Ch 430 Mhz calibration
There is a 430 Mhz receiver system on the
carriage house line feed. It can be used for transmitting and
receiving. It has native circular polarization. Other 430 systems
include the dome 430
and the 430
yagi (mounted on the carriage house).
Note sure about the date: strongest digital tv stations no
longer falling in cavity filter notches.
Probably getting intermods with
PolA: removed cavity filter, put
bandpass filter (that was after lna) before the dewar to cut down
on the intermods.
jan05: last week crr2/lrr2 10 Mhz IF filter replaced with 20
Mhz IF FILTER
27sep05: updated cal values.
30dec04: filters now in front of both pols to get rid of tv
oct04: filter placed in front of dome polA dewar removes
Calibration data taken mar05 was used to compute
a gain curve at 430 Mhz. The gain curve was a function of za only :
g(za)= c0 + c1*za + c2*(za-14)^2 + c3*(za-14)^3 . The last two terms
(za-14) are only used for za gt than 14 degrees. The plots
the data and the gain curve fits (.ps) (.pdf)
mar05 GAIN CURVE.
This gain curve is now installed in the ao idl
installation. There is also
a description of the gain curves and how to access them.
- fig 1: This is the az/za coverage for the gain curves.
- Fig2: The gain, tsys, sefd, and average beam widths for the
data used to make the gain curves. The data was taken in mar05.
Most of this data was used to make a pointing model for the
- Fig 3: Top the data and fits. Bottom the fit residuals. The
fit residuals are .57 Jy. The source B1843+098 looks like it's
flux is a bit high at 430Mhz.