[evlatests] R/L phase differences, ~5deg at Ka band too.

[Vivek Dhawan]

Ka band was done last night, 9 antennas worked. EA was 28 dead?
and show very similar results to the EVLA K and Q bands, i.e.
most antennas have about 5deg variation of (R-L) phase on
timescales of minutes. So also (A-B) phases when set to the
identical frequency.

The variations look to be bounded with very few exceptions, and
average out over a time scale of ~10min (I had an hour of data).

So this would appear (?) to eliminate the lack of isolators as
the root cause, going by  Bob's comment below.

Vivek.


Bob Hayward wrote:
> I'm not quite sure I agree with Vivek's contention that this time 
> variation is being caused by not having enough isolation in the LO 
> splitters inside the various receivers.

> The EVLA Ka-Band receivers, by 
> the way, have extra isolators already (we had a bigger budget) so if it 
> is an LO splitter problem, they should look much better.