[mythtv-users] HDHomerun signal strength required

Brian Wood beww at beww.org
Fri Feb 22 15:33:15 UTC 2008


backuppc at sundquist.imapmail.org wrote:

> This image can address both of these comments:
> 
> http://www.remotecentral.com/hdtv/toronto-buffalo.png
> 
> I am located right about at the southeast corner of the box that says
> "WIVB 4/39".  So the two directions from which I need to receive signals
> from are almost 180 degrees apart, with the old big 3 networks to the
> south-southeast, and the rest on on Grand Island to the north-northwest.
> My understanding is that so long as they are in opposite direction
> things are OK.  But I should probably check the aim.  The antennas, 300-
> 75 ohm connectors, and 3-foot leads to the splitter/merger are
> identical, so phasing should be OK.

Actually that situation almost guarantees things are not "OK". Unless 
the antennas are spaced so that they are receiving the signal in phase 
with each other, having identical lead lengths will not work well, and 
will result in at least some phase cancellation.

And if they are spaced for proper phasing on one channel, they will be 
wrong for all others, since phasing depends on wavelength (frequency). 
Stacked phased arrays are almost always single-channel affairs for that 
reason.

> 
> Another goal is to try to get some of the stations on the CN tower in
> Toronto (same direction as Grand Island).  It's far away, but it's the
> tallest freestanding structure in the world so a lot of people in the
> area can pick up (at least NTSC) stations from there.
> 
> Also, as you can tell from the map, the "bad weather" I refer to is
> snow, not rain.  I also have some evergreens near the house that can
> collect snow.  Right now the antenna is the attic, so weatherproofing
> isn't an issue, but I may consider moving it outdoors next summer.

I would think that snow on the roof might be a problem as well.

beww


More information about the mythtv-users mailing list