Thank you for making another test.
Signal strength is just about enough, but signal quality and symbol quality aren't what they should be. Signal quality is similar to SNR and symbol quality is the inverse of uncorrected errors. You want 100% symbol quality for no uncorrected errors.
I think I know what is going on. If you look at your tvfool report you will see a red "a" next to the KCKS callsign. This is a warning of adjacent channel interference, in this case from KCTV with a NM of 72.4 dB, making it 70.7 dB stronger than KCKS with a NM of 1.7 dB.
The signal strength reading you are getting might not be only from KCKS, it might also include some signal from KCTV spilling over into the KCKS channel.
TV tuners are expected to be able to decode a weak signal that is 33 dB weaker than a stronger adjacent channel. It is not known if your HDHR or the TV tuners meet or exceed that spec, but 70.7 dB is a lot more than 33 dB.
ATSC Recommended Practice:
Receiver Performance Guidelines
Document A/74:2010, 7 April 2010
RECEIVER PERFORMANCE GUIDELINES
5.4.2 Adjacent Channel Rejection
Quote:
|
The receiver should meet or exceed the thresholds given in Table 5.2 for rejection of first adjacent-channel interference at the desired signal levels shown above the columns therein.
|
The antenna pattern for the 91XG will make KCTV 20 dB weaker when it is aimed at KCKS, so it is now only 17.7 dB over spec.
So, try the 91XG when it comes, with the HDHR and the TV tuners and let us know the results.
If you are not quite there yet, a custom filter, the two-antenna trick, or a shielded antenna enclosure are next on the scale of extreme measures for your grandfather.