Originally Posted by ToddUGA
A dish????? What kind of dish for Macon stations? Do you mean a parbolic reflector antenna?
Im 8 miles from the Macon transmitters. I have an antenna about 40 ft up that is advertised to have 7.8 dB gain. I am using low loss Belden 1694A coax (no more than 50 ft) without an amp. I get all the macon stations except Fox and I got it till the trees leaved out a few weeks ago. (Fox is transmitting low power and my antenna is actually looking thru some trees in my yard)
You are 60 miles from "the farm." If you need to acheive the same signal level as me to receive the stations, the inverse square law says you need 6dB additional gain for each doubling of the distance. 8 to 16, 16 to 32, and 32 to 64 gets to your range 3 "doubles" then means you need 3x6=18 dB more gain than me. 18+7.8 = 25.8 dB.
My calcs for a parabolic reflector antenna show you would need an 11 meter diameter dish to get this gain at 633 MHz (WMGT-DT carrier) and a 20 meter diameter dish at 211.25 MHz (WMAZ-DT carrier)! Got a source for spare radio astronomy antennas? Suggest you go with available yagi or bowtie reflector antenna types, as most people seem to do.
Commercially available long range antenna gains are not going to be more than 16 or 17 dB. And if you want a combined VHF/UHF antenna (You want to get WMAZ-DT so you can watch The Unit in Hi def dont you?), it is going to be lower.
Here is a good reference: http://www.hdtvprimer.com/ANTENNAS/comparing.html
Look at the "Net Gain" plot.
heres a UHF only antenna claiming 16.7dB max gain:http://www.antennasdirect.com/91XG_HDTV_antenna.html
but no VHF (cant get WMAZ-DT with this one)
Highest gain UHF/VHF i see from same place has 12.9 dB gainhttp://www.antennasdirect.com/V21_vhf_antenna.html
Here is a good reference i just found tonite. And prices dont seem too bad either.http://www.solidsignal.com/winegard_antenna_chart.asp
Note the longest UHF range they advertise is 60 miles.
So for UHF only, you need to make up 25.8 - 16 = 10 dB of antenna gain with a mast-mount Amp. For combined VHF/UHF, you need to make up 25.8 - 12.9 = 12.9 dB amp gain. And you need to make up any cable loss also. So you are going to need more than 13dB of gain out of the Amp. According to online vendor claims, you can get 18 to 28 dB amp gain (watch out for vendor claims). The amp will decrease signal to noise ratio a few dB which is something you cant do anything about. Hopefully, there is enough margin in the starting point (my setup gain and signal to noise ratio) and extra amp gain so your receiver will not have a problem.
All these gains considered, you also need "line of sight" which at 60 miles range, means you need the antenna way up in the air or you live on a mountain (i havent seen any in Eastman). If you are in a depression (elevation wise, not psycologically), forget it.
Bear in mind that all this is "seat of the pants" calculations and some based on vendor claims but you might get lucky. I have no idea what typical signal strengths are in Eastman, nor what minimum sensitivity is for any HDTV receiver. I would bet against you seeing anything (maybe WMAZ-DT at night) unless your land elevation is at least as much as surrounding terrain, you have a high gain antenna, TBD
(60 ft, 100 ft? I dont know what is needed for line of sight at your location) or higher above the ground, no blockage by buildings or trees, mast mount preamp of 15dB or greater, and low loss, high shield coverage cable.
Suggest you find someone else out there who successfully did it and assess your situation from their installation. Anybody in Eastman pulling Macon HDTV off the air?????