:welcome: Morty,
To begin, low-band VHF television is very prone to receive interference from man-made noises such as fluorescent light ballasts, electric motors like your kitchen blender or a neighbor's air conditioner, etc., so I propose a very inexpensive test to see if you have enough signal versus noise to allow reception of channel 5. If you find 'noise interference' you may be able to track the sources down and eliminate them, before you continue with permanent antenna plans.
I am an experimenter and I'm shooting from the hip on this one, but why not! Any "conventual" low-band television antenna is going to be VERY large but since your station is LOS, I have a wild idea.
The transmitter is located at 100 degrees almost due east to you. Does your home have an outdoor wall that 'broadsides' that direction? I'm thinking about building a simple half-wave folded-dipole wire antenna, cut to that channel. Half of the people on the Forum will think I'm nuts to suggest this, but the Ham Radio operators here will understand the simplicity of the test I propose.
All outside TV antennas that were designed (compromised) to work on low band-high band VHF are now considered to be obsolete, as there are very few low band VHF stations remaining. This is not to say a VHF-high band/UHF combo antenna might be the answer for you, but I suggest you try a simple test and if it works, you could use a far smaller antenna for the rest of your channels and combine my 'plan' with a smaller UHF antenna. Here we go:
This link--->
http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=73&SECTION=603&YEAR=2002&TYPE=TEXT shows channel 5 spans 76-82 mHz, so your design frequency should be 79 mHz.
This link --->
http://www.angelfire.com/mb/amandx/dipole.html determines the length of a dipole antenna.
For 79 mHz, you would need a little over 12 feet of wire: I prefer stranded bare copper, but anything would work for a simple test (possibly all you need)! The actual lengths are 5.92 feet in overall length, 2.96 feet per half. Now you see, a dedicated channel 5 'conventual' rooftop antenna would have to be be a six-foot-wide monster.
The second link (above) pictures from left to right shows a ceramic or plastic insulator, a quarter-wavelength section of wire, a center insulator where the coaxial feedline is attached, a second length of wire cut to the same length as the first one, and a third insulator. This could be fabricated in a few minutes and it would cost virtually nothing to try. Test this horizontally.
Regarding coaxial cable, there are big differences between brands. A local Engineer tested several brands and he determined Radio Shack coax is leaky and lossy: next, be certain to use black-jacketed coax rather than white as it resists ultra-violet (sun) rays far better than other colors. Preferred are commercially installed coaxial fittings (factory cut 25/50/75/100 foot lengths) unless you have the proper tools to install fittings.
Regarding grounding your antenna mast, there are posts here on the Forum (search grounding) that illustrate why a simple 'Radio Shack' coaxial grounding block is not considered to be enough for safety and they do not meet National Code. Once you are satisfied with your antenna setup, be sure to waterproof all of the coaxial fittings using RTV or a similar product.
Jim
