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Re: LF: Amp metres

To: [email protected]
Subject: Re: LF: Amp metres
From: "vernall" <[email protected]>
Date: Thu, 30 Mar 2000 23:05:49 +1200
References: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Bob Eldridge wrote:

>An amateur regulatory constraint of 1 watt eirp limit starts to bite in
>to the transmitter power budget for taller (more efficient) antenna
>systems.
>
Bites in even more with a smaller antenna surely!

What I meant to suggest was that a small antenna needs a great deal of
applied power to achieve a radiated power of 1 watt.  For most hams, it
is impractical to get near 1 watt eirp with realistic transmitter
power.  On the other hand, the big antenna only nneds a QRP transmitter
connected to get 1 watt eirp.

Didn't Dud Charman's indoor antenna circus demonstrate the truth of the
axiom that a small antenna has the same radiation pattern as a very small
antenna?

I also believe that all short verticals have the same basic radiation
pattern (the upper hemishere of a doughnut, with low angle suckin if
ground loss is significant).
Maybe a decommissioned Decca site could be better used to demonstrate the
efficacy of passive reradiation from an adjacent tower.

Any tests would be interesting.  Big sticks are hard to come by.

Bob ZL2CA




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