Question on TV Fool Report/pixelation

rob72ota

DTVUSA Rookie
#1
I am in San Jose, CA. I have a Mohu SKY 60 antenna mounted on a single story house (15 ft height) with 60' RG6 quad shield (one balun) , no splitter to one TV.

I get good reception with this antenna even though I am 45 miles from the Mt Sutro/Mt San Bruno transmitters. However sometimes I get some pixelation especially in the mornings especially on KPIX, KRON, KNTV, KQED. The signal strength on these channels is always at least 95%. Nighttime reception is usually perfect.

The TV fool report shows these channels are 1Edge for 15' antenna height, but I don't know how much that comes into play-
TV Fool

I tried generating another TV fool report for 18' height and the channels then became LOS-
TV Fool

I also moved the location to my neighbor house across the street and found that even at 15' all channels I want are LOS-
TV Fool

So I am trying to determine how accurate the TV Fool reports is to my exact location and whether increasing the antenna height would make a difference. I know its a simulation so I am hesitant to do this, since the problem is that the Mohu SKY mounting bracket cannot go any higher, so I would have to find a longer mounting pole.

Another observation is that KGO (UHF 35) also has pixelation at the same time, but I receive that from the Mount Allison transmitter, which is only 13 miles away.

Was wondering if a pre-amp would help, (I ditched the amp that came with the Mohu as it seems to make things worse), but having doubts on that, as the signal strength is already 95% and may cause problems with the nearby channels.

I wouldn't have thought it could be weather related since the issue appears to be from channels received at different distances and degrees.

There are some trees in the LOS to the Mount Allison transmitter which could explain KGO, but there are not trees in the direction of the Mt Sutro/Mt San Bruno transmitter.

Any suggestion would be appreciated.
 
#2
Short fast response to your post is go 20 feet buy more mast. The Mohu sky is nothing more then a well designed UHF single bow tie antenna. If nearby trees and buildings aren't in the way TV Fool predictions can be quite accurate.
 

dkreichen1968

Moderator
Staff member
#3
Which direction is the Mohu Sky pointed. The flat sides should be north/south. It would seem that you are experiencing multipath interference in the mornings.
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#4
:welcome: Rob

Sometimes the best location for an antenna is lower so before you buy a longer mast, try lowering your antenna 6-12" compare your reception and drop it again. I receive one channel with my antenna at a specific height and locating it 6" higher or 6" lower kills my reception. There may be a 'sweet-spot' location only a few inches away.

Jim
 
#6
Mr Pogi has given some good advice. At my previous place of residence I was right on the edge of line of sight where moving the antenna 20 feet one direction or the other can make a big difference. While the desired signals came from the same mountain peak with a short distance apart at the transmitter site. The TV Fool site, and Rabbitear.info site revealed that there was a big difference in which signals were line of sight at different locations on the property. On the rabbitears.info site you need to dig deep, and look at the Longley Rice signal propagation map for a given transmitter clicking on satellite view, and zooming in. A bit of a learning curve to learn to navigate, but can be quite useful. The Longley-Rice Propagation model is not without flaws, it is what TV Fool uses and is the most accurate signal propagation tool we have to work with. What amazes me is that signal predictions are available and very accurate in a sparsely populated part of Wyoming with very few signals available.
Steve
 
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