[daip] SNR of 999.0 in FRING

[Sang-Sung Lee]

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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>>
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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