Re: Back to fundamentals


"Richard Harrison" <richardharrison@xxxxxxxxx> wrote in message
news:14250-43990B83-224@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Reg, G4FGQ wrote:
> "According to textbooks, the field strength from 1 KW at 1 kilometre
=
> 300 millivolts per metre."
>
> Terman agrees with Reg`s signal strength produced by 1 KW radiated
at a
> distance of 1 kilometer of: 300 millivolts per meter.
>
> There are some conditions. The transmitting antenna is vertical and
> short compared with a 1/4-wavelength. It is nondirectional in a
> horizontal plane. The height of both antennas is low enough so that
the
> space wave does not dominate propagation between them. Terman`s
field
> strength derives from the equation first given by Sommerfeld and
> includes a factor aounting for ground losses.
>
> Best regards, Richard Harrison, KB5WZI

========================================

Richard, thanks for the confirmation.

All you have to do now is calculate from the field strength the power
available to a matched receiver at 20 MHz with a vertical receiving
antenna 1 metre high.

If I tell you the antenna's radiation resistance is 1.758 ohms then
you can forget about the frequency.
----
Reg.


.

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