Thursday, August 6, 2009

Tards repeated on 2 meter amateur radio

Aaron has constructed a 2m receiver and we finished aligning it. Ollie duct-taped a dual band whip base station antenna to make it vertical and we connected it to a vhf/uhf duplexer. The UHF side was connected to a 448.500 MHz transmitter at about 1.5 Watts. The receiver was connected to the VHF side at 147.740. The units were linked with a small PIC microcontroller that Ollie helped me build during the long winter. This provides Morse code ID, tail, and tailbeep, as well as timeout functions. This is all the features you need for a ham repeater which allows you to be rebroadcast from a good vantage point. After a cranky solder joint on the transmitting crystal was identified, I did a road test with KB1FLG with my HT in the car. I was able to go 4.5 miles up route 12 before things got scratchy, not bad for an antenna laying the driveway. This could be the basis of a system that is remotely located and/or solar powered. (BTW, in case you care, the TX crystal was from a toy walkie talkie at 49.830 MHz, which x3 and x3 is 448.5)

1 comment:

  1. Cool project, pictures or videos please!

    Have you discovered the magic of the Atmel AVR? It's just like the PIC except with a real RAM stack so it supports ANSI C and it's fully supported by GCC and the GNU toolchain. I started using one to make a remote head for my Elecraft K2. I implemented the tuning knob, LCD display, and serial remote control. It was great finally being able to do 8 bit micro development in C on Linux (or windows) using all free tools.