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[Orion] S meter

To: orion@contesting.com
Subject: [Orion] S meter
From: Martin Ewing <martin@aa6e.net>
Date: Mon, 29 Mar 2004 16:08:55 -0500
List-post: <mailto:orion@contesting.com>
The discussion about S meter calibration reminds me of a question I have for all the grey beards out there.

If S9 = 50 uV is standard, and 6 dB per S unit (or is it 5 dB?), my question is what is the "reference plane" for the measurement?

The useful reference, to me, should be the input connector. If that were true, the S meter reading should NOT CHANGE when switching the preamp on or off or changing the attenuator. This is clearly not the case with the Orion - or with many (all?) rigs I've used.

Except for history, we would be better served by power measurements -- "Your sigs today are -120 dBm, old man". Or maybe, "Your sig is 10 dB above my noise level."

Accurate S readings (or power for that matter) aren't very meaningful if you don't know the antenna/feed line gain/loss. Frequently I am getting 589 or 599 when my Orion's meter shows S4 for the other guy.

Oh well, it's a hobby!

73, Martin AA6E

p.s. Nice S meter stuff at http://www.geocities.com/ja1vbn2000/etc/S-unit.html

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