New Allen Telescope Array Development

June 05, 2018 - received the mini circuits attenuator and 8 port RF switch. Two of each.

Note: That is a quarter coin in the center for size reference.

Plugged into VM server ngs-work1 (sonata@10.1.49.174, polaris)

1. Attenuator RUDAT-6000-30: https://www.minicircuits.com/WebStore/dashboard.html?model=RUDAT-6000-30
2. RF Switch USB-1SP8T-63H: https://www.minicircuits.com/WebStore/dashboard.html?model=USB-1SP8T-63H

lsusb | grep Mini

Bus 004 Device 003: ID 20ce:0023 Minicircuits 
Bus 004 Device 002: ID 20ce:0022 Minicircuits I/O Controller
Bus 003 Device 003: ID 20ce:0022 Minicircuits I/O Controller
Bus 003 Device 002: ID 20ce:0023 Minicircuits 

Looks like all of the available software is Window, not Linux. Bummer.

1. Programming guide: https://www.minicircuits.com/softwaredownload/Prog_Examples_Troubleshooting.pdf

Needed to install libhid to be able to communicate with the USB devices:

a. sudo apt-get install libusb-dev
b. cd libhid-0.2.16
c. ./configure --enable-werror=no
d. make
e. sudo make install
f. sudo ldconfig

Various feed measurements using the spectrum analyzer. Using feed 4jx. May 09, 2018

In all these pictures please pay attention to the dB and bandwidth scaling, these are not the same in all pictures.

Turns out that without the filter there is 600MHz bandwidth to play with.

With 200MHz filter, pointed at az 330, el 30:

Without 200MHz filter:

Pic of the filters, and the 200MHz filter bypassed for feed 4jx:

For reference, here is the original RFCB drawing I found:

CasA at 1420, looks like it always does:

Did not see the bump at 1665MHz.

1613.9MHz:

1667.348MHz:

1718.74MHz

Using the spectrum analyzer I discovered there is a spike every 8MHz from 1000 to 2016MHz. ONLY on the new feeds. No matter where i pointed. The old feeds do not have this spike.

On feed 3Lx it was very strong, this is a 120MHz badwidth shot: