Hi Tim.
Iuse my 102ft doublet with 8m of 430 ohm feeder as a 'T' antenna loaded with
a variometer, and an earthing system of 36 radials of varing length in a 270
degree pattern. The variometer consists of :
Outer winding 26 + 26 turns 140mm dia 16/0.2 wire, giving 313uH
Inner Rotor 34 + 34 turns 40mm dia 16/0.2 wire, giving 84uH.
I have connected the rotor winding in series with the two outer windings at
their centre point, this may not be the best position but it suited my
construction and it works ok. The TX is running 23W into a 50 ohm dummy
load, and the peak antenna current is about 900mA, ERP approx 100mW.
I hope this is of use to you.
73
Ken.
M0KHW IO91TV
----- Original Message -----
From: "tim hague" <[email protected]>
To: <[email protected]>
Sent: Sunday, March 28, 2010 11:10 AM
Subject: LF: Antenna Matching
I'm just about to apply for my 500kHz NoV, I've got around 100W of Tx
power available and I'm looking for some information on antenna matching,
my Tx antenna is just going to be a 132ft Marconi T with a 50ft vertical
section, can I get away with just a series tuned matching cct or are the
voltages across my matching C going to be very high, I have a wide spaced
C approx 200 to 700pF.
Thanks Tim M0AFJ
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