All About Gain

Repeater Section

Index

Basic Installation

Donor Antennas

Coverage Antennas

Other Issues

Repeater
Differences

Repeater FAQ's

Antenna Section

Index

Basics

Bands and
Frequencies

Gain

Home and
Office

Vehicle
Reception

Pointing an
Antenna

Finding Your
Frequency

Frequently Asked
Questions

Another important note: There is a TON of misinformation being presented out there on the internet. Many un-truths and wild claims of quick and easy fixes. Reading this page will help you sort the real information from the "snake oil".

Without getting too complicated, Gain is the measurement of an antenna to receive and transmit signal. Gain is stated as dB . In general , higher is better. A typical portable phone antenna has a gain of 0dBd (zero dB) also known as Unity Gain. This will work well for high coverage areas but not out in the fringe areas. For the fringe areas a higher gain antenna is needed to reach out to the cell site. Typical gain for external antennas range from 0dBd up to 12.2dBd . This becomes quite a help when you are far out in the country away from the city with all of those cell sites. Higher gain antennas translate directly into more power or ability to reach out to the cell site.

That said, it is not true that simply attaching a higher gain antenna to your phone will get you better reception. In the diagram above let's say that we put the external antenna down in the basement where the (D) is. The higher gain antenna would still be blocked by the concrete, earth and the building. Notice how the external antenna (C) is mounted in plain view of the cell site . Considering that you are using the correct frequency antenna , a higher gain antenna will get you better reception especially if you are farther from the cell site. In this example we are illustrating the best use of a fixed application Panel antenna. Follow link to get further details on these antennas. Or just keep reading and check them out a little later...

Playing Games with Gain Ratings

There are two scales that antennas are commonly measured on -- dBi and dBd . dBi is approximately 2 units higher than dBd. 5dBi = 3dBd. 2.2dBi = 0 dBd, etc.All antennas can be represented by either dBi or dBd - So an antenna at 5dBi is equivalent to an antenna at 3dBd.

One major problem in the Cellular Antenna industry is that many manufacturers don't always disclose which scale they are using to measure the gain of their antennas --  dBd or dBi . They simply say that their antenna gain is say 5dB and claim that it is better than a competitor's antenna at 3dB. Try asking the salesperson "is that dBi or dBd?" Then watch their eyes gloss over.  Now that you know, the first manufacturer may actually have a 5dBi antenna and the second manufacturer has a 3dBd antenna -- They are the same in gain.

Another growing tactic that some manufacturers and retailers use is padding the numbers . Placing (much) higher gain ratings on antennas than is actually true. They are able to specify any number they want since there is no way the average user can verify what the true gain rating is of any particular antenna. The equipment used to measure gain is expensive, complicated and has many variables too numerous to explain. It will suffice to say, you're stuck having to trust their numbers.

A Common example:

This type of Magnet Mount antenna is advertised all over the internet as a 5dB Dual Band . In fact it is a 0dBd antenna. On top of that it uses RG174 High Loss cable--so what little gain it has is not much good by the time it reaches your phone. We have a whole box of these collecting dust in our warehouse.

Special Note: The antenna in or on your cellular phone as you purchased it from the retailer is a 0dBd (2.2dBi) antenna. This information will be useful in helping you select antennas later in this tutorial.

The antennas we sell are only from reputable and reliable companies that don't play games with numbers.   When they state gain ratings they are accurate. We've been installing these antennas since the early 1980's and our testing has always found them to be accurate and many times conservative in their gain ratings. As you are looking at the antennas and their specifications on our site , gain is usually stated as dB =dBd unless otherwise noted. As you now know, other manufacturers and retailers may not disclose or even know which scale their antenna is measured on. And some are simply assigning whatever gain rating they think will make you buy their junk.

Next step, please select where you would like to improve your reception...

In Your Home or Office

In Your Vehicle

Back to learning index

Privacy Notice.

.