Re: LF: Re: VLF Transmissions

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Chris,

My VLF grabber is running and will be on this evening connected to my loop aiming in your direction. See https://dl.dropbox.com/u/15047843/xbm_grab.jpg . I am also capturing in Spectran locally every few minutes and will let you have any screen shots.

Good luck!

73s
Roger G3XBM

On 22 November 2010 17:12, Chris Osborn <g3xiz@yahoo.co.uk> wrote:

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

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From: mal hamilton <g3kevmal@talktalk.net>
To: rsgb_lf_group@blacksheep.org
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 -----

From: Chris Osborn

To: LF Group

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

-- 
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
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G3XBM   GQRP 1678    ISWL G11088