[RadioTelescope] Stepping rates

Andrew Williams andrew at physics.uwa.edu.au
Mon Oct 11 21:51:56 WST 2010


On 11/10/2010 9:09 PM, Harry McNally wrote:

> Ok. I was either being ambitious (put all the radio electronics out on the
> dish) or you -could- buy a slip ring that includes coax connections. They are
> available with many different options.
>
> Have another look at that link again, it's mainly signal rather than power
> connections including fibre.
>
> It even lists radio telescopes here:
> http://en.wikipedia.org/wiki/Slip_ring

I suspect all the slip rings are expensive, and that the high-frequency 
and optical fibre slip rings are staggeringly expensive...

Also, it probably won't be UCC that builds the receiver electronics - 
it's likely to be a commercial or custom made feed horn and low noise 
amplifier unit that someone at UWA or Curtin has lying around, probably 
needing dual 50 ohm coax with DC power for the LNA's via the coax (and 
those 500MHz slip rings might not work down at DC). If there any RF 
hardware hackers around UCC, they could probably adapt a Foxtel 
satellite horn and LNA's - not sure what frequency or bandwidth they 
would use though.

Then you'd need all the gear to digitise the result - computer 
controlled signal generator, ADC, etc. The individual components are 
likely to be lying around physics, or you (or Physics) could just buy a 
complete USRP kit: http://www.ettus.com/.

The MWA folks were using a USRP2 and a wideband antenna to do RFI 
monitoring at Boolardy on the last site visit - they picked up a signal 
at 98.9 Mhz, fired up Gnu Radio on the server collecting the data, and 
listened to JJJ from Geraldton...

Andrew


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