Re: Odd behaviour at Ceduna - Who would have believed it?
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From: <Brett.Reid_at_email.protected>
Date: Fri, 05 Mar 2010 09:17:34 +1100
Hi Richard and John,
So this experiment was performed about 12 months ago. Aidan, Bruce and I
installed the additional new maser and IF cables in the twister prior to
the December run, 3 months ago.
I wonder if the problem is fixed?
Regards,
Brett
John Dickey wrote:
>Dear Richard,
>
>That is odd behavior. But I only have one plot, did you attach
>more? The one I got is 4.2 Mby, a bit much for just 25 or 30 points to
>display. There seem to be frequent jumps from low rate to high rate,
>but both are pretty consistent. A wrap problem is possible, but we just
>replaced all the cables, all the way from the receivers to the control
>room.
>
>Anyway, if there were more figures in your mail, could you please
>compress them and resend? Thanks for your help.
>
>cheers,
>jd
>
>On 05/03/2010, at 2:00 AM, Richard Dodson wrote:
>
>>Hi Tassie-siders
>>
>>You must tremble every time I get some data. Here is something from
>>VX014B which _might_ help with the Ceduna problems.
>>
>>After a few steps to remove basic instrument offsets I get these
>>residuals.
>>
>>See how Ceduna has a high rate about 1/2 the time? (page 1, PL 4).
>>I thought at first that a source must have a very bad position, or
>>that the antenna position must be bad and only sensitive to some
>>source coordinates.
>>
>>But compare that to Ceduna (and everyone else) plotted against
>>Hour Angle. When HA is negative rates are low. When HA is positive
>>rates are high. (page 2 PL 2, page 3 PL 3).
>>
>>Odd behaviour at Ceduna - Who would have believed it?
>>
>>I am guessing that what we see here is a change of rate when the
>>wrap changes, which I guess means that something is getting stretched,
>>but I don't see what that would introduce a rate change.
>>
>>Phases are fine pre-HA=0, all over the shop post HA=0. (page 4, PL 5
>>for amplitude RMS, page 5 PL 7 for phases).
>>
>>
>>Have fun with this info!
>>
>>Richard
>><CEDUNA_ODD.PS>
>
>
Date: Fri, 05 Mar 2010 09:17:34 +1100
Hi Richard and John,
So this experiment was performed about 12 months ago. Aidan, Bruce and I
installed the additional new maser and IF cables in the twister prior to
the December run, 3 months ago.
I wonder if the problem is fixed?
Regards,
Brett
John Dickey wrote:
>Dear Richard,
>
>That is odd behavior. But I only have one plot, did you attach
>more? The one I got is 4.2 Mby, a bit much for just 25 or 30 points to
>display. There seem to be frequent jumps from low rate to high rate,
>but both are pretty consistent. A wrap problem is possible, but we just
>replaced all the cables, all the way from the receivers to the control
>room.
>
>Anyway, if there were more figures in your mail, could you please
>compress them and resend? Thanks for your help.
>
>cheers,
>jd
>
>On 05/03/2010, at 2:00 AM, Richard Dodson wrote:
>
>>Hi Tassie-siders
>>
>>You must tremble every time I get some data. Here is something from
>>VX014B which _might_ help with the Ceduna problems.
>>
>>After a few steps to remove basic instrument offsets I get these
>>residuals.
>>
>>See how Ceduna has a high rate about 1/2 the time? (page 1, PL 4).
>>I thought at first that a source must have a very bad position, or
>>that the antenna position must be bad and only sensitive to some
>>source coordinates.
>>
>>But compare that to Ceduna (and everyone else) plotted against
>>Hour Angle. When HA is negative rates are low. When HA is positive
>>rates are high. (page 2 PL 2, page 3 PL 3).
>>
>>Odd behaviour at Ceduna - Who would have believed it?
>>
>>I am guessing that what we see here is a change of rate when the
>>wrap changes, which I guess means that something is getting stretched,
>>but I don't see what that would introduce a rate change.
>>
>>Phases are fine pre-HA=0, all over the shop post HA=0. (page 4, PL 5
>>for amplitude RMS, page 5 PL 7 for phases).
>>
>>
>>Have fun with this info!
>>
>>Richard
>><CEDUNA_ODD.PS>
>
>
-- Brett Reid Observatory Manager, Radio Astronomy Group University of Tasmania, School of Mathematics and Physics Phone +61 3 6248 5285 Mobile 0407 955 283 email brett.reid_at_utas.<!--nospam-->edu.au web http://www-ra.phys.utas.edu.au/~breidReceived on 2010-03-05 09:17:52