projects:mkat_sband:pub:start [Fundamental Physics in Radio Astronomy]

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====== MeerKAT S band receiver commissioning (public part) ======

This area is for notes and results on the receiver commissioning. The namespace ''[[projects:mkat_sband|projects:mkat_sband]]'' is private to the MPIfR, the subspace ''[[projects:mkat_sband:pub:start|projects:mkat__sband:pub]]'' has public read access.


===== Links and external info =====

[[https://archive.sarao.ac.za/proposalid/SSV-20200929-OW-01/order/true/|SARAO web archive for commissioning proposal SSV-20200929-OW-01]]

[[https://www.google.com/maps/d/viewer?hl=en&mid=1cGIe7eVdlZIk_YL5TyTw5kmYo1g&ll=-30.715290268345356%2C21.4427763122559&z=13|Map of array]]

==== SARAO google drive S band ====

[[https://drive.google.com/drive/folders/1_Cc_1-d86HrNx0bGxtNbmJudp2rgt_EQ|main]]

[[https://docs.google.com/spreadsheets/d/1Kcn48aHiSXWQGsyCg1gFJL12ohdVVIlazhyaWkJoNkg/edit?skip_itp2_check=true#gid=1500988692|receptor status]]

[[https://docs.google.com/spreadsheets/d/1eVk43O1ZKbCWLaD_M_JKbQ4ROevFWJniiOHfXI1WJLg/edit?usp=sharing|S band install SN]]

==== SKA Africa JIRA ====


[[https://skaafrica.atlassian.net/jira/software/c/projects/SBAND/issues/SBAND-197|Review of SARAO provided test data]]

[[https://skaafrica.atlassian.net/jira/software/c/projects/SBAND/issues|S band main page]]

===== Subband identifiers =====

[[https://skaafrica.atlassian.net/browse/SBAND-197?focusedCommentId=129532|reference]]

All in MHz:

^  name  ^  centre  ^  range  ^
^  S0    |  2187.50  |  1750.00 - 2625.00  |
^  S1    |  2406.25  |  1968.75 - 2843.75  |
^  S2    |  2625.00  |  2187.50 - 3062.50  |
^  S3    |  2843.75  |  2406.25 - 3281.25  |
^  S4    |  3062.50  |  2625.00 - 3500.00  |

**Please note that these are the total band ranges. The filters are pretty narrow so that significantly less is usable.**


===== Filters =====

A discussion of the digital decimation filters can be found [[projects:mkat_sband:pub:decfilters|here]].





===== Phased array/pulsar mode =====

TO DO



===== Imaging/correlator mode =====

==== Data sets ====

[[projects:mkat_sband:pub:imobs_list|List of data sets]] (automatically created with ''obs_info.py'')

The data sets can be found in ''/fpra/polmag/01/MK_S_BAND_COM/MS/'', some have copies (also of variants) in ''/media/storage_1/wucknitz/MEERKAT''. Own conversion to MS via ''mvftoms.py'' have their capture block number as directory name, ones via the archive have e.g. ''1603193556_sdp_l0.ms''.


==== Theory/procedures ====

We determine delays and phases with [[projects:mkat_sband:pub:fringefit|fringe-fitting (click for details)]] per baseline. After calibrating the phases per baseline, we can [[projects:mkat_sband:pub:snrdet|measure the SNR (click for details)]] per baseline and channel and try to separate the baseline values to obtain station-based parameters. A similar approach is used for the [[projects:mkat_sband:pub:bandpass|bandpass (amplitude and phase, click for details)]].


==== Results ====



**[[projects:mkat_sband:pub:results_obs|Details of results for individual observations can be found here.]]**

==== Collected SEFD and bandpass information ====

For a quick overview of the performance of all antennas, we provide curves for all antennas from all relevant observations over all available subbands (sorted by observation id):

{{:projects:mkat_sband:pub:sefd_allants.pdf|PDF with SEFD curves}} \\
{{:projects:mkat_sband:pub:bandpass_allants.pdf|PDF with bandpass curves (linear)}}\\
{{:projects:mkat_sband:pub:bandpass_corr_allants.pdf|PDF with bandpass curves (linear), amplitude corrected for digital decimation filter for a better comparison}} \\
{{:projects:mkat_sband:pub:sefd_bandpass_allants.pdf|PDF with SEFD and bandpass curves (dB)}}\\
{{:projects:mkat_sband:pub:sefd_bandpass_corr_allants.pdf|PDF with SEFD and bandpass curves (dB), amplitude corrected for digital decimation filter for a better comparison}}

In addition we have plots that only include post-repair data for the receivers that have been fixed at some point. They are sorted by subband:

{{:projects:mkat_sband:pub:sefd_goodants.pdf|PDF with SEFD curves}} \\
{{:projects:mkat_sband:pub:bandpass_goodants.pdf|PDF with bandpass curves}}\\
{{:projects:mkat_sband:pub:bandpass_corr_goodants.pdf|PDF with bandpass curves, amplitude corrected for digital decimation filter for a better comparison}}\\
{{:projects:mkat_sband:pub:sefd_bandpass_goodants.pdf|PDF with SEFD and bandpass curves (dB)}}\\
{{:projects:mkat_sband:pub:sefd_bandpass_corr_goodants.pdf|PDF with SEFD and bandpass curves (dB), amplitude corrected for digital decimation filter for a better comparison}}

The following plots are meant to represent the latest status of measurements. Only the latest observations are included (currently only the S2 and S4 of 11th Oct 2021, and S2 19th Oct):

{{:projects:mkat_sband:pub:sefd_latest.pdf|PDF with SEFD curves}} \\
{{:projects:mkat_sband:pub:bandpass_latest.pdf|PDF with bandpass curves}}\\
{{:projects:mkat_sband:pub:bandpass_corr_latest.pdf|PDF with bandpass curves, amplitude corrected for digital decimation filter for a better comparison}}\\
{{:projects:mkat_sband:pub:sefd_bandpass_latest.pdf|PDF with SEFD and bandpass curves (dB)}}\\
{{:projects:mkat_sband:pub:sefd_bandpass_corr_latest.pdf|PDF with SEFD and bandpass curves (dB), amplitude corrected for digital decimation filter for a better comparison}}

The filter-corrected bandpass curves can be used to see how consistent the bandpass is between observations in different subband modes. This is possible because of a large overlap between the bands.

