0000067: RFI in autocorr AX & AY in 1 band lineobservations (LBand)
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ID Category Severity Reproducibility Date Submitted Last Update
0000067 [IVC/ADC] 0.unknown/unspecified minor always 05-09-08 09:42 22-06-11 07:14
Reporter Jurjen Sluman View Status public  
Assigned To Hans Weggemans
Priority low Resolution open  
Status closed  
Summary 0000067: RFI in autocorr AX & AY in 1 band lineobservations (LBand)
Description The last time we see in several lineobservations, that there
is a RFI signal in the AX & AY autocorr's.
This RFI is not seen in the cross corr's, so it doesn't have
a direct influence on the observations.
Some observations effected:
10804138..40,10804156..58,10804168..70
The RFI Freq is not always the same, different line obssettings,
have also different RFI freq's.
 
Additional Information 07/10,2008
The power supply(+/-18V) of AX,AY for the filters in the IVC
has been replaced.
RT A
sub-band 0
polarisation
Attached Files

- Relationships

- Notes
(0000078)
Jurjen Sluman
08-09-08 11:07

 MFFE will be removed
 
(0000092)
Hans van der Marel
24-09-08 12:12

 The reported RFI is only visible during line observations at 10 MHz BW. The frequency is not always the same, e.g. for an MFFE frequency of 1418 MHz the RFI (CW) has been seen at 1417.64, 1417.74, 1417.76, 1417.85... and for an MFFE freq of 1420 MHz at has been seen at 1419.76 and 1419.74.
It can be concluded that the RFI is not locked to the LO. Something is oscillating. It looks like it is moving with the MFFE frequency, so there is probably something in the back-end and because it seems to be BW related, it might be a filter unit of the IVC.
 
(0000094)
Jurjen Sluman
03-10-08 09:33

 This problem is also seen in a 1 bands line observation in with a freq. in the UHFH band. (10804812..10804813)
 
(0000095)
Bert Woestenburg
06-10-08 14:37

 The problem is not related to the MFFE, but most likely IVC. Based on remarks of Hans van der Marel now assigned to Hans Weggemans
 
(0000100)
Hans Weggemans
29-10-08 06:33

 27-10-2008
to trace the RFI at AX,Ay(at 21cm with BW=10), the preselector board 2 has been swapped with preselector board 0.
 
(0000110)
Yuan Tang
21-11-08 08:51

 21-11-2008
This problem is still there, see 10805789-10805791.
 
(0000114)
Bert Woestenburg
03-12-08 11:18

 The RFI has disappeared in recent observations after work on the system by Albert Bos, but it is unclear what caused this change. Status set to "Information" on 1-12-08.
 
(0000118)
Yuan Tang
11-12-08 15:31

 20081211:
The problem appears again after installing the new version of DZB at Dec.09.
 
(0000121)
Jurjen Sluman
13-01-09 08:10

 We have not seen this effect for a long term.
 

- Issue History
Date Modified Username Field Change
05-09-08 09:42 Jurjen Sluman New Issue
08-09-08 11:07 Jurjen Sluman Note Added: 0000078
08-09-08 11:08 Jurjen Sluman Category 0.unknown/unspecified => front-end
08-09-08 11:09 Jurjen Sluman Project submission => MFFE
08-09-08 11:09 Jurjen Sluman MFFE  => 00
08-09-08 11:09 Jurjen Sluman RT  => 0
08-09-08 11:09 Jurjen Sluman Assigned To  => Harm-Jan Stiepel
08-09-08 11:09 Jurjen Sluman Status new => assigned
08-09-08 11:09 Jurjen Sluman Category front-end => 0.unknown/unspecified
24-09-08 12:00 Hans van der Marel Project MFFE => RFI
24-09-08 12:03 Hans van der Marel MFFE-band  => 21cm, L-band
24-09-08 12:03 Hans van der Marel RT 0 => A
24-09-08 12:03 Hans van der Marel character of RFI  => constant
24-09-08 12:03 Hans van der Marel Category 0.unknown/unspecified => internal
24-09-08 12:12 Hans van der Marel Note Added: 0000092
25-09-08 08:05 Bert Woestenburg Description Updated
25-09-08 08:05 Bert Woestenburg Additional Information Updated
03-10-08 09:33 Jurjen Sluman Note Added: 0000094
06-10-08 14:37 Bert Woestenburg Note Added: 0000095
06-10-08 14:39 Bert Woestenburg Assigned To Harm-Jan Stiepel => Bert Woestenburg
06-10-08 14:40 Bert Woestenburg Assigned To Bert Woestenburg => Harm-Jan Stiepel
07-10-08 06:41 Bert Woestenburg MFFE-band 21cm, L-band => UHF-high, 21cm, L-band
08-10-08 09:03 Yuan Tang Additional Information Updated
08-10-08 09:04 Yuan Tang Status assigned => testing
08-10-08 10:02 Hans van der Marel Project RFI => IVC/ADC
08-10-08 10:03 Hans van der Marel Status testing => assigned
08-10-08 10:03 Hans van der Marel Assigned To Harm-Jan Stiepel => Hans Weggemans
29-10-08 06:33 Hans Weggemans Note Added: 0000100
31-10-08 10:56 Yuan Tang sub-band  => 0
31-10-08 10:56 Yuan Tang Category internal => 0.unknown/unspecified
21-11-08 08:51 Yuan Tang Note Added: 0000110
01-12-08 09:37 Jurjen Sluman Status assigned => information
03-12-08 11:18 Bert Woestenburg Note Added: 0000114
11-12-08 15:31 Yuan Tang Note Added: 0000118
13-01-09 08:11 Jurjen Sluman Note Added: 0000121
13-01-09 08:11 Jurjen Sluman Status information => resolved
22-06-11 07:14 Juergen Morawietz Status resolved => closed