Im gonna buy a new antenna but I notice that the "db gain" is different on some than others. Some are 8 and others are 10.2, will someone please tell me what the difference and how it will effect the antenna, more importantly my scanner. Thanks!!!
How does "gain" effect antenna?
- Thread starter Duramaxman
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nd5y
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Antenna gain - Wikipedia, the free encyclopedia
As a general rule of thumb the higher the number the better.
You have to know what the gain is referenced to and what type of antenna it is.
Many manufacturers of consumer grade antennas (amateur, scanner, TV, etc.) lie about gain for marketing purposes.
As a general rule of thumb the higher the number the better.
You have to know what the gain is referenced to and what type of antenna it is.
Many manufacturers of consumer grade antennas (amateur, scanner, TV, etc.) lie about gain for marketing purposes.
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n5ims
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The point that Tom was making about "what the gain is referenced to" is important. There are two main types of references being made by antenna makers, dBi and dBd. They both are called by the generic name of dB, but are very different in the base number they use. dBd is a smaller number while dBi is a larger number (2.15 dB difference between the two) for the exact same antenna.
The folks that do the marketing (and often end up winning on what number is used on the antenna's spec) is the larger of the two, since it sounds like it's a much better antenna (although it really isn't). You should assume that dBi is used if they don't specify and add 2.15 to the number if they specify dBd when you make your own comparisons. e.g. one antenna indicates it has a 3 dBd of gain and the other antenna indicates it has a gain of 5 dB. Compare the two as being basically the same (3 + 2.15 = 5.15 dB for the first one and the reported 5 dB for the second).
Your example of the two being 8 dB and 10.2 dB make it sound (without any additional details) that they're both the same basic gain (8 + 2.15 is awfully close to 10.2). You may want to verify what they're reporting the gain in, dBd or dBi to confirm.
The folks that do the marketing (and often end up winning on what number is used on the antenna's spec) is the larger of the two, since it sounds like it's a much better antenna (although it really isn't). You should assume that dBi is used if they don't specify and add 2.15 to the number if they specify dBd when you make your own comparisons. e.g. one antenna indicates it has a 3 dBd of gain and the other antenna indicates it has a gain of 5 dB. Compare the two as being basically the same (3 + 2.15 = 5.15 dB for the first one and the reported 5 dB for the second).
Your example of the two being 8 dB and 10.2 dB make it sound (without any additional details) that they're both the same basic gain (8 + 2.15 is awfully close to 10.2). You may want to verify what they're reporting the gain in, dBd or dBi to confirm.
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