[Pete Higgins]

kenj66,

As GroundUrMast alluded to in post 19, it is better to keep an amplifier as close to the antenna as is practically possible. The reason is that for a given antenna and location the best signal exists at the antenna terminals. Everything beyond that degrades the received signal (connectors ~.05 dB ea., coax (depends on frequency & length), splitters ~3.5 dB for a two way, ~7 dB for a 4-way etc.). Once the signal is lost, nothing can restore it. The idea behind using an amplifier is to take the cleanest signal possible and amplify it up before it is degraded by traveling through your distribution system. The amplifier compensates (or more than compensates) for the distribution losses. So as not to sound too negative, however, no matter where you put the amplifier, it will accept whatever quality signal exists at that point and alleviate loss beyond that point in your distribution system.

As I already mentioned, cable loss in coaxial cable increases with both frequency and run length. Channel 14 starts @ 470 MHz and the high frequency edge of channel 51 is at 698 MHz. To give you a feel for the difference in performance I compared the losses between mounting the amp very near the antenna using a 3’ section and further down using a 12’ length. I also thru in a 38’ length of coax with 3 dB loss @ 698 MHz because most people are familiar with 3 dB doubling the signal and -3 dB halving the signal.

Cable loss in typical RG-6 with connectors:
3’ @ 470 MHz (Ch. 14) = .2 dB ~= 5% or you retain 95 % of your antenna terminal signal
3’ @ 698 MHz (Ch. 51) = .3dB~= 7% or you retain 93 % of your antenna terminal signal

12’ @ 470 MHz (Ch. 14) = .8 dB~= 17% or you retain 83 % of your antenna terminal signal
12’ @ 698 MHz (Ch. 51) = 1.0 dB~= 21% or you retain 79 % of your antenna terminal signal

38’ @ 470 MHz (Ch. 14) = 2.4 dB~= 42% or you retain 58 % of your antenna terminal signal
38’ @ 698 MHz (Ch. 51) = 3.0 dB~= 50% or you retain 50 % of your antenna terminal signal

If your signals are strong enough, the extra .6-.7 dB loss won’t make any difference. If you’re near the “digital cliff” on some channels it may make all the difference in the world.

Here is an example of how I mounted my smaller PCT MA2-M’s to my 91XG's:

https://docs.google.com/file/d/0B4AM...p=docslist_api