Quote:
Originally Posted by JoeAZ
OK Guys, rant and rebuttals aside, I want to draw your attention to the TV Fool
report that indicates KVOA, NBC 4 Tucson, on Rf 23. The Tucson stations on Mt.
Bigelow appear unrecoverable in the report yet they do manage to be received
in Ftn. Hills. My "take" on this is that the TV Fool report is erroneous. The Phoenix
stations are over-represented and the Tucson stations under represented.
Since the Tucson stations are being received consistently, how can this be tropo?
Your thoughts???
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Yes, Joe; the report makes it look like Phoenix channels will be easy to receive and the Tucson channels will be impossible to receive.
It is well known that the reports are much less accurate for 1Edge and 2Edge signals than for LOS signals because of limitations in the software used to generate the reports. This is an extract of the report:
For comparison I did a rabbitears.info report based on my estimate of his location:
Next, I did terrain profiles of the two channels:
In the KTVK terrain profile the signal grazes the surface just before the receiving antenna, which causes a lot of scattering of the signal much like multipath. Raising the antenna helps a lot to reduce the scattering received and helps the signals clear the neighbor's house.
The KVOA signal only has to make it over one peak.
My theory to explain the paradox consists of two parts:
1. The KTVK signal is deflected from its path to the receiving antenna by a temperature inversion that is formed in the terrain bowl between the transmitter and the first peak.
2. The KVOA signal enters a high altitude duct because the transmitting antenna is at a high altitude. This duct, acting like permanent Tropo, carries the weaker KVOA signal much further, before refraction bends it down to the receiving antenna.
My advice is to raise the antenna as high as possible, add a preamp, and insert an FM filter between the antenna and the preamp. The coax must be grounded with a grounding block connected to the house electrical system ground. If 12 is still a problem, suspect local electrical interference.