[ICOM] IC-7000 AM Modulation Problem

[w8okn at charter.net]

DB is simply a method of comparison based on logarithm if I recall my EE math.

The logarithm of any given number is the exponent of a power to which another given invariable number, called the base, must be raised in order to produce that given number. Thus, let 10 be the base, then 2 is the logarithm of 100, because 10^{2} = 100, and 3 is the logarithm of 1,000, because 10^{3} = 1,000.

So, 10 to the 3rd is therefore 2x.  3db gain (or differential perhaps might be easier to think about) is a comparison of one value to another, in simple terms.   3 dbd would then be 2x over a dipole.  



---- D C *Mac* Macdonald <k2gkk at hotmail.com> wrote: 
> dB   ARE   dB.  They are identical in absolute quantity.
> The difference is that they are derived differently for
> voltage, current and power.  The formulas for computing
> dB are different, but the absolute difference in dB between
> two signals will be the same if calculated with the correct
> formula.
> 
> Application of Ohms Law will show that doubling the
> applied voltage will also double the current, resulting in
> quadrupling of the power.  Figure dB change for any
> of these three specific quantities with the correct
> formula will give the same result.
> 
> 
> Mac - K2GKK/5
> 
> 
> 
> ----Original Message Follows----
> From: C Whitaker <whitaker at pa.net>
> Reply-To: ICOM Reflector <icom at mailman.qth.net>
> To: ICOM Reflector <icom at mailman.qth.net>
> Subject: Re: [ICOM] IC-7000 AM Modulation Problem
> Date: Fri, 07 Apr 2006 14:20:06 -0400
> 
> de WB2CPN
> 
> I wonder if we get confused when we're calculating
> dB when we don't consider whether it's Voltage dB
> or Power dB, there being considerable difference in
> the numbers.
> 
> 73  Clete
> 
> 
> 
> 
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
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> 
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
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