Thursday, October 13, 2011

HAM Control

Yeah, its been raining outside alot, so we've been inside doing "nerdy" stuff with the kids.

We've quickly learned that HAM radio is all about messing with gadgets, and NOT talking on the air. No one seems to have anything good to rag about!

Here is our HT, talking to the PC to program its frequencies. In between the two we have a breakout box and Bus Pirate, listening to the commands and data passing between the two.

The Bus Pirate is a VERY COOL TOOL! Highly recommended. The HT talks to the PC with simple RS232 at 19.2kbps. The data has is thinking up all kinds of fun projects!

How about a small uController, programming a new freq into the radio, then listenning for a repeater as it steps through all available frequencies. In the end, we dump a table of all repeaters (and their associated CTCSS).

We hooked up an ADC and captured the PTT and Speaker voltages.

Here, you can see the blue PTT line pulled low, and the yellow Speaker voltage shows the repeater key up in response.

Here is the repeater responding with its verbal callsign after we PTT it.

What if we had a $2 uController that pulled the PTT low, then 'listened' for a response on the Speaker line?

Another idea we are soldering up is a cheap voice recorder ($3) into the setup. Using this and a low-cost HT, we could make a simple repeater: the uController listens on the Speaker and when it detects a signal, it activates the voice recorder to record up to 40 seconds of voice. Then, after it senses the signal completed, the uController commands the radio to switch frequencies and then broadcasts the received signal from the recorder. It waits for a response, and repeats what it hears back on the original frequency to the HAM down in the canyon.

What other ideas can you think of? Come on, its raining outside and we need more projects!