21st February 2014 - (Nearly) Final testing of the telescope

18 March 2014 by Angela Taylor

Mike with the transmitter on a nearby hillside.

Luke, Mike and I have travelled back to South Africa to hopefully do the final testing of the C-BASS antenna. We want to try and test the response of the telescope to something we know - a transmitter on a hillside - so that we can then compare that to what we measure in the sky. It's a fairly tricky experiment to do as you need to transmit a signal that you know the brightness and angle of very accurately. You also want to make sure that you don't pick up reflections from everything around you. We had spent a lot of time back in Oxford making sure we had all the accurately made equipment that we needed for the measurement, so we were fairly hopeful that we could achieve what was needed.

Anyhow, in the end it turned out that transmitting an accurate signal was the least of our problems...

First we had to drive off-road to the top of a nearby hillside - not too bad in a 4-wheel drive - and then we had to trek cross-country to get to the edge of the hill whilst avoiding stepping on snakes. Once there we had to try and work out how to balance and power all the test-equipment that we needed to take with us. This was where the problems started. Getting reliable power to our transmitter turned out to take up several days of effort - broken generators, flat batteries, dodgy switches - but eventually we got there and managed to transmit a signal. Only for a thunderstorm to pass through and us have to pack everything up again.

We tried this on several days. I stayed down at the telescope so that I could drive it around and make sure that we collected the data we needed, while Luke and Mike traipsed up and down the hillside. Take a look at their setup in the picture. The sun shade is rather fetching!

Angela and Charles trying to reach the edge of the hillside ...

Every time Luke and Mike went up the hillside we were sadly thwarted in our efforts to do the final measurements, usually by passing thunderstorms. However, in the end we did know how to do the measurement and how to set-up everything reliably. The weather just didn't play ball, and so we'll have to repeat this all again on our next trip. Fortunately we are heading into the dry season now, so there should be better luck next time. Fingers crossed.