Re: [HCDX]: PNG and Solomons heard

["Mark J. Fine" <fineware@xxxxxxxxx>]

The antenna's effective surface area (in m**2) converts the field strength to
a received voltage level.  The impedance is really important here, since you
need to convert the resulting uV to milliwatts, then to the base DBm figure.
If the antenna is balanced, 50 Ohms is a fair figure to use.  If it's
unbalanced, anywhere from 300-600 Ohms is a good rough estimate.  This is a
nominal vector, you really don't need a Smith Chart. <G>

If you know the receiver's BW setting and the ambient noise level (which can
be assumed by standard Urban, Residential, etc.) there are formulae for
calculating the received noise power in DBm, which also includes the
receiver's noise figure, galactic and atmospheric noise.  I wouldn't even
worry about including the receive antenna's gain profile.  Subtract the
resulting noise level from the signal power and you have something even more
important: Signal to Noise Ratio.

Oh for the days when I was a radio/communications engineer, and not in
software... but *that* was like 20 years ago.

73,

[*     Mark J. Fine * FineWare * 11252 Cardinal Drive     *]
[*  Remington, Virginia  22734-2032 * USA * 3834N 07751W  *]
[*   fineware@xxxxxxxxx * http://www.erols.com/fineware/  *]
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----- Original Message -----
From: "Thomas B. Roach" <sigint@xxxxxxxxxxx>
To: <hard-core-dx@xxxxxxxxxxxxxxxx>
Sent: Friday, April 28, 2000 7:08 AM
Subject: RE: [HCDX]: PNG and Solomons heard


> Mark:
>
> No problem. Sometimes this forum can get TOO serious, so I like a joke.
> But ... it did sound like an interesting idea. The receiver's noise
> figure can probably be known but the "exact" impedance of an antenna,
> now that is a fun concept.

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