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Re: The "Spreadsheet"



I think the confusion is due to the spreadsheet saying gain in dBi. No one
but the author knows for sure whether he assumed dBi circular or linear. If
he assumed circular and a bunch of us are running linear antennas, then
there is a 3 dB loss from circular to linear. If he assumed linear, then he
already subtracted the circular to linear 3 db and we would be subtracting
it twice.

If that doesn't confuse you....well, it certainly does me. Not that it is
all that important. The loss is not a noise figure problem...it just reduces
the MDS and ultimate S/N by the 3 dB. It would be nice to know, but not
critical for the evaluations we're trying to perform.


hasan schiers, NØAN
schiers@netins.net

----- Original Message -----
From: "Alan K. Adamson" <ne1h@highrf.com>
To: <amsat-bb@AMSAT.Org>
Sent: Saturday, May 19, 2001 8:34 PM
Subject: [amsat-bb] The "Spreadsheet"


> I'm trying to catch up from being at Dayton, but I'm confused about a
> comment that was made about converting dbc to dbi or vice-versa.
>
> The Spreadsheet wants antenna gain in dbi (linear) right?  So, why are you
> converting the BBQ antennas to dbc by subtracting 3 db from them???  The
> 24db is linear on those antennas, they *are* not circular.
>
> Ok, now if you are talking about dbi to dbd.  then it's 2.14 not 3db.
>
> Can someone clear that up for me?
>
> Thanks,
> Alan
>
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