Thank you for the guidance, krusty79
; I need all the help I can get. Being from Virginia, I do not have sufficient knowledge of your local conditions.
What is important is that CBFT-DT and CBMT-DT are much stronger than CIVM-DT and more likely to cause overload.
Aiming the two sections of the antenna in different directions doesn't always work, in spite of what the marketing departments say. The same signals from each panel can interfere with each other if they don't arrive at the combining point in phase (at the same instant). You didn't answer my previous question:
How does NBC do if you aim both panels at it?
I'm wondering if I could/should put an amplifier on the US pointing side only (and leave the Montreal pointing side well enough alone), or is that likely to mess things up even further...
If you did that, you would need a combiner that passes DC power to just one side for the preamp between the combiner and the antenna. But, a preamp would most likely cause overload.
Now that The Games have begun, I'm super happy that we can watch it on CBC, but I find that NBC (channel 5.1) is completely unreliable. The signal strength seems unchanged from before, varying between 40% and 45%, but it drops it constantly... Part of what's confusing me is that the signal's "Effective Power" (according to TVFool) should be 103.8 kW, while Vermont PBS is crystal clear from the same mountain with and "Effective Power" of 90 kW... Does anyone have any guidance for me on how strong a signal needs to be for it to be reliable?
The fact that the two panels are aimed in different directions might be a factor, as mentioned above.
The difference in ERP sent your way is quite small.
dB = 10log(P1/P2)
10 log 103.8/90 = 10log 1.15333 = 10 x 0.062 = 0.62 dB
Most UHF antennas of that design have a gain curve that starts out low at the CH 14 end, and rises with frequency, so the gain of your antenna is less for WPTZ on channel 14 than for WETK on channel 32.
The antenna pattern for the WETK transmitter is omni-directional, but the antenna pattern for the WPTZ transmitter is severely restricted in your direction to protect the reception of your local channels according to border agreements.
Although it looks like the two antennas are on the same tower, they are not. The slightly different location and the difference in frequency can make a difference in propagation.
I don't yet have your tvfool report, so I will have to use the numbers on my estimated report.
CBFT-DT has a signal power of -28.3 dBm = 20.7 dBmV
Max input of Channel Master 7778 = 34 dBmV
20.7 dBmV + 12 dBd ant gain = 32.7 dBmV; OK
CBFT -28.3 dBm + ant 12 dB + preamp 16 dB = -0.3 dBm; tuner overload if the antenna is aimed in that direction