[Boatanchors] Using a SG-230 tuner on AM
Gary Schafer
garyschafer at comcast.net
Mon Aug 10 15:34:18 EDT 2009
Sorry, Sorry, slip of the keyboard I did not mean to type dBm. I meant to
type just plain old dB. Now does that make sense?
73
Gary K4FMX
> -----Original Message-----
> From: rbethman [mailto:rbethman at comcast.net]
> Sent: Monday, August 10, 2009 2:23 PM
> To: Gary Schafer
> Subject: Re: [Boatanchors] Using a SG-230 tuner on AM
>
> The beef happens to be when YOU tell me I'm looking at a dBm.
>
> You aren't R-E-A-D-I-N-G!
>
> Gary Schafer wrote:
> > Bob,
> >
> > I don't know what you are arguing about. If the table shows 0 dBm = .006
> > watts then 3 dB above that should show 2X that or .012 watts. 6 dB
> should
> > show 4 times that or .024 watts.
> >
> > Note that 3 dB is 2x the power and 6 dB is 4 times the power.
> >
> > It doesn't matter what reference you want to start out with. That is the
> > beauty of the dB. With a 100 watt reference 3 dB above that is 200
> watts. 6
> > dB is 400 watts.
> >
> > If you want to reference different levels of voltage it takes 6 dB to
> double
> > the voltage.
> >
> > Where's the beef?
> >
> > 73
> > Gary K4FMX
> >
> >
> >> -----Original Message-----
> >> From: rbethman [mailto:rbethman at comcast.net]
> >> Sent: Monday, August 10, 2009 2:08 PM
> >> To: boatanchors at mailman.qth.net
> >> Cc: Gary Schafer; jfor at quik.com
> >> Subject: Re: [Boatanchors] Using a SG-230 tuner on AM
> >>
> >> Gary,
> >>
> >> The reference cited specifically states dB. No where is it a dBM
> >> table. I am quite aware of the differences.
> >>
> >> I gave the specific edition, title, and date. It is VERY specific that
> >> the table is based on ZERO = 0.006 Watt.
> >>
> >> The formula for this is: [ Parenthesis denotes sub ]
> >>
> >> N(dB) = 10 log X P(out)/P(reference)
> >>
> >> This is what Carl just sent.
> >>
> >> Bob N0DGN
> >>
> >> Gary Schafer wrote:
> >>
> >>> 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.
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>> ______________________________________________________________
> >>>>> Boatanchors mailing list
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> >>>>> Help: http://mailman.qth.net/mmfaq.htm
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> >>>>>
> >>>>> This list hosted by: http://www.qsl.net
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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----------------------------+
> >>>>
> >>>> ______________________________________________________________
> >>>> Boatanchors mailing list
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> >>>>
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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----------------------------+
> >>
> >
> >
> >
> >
> >
>
> --
> +------------------------------------------------------------------+
> | 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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