L BAND NARROW NEWS
The system cals were measured for this
receiver today due to the recent change in amplifiers and isolators in the
dewar: ChA/B: 1.78K/1.84K which are close to the previous
values.
The system temperatures last week (July 27) were
ChA/B: 33.9K/29.4K so the receiver was warmed up and worked on in hopes
that replacing the amplifiers & isolators would reduce Ch A and remove some
possible impedance mis-match in Ch B. But to no avail, when the dewar was
cooled back down on August 2, the temperatures were ChA/B: 32.2K/34.3K and has
increased since then to a gargantuan ChA/B: 37.3K/49.9K as of 1pm August
4.
Since this makes the
receiver rather useless, it has been decided with the help of Karen O'Neil to
take down the L Band Narrow again on Monday August 7, in order to put back
the original amplifiers and isolators. Monday and Tuesday are electronics
maintenance days which allows us to be on the rotary floor and to move it at
will. This would not be possible if the maintenance was done over the
weekend. The receiver will be out of service until at least Tuesday
around noon. The dewar will be warmed up this weekend. All affected
observers are being notified by Karen.
Lisa Wray