Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
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Below are all of the forum threads, including all
the responses to the original posts.
Post subject: More Bang for you Buck
Posted: Mon Sep 12, 2005 4:15 pm
Joined: Mon Sep 12, 2005 4:02 pm
Location: Washington DC
I'm interested in combining the inputs of an S-band signal from two 1-meter antennas. I was hoping to use separate LNAs at each antenna, then provide an IF delay line that could compensate so that the indivdual antenna feeds could be summed PRIOR to modem input. Can something like this be done to effectively enhance the G/T or am I smokin something?
Posted: Mon Sep 12, 2005 5:47 pm
Joined: Mon Jul 18, 2005 4:31 pm
Location: Baltimore, MD
My first reaction was "Gasp, the signals won't be in perfect phase!" Then I saw you already planned for the delay line to bring them together.
I guess the only thing preventing it would be the delay stability of the LNAs. If the delay line is fixed, any delay drift in the LNAs would mess everything up. You'd have to check with the LNA mfr, I guess.
But actually, I don't think you would gain anything because I think the SNR of the signal is basically set by the noise floor of the LNA. Summing two LNAs together would give you the noise floor of whichever one is highest.