From vicente@cay.oan.es Mon Oct 25 16:24:08 MET 1999 Received: from siva.cay.oan.es (siva.cay.oan.es [193.146.252.16]) by picasso.geod.uni-bonn.de with ESMTP (8.8.6 (PHNE_14041)/8.8.8) id QAA11711; Mon, 25 Oct 1999 16:23:54 +0200 (METDST) Received: from polifemo (vicente@polifemo [193.146.252.30]) by siva.cay.oan.es (8.9.3/8.9.1) with SMTP id QAA05099; Mon, 25 Oct 1999 16:22:11 +0200 (METDST) From: Pablo de Vicente Reply-To: vicente@cay.oan.es Organization: Observatorio Astronomico Nacional To: Brian Corey , petrov@picasso.geod.uni-bonn.de (Leonid Petrov) Subject: Re: YEBES in Europe51 Date: Mon, 25 Oct 1999 10:02:17 +0200 X-Mailer: KMail [version 1.0.28] Content-Type: text/plain Cc: aen@haystack.mit.edu, baa@casa.usno.navy.mil, dgg@aquila.gsfc.nasa.gov, mueskens@mpifr-bonn.mpg.de, nothnage@picasso.geod.uni-bonn.de, nrv@bootes.gsfc.nasa.gov, sorgente@hp138.mpifr-bonn.mpg.de, tme@cygx3.usno.navy.mil, vicente@cay.oan.es, weh@ivscc.gsfc.nasa.gov References: <199910221935.PAA00720@dopey.haystack.edu> In-Reply-To: <199910221935.PAA00720@dopey.haystack.edu> MIME-Version: 1.0 Message-Id: <99102516221102.16129@polifemo> Content-Transfer-Encoding: 8bit Status: R Dear all: Sorry for the delay but today I had a very busy day and it took me 2 hours to digitize and enter the temperature values by hand, and the result is poor but significative !! >> It has maximal value >> 1.D-6 (one phase turn for 100-200 seconds at X-band) while other stations has >> it in the range 1-4.D-8. We had the same in Europe50 and in CORE-B504. > >1e-6 us/s is actually worse than any pcal rates in CB504. The highest >we see there is 4e-7. > >I think we're seeing exactly what was predicted for the case of a good, >stable receiver LO (now that the 5 MHz to the receiver LO comes straight >from the maser), that is, fringing with manual phases is better. Why >phase cal looks bad (or even worse than before) depends on the precise >hardware configuration during Europe-51. > > Pablo: What was the situation in Europe-51 with the 5 MHz to the > phase calibrator? Did you block the air flow on the 5 MHz distributor > from the air conditioner, or did you leave it as it was during > Europes 49 and 50? The Europe-51 phase cal looks like its 5 MHz > may still have been affected by temperature swings. If you did block > the air flow, could some of the air still have reached the distributor > so that its temperature was affected? Well, the VLBA DAR, recorder , MKIV formatter and 5MHz distributor are in the antenna control room. There are 3 air conditioning outlets in that room. One is just in front of the equipment. Before the observation began I blocked that outlet but left the others open. The first 45 minutes the air conditioning system was off, but it was getting so warm inside that we turned it on. 2 hours later I noticed that the second air conditioning outlet had its blinds pointing straight to the equipment and I redirected them towards another direction. Fortunately I had followed Leonid's advise and placed an analog thermometer close to the 5MHz distributor. The log register showed me that during these two hours the temperature oscilated nearly 4 degrees each 7 minutes!. After redirecting the flow of the second outlet towards another direction the amplitude of the temperature oscillations decreased. Unfortunately that night and day were warm and the system was working constantly. I think that the peak you see in the residual phase cal rate corresponds exactly to those +-2 degrees C (4 peak to peak). Later things improve a little I have entered by hand all temperature values (for next observation I have bought a couple of thermometers with a serial output). The values for the time and temperature intensity should be taken with care since the record was taken on a paper log and I have entered them manually. My eyes have read plenty of values in a very small scale and I may fail in evaluating the data. Next observation in November I should expect the air conditioning to work in long cycles or not to work at all if the days are colder. I hope the plot helps. Leonid may be you could include it in the web pages you have for Yebes. If you cannot extract the attachment send me a mail and i can place the GIF file (or the data) in our anonymous ftp. regards Pablo. ________________________________________________________ Pablo de Vicente (vicente@oan.es), http://www.oan.es, OAN Spain