I was going to suggest the same thing. We could have an ‘active’ long cable (i.e. a pre-post-amp right at the balun). And how long do we need — 150m is already uncomfortably long…
> On Apr 12, 2016, at 1:50 PM, danny jacobs <[email protected]> wrote: > > What about making most of them short and then some of them really long? > > On Tue, Apr 12, 2016 at 1:49 PM, Adam Beardsley <[email protected] > <mailto:[email protected]>> wrote: > My concern would be pushing any cable reflection contamination to modes in > the window. Currently only a small subset of MWA antennas have 150 meter > cables, but the reflection line shows up very clearly. 45 meters puts the > delay right at 0.2 h/Mpc, which is where we do a lot of our sensitivity > forecasts. I doubt moving to 0.3 would change sensitivity much, but just food > for thought. > > -Adam > > On Tue, Apr 12, 2016 at 1:26 PM danny jacobs <[email protected] > <mailto:[email protected]>> wrote: > The 35m length has been worrying me a little lately. Would there be any > downsides like having a different spectral response for the longer cables? > > ~D > > On Tue, Apr 12, 2016 at 1:24 PM, DAVID DEBOER <[email protected] > <mailto:[email protected]>> wrote: > Hi - I was thinking about the analog cable lengths a bit. We have a spec at > 35 m (30m+the vertical part to the feed). This puts the delay at about > 0.15h/Mpc. Would it be advantageous to have, say, most of the cable lengths > at 25m and a smaller subset at 45m? > > Dave > > > > -- > ================================================================ > Daniel C. Jacobs > KE7DHQ > National Science Foundation Fellow > Arizona State University > School of Earth and Space Exploration > Low Frequency Cosmology > Phone: (505) 500 4521 <tel:%28505%29%20500%204521> > Homepage: http://loco.lab.asu.edu/danny_jacobs/ > <http://loco.lab.asu.edu/danny_jacobs/> > MWA: mwatelescope.org <http://mwatelescope.org/> > HERA: reionization.org <http://reionization.org/> > PAPER: eor.berkeley.edu <http://eor.berkeley.edu/> > > > -- > ================================================================ > Daniel C. Jacobs > KE7DHQ > National Science Foundation Fellow > Arizona State University > School of Earth and Space Exploration > Low Frequency Cosmology > Phone: (505) 500 4521 > Homepage: http://loco.lab.asu.edu/danny_jacobs/ > <http://loco.lab.asu.edu/danny_jacobs/> > MWA: mwatelescope.org <http://mwatelescope.org/> > HERA: reionization.org <http://reionization.org/> > PAPER: eor.berkeley.edu <http://eor.berkeley.edu/>
