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 usable range is smaller. See [[projects:mkat_sband:pub:decfilters#final_design_ver2|description of the decimation filters]] for details.**


===== 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 ====


=== Results for typical antennas ===

The performance of the entire array can be estimated best by taking the median (or some other percentile) over all antennas. Here are corresponding results from the 2022-11-19 observations (see below). First we take the median over all antennas and plot both polarisations individually:

{{:projects:mkat_sband:pub:sefd_allants_pols.pdf|Both polarisations}}

Second we average the polarisations but show the 10/50/90% percentile over all antennas. This means we see the typical range of antennas:

{{:projects:mkat_sband:pub:sefd_allants_perc.pdf|10/50/90% percentiles, polarisations averaged}}


=== Results for individual antennas ===

For a quick overview of the performance of all antennas, we provide curves for all antennas from relevant observations over all available subbands.

**The first set of plots is meant to represent the latest measurements. These are currently the final SEFD measurements of 2022-11-19 at high elevations:**

{{: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}}

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.


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_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.



**The following plots include all observations, which makes very large and difficult to view. These are mainly good for historical purposes:**

{{: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}}

Here are the corresponding 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:decfilters#test_observations|A comparison of old and new decimation filters can be found here.]]**




==== 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 of the final measurements (only at the best frequencies). The replacement status is not necessarily up to date:

^ ant  ^  best SEFD pol 0/1 [Jy]  ^ batch      ^ notes   ^
^ m000 |  390/410                 |   1        |         |
^ m001 |  390/400                 |   2        |         |
^ m002 |  390                     |   1        |         |
^ m003 |  390                     |   1        | from previous obs, not included in last      |
^ m004 |  400                     |   1        | from previous obs, not included in last      |
^ m005 |  400/420                 |   1        |         |
^ m006 |  390/440                 |   1        |         |
^ m007 |  410                     |  (was pre-prod)  |         |
^ m008 |  400                     |  (replaced)  |    |
^ m009 |  400                     |   3        |         |
^ m010 |  400/410                 |   3        |         |
^ m011 |  380/400                 |   1        |         |
^ m012 |  400/470                 |   2        |         |
^ m013 |  400                     |   2        |         |
^ m014 |  410/400                 |   3        |         |
^ m015 |  420/**450**             |   3        | **second pol huge variations with freq**  |
^ m016 |  410                     |   2        |         |
^ m017 |  430/410                 |   3        |         |
^ m018 |  420                     |   2        |         |
^ m019 |  400/470                 |   3        |         |
^ m020 |  390/440                 |   3        |         |
^ m021 |  400                     |   1        |         |
^ m022 |  400/470                 |   2        |         |
^ m023 |  380/410                 |   2        |         |
^ m024 |  410/400                 |   4        |         |
^ m025 |  400/420                 |   3        |         |
^ m026 |  470                     |   3        |         |
^ m027 |  400                     |   2        |         |
^ m028 |  380/420                 |   4        |         |
^ m029 |  430/440                 |   4        |         |
^ m030 |  400                     |   1        |         |
^ m031 |  400                     |   3        |    |
^ m032 |  420/400                 |   3        |         |
^ m033 |  390                     |   3        |         |
^ m034 |  400/440                 |   3        |         |
^ m035 |  400                     |   3        |         |
^ m036 |  400/**700**             |   3        | **second pol very bad**     |
^ m037 |  400                     |   4        |         |
^ m038 |  400/420                 |   2        |  |
^ m039 |  390                     |   4        |         |
^ m040 |  390/420                 |   4        |         |
^ m041 |  390/430                 |   4        |         |
^ m042 |  410/430                 |   4        |         |
^ m043 |  400                     |   1        | from previous obs, not included in last       |
^ m044 |  430                     |   4        |         |
^ m045 |  400                     |   1        |         |
^ m046 |  450                     |   4        |         |
^ m047 |  400                     |   4        |         |
^ m048 |  420/390                 |   2        |         |
^ m049 |  430/410                 |   1        |         |
^ m050 |  370/380                 |   2        |         |
^ m051 |  400/450                 |   4        |         |
^ m052 |  390/420                 |   4        |         |
^ m053 |  410/400                 |   1        |         |
^ m054 |  390                     |   2        |         |
^ m055 |  400/410                 |   4        |         |
^ m056 |  420                     |   1        | from previous obs, not included in last        |
^ m057 |  370/380                 |   1        |         |
^ m058 |  450/390                 |   4        |         |
^ m059 |  370/400                 |   2        |         |
^ m060 |  430                     |   1        |         |
^ m061 |  410                     |   2        |         |
^ m062 |  420/400                 |   2        | **high bumps in first polarisation**  |
^ m063 |  390/400                 |   2        |         |

Three receivers/antennas (m015,m036,m062) are having problems at the moment. The others are all good, but have slightly different SEFD levels.



==== Noise variations ====

[[projects:mkat_sband:pub:noisevar|Analysis of several types of system noise variations]]
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