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4. Front End |
 |
4.4 Frequency
Agility
It is
possible to switch between the various receivers in a very
short time.
We here indicate the typical overall switching+setup time
intervals, so that they correspond to the waiting times the
observers actually face.
Secondary focus receivers can be switched between one
another, or commanded a new setup, very quickly (10
seconds).
Primary focus receivers switch between one another in a
slightly longer time (45 seconds).
The commutation from a primary focus receiver to a secondary
focus one, and viceversa, are slower (about 3 min 50 s)
because the subreflector
must be repositioned - it runs a path exceeding 2 metres.
| SXp/XXp/SSp | LLp/LHp | KKc | CCc | CHc | |
| SXp/XXp/SSp | 10 s |
45 s |
3 min 56 s | 3 min 56 s | 4 min |
| LLp/LHp | 45 s |
10 s |
3 min 45 s | 3 min 50 s | 3 min 53 s |
| KKc | 3 min 56 s |
3 min 45 s |
10 s |
11 s |
15 s |
| CCc | 3 min 56 s | 3 min 56 s |
10 s |
10 s |
14 s |
| CHc | 4 min |
3 min 53 s |
14 s |
14 s |
10 s |
Tab. 4.3: Typical receiver
switching+setup times.
