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Australia Telescope Compact Array
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Recommended continuum frequencies
The ATCA allows significant flexibility in setting the observing frequency.
For continuum observations, where the exact frequency is not of significant
importance, the table below gives the recommended observing frequencies. These
frequencies have been chosen for a variety of reasons, such as low system
temperature and little radio frequency interference. As many observers will
use these frequencies, it is likely
that there will be less set-up effort than with other arbitrary
frequencies. Consequently these frequencies
should generally be used when possible.
With the old (pre-March 2009) correlator, observing frequencies were
carefully chosen (at odd multiples of 64 MHz) to minimise various
instrumental effects. With the (post-March 2009) CABB, there are no
such constraints.
For the 20cm and 13cm bands, the
receivers will limit the useful bandwidth to ~500MHz,
though
RFI
may further limit the useful bandwidth in practise, particularly
in the 20cm band.
In addition, note that:
- Simultaneous 6cm and 3cm observing continues to be possible, but
that simultaneous 20am and 13cm observing is not (at least until the 20/13cm
frontend upgrade).
- At 12mm, 7mm, and 3mm wavelength, the two IF frequencies can differ by more
than previous constaint of 2.7 GHz,
but must be less than 6 GHz and will depend on the observing frequencies chosen.
- The 7mm and 3mm frequencies given below for CABB are nominal. Some sets of
observing frequencies in these (wide) bands suffer from
poor image rejection
and so these recommended frequencies will be revisited once more experience
is obtained with CABB.
Note: All frequencies below are centre frequencies.
| Band |
CABB Freq1 (& b/w) |
CABB Freq2 (& b/w) |
Old Freq1 |
Old Freq2 |
| 20 cm |
1750 MHz (500 MHz) |
|
1384 MHz1 |
|
| 13 cm |
2450 MHz (500 MHz) |
|
|
2368 MHz2 |
| 6 cm |
5500 MHz (2048 MHz) |
|
4800 MHz |
|
| 3 cm |
|
9000 MHz (2048 MHz) |
|
8640 MHz |
| 12 mm |
17000 MHz (2048 MHz) |
19000 MHz (2048 MHz) |
18496 MHz |
19520 MHz |
| 7 mm |
33000 MHz (2048 MHz) |
35000 MHz (2048 MHz) |
34496 MHz |
34624 MHz |
| 7 mm |
43000 MHz (2048 MHz) |
45000 MHz (2048 MHz) |
44096 MHz |
44224 MHz |
| 3 mm |
93000 MHz (2048 MHz) |
95000 MHz (2048 MHz) |
93504 MHz |
95552 MHz |
Notes:
- With the old correlator, when observing with both IFs set to 20cm continuum, the recommended
frequencies were 1344 and 1432 MHz.
- With the old correlator, when observing with two IFs set to 13cm continuum, the recommended
frequencies were 2368 and 2496 MHz. Note that there is strong, narrowband
interference at 2493 MHz from Globalstar satellite mobile phones.
Original: Bob Sault (04-Sep-2005)
Modified: Phil Edwards (04-jun-2009)