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HB9ABX > ANTENN 01.01.05 19:59l 62 Lines 2055 Bytes #-7407 (90) @ WW
BID : I9NGHBHB9EAS
Read: DL7NDF GUEST
Subj: Magloop control through coax
Path: DB0FHN<DB0FOR<DB0SIF<HB9EAS
Sent: 050101/1756z @:HB9EAS.CHE.EU [Basel JN37TM] DP6.00 $:I9NGHBHB9EAS
From: HB9ABX @ HB9EAS.CHE.EU (Felix)
To: ANTENN @ WW
Magnetic Loop control through coax
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Questions from several OMs lead me to complete the existing
description of the antenna system. Furthermore I have adapted
the ABXKOPPEL in the new design.
The revision includes several technical changes of the design
and should be studied completely.
Here follows the text referring to the remote control:
The motor controlling the tuning capacitor of a magnetic loop may
well be fed through the same coax which feeds the coupling loop.
Hereby a separate cable for remote control becomes unnecessary.
Circuit used on antenna-side: picture
1 = Coupling loop (ABXKOPPEL)
2 = twisted line (10cm ... 100 cm)
3 = Current balun 1:1
4 = Coax cable 50 Ohm (10cm ... 2m)
C1 = 20nF ... 50 nF, low inductivity , 2A hf current
C2 = 4,7nF, 100V
Dr = Coil, 45 turns copper enameld 0.4mm diameter
wound close spaced on 11mm diameter plastic reel
The capacitor C1 (20...50nF) is low inductance, suited for 2A hf current.
Well suited are ceramic disk caps with thick wires, suppressor type, or
type FKP 1.
The circuit C1, C2 and Dr is enclosed in a plastic box, approx.45 x 65 x 25 mm.
The output leads to the motor of the tuning capacitor.
Circuit used on transmitter side: picture
C1 = 20nF ... 50 nF, low inductivity , suited for 2A hf current
C2 = 4,7nF, 100V
Dr = Coil, 45 turns copper enameld 0.4mm diameter
wound close spaced on 11mm diameter plastic reel
The circuit C1, C2 and Dr is enclosed in a plastic box, approx.45 x 65 x 25 mm.
The motor needs good filtering in order to prevent hf noise
during operation of the motor.
The following circuit proved to be very effective for filtering: picture
Dr = Coil, 45 turns copper enameld 0.4mm diameter
wound close spaced on 11mm diameter plastic reel
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The complete text with all pictures is found here:
http://home.tiscali.ch/hb9abx/loop1-e.htm
with my best 73s
and wishes for a HAPPY NEW YEAR
Felix HB9ABX
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