[evlatests] WIDAR0 results -- antenna 23

[Ken Sowinski]

On Wed, 3 Jun 2009, Rob Long wrote:

> The other thing we should check is optical levels into the L304 in the
> antenna.  If the signal is high, we have seen oscillations in the LO due
> to overdriving the receiver diode.

Maybe not, because this antenna looks OK with the old correlator.
I lean toward the deformatter on the station board or something
in the wideband part of the station board signal path.


> Rick Perley wrote:
>>     Quick look at WIDAR0 data reveals an interesting problem with
>> antenna 23:
>>
>>     The bandpass has an 8 MHz wide sinusoidal modulation, in all IFs.
>> The amplitude of the modulation is 100% -- so the bandpass amplitude
>> looks like a rectified wave with 4 MHz period, and the phase of each
>> 'lobe' alternates by 180 degrees.
>>
>>     All IFs are identically modulated.
>>
>>     Ken thinks this is a DTS problem.
>>
>>     All other antennas look very good (other than having large delay
>> errors).
>>
>>     More, as I sort through this huge database ...
>>
>>     Rick
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