Re: LF: Problem with generator to VLF transmitter

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

 

two signals shifted by 180 degrees...Is this  in time  ? or  amplitude  ? [if  amp  then  invert ?]

 

change to  duty cycle ? square wave  drive  ?

 

would this  be  better in hardware  , then  any  signal  could  be  used to  drive  ?

 

G..

 

 

 

From: Marcin

Sent: Sunday, December 02, 