[Tagging] Radio telescopes
61sundowner at gmail.com
Fri Oct 26 02:21:49 UTC 2018
On 26/10/18 09:44, Graeme Fitzpatrick wrote:
> & to throw another spanner in the works :-), what do you call
> satellite dishes, either bubby ones for home use
> https://goo.gl/images/qaDzSX or big commercial versions
> They're certainly not towers, but they definitely are for
> communication purposes.
Err the first one could be for reception only, so not communication.
They usually receive TV signals. They are fairly frequent in remote
areas, and with ex-pats who want to look at their home TV stations.
There is little to distinguish between the reception only and two way
> On Fri, 26 Oct 2018 at 07:45, Kevin Kenny <kevin.b.kenny at gmail.com
> <mailto:kevin.b.kenny at gmail.com>> wrote:
> On Thu, Oct 25, 2018 at 4:46 PM Warin <61sundowner at gmail.com
> <mailto:61sundowner at gmail.com>> wrote:
> On 25/10/18 23:56, Paul Allen wrote:
>> BTW, these days few radio telescopes are dishes. Most of
>> them are phased arrays and not on towers
>> or masts.
> That depends on the frequency of operation.
> New dish reflecting ones are being build. They simply perform
> the best for the intended frequencies.
> And there are dishes with phased arrays at the feed point, for
> beam forming, and phased arrays of dishes, for long-baseline
> interferometry. It all depends on what frequency, SNR,
> polarization and angular resolution you need. Paul is right that
> larger phased arrays are now practicable because of better
> electronics, giving dishes less of an advantage, but phased arrays
> are as old as radio astronomy.
Arrays of dishes are being used too, over very large distances. But
they can also be used individually, so each one needs to be tagged as a
Where it is known that they are in some way combined for use then
perhaps a relation could be used to signify this.
See Way: Murchison Widefield Array (607964749)
"antenna"="2048 dual-polarization dipoles"
"name"="Murchison Widefield Array"
"description"="when combined from each antenna forms a single
"frequency"="80 - 300 MHz"
This encompasses the area, but does not link the individual antennas
nor any other infrastructure. Maybe a site relation could be used.
> Jansky built his "merry-go-round" Bruce antenna (20.5 MHz) in
> 1932, while Reber didn't build his first dish until 1937. Jocelyn
> Bell discovered pulsars on a phased array built at Cambridge by
> Ryle and Hewish (which also produced the 3C catalog of radio
> sources - including 3C273, the first known quasar).
> The conclusion is either, "Life is full of tradeoffs," or "you
> really don't want to know!"
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