[Amps] conversion scale from dbu to microvolts

[Fern Rivard]

Many thanks to all that have responded to my query re dbu conversion to 
either microvolts or dbm.  Got it all in order now.   Thanks from Fern


----- Original Message ----- 
From: "Karl-Arne Markström" <sm0aom at telia.com>
To: "Fern Rivard" <crc at cyberlink.bc.ca>; <amps at contesting.com>
Sent: Saturday, July 29, 2006 8:12 AM
Subject: Re: [Amps] conversion scale from dbu to microvolts


dBu is a measure of voltage, expressed as dB relative to 1 microvolt.

There is one major problem with this expression, as it also has to be 
referred
to the termination.

It can be either "dBu EMF" which is the preferred way of expressing 
receiver sensitivities in terms of the generator
EMF before its output impedance, or "dBu pd" which is the actual 
potential difference over the receiver input.

They differ by a factor 2 or 6 dB.

If "dBu EMF" is assumed,

- 7 dBu corresponds to 0,44 uV EMF or -120 dBm
- 13 dBu corresponds to 0,22 uV EMF or -126 dBm
+20 dBu corresponds to 10 uV EMF or - 93 dBm


73/

Karl-Arne
SM0AOM


----- Original Message ----- 
From: "Fern Rivard" <crc at cyberlink.bc.ca>
To: <amps at contesting.com>
Sent: Saturday, July 29, 2006 3:06 PM
Subject: [Amps] conversion scale from dbu to microvolts


>
>
>
> >    I just received the service manual for my Yaesu FT-1500M and 
> > would
> > like to calibrate the S-Meter but unfortunately Yaesu uses dbu's 
> > which
> > is all dutch to me as all of my test gear use either microvolts or
> > dbm.
> >    It would be nice to find a conversion scale for this but Google 
> > did
> > not bring up a chart for me.  For now, I need the conversion into
> > either microvolts or dbm of:
> >
> > 1)   -7dbu
> >
> > 2) -13 dbu
> >
> > 3) + 20 dbu
> >
> >    Thanks from Fern
> >
> >
>
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