In order to study the differences between the two polarisations, we also provide plots of the logarithm of the radio pol0/pol1 for bandpass (signal, green), noise (SEFD, yellow) and signal-to-noise (red):

{{:projects:mkat_sband:pub:polratio_allants.pdf|Ratio pol0/pol1 of signal, noise and signal/noise (all obs)}}\\
{{:projects:mkat_sband:pub:polratio_goodants.pdf|Ratio pol0/pol1 of signal, noise and signal/noise (only good obs)}}

And here the same for only the latest measurements:

{{:projects:mkat_sband:pub:polratio_latest.pdf|Ratio pol0/pol1 of signal, noise and signal/noise}}

Different signal levels for the two polarisation can move the green and yellow curves up or down together but would not affect the red one.



**Note that the scales for some antennas are treated specially here for the moment, because the SEFD and bandpass phases are not in normal ranges. This is probably because those receivers were not ready for observations.**



==== Status of receivers (from interferometric data) ====


[[https://project.mpifr-bonn.mpg.de/projects/meerkat-meerkat-installation-and-commissioning/wiki/Rx_states|Receiver status (table at MPIfR)]] \\
[[https://cloud.mpifr-bonn.mpg.de/index.php/s/iNLBCorSAbY2f3w|new receiver status table (MPIfR)]]\\
[[https://docs.google.com/spreadsheets/d/1vkU8JbORwRnFbOLsAbmyU3Sf4chTLwfOdXe26Yq93r4/edit?usp=sharing|Pieter Kotze's receiver status table]]

These are just rought numbers taken from the plots (only at the best frequencies):

^ ant  ^  best SEFD pol 0/1 [Jy]  ^ batch      ^ notes   ^
^ m000 |  400/420                 |   1        |         |
^ m001 |  390/400                 |   2        |         |
^ m002 |  390/440                 |   1        |         |
^ m003 |  410                     |   1        |         |
^ m004 |  400                     |   1        |         |
^ m005 |  400/**490**             |   1        |         |
^ m006 |  390/**440**             |   1        |         |
^ m007 |  420                     |  pre-prod  |         |
^ m008 |  (450)                   |  replaced  | not included in last observation   |
^ m009 |  410                     |   3        |         |
^ m010 |  400/410                 |   3        |         |
^ m011 |  380/400                 |   1        |         |
^ m012 |  400/**470**             |   2        |         |
^ m013 |  400                     |   2        |         |
^ m014 |  400                     |   3        |         |
^ m015 |  430/**450**             |   3        | **second pol huge variations with freq**  |
^ m016 |  400                     |   2        |         |
^ m017 |  430/450                 |   3        |         |
^ m018 |  420                     |   2        |         |
^ m019 |  390/**450**             |   3        |         |
^ m020 |  390/**450**             |   3        |         |
^ m021 |  400                     |   1        |         |
^ m022 |  400/**490**             |   2        |         |
^ m023 |  380/**420**             |   2        |         |
^ m024 |  400/410                 |   4        |         |
^ m025 |  380/**410**             |   3        |         |
^ m026 |  390/400                 |   3        |         |
^ m027 |  400/390                 |   2        |         |
^ m028 |  370/**420**             |   4        |         |
^ m029 |  420/440                 |   4        |         |
^ m030 |  400/420                 |   1        |         |
^ m031 |  **>3000**               |   3        | **was 430 earlier**  |
^ m032 |  **420**/390             |   3        |         |
^ m033 |  390/400                 |   3        |         |
^ m034 |  **450/530**             |   3        |         |
^ m035 |  400                     |   3        |         |
^ m036 |  390/380                 |   3        |         |
^ m037 |  390/400                 |   4        |         |
^ m038 |  (400/420)               |   2        | not included in last observation  |
^ m039 |                          |   4        |         |
^ m040 |  380/**430**             |   4        |         |
^ m041 |  390/**440**             |   4        |         |
^ m042 |  420/430                 |   4        |         |
^ m043 |  400                     |   1        |         |
^ m044 |  450                     |   4        |         |
^ m045 |  400/410                 |   1        |         |
^ m046 |                          |   4        |         |
^ m047 |  410/420                 |   4        |         |
^ m048 |  400/380                 |   2        |         |
^ m049 |  430/420                 |   1        |         |
^ m050 |  370/390                 |   2        |         |
^ m051 |  400/**440**             |   4        |         |
^ m052 |                          |   4        |         |
^ m053 |  400                     |   1        |         |
^ m054 |  380                     |   2        |         |
^ m055 |  400/420                 |   4        |         |
^ m056 |  420                     |   1        |         |
^ m057 |  380/400                 |   1        |         |
^ m058 |  400                     |   4        |         |
^ m059 |  370/400                 |   2        |         |
^ m060 |  400/**430**             |   1        |         |
^ m061 |  410/400                 |   2        |         |
^ m062 |  **420**/410             |   2        | **first polarisation strange variations with frequency**  |
^ m063 |  400                     |   2        |         |

Total good: 53, minor issues: 7, bad: 1, no signal yet: 3
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