Originally Posted by Avio
Thanks for your critical comments... they puts this article in perspective.
I've stopped using and recommending www.antennaweb.org
and have been using www.TVfool.com
Do you agree with my impression that TVfool.com is better than antennaweb.org? Do you have any other recommendations?
I use www.tvfool.com
whenever I analyze someone's situation.
But I have not (yet) seen or conducted some sort of accuracy verification.
I also use RADIO MOBILE, a FREE propagation prediction program download:http://www.cplus.org/rmw/english1.htmlhttp://hdtv.forsandiego.com/messages...html#POST28428
R-M automatically downloads SRTM-3 (medium rez) topo database, although
I've manually downloaded the hi-rez SRTM-1 topo database for my area.
And SRTM-1 is barely adequate to resolve local terrain variations....
I normally calculate F(50,50) and/or F(50,90) statistics and then estimate
how much Fade Margin is remaining (typically need 15-20+ dB).
I've developed a set of Excel spread sheets which takes the tvfool results
(and/or Path Loss from Radio-Mobile) and incorporates numerous gain/loss
factors not incorporated into either antennaweb or tvfool (a critical oversight).
This includes Land Use Clutter Loss, Tree Loss, Attic/Indoor Loss, sensitivity
reduction due to Antenna VSWR (ala Oded Bendov), Antenna Gain, Balun loss,
Preamp Gain/Noise Figure, Cable/Splitter loss and receiver Noise Figure.
[Some of these can't help but be guestimates....]
I posted a copy of these spread sheets, attempting to "calibrate" the tvfool
F(99,99) results against the more commonly used F(50,50) and F(50,90)
statistical criteria. [50% of "locations", 90% of the "time"]:http://www.avsforum.com/avs-vb/showt...&#post10961518
Equations are fully described with references to various supporting documents.
Because tvfool calculates "RX(dBm)" using F(99,99) statistics, the levels represent
the signal level during one of the worst fading events during the year (decade?).
This results in calculated RX(dBm) being considerably lower than not only the
best receiver sensitivity...but also well below the thermal noise floor.
Hence it isn't very useful wrt overload calculations....so I calculated a conversion factor.