[evlatests] VLA polarizer check -- all bands, all frequencies

[Rick Perley]

Recent wideband data taken for the spectacular gamma-raya burst source GRB260310A have allowed a check of the antenna polarizations.   All antennas were measured, except for ea20.

For the great majority, all is well:  antenna polarizations less than 5% for Sband, and  X through Q bands, and 10% for L and C.  (C-band is notably worse than the others, on average).

Notable exceptions are:

S-band:  ea17 at 8%.

C-band:  ea5 is > 20% above 6.5 GHz, peaking at 7.2 GHz.
                    ea15 > 20% all frequencies
                    ea18 ~ 15% all frequencies

X-band:  ea02 ~10% from 10 to 11.5 GHz.

Ku-band:  ea03 > 10% from 16.5 to 17.5 GHz
                     ea07 > 20% near 14.4 GHz, >> 20% near 16.6 GHz, and 15% near 17.5 GHz.
                     ea14 > 10% from 16.8 to 17.8 GHz
                 NB:  many antennas have poor polarizatino above 17.6 GHz, near the upper band edge.

K-band:     ea21 ~ 10% all frequencies
                     ea22 has wild behavior, with > 8 resonances ~evenly spaced.

Ka-band:  ea10 has wild behavior, with > 7 resonances each > 20% cross-pol.
                      ea26 has a single resonance (20%) near 32.1 GHz.

Q-band:  ea12 is >>20% above 46 GHz.

----------------------
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20260729/3b920da9/attachment.html>