0000193: New RFI feature in L-band, probably from control building
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ID Category Severity Reproducibility Date Submitted Last Update
0000193 [RFI] local major always 04-12-09 12:57 19-05-10 10:06
Reporter Gyula Jozsa View Status public  
Assigned To Hans van der Marel
Priority normal Resolution fixed  
Status closed  
Summary 0000193: New RFI feature in L-band, probably from control building
Description In several recent HI (L-band line) observations (three checked so far), the visibilities of the baseline RT6-RT7 at hour angles +4h<HA<+6h are corrupted (by RFI). The feature does not occur in other baselines (e.g. RT0-RT1, RT1-RT2). The feature occurs since approximately a month (more precise constraints are possible, but time consuming). Since RT6 and RT7 are closest to the control building, and at HA -> 6 the telescopes are directed more and more towards the control building, the RFI source could well be located in the control building (and has got there recently).

The feature is connected to the electronics of the Galileo experiment located at RT6. Once they are switched on, the feature occurs, while it is not observed with the Galileo electronics switched off. The simplest solution is to be switch off the Galileo electronics during astronomical experiments, while there might be a more time-saving solution. A quick solution is desirable.
Additional Information
RFI frequency (MHz) 1420
RFI bandwidth (MHz) 10
MFFE-band L-band
RT 6
character of RFI constant
Attached Files  rt6_7_q.ps [^] (25,722 bytes) 04-12-09 12:57

- Relationships

- Notes
(0000209)
Gyula Jozsa
04-12-09 13:06

 The feature is also seen in baseline RT6-RT8 on a smaller scale.
 
(0000211)
Gyula Jozsa
17-12-09 10:31

 on 07-12-2009 the feature was still present in L-band data, while on the next data set that was suitable for inspection on 15-12-2009, it did not occur anymore. Hence, the RFI might have come from active electronics of a comb generator for the Galileo experiments that have been switched off on 8-12-2009. For a positive test, it would be necessary to switch the electronics on again and to make a short test observation of some source at HA 5h-6h. Until then, I recommend to leave those electronics switched off during science runs.
 
(0000231)
Gyula Jozsa
20-01-10 10:40

 The feature is connected to the electronics of the Galileo experiment located at RT6. Once they are switched on, the feature occurs, while it is not observed with the Galileo electronics switched off. The simplest solution is to be switch off the Galileo electronics during astronomical experiments, while there might be a more time-saving solution. A quick solution is desirable.
 
(0000256)
Hans van der Marel
10-02-10 11:21

 Switch off electronics for phase calibration in huisje 6 when not in use. Equipment should be placed in RFI-tight enclosure.
 

- Issue History
Date Modified Username Field Change
04-12-09 12:57 Gyula Jozsa New Issue
04-12-09 12:57 Gyula Jozsa File Added: rt6_7_q.ps
04-12-09 12:57 Gyula Jozsa RFI frequency (MHz)  => 1420
04-12-09 12:57 Gyula Jozsa RFI bandwidth (MHz)  => 10
04-12-09 12:57 Gyula Jozsa MFFE-band  => L-band
04-12-09 12:57 Gyula Jozsa RT  => 6
04-12-09 12:57 Gyula Jozsa character of RFI  => constant
04-12-09 13:06 Gyula Jozsa Note Added: 0000209
04-12-09 15:03 Yuan Tang Assigned To  => Harm-Jan Stiepel
04-12-09 15:03 Yuan Tang Status new => assigned
17-12-09 10:31 Gyula Jozsa Note Added: 0000211
20-01-10 10:40 Gyula Jozsa Note Added: 0000231
20-01-10 10:40 Gyula Jozsa Description Updated
25-01-10 09:55 Harm Munk Assigned To Harm-Jan Stiepel => Hans van der Marel
10-02-10 11:21 Hans van der Marel Note Added: 0000256
10-02-10 11:21 Hans van der Marel Status assigned => information
19-05-10 10:06 Hans van der Marel Status information => closed
19-05-10 10:06 Hans van der Marel Resolution open => fixed