Please Advise: Weak Signal, even woth trying more?

[BarberSurgeon16]

Originally Posted by rabbit73

I think you must mean -5 to -10 dB Noise Margin (NM) range. Signals that are -5 to -10 dBm are extremely strong; strong enough to overload a tuner.

If an antenna is in the clear, it is possible to receive signals as weak as -15 dB NM. It is not possible to receive signals any weaker than NM -15 dB, because they are below the Thermal Noise Floor at -106 dBm. If you are able to receive signals weaker than -15 dB NM, either the TVFool report is wrong or the signals have been enhanced by Tropospheric Propagation.



Where the -106 dBm comes from:

http://www.aa6g.org/DTV/Noise/noise.html

I expect you to spend at least as much time testing as I have spent answering your questions.

Good luck

and

best regards,
rabbit

Thank you for this post. I spent quite a bit of time on google searching for that exact information...

[rabbit73]

Thank you for this post. I spent quite a bit of time on google searching for that exact information...

Glad that I was able to give you more useful information. In the Fall of 2015, I decided I needed to learn more about Noise Margin; that's when I did my research and drew the diagram.

If you want to learn more, my original inspiration came from a post about Noise Margin by Andy Lee, who created the TVFool website:
http://www.avsforum.com/forum/25-hdt...l#post15700679
post #397 of 654

I have reproduced his original two diagrams in Attachments #3 and 5. My revisions are in Attachments #4 and 6.

The last time I checked, the HDB91X was on sale:
http://www.solidsignal.com/pview.asp?p=hdb91x

This is what the HDB91X and the MCM 30-2476 look like up in the air:





Bobsgarage lives north of Chicago, and has two antenna systems on two separate masts; one UHF/VHF system facing north to Milwaukee, and one facing south to Chicago. (In the photo, they are both aimed in about the same direction.) He wanted so many channels, he found it impossible to combine them without losing some. He is using separate tuners.

[BarberSurgeon16]

I think we're just going to give up on this location working reliably OTA. I might tinker some in the future, but return doesn't seem to be worth the time and cost in this case.

Thanks for all the help from everyone here. I'm still enjoying 21 channels at my house OTA!