[BC] dbu to microvolt program

[Richard Fry]

Peter Burk wrote:
>I took the original poster's reference to dbu to be the traditional
>fcc definition of dBu, not shorthand for microvolts as in your dB?v.

But my definition of "dBu" and I expect also for Ron D is the same as the 
FCC's, ie, the radiated electric field strength expressed in decibels with 
respect to 1 microvolt/meter.

>We do not disagree that you can convert volts/meter to dB referenced
>to 1 microvolt/meter.  Both terms are in the same units. Ron D is asking
>to convert dBu to ?V.

As most people including you, I think, believe that the common meaning of 
''dBu" as applied to broadcast r-f propagation is field strength in 
decibels with respect to 1 ?V/m, then the field in "dBu" can be re-stated 
as the field in microvolts (per meter), with no need for a frequency term 
in the conversion equation.  In this context, dBu and ?V are simply 
different units of measure of the same basic parameter (volts) in the same 
impedance (free space) over the same linear distance (1 meter).

>Perhaps it will be easier to understand the point if you consider a real
>world example.  A signal is known or predicted to have a 40dBu signal at
>your location. You have a receiver with 20?V sensitivity. Can you receive
>the signal? Answer:  It depends on the frequency.

Well understood, however this is not the proper approach for converting the 
units used to describe a radiated field between "dBu," ?V/m or mV/m --  
which I believe is what Ron D first asked about.  You are looking at a 
complete receiving system, whereas this conversion applies only to the 
_field strength_ that exists at a given location (no hardware there, at 
all).   Using your approach for this query answers a question that, IMO, 
was not asked.

> ... Again, doing dBu to volts using the spreadsheet  requires the 
> two-step
> process outlined earlier.

Sorry, but no. That spreadsheet doesn't have a section or sections to do 
that, in any number of steps.

But all it takes is the simple equations I posted -- which, again, have no 
frequency term.

RF