[evlatests] 3-bit, 8-bit alternation test (was Any Volunteers ?)

[Ken Sowinski]

On Thu, 17 Nov 2011, Mark Claussen wrote:

> I took a look at this data.   There are 28 minutes of data at Ku band,
> alternating  between 3-bit and 8-bit, each in ~2m scans.  The purpose
> of this  (I believe) was to  determine how stable the data was in this
> switching mode (the 3 bit samplers were not turned off, but the output
> was switched between the 3-bit and 8-bit devices).
>
> Except for some startup and atmospheric nuisances, the stability looks
> quite good.  Phases and amplitudes come back to the same values for
> each baseline each time the 3- or 8- bit outputs are selected.   I have
> shared the results with Ken, and he seemed happy with them.
>
> One note:  EA07 seems to have low gain as compared with the
> rest of the antennas (this test only used the antennas outfitted with
> 3-bit samplers), but this is true for both 3- and 8-bit paths.

This test provides evidence that we can switch between
3-bit and 8-bit setups when needed.  The need for this
arose recently when we wanted to do 3-bit tests at Ku
band, yet have the antennas well pointed.

In separate work telcal has been updated and we now expect it
to provide pointing solutions for 3-bit data, but that is yet
to be tested.



> On Wednesday 16 November 2011 12:49, Rick Perley wrote:
>>     Ken took this short test.  I'm complete buried in 3-bit data from
>> last night.
>>     Any takers?  This one is easy to reduce.
>>
>>
>>
>> -------- Original Message --------
>> Subject: 	another 3/bit-8bit alternation test
>> Date: 	Wed, 16 Nov 2011 11:37:24 -0700 (MST)
>> From: 	Ken Sowinski <ksowinsk at aoc.nrao.edu>
>> To: 	Rick Perley <rperley at aoc.nrao.edu>, Michael Rupen
>> <mrupen at aoc.nrao.edu>
>>
>>
>>
>> Rick,
>>
>> Here is another example of alternating 3-bit and 8-bit scans.
>> This time the 3-bit is 2GHZ, the 8-bit is a single 128 MHz
>> subband pair.  What I expect is that the data is stable
>> from scan to scan.
>>
>> ku_switch_2GHz was run from 1800 to 1828 UT.