[daip] UVCON

[Leonia Kogan]

Andy Biggs wrote:

> Hi Leonia. Thanks for your email.
>
> Could you explain to me a little more about the efficiency in IN2FILE?
> Basically, I have no idea what to put. Tsys as a function of elevation 
> I think I know. But the only thing I know about the efficiency is that 
> it is 0.55, presumably at 45 degrees. This is at L band.

I guess you are speaking about VLA. Are you?

>
> Are the change in efficiency and change in Tsys different things? Or 
> does the change in efficiency simply reflect the change in Tsys?

Tsys is a sum of the receiver noise temperature and atmosphere noise 
temerature.
The receever noise temperature can consider independent on elevation. 
Atmosphere noise temerature dependance on the elevation is described at 
first approach by cosec law.

The efficiency of  an antenna dependanse on elevation is estimated by 
design of antenna (because of the deformation
for example) and by effect of atmosphere also.

Dr. Rick Perley carried out a big job investigating the VLA antenna 
efficiency (specifically for each VLA antenna) dependance on elevation. 
He is not at the office now but he is back this Monday
So I think he is the best person to ask   rperley at nrao.edu



LK

>
> Cheers,
>
> Andy