[evlatests] Three birdies at S-band

[Ken Sowinski]

On Wed, 30 Dec 2009, Rick Perley wrote:

>    Three birdies are seen in S-band spectra taken with WIDAR.  They are
> all pure tones (unresolved at 125 kHz resolution).  Their frequencies
> make it highly unlikely they are external:
>
>    2945 MHz
>    3200 MHz
>    3455 MHz
>
>    Note that the first and third are each located 255 MHz away from the
> middle.  That can't be an accident ...Very suspicious ...
>
>    Any ideas?

The first LO at L band for the old VLA antennas is 3.2 GHz and
there are still two of them out there.  Satellite lines at
255 (or 256 ?) MHz are much harder to explain unless it is so
strong as to get through the skirsts of the subband FIRs.  If
so, we would see it in every other subband because LO offset
would wash it out in the subbands apced an odd number away.