[evlatests] Bandpass Ripple in ea28, RCP, L-band

[jjackson]

Wes and I just had a chat about this and our chief suspect would be the 
W8 RFI monitor cable that is connected to L-band on this antenna.  The 
length is just too long for anything else to make sense on a single 
polarization.  30 meters would be about right for the length of the 
cable running down the antenna.  We'll have someone take a look at it.

Jim





On 9/3/2019 11:01 AM, Rick Perley via evlatests wrote:
>      Bandpass solutions from my Cygnus A observations, taken in April 
> and August this year show a strong bandpass ripple in RCP only, for 
> antenna 28 and L-band.  The period of the ripple is about 4.6 MHz, 
> corresponding to 30 meters if the cause is a reflection.  The problem 
> was not visible in data taken in December last year.
> 
>      The ripple pattern is strongly time dependent (both in its 
> amplitude and phase), so is very difficult to calibrate out.
> 
> 
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