[evlatests] ea09 below 30 degrees...

[rperley]

And indeed, this is exactly what was wrong.  Only this antenna was 
shadowed -- by ea12, sitting on N01.

Sorry for the red herring.  Shadowing in C configuration is rarely an 
issue...

Rick

On 2020-05-26 11:54, Vivek Dhawan wrote:
> ea09 is on W02. Shadowing?
> 
> On Tue, May 26, 2020 09:18, Ken Sowinski via evlatests wrote:
> | I haven't looked at pointing results recently because it hard to do 
> from
> | home.  But, on the face of it an effect that large suggests there 
> might
> | be someting loose up at the apex.  As a pointing model error is has 
> to
> | be well over an arc-min to cause consistent failures at X band.
> |
> | Ken
> |
> |
> | On Mon, 25 May 2020, rperley via evlatests wrote:
> |
> |> We ran the 'gain-elevation' script last night.  The purpose is to 
> remeasure
> |> the gains as a function of elevation, from X through Q bands.  The 
> method
> |> uses 'double-referenced pointing' -- referenced pointing is done 
> first at
> |> X-band, and these results are used to 'peak up' Ku-band, then 
> K-band, then
> |> Ka, and ending with Q-band.  This is to ensure the antennas as 
> peaked up on
> |> the source for each band and elevation.
> |>
> |> Observations started with the source (J2007+4029) at 11 degrees 
> elevation,
> |> and proceeded cyclically  through the bands until meridian transit.  
> For
> |> each
> |> cycle, the old referenced pointing solutions were 'forgotten' when 
> X-band
> |> was
> |> next scheduled.  This procedure worked very well for nearly all 
> antennas.
> |> But not ea09...
> |>
> |> Something is seriously amiss with this antenna, for elevations below 
> 30
> |> degrees.
> |>
> |> All referenced pointing attempts failed, including the initial 
> X-band one,
> |> until the antennas reached 23 degrees elevation.  At this elevation, 
> the
> |> solution offset parameters looked good, but in fact were not, as the 
> gains
> |> (at X-band!) were low by 40%.  As the antenna rose, the gains 
> rapidly
> |> increased until, at elevation 34 degrees, all looked normal at all 
> bands.
> |> From then until meridian transit, all was well.
> |>
> |> I have no idea what is wrong here.  Any ideas?
> |>
> |> Rick
> |>
> |> _______________________________________________
> |> evlatests mailing list
> |> evlatests at listmgr.nrao.edu
> |> https://listmgr.nrao.edu/mailman/listinfo/evlatests
> |>
> |
> | _______________________________________________
> | evlatests mailing list
> | evlatests at listmgr.nrao.edu
> | https://listmgr.nrao.edu/mailman/listinfo/evlatests
> |