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Old 18-Nov-2014, 3:29 AM   #104
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,569
Thank you for answering my PMs and for understanding my situation here in VA.

I think I haven't been getting enough sleep.

Excellent photos! They give me a much better idea of your antenna system. What was confusing me is that you have two roof peaks. The higher one on the west side, and the lower one on the east side above the garage.

Thank you also for the doing the attenuator tests so quickly. Your photos and tests were worth the trouble because they give us clues to solve your reception problem with the Roamio. I couldn't have done any better if I were there with you. Well done!

The 91XG seems to be doing well for Fox. I will need to take some time to study the results. My first impression is that the problem is NOT too much signal strength for the Roamio from the C2V, but a problem with the signal quality from the C2V; maybe multipath reflections.

Earlier in this thread, post 26, I thought the problem was multipath reflections.
Quote:
Originally Posted by rabbit73 View Post
IF the problem is multipath, and IF a more directional VHF-hi antenna helps, then another alternative would be to replace the C2V with a UHF/VHF-hi combo antenna.

IIRC, the early TiVo tuners didn't handle multipath reflections very well.
https://www.google.com/?gws_rd=ssl#q=TiVo+tuner+doesn't+handle+multipath+very+well
Later, I was convinced that the problem was signals that were too strong, based on what other Roamio users had posted. Now, based on your attenuator tests, I'm back to multipath.

That metal stack in front of the C2V couldn't be doing much good for the signals from the NE. I also wonder if they can clear the roof of the house to the East of you. If not, it would cause diffraction and scattering of the signals.

Any chance you can raise the C2V a little higher on that mount to clear the stack for a test?

Your antennas are in a "valley" between the higher roof on the west side of your house, and the roof of the house to your east. It doesn't seem to bother the 91XG because it can look out the end of the valley to Fox. But, the C2V can't see the transmitters from the NE because of the house to your east. How high is your C2V in comparison to the peak of the roof on the house to the east? Can the C2V see above that peak?

You probably will need to get the C2V out of that valley. The best location would be at the rear of the peak of your higher roof, mounted on an eave bracket. A 5 ft mast would probably do it if you didn't want to run the mast all the way down to the deck. A 10 ft mast would be needed if you wanted to stack the 91XG and the C2V on the same mast.

If you try the C2V in that better location, and it still has problems, then you will need to switch to a UHF/VHF-hi combo antenna for the signals from the NE.

The new coordinates you gave me are right for the 45 degree photo, but wrong for the 90 degree image. The green lines from the transmitters would also cross the peak of the house to the east for the 90 degree image if the indicator were moved to the location of your antenna. The default for the tvfool interactive map is 45 degrees for satellite images.

Attached Images
File Type: jpg Location 3-45 deg.JPG (94.7 KB, 848 views)

Last edited by rabbit73; 18-Nov-2014 at 11:57 PM.
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