By now you’ve probably read our tutorial on combining two antennas. It’s one of the most popular articles in our history. Is it really the better way to go, though? Or, will a simple antenna amplifier do a better job for you? Let’s take a look.
What’s the point?
Whether it’s amplifying or adding hardware, the reason is the same: more signal. Specifically, more gain. We want better reception, we want to be able to pick up signals we couldn’t pick up before. In order to do that, we need more of something. I like to tell people that RF signals are like butterflies and an antenna is like a net. The easiest way to catch more of them is with a bigger net.
I admit that’s not a perfect analogy because it’s not enough to make an antenna bigger just to make it bigger. It has to be bigger in just the right way. Broadcasts are all on “frequencies” and “frequencies” translate out to “wavelengths.” I put all these terms in quotes because it’s not about your deep understanding of the physics behind it all. It’s about understanding that the higher the frequency (or the channel number, in the case of TV) the shorter the wavelengths get. And, an antenna does its best work when its physical size is matched up to the length of the wave it’s trying to receive.
If you look at at it that way, two or four antennas should pick up a lot more signal. And they do, if they’re put together right. An array of two antennas should pull in double the signal, and an array of four should pull in four times the signal. That’s the idea behind our Xtreme Signal HDB8X. At its heart, it’s four of our HDB2X antennas put together. The HDB2X has about 8dB of gain, while the HDB8X has about 18dB. In a perfect world it would have 24dB of gain but you lose some of that in the wiring and splitters that make up the rest of the antenna.
And then there are amplifiers.
An amplifier takes a signal from an antenna (or anything, really) and adds to it. It’s pretty common for amplifiers to have up to 20dB of gain. All you have to do is put it inline with the antenna and plug it in. It’s a lot simpler than wiring up two antennas. It’s usually less expensive too.
More gain is better gain, unless…
You might have noticed that an amplifier can add 20dB of gain while adding three more panel antennas only added 10dB of gain. You don’t have to know much about signals or dBs or any of that to know that you want more dBs and 20 is more than 10. So on the face of it the amplifier would win hands down, right? There’s only one thing you really need to think about here. And that one thing… changes it all.
An amplifier can increase the strength of a signal, but it can’t create a signal where one isn’t there. It also amplifies the noise that’s around the signal, and that’s a problem with really weak signals. (Face it, if the signal were strong you wouldn’t want to amplify it anyway.) An amplifier is a good bet where the signal is pretty weak but not very weak, but for truly weak signals an amplifier won’t do anything for you. It could actually make things worse.
The old-schoolers say…
Ask your typical grizzled antenna veteran and he will tell you that the better way to go is to add more antennas. This is going to pull in the weakest of the weak signals. Another option is a truly giant antenna but sometimes those are hard to come by.
However, that veteran would be well versed in making his own cables and making sure that everything is properly spaced. That’s critical to avoid “phasing” issues where the signal from one antenna cancels out the signal from another. If you’re good at that stuff, it’s easy. If you’re not, it can be a big issue.
An array of multiple antennas is going to give you the best chance of pulling in truly weak signals. It’s just up to you to decide if you can make it happen.
The modern solution
A lot of people use amplifiers today instead of using multiple antennas. This means the antenna itself can be smaller and you will still get some benefit from the extra gain. Smaller antennas look better to many people and you won’t run afoul of the homeowners association. The HOA or condo board has the right to complain if your antenna gets bigger than 39″ in any direction. So, while an amplifier might not be a perfect solution… like a lot of things today it’s a good compromise.