for RF performance. Two dedicated RF test coupons were designed: Based on the results of long simulations, prototype designs for SMA connector footprints, microstrip, coplanar waveguides etc were designed.
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 ===== Testing =====
+{{ :projekte:3cmbeacon:pcb_v2_small.jpeg?400|}}
 Before going into continuous operation at DB0HDF, the transmitter hard- and software were extensively tested on the lab workbench. The output power, phase noise and spurious performance was first evaluated, with a particular emphasis on varying input voltage conditions. Long supply wires could possibly cause regulator instabilities in final installations, and (resistive) voltage drop could across the cable could cause unexpected input voltage conditions.
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 ===== Transmitter Integration at DB0HDF =====
 With the PCB battle-tested, the beacon needed to be assembled in a setup suitable for extended outdoor installation. A small add-on PCB allows supplying power and serial data through a common Cat.5 Ethernet cable with RJ-45 connectors. On the receiving end, a Raspberry Pi shield was designed that houses a relay for power control and RS-422 level conversion for the on-board serial port.
-{{:projekte:3cmbeacon:odu_tx_ref.jpg?600|Fully assembled transmitter PCB on temporary heat sink}}
 {{:projekte:3cmbeacon:idu_shield_ref.jpg?600|Raspberry Pi Shield}}