Getting from outside to inside
I have spent quite a bit of time on indoor antennas, but I want to touch on outdoor antennas for a while. These are the more reliable way to get DTV signals, but they too have some traps newbies can fall into. Face it, many of us have forgotten it’s out there, or it has been working just fine for analog, thank you, and it should work for digital too. After all, I did say an HD antenna is no different than those made 30 years ago, and that’s true. I would never lie to you; Momma brought me up right.
If it has been outside for several years, however, it can have issues that will only show up on DTV signals. In this area, rust can be a killer! It can actually attenuate one channel or several, and it could distort the RF enough that the receiver can’t decode the bits.
The balum, which is a little transformer that connects the cable to the antenna, will also cause a lot of trouble. They certainly can be fried by lightning and not pass any RF at all. In this case, the lead in wire will pick up some signals, but not very reliably. The balum connects to the antenna with wing nuts, and corrosion will build up on these, which is not good at all.
Sometimes a pre-amp is next in the line, and these things can go bad from lightning strikes, or only pass limited signals. Don’t overlook these things, they can cause more trouble than they fix.
Lightning Protection should be used near the base of the antenna with a good connection to earth ground. A metal rod driven several feet into the ground with a copper wire connecting it to the cable helps protect your internal equipment in the event of a lightning strike. Lightning is a funny thing though, so don’t think you can prevent it, and it does strike the same place twice if it wants to, it just has to be in the mood.
Usually a splitter will split the signals to several areas throughout the house. Some may have an amplifier with multiple outputs, and some amps will feed into a separate splitter and then through the house. This is a very common problem area. Amps will de-tune over time and may not pass all channels equally. Splitters can cause the same issues.
Some may have cables run to 3 or 4 rooms from a splitter, with nothing connected in say, a spare bedroom. An open ended cable at just the right length, can become a band-trap filter. In other words, it can actually remove one or more channels from the distribution system.
The wire from the antenna down into the house is important too. Some home-builders will pre-wire your new mansion with cables to each room. That is a very convenient feature when buying a new house, but contractors sometimes will skimp on the quality of the cable used. The cable may work fine for analog signals, but at digital television bit-rates, the cable needs to perform more like waveguide. (I’ll show you waveguide later, I promise)
So if you have trouble, the best way to troubleshoot it is to divide it into smaller parts. I’d look at the back of the TV, and follow the wires to the next device, bypass it and check the signal. Then move to the next piece, ending up at the antenna.
Don’t scrimp. Use a good quality RG-6/U cable. Secure it properly from the antenna all the way to the TV. Use the best splitters you can find. Most will have a frequency rating printed on it. Look for 1 Gig or 1,000 MHz units. Others being sold are rated at 850-900 Mhz, and may not be very suited to digital. Spend the bucks for the better units.
Zip ties or tie wraps are great for fastening the cable securely, but be careful. Remember I said the cable will act more like waveguide (yes, I promise to show you some) and I have seen people pull these things so tight, it squeezes into the cable. That can be a major problem passing DTV signals. Do not distort or bend the cable in “L” shaped bends. It should remain round all the way from the antenna to the TV. A crimp or knot will affect it significantly from passing digital while not having much affect on analog.
If you don’t know if your amp is working properly, use a barrel connector to bypass it and see how much the signal changes. Most converter boxes have a signal strength meter built in which will help you determine if something makes it better or worse.
Kiss it! No not the musical group, or a stranger in the electronics store during H.A.D.N.M., but K.I.S.S. Keep It Simple Stupid! Make a direct run from the antenna to the TV, and then add amps, splitters, etc as needed.
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We live about 5 miles SE from Broadway. Most of the local stations are located at about 60 degrees and a bit over 31 miles from us. I have a Channel Master 4221HD aimed at 60 deg. and a Radio Shack VHF/UHF aimed at 190 degrees to pick up the PBS & ION stations(41 & 35 miles away). We do not use a rotar since it’s harder to just change a channel. I keep learning new things like co-phasing two antennas. I currently have the two antennas connected together with two lengths of 18 gauge wire. It’s working but we get interference every time a car goes by.