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Jim Lovell - 26 May 2016
Kashima 34m
- Our station is still single linear (V) polarization. Planning to enable dual (VH) polarization at Kashima 34m in near future.
- Broadband 24h experiment has been conducted about 10 times
- 34m antenna ACU trouble was fixed. There are no significant change and progress at 34m station.
- Broadband 24h experiment was conducted between MBL1-MBL2-Ishioka13 stations. Purpose was to check improvement of residual and precision in geodetic observation. Since precision of delay observables have been exceeding the post fit residuals in Kas34-MBL1-MBL2 observations and it has been indicating troposphere is the limiting factor of geodetic/frequency transfer VLBI. I expected improvement by fast switching with Ishioka-MBL1-MBL2 network. Though the network is small and elevation angles are almost the same for all stations, thus it seems that independence of parameter estimation of Atm is not good enough, unfortunately. Experiment was in 12-13 Sep. and correlation processing has finished. We will try to see the analysis next week.
Kashima34 network. After replacement of 1.5m->2.4m dish at MBL2 station, Performance has been improved more than 4 times. Collecting are of the dish is factor 2. Efficiency was aslo improved by modification from prime focus optics with QRFH(Rindgren) to Cassegrain focus optics with NINJA(NICT) feed.
This is correlation amplitude between Kashima34(O)-MBL2(B) baseline for scans of 3C84 at Eleveation angle above 80 deg. Four of each symbol of the plot indicated as A, B, C, D are frequency band from lower side, though they are not constant for all the sessions. Center frequency of the frequency array were [3.7, 5.3, 10.1, and 13.3GHz] for 26th Jan., [5.9, 7.1, 8.7, and 10.6GHz] from 12th Feb. to 25th Nov., and [3.8, 5.9, 8.7, and 10.6GHz] for 9th Dec. - We are going to replace the dish and feed at MBL1 too in March.
- If any station can do broadband fringe test observation (1GHz bandwidth for single channel), we are pleased to be a counterpart of the experiment. We will make correlation and provide the results.
Mamoru Sekido - 26 Jan. 2017Mamoru Sekido - 22 Sep. 2016
Yebes
We are taking part in the biweekly 24 hour VGOS tests. For those observations we use 4 RDBE-G units, 500 MHz bandwidth each band and polarization. We do not plan to make any hardware update in the near term. Our next mid-term goal is installing a combination of filters that will filter out frequencies below 3 GHz but will allow the passage of the legacy S band. That should allow us to install two amplifiers per polarization and not saturate the optical fiber amplifiers.
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