Re: Counterpoise and MMC demise

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, June 21, 2003 9:42 AM
Subject: Re: Counterpoise and MMC demise


 > Original poster: "davep by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<davep-at-quik-dot-com>
 >
 >
 > >>A rule of thumb for designing vertical broadcast antennas
 >
 > >>is that the there is little benefit in having a
 >
 > >>counterpoise whose RADIUS is equal to the height of the
 >
 > >>antenna.
 >
 >          The rule given in (eg Antenna Engineer's Handbook
 >          Jasik, others) is that radials should be about
 >          1/4 wave long, which is roughly the tower height in
 >          many cases.  The same maybe observed in CB and
 >          scanner antennas...

That would be for a resonant antenna... A TC is hardly resonant (at least in
a linear distributed sense, like a vertical monopole..)  The familiar
drooping 3-4 radials also makes a nice 50 ohm impedance (if you pick the
droop angle right).

However, TC's are not antennas.  Counterpoise for a TC should be considered
just another capacitor plate.. of dimensions << wavelength

 >
 > >>I can't see why this shouldn't be at least as applicable to TC's.
 >
 >          Broadcast practice is designed for radiation.
 >          Tesla Coils commonly are not.
 >          8)>>
 >          And a 1/4 Wave at (say) 150 KHz is 'interesting'.
 > --
 >          best
 >          dwp
 >
 >
 >