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Old 23-Aug-2012, 5:34 AM   #8
GroundUrMast's Avatar
Join Date: Oct 2010
Location: Greater Seattle Area
Posts: 4,773

Consider, if both antennas receive identical amounts of power and then deliver equal signal power to their respective combiner ports, the combiner is being driven with twice as much power (+3 dB = an increase of power by two times) than that of a single antenna. Sounds great, we should hope that the increase in power may help reception... right? But alas, the splitter/combiner has 3.5 to 4 dB loss between the input and output ports. So, the net gain is between -0.5 and -1.0 dB when compared to the net gain of a single antenna.

There is a way to combine two antennas using transmission line as a combiner: However, expecting more than 2 dB net gain is unrealistic. Antennas that have balanced 300Ω outputs lend themselves to ganging via 450Ω twin-lead harness rather easily. Unfortunately, many antennas are now equipped with integral baluns which would require some sort of modification to the antenna if one wanted to connect twin-lead.

Last edited by GroundUrMast; 23-Aug-2012 at 5:49 AM. Reason: integral balans
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