[daip] SNR of 999.0 in FRING

[Amy Mioduszewski]

Dear Sang-Sung,

It is very common to get SNR=999.0 if the source is very bright.  So that is not 
unusual at all.

Amy

Sang-Sung Lee wrote:
> Dear Amy,
> 
> thanks alot!
> Since I expected that the SNR of B=01-06 should be lower by more than
> three times than that of B=01-05, I was very curious about the SNR of
> 999.0.
> If FRING in AIPS does properly its job, I would assume that the data
> for the baseline of B=01-06 have some problem such as spurious
> signals, DC signals, etc, and so the final solutions for the ant 06
> are to be non-real.
> I have tried FRING for other sources and timer ranges, I also had such
> high SNRs for many scans and other ants as well.
> 
> I wonder if you or any one in this forum has such a high SNR.
> 
> Best regards,
> Sang-Sung
> 
> 
> On 23 February 2010 01:25, Amy Mioduszewski <amiodusz at nrao.edu> wrote:
>> Hi Sang-Sung,
>>
>> Your data is fine.  FRING will only report SNRs up to 999.0, it just means that you have a very high (> 999.0) SNR for that baseline.
>>
>> Amy
>>
>> Sang-Sung Lee wrote:
>>> Dear all,
>>>
>>> I've got SNR of 999.0 as a result after running FRING with my data as below.
>>> If you have any idea on the strange number of SNR, please let me know
>>> what the number means, why it happens, if my data is OK or not, etc.
>>>
>>> Best regards,
>>> Sang-Sung
>>> ---------
>>>
>>>   1    2   10-FEB-2010  16:14:30     FRING     Time=   0/ 14 46 34, Polarization = 1
>>>   1    2   10-FEB-2010  16:14:30     FRING     B= 01 - 02 IF=  1 R=       3.9 D=       1.1 SNR=  86.1
>>>   1    2   10-FEB-2010  16:14:30     FRING     B= 01 - 03 IF=  1 R=       0.0 D=     -22.3 SNR= 169.1
>>>   1    2   10-FEB-2010  16:14:30     FRING     B= 01 - 04 IF=  1 R=       0.0 D=     -25.6 SNR=  63.3
>>>   1    2   10-FEB-2010  16:14:30     FRING     B= 01 - 05 IF=  1 R=       0.0 D=     -28.9 SNR= 124.1
>>>   1    2   10-FEB-2010  16:14:30     FRING     B= 01 - 06 IF=  1 R=       0.0 D=     -32.2 SNR= 999.0
>>>   1    3   10-FEB-2010  16:14:30     FRING     IF number =    1 Poln. =   1
>>>   1    3   10-FEB-2010  16:14:30     FRING     Fitted phases, rates, delays and SNR: [ P = phase(deg),
>>>   1    3   10-FEB-2010  16:14:30     FRING       R = rate(mHz), D = Single-Band Delay(nsec), S = SNR ]
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(02): Phas= -87.8 rate=      3.44 delay=      1.17 SNR=  17.0
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(03): Phas= -34.0 rate=      6.57 delay=    -20.93 SNR=  16.5
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(04): Phas= -85.9 rate=     -6.19 delay=    -24.91 SNR=  14.0
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(05): Phas= -52.2 rate=      3.09 delay=    -28.53 SNR=  16.7
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(06): Phas= 109.4 rate=    -20.11 delay=    -29.59 SNR=   5.9
>>>   1    3   10-FEB-2010  16:14:30     FRING     Standard RMS errors (deg, mHz, nsec):
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(02): Phas=  3.37 rate=     0.368 delay=     0.043
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(03): Phas=  3.48 rate=     0.380 delay=     0.045
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(04): Phas=  4.11 rate=     0.429 delay=     0.054
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(05): Phas=  3.43 rate=     0.376 delay=     0.044
>>>   1    3   10-FEB-2010  16:14:30     FRING     Ant(06): Phas=  9.77 rate=     1.223 delay=     0.135
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
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> 
> 
> 
> --
> -----
> Dr. Sang-Sung Lee
> Senior Researcher in
> Korean VLBI Network (KVN)
> Korea Astronomy & Space Science Institute (KASI)
> Seoul, Korea
> Tel.: +82-2-2012-7524
> Fax: +82-2-2012-7501
> e-mail: sslee at kasi.re.kr
> 
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