[evlatests] EVLA Hardware

[Ken Sowinski]

On Thu, 4 May 2006, Jim Jackson wrote:

> This is a long shot but I'll bring it up just in case.  Is there any chance 
> the spectral inversion in the D351 is being set wrong.  In the eventual 
> configuration, there is a mixer in the BD path of the UX converter that will 
> cause a spectral inversion when it is switched in. Is it possible something 
> in the software is setting this bit in the D351 to compensate for this even 
> though the converter is currently hardwired to bypass this mixer?
>
> Jim

A good thought, but the software is not yet smart enough to do
this.  It is not likely that we just have it wrong because
BD works at the other bands.

Ken


> At 06:13 PM 5/3/2006, Rob Long wrote:
>> The L302 with the latest software revision has been installed in Ant 13, 
>> L302-1 slot and appears to be working.
>> 
>> We spent the afternoon looking into the U/X converter cabling and the 
>> L302-2 performance on Ant 13 to try and understand why we can not fringe at 
>> K and Q bands, IFs B and D.  All cables were correct and bandshapes/power 
>> looked good at the output of the T304's using a spectrum analyzer.  We used 
>> several frequencies to determine any offset  in the test equipment and then 
>> verified that the L302-2 was locking properly every time.  We commanded up 
>> and down in large and small steps and the L302 appeared to lock properly 
>> every time.  Total power and switched power at the T5 seem to be reasonable 
>> for IFs B and D and if the L302 is off frequency, it would have to be a 
>> small value that I may have trouble resolving on the spec an.  After 
>> talking with Ken, I'm unsure of what to look at next. ??