[rabbit73]

The strongest TV signal is WNLO with a Noise Margin of 73.2 dB, which puts it in the overload category. To that you can add ~10 dB of antenna gain which brings you up to a NM of 83.2 dB.



Interpreting Noise Margin in the TV Fool Report
http://www.aa6g.org/DTV/Reception/tvfool_nm.html

Going on the basis of Signal Power dBm in the report, WNLO is -17.6 dBm, and adding 10 dB antenna gain gives -7.6 dBm.

ATSC Recommended Practice:
Receiver Performance Guidelines
Document A/74:2010, 7 April 2010

RECEIVER PERFORMANCE GUIDELINES

5.1 Sensitivity

A DTV receiver should achieve a bit error rate in the transport stream of no worse than 3x10E-6 (i.e., the FCC Advisory Committee on Advanced Television Service, ACATS, Threshold of Visibility, TOV) for input RF signal levels directly to the tuner from –83 dBm to –5 dBm for both the VHF and UHF bands.

5.2 Multi-Signal Overload

The DTV receiver should accommodate more than one undesired, high-level, NSTC or DTV signal at its input, received from transmission facilities that are in close proximity to one another. For purposes of this guideline, it should be assumed that multiple signals, each approaching –8 dBm, will exist at the input of the receiver.

You can see why an attenuator might be necessary.

I will advise him to place the antenna on a tripod on his roof. I have grounded my antenna in the past, so I will make sure that the tripod/mast and the coax run will be grounded before entering the house.

Good, that will reduce the chance of strong TV and FM signals from causing interference. They can get directly into the TV set if the coax isn't grounded with a grounding block.

The coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge, but the system will not survive a direct strike.