Living on the edge...

byetocable · 28-Feb-2015, 8:35 PM

http://www.tvfool.com/?option=com_wr...f1f04c55994439

Looking to get rid of cable after having it since it came to my town some 35+ years ago. Right now just wanting to get the major networks and a few independents. Purchased one of these imported directional, rotor-equipped antennas and have it on a light stand in my upstairs bedroom. Eventually, if the temperature ever gets about 10 degrees here in Connecticut, I might install it on a mast on the chimney like in the good old days.

All the local network stations I hoped I'd be able to get are now coming in fine. Many have their antennas on the same mountain, so easy pickings there. Get some break up now and then. I assume that is to be expected. One thing cable did provide was a perfect (though lower quality) signal all the time.

My question has to do with the "PATH" as shown on the report (see above) and what, if anything, can I do to get signals that are not now "LOS" or line of sight.

The ones that are 1Edge and 2Edge... and there are many on my report... are they basically out of my reach no matter what I do or can someone make some suggestions I can use for the future.

Thanks. All your help is much appreciated.

timgr · 28-Feb-2015, 11:17 PM

The 1-edge and 2-edge stations are being diffracted over edges in the terrain in your direction. Essentially, they are over the horizon, either due to a hill/mountain or due to the curvature of the earth.

You can receive them if they strong enough. In an ideal situation, you should be able to receive down into, say, the single digits in noise margin. But this would require a roof mounted antenna pointed directly at the transmitter, and a sensitive (ie big) antenna. Obstructions (trees, the building walls,, etc) and local interference disrupt that ideal situation. There can also be local nulls that you simply have to work around - see here: http://www.hdtvprimer.com/antennas/siting.html

Tower Guy · 1-Mar-2015, 1:16 AM

If I lived in your house I'd be thinking about a 4 bay or C2 UHF only aimed at about 285 degrees coupled with a Y10-7-13 VHF antenna aimed at WTNH. Use a UVSJ to join the antennas. No preamp needed. If you also wanted the Springfield stations use a DB-8e as your UHF only and splay the panels at 285 and north.

byetocable · 1-Mar-2015, 3:00 PM

Thank you for the detailed replies. Two questions...

I have a "subscriber amplifier" and a 1 to 8 distribution unit from the cable company. Marked as for 53 to 1000Mhz. Can I use that with these antennas to split my feed (at my office location in town)?

I'm also confused by one point. Am I correct in assuming the four main commercial stations broadcast both their 16 x 9 HD and 4 x 3 SD signals on the same channel or is it the cable station that down converts each HD signal to SD for their customers?

All four stations on Cox Cable come in both HD and SD on different QAM channels but I cannot find any mention of SD for OTA reception.

timgr · 1-Mar-2015, 3:25 PM

Each real channel has one or more virtual channels multiplexed into the signal. Usually that means one HD channel and 2 or 3 SD channels, although I receive two RCH that have 4 SD VCH on them. I suspect there is not enough digital bandwidth on a single RCH for more than one HD stream. The signal is a compressed digital stream, encoded to the analog carrier. Your tuner locks on to the carrier and picks out the channels from the stream.

The cable companies pick these channels from the air or from satellite - I'd presume - and then send it down the cable using different encoding and more compression. Supposedly the additional compression is why these channels when distibuted by cable are of lower quality than the OTA TV. I get WGBH OTA here, and I was shocked at how good the picture quality is.

byetocable · 1-Mar-2015, 3:51 PM

Well, I don't think this is completely correct. First, I believe some stations provide a fiber feed to the cable systems in their area. This is now they get them with no interference like I and others are dealing with using antennas. I remember in the old days (before digital) the cable system would lose channels in bad weather. That does not happen any more around here.

Second, if you look at a given channels specs... Take WTIC (Fox) in Hartford. They have 61.1 for their HD and 61.2, an SD called Antenna TV. Mainly old TV shows with tons of ads.

I see no mention of an SD signal. But on Cox their SD is QAM channel 2162. It is a 4 x 3 format signal identical to their 16 x 9 HD on QAM channel 2611.

I have a feeling it is Cox (for my area) that is creating the SD from the HD.

Can anyone say for sure?