[Boatanchors] Using a SG-230 tuner on AM

[Gary Schafer]

Ah, Bob,

I think that you are looking at a DBM table where the reference 0 DBM is 1
milliwatt. What the rest of us are talking about is the number of DB (not
DBM) above some given power level. When using DB we can use any reference we
wish as the starting point. If expressing in DBM then you start at 1
milliwatt as your reference.

73
Gary  K4FMX

> -----Original Message-----
> From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-
> bounces at mailman.qth.net] On Behalf Of rbethman
> Sent: Monday, August 10, 2009 1:46 PM
> To: boatanchors at mailman.qth.net
> Cc: jfor at quik.com
> Subject: Re: [Boatanchors] Using a SG-230 tuner on AM
> 
> The dB table is ALREADY for power, page 651, "The Radio Handbook", 13th
> Edition, copyright 1951.
> 
> Again, 2X = 3dB.  The table establishes zero as 0.006 watts.
> 
> Mac, you can't mix apples and oranges.  That is precisely what you are
> trying to do in your statement.
> 
> Now go back and read at least one of the Orr Handbooks.  I have 13th,
> 16th, and either 20th or 21st Editions.
> 
> Bob - N0DGN
> 
> D C *Mac* Macdonald wrote:
> > 2 X the voltage  IS  6 dB because when voltage is doubled
> > into a constant load, the current will also be doubled.
> >
> > 73 - Mac, K2GKK/5
> > (Since 30 Nov 53)
> > Oklahoma City, OK
> >
> >
> >> Date: Mon, 10 Aug 2009 10:52:30 -0700
> >> From: jfor at quik.com
> >> To: km1h at jeremy.mv.com
> >> CC: boatanchors at mailman.qth.net
> >> Subject: Re: [Boatanchors] Using a SG-230 tuner on AM
> >>
> >> Look at my table from two posts ago, which you quoted below... I said
> >> EXACTLY that.
> >>
> >> -John
> >>
> >> ===========
> >>
> >>
> >>
> >>> 4X is doubling twice so it is 3+3=6
> >>>
> >>> Carl
> >>> KM1H
> >>>
> >>>
> >>> ----- Original Message -----
> >>> From: "rbethman" <rbethman at comcast.net>
> >>> To: <boatanchors at mailman.qth.net>
> >>> Cc: <jfor at quik.com>; "Gary Schafer" <garyschafer at comcast.net>
> >>> Sent: Monday, August 10, 2009 1:37 PM
> >>> Subject: Re: [Boatanchors] Using a SG-230 tuner on AM
> >>>
> >>>
> >>>
> >>>> This will ONLY apply *IF* you read the rest of the text.
> >>>>
> >>>> "You must first agree where ZERO is at".
> >>>>
> >>>> From 13th Edition Radio Handbook. Also in Radiotron Handbook.
> >>>>
> >>>> In any event, 2X isn't 6dB in any table I've seen.
> >>>>
> >>>> Bob - N0DGN
> >>>>
> >>>> J. Forster wrote:
> >>>>
> >>>>> No:
> >>>>>
> >>>>> 3 dB is 2x power
> >>>>> 6 dB is 4x power
> >>>>> 9 dB is 8x power
> >>>>> 10 dB is 10x power.
> >>>>>
> >>>>> -John
> >>>>>
> >>>>> ============
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> Carl,
> >>>>>>
> >>>>>> Isn't 6dB actually a power increase 10 times the original?
> >>>>>>
> >>>>>> My understanding that 3dB is a doubling.
> >>>>>>
> > ______________________________________________________________
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> 
> --
> +------------------------------------------------------------------+
> |             AM Amateur Radio Operator    NØDGN                   |
> +------------------------------------------------------------------+
> | Bob Bethman                \\\|///     " The absence of a danger |
> |                           \\ ~ ~ //      signal does *NOT* mean  |
> | rbethman at comcast.net      (/ @ @ /)      that everything is OK " |
> +-------------------------oOOo-(_)-oOOo----------------------------+
> 
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