[evlatests] P-band status update: 15APR2014

[Paul Harden]

On 4/16/2014 12:30 PM, Huib Intema (NRAO) wrote:
> Note that the
> following antenna/polarization pairs deviate from Paul's values:
> - EA02 RCP: 15K instead of 14K

Receiver SN06 in EA02 was repaired with hot/cold Tcal tests done March 
10, 2014.  Tcal values were 15K LCP and 14K RCP (Trx=75K and 69K LCP/RCP).

At these temperatures (non-cooled receivers), I can only measure the 
Y-factor and noise CAL power (on/off delta) with about 0.1dB accuracy 
with several seconds integration time, which equates to 2-3K accuracy in 
deriving Tcal.  Thus, I'm actually quite happy to see Tcals verified 
within 1-2K.

> - EA22 RCP: 17K instead of 19K

EA22 has rcvr SN08, which was rebuilt and set to the lower Tcal values 
on Jan. 23, 2014.  Final Tcals were 14K LCP and 17K RCP.  I don't know 
where the 19K came from, probably my error, but will correct the website 
and Tcal table immediately.

Range of hot/cold load test values at P-band are:
Y-factor: 3.9-4.2, 4.0 typ. (for noise figure 0.8-1.0 dB, 0.9dB typ.)
Pc-Pcc: 0.3 dB max. (cold difference between CAL on/off)
Measurement accuracy: 0.1 dB  (+/- 0.05 dB)

Trx and Tcal power is measured at 350 MHz (mid-band) through a 25 MHz 
wide filter.  Measurements done from 200-450 MHz shows Trx and Tcal is 
quite consistent (within 1-2K) across the pass band.

Paul