Monday, January 09, 2012

GAGA-2: Distance RTTY Test

As I said in my previous post about GAGA-2 one vital test was the the radio transmitter worked over a long distance. I'd done the same test for GAGA-1 and went back to the same location for a GAGA-2 test.

My father drove off to one end of the reservoir with GAGA-2 transmitting happily from the back of his car (an estate car) and I drove to the other with my radio and a Yagi. It was obvious as I was driving to the listening point across the reservoir that things were going to work because I could still hear GAGA-2 from time to time using a simple whip aerial.

Once on the causeway in the left of the picture I hopped out of the car and pointed the Yagi in roughly the right direction. The RTTY signal came in loud and clear. Moving the Yagi from side to side made it easy to figure out where the transmitter was.

Measuring on Google Maps shows that this time the distance was roughly 6km (3.7 miles) with trees and the body of the car in the way (GAGA-2 wasn't even lifted up to window level). That's still about 1/5 to 1/6 of the distance that GAGA-2 will lift up to, but gives confidence that the 10mW transmitter and, most importantly, the new antenna are going to supply clear enough telemetry for the flight.

Here's a shot from the car while transmitting. I was about 6km on the other side of those trees and across the reservoir. Happily there won't be any trees or car between GAGA-2 and the radio on the day.

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