shimming the 12m horn

13jun23
xband plots
3GHz plots

Intro

    Shims were used to move the wideband horn closer/farther from the secondary to search for the focal point.  The shims were 1" thick.

more info:

Dates for data taking:

date
#shims/distance
to secondary

freq
230529
2, 22.6"
xb
230531
1, 23.6"
xb
230601
0, 24.6"
xb
230602
2, 22.6"
xb
230603
2, 22.6"
xb
230604
2,22.6"
3ghz
230607
3, 21.6"
xb
230608
3,21.6"
3ghz
230609
4,20.6"
3ghz
230610
4, 20.6"
xb
230611
4, 20.6"
xb
230612
4, 20.6"
xb
230613
4,20.6"
3ghz
230614
5,19.6"
xb
230615
5,19.6"
3ghz
230616
5,19.6
xb
230617
5,19.6
xb
230619
4,20.6"
xb


Processing:

plotting the results:

    Plots were made for each 172MHz freq band.

Each plot has 8  pages


xband plots


freq (MHz)
all shims
vs elevation
all shims
vs azimuth
2-5" shims
vs elevation
2-5" shims
vs azimuth
8223
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
8363
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
8505
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
8647
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
8789
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
8931
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
9073
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)
(.ps)  (.pdf)


We observed some shim positions on multiple days. The above plots show that there can be a lot of variation in tsys on different days (from the weather).
To  try and exclude variations caused by weather:

The table below replots the data using 3C405 and M87 , shim spacings 2" to 5"  and only using the "Best day" for those shim spacings
measured multiple times.

Using "best Day" for multiple shim measurements
freq (MHz) 2-5" shims
vs elevation
2-5" shims
vs azimuth
8223
(.ps)  (.pdf) (.ps)  (.pdf)
8363
(.ps)  (.pdf) (.ps)  (.pdf)
8505
(.ps)  (.pdf) (.ps)  (.pdf)
8647
(.ps)  (.pdf) (.ps)  (.pdf)
8789
(.ps)  (.pdf) (.ps)  (.pdf)
8931
(.ps)  (.pdf) (.ps)  (.pdf)
9073
(.ps)  (.pdf) (.ps)  (.pdf)





XBand Notes:

processing:


3 GHz plots


freq
all shims
vs elevation
all shims
vs azimuth
2846 (.ps)  (.pdf) (.ps)   (.pdf)
2988
(.ps)  (.pdf) (.ps)   (.pdf)
3130
(.ps)  (.pdf) (.ps)   (.pdf)
3272
(.ps)  (.pdf) (.ps)   (.pdf)
3414
(.ps)  (.pdf) (.ps)   (.pdf)

3GHz Notes:

Processing:  x101/230604,09,13 / wb3cross.pro
                    x101/12meter/comm/shimproc_wb3.pro




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