[daip] Re: combining frequencies

[Eric Greisen]

Tracy Clarke (Foreign National) writes:

 >  	I've been trying to understand what the best method is to combine 
 > two or more frequencies observed during the same configuration. I asked a 
 > couple of people and got different answers on how they do this but I'm not 
 > sure what is the correct way. Could you give me a brief summary of how to 
 > best do this? Thanks.

It depends some on what you mean.  If the 2 frequencies are fairly
close together, using DBCON will work.  It ignores the frequency
difference and makes the two separate subarrays in the normal usage.
Since, u,v,w are recorded in wavelengths this is okay - although
multi-channel data will have a 2nd order error in imaging (the
correction of u,v,w will be made as if the 2nd subarray was at the 1st
subarray frequencies).  If the 2 frequencies are farther apart, then
spectral-index variations in the image may matter and one may have to
keep the data separate.

What suggestions did you receive?

Eric Greisen