Issue # 1 - The Cliff Effect
The cliff effect is a term used to characterize the all or nothing picture associated with digital reception. Analog reception works differently with your TV tuner than digital reception.
With analog, you're able to view good-to-bad signals even if the image has ghosting, static or comes in and out. Digital doesn’t work that way. A digital tuner must receive a complete signal in order to display it on a TV. A partial signal will result in something like no picture or a frozen image on-screen.
- How to Fix + Buying Advice
- If you’re using a directional indoor antenna, like rabbit ears, then it might be as simple as switching to a multi-directional indoor antenna that's designed specifically for digital reception. These newer antennas are flat and may be amplified.
- You might have to upgrade to an outdoor multi-directional antenna if you're receiving a bad signal due to proximity to the transmission tower or obstacles blocking the signal. Antenna Web is great resource for finding the right outdoor antenna for your address.
- If you know your antenna isn’t the issue then you might need to change the coaxial cable connecting the antenna to the tuner. RG6, preferably quad-shielded, is the recommended type of coaxial.
- It’s possible that the digital signal is coming a lower point on the tower than the analog signal. This is a line of sight issue. Once analog disappears the signal should go back to the top of the tower.
Issue # 2 - Antenna Amplification
Amplification used to be a foolproof method for improving an analog signal. The more the db the better. The opposite is true with digital.
Too much amplification can blow out a digital TV tuner much like too much audio can blow out a speaker. Instead of a popping sound coming through a speaker you get black screens.
- How to Fix + Buying Advice
- The fix for amplification is to get a better signal. You don't need to raise the roof on power going to the antenna. See Issue # 1 above for more information on the Cliff Effect.
- The optimum amplification for digital signals is anywhere between 10 and 14db.
- The problem with buying an antenna is that not all packaging will state in bold print the amplification of that antenna. You’ll need to look for the fine print when selecting an antenna based on amplification.
Issue # 3 - Your TV's Scan Process
The scan process is something all antenna users should be familiar with. This is where you go into the menu settings and scan for signals picked up by the antenna.
The problem with scanning for digital signals is that you need a good signal and the antenna needs to be pointed towards this good signal.
- How to Fix + Buying Advice
- There is no catch-all fix for this. If you use a directional antenna, like rabbit ears, then you must scan every time you point the antenna in a different direction.
- Back and forth scanning is not efficient. You can manually enter channels into your channel lineup but you'll need to know the frequency the signal is using, which does not necessarily match its channel assignment.
- Something else to consider is that when the digital transition occurs a lot digital signals will change frequencies, which will force you to rescan again. Your TV may still go dark on February 17, 2009, so be sure to rescan your tuner for channels before freaking out when you see a dark screen.
Issue # 4 - Directional v. Multi-Directional Antennas
A multi-directional antenna is the best type to use for digital signals because the antenna will scan a full 360-degrees for signals.
Using a directional antenna you increase the risk that you won’t pick up all the channels in your market.
- How to Fix + Buying Advice
- Buy an antenna designed for digital reception. This doesn't mean one with more amplification (see issue #2).
- Using a directional antenna increases the cliff effect because channels on the fringe of your antenna’s reception won’t be picked up due to their weak signal. (see issue # 1)
