Hello
Mal,
I've wound an air-cored loading coil of about 1.3 H
It's on a
wooden frame with hexagonal ends (all yacht varnished) and has a mean diameter
of 2 feet.
The winding length is 20 inches and it resonates my 40m inverted
'L' at the correct frequency of 8.97 kHz
I've made a VLF exciter which
generates the drive frequency and interfaces with the PC's software.
It
uses a 2297 kHz crystal divided by 256 and gives a square wave output for the
PA FET's.
I can run CW, QRSS or DFCW with 0.05 Hz shift.
For the TX
I've modified my existing 200 watt 500 kHz PA and for matching use an ex-UPS
transformer.
The PA seems quite efficient into a 2000 - 3000 ohm resistive
load.
I have yet to be picked up beyond the boundary of my own garden
so would be over the moon if anyone else can detect my signals.
73
Chris
G3XIZ
From: mal hamilton
<[email protected]>
To:
[email protected]
Sent: Mon, 22 November, 2010
16:12:15
Subject: LF: Re: VLF
Transmissions
Chris
What are u using for a loading coil, amp
etc
mal/g3kev
-----
Original Message -----
Sent:
Monday, November 22, 2010 3:13 PM
Subject:
LF: VLF Transmissions
LF,
I have permission to transmit VLF this evening and details
are as follows:-
DETAILS OF TESTS
Loc:
Biggleswade IO 92 UB
Time: Monday
22nd November 2010 20.00 - 22.00 GMT
Freq: 8.9719 kHz
Mode: QRSS - 10 second dot length / DFCW
with 0.05 Hz shift / CW identifier at 5 wpm
Power: Limited to 20 watts RF output (ERP
unknown)
Aer: 40m inverted 'L'
at 10 m above ground.
Any reports or comments are
welcome.I
Regards,
Chris
G3XIZ
