At 04:57 PM 5/29/2007, WA3GIN in Alex. City, VA wrote:
>I think your efforts should be rewarded but the test is flawed.
>
>Try using QRP and an attenuator. Get a distant station to record the two
>transmissions...one with and one without the 1db attenuator in the output.
This too, isn't necessarily a fair test. It will changed the
received SNR at the receiver IF the atmospheric noise dominates over
the receiver noise, so in that sense it's fair as a test of "is a dB
on Tx worth it".
However, it doesn't address the effects of directivity on receive..
increased gain on receive implies smaller beamwidth, which might
reduce received noise. As long as the loss in the system isn't so
much that receiver noise starts to be significant, you could make the
tradeoff of less antenna efficiency (more loss) in exchange for more
directivity.
But it's that question of "is 1 dB worth it" that makes this all
fun.. just because it's somewhat subjective, and not all dBs are the
same. Rarely are we dealing with nice symmetrical signalling in a
additive white gaussian noise environment, where you could
mathematically calculate the effect of a 1dB change.
Jim, W6RMK
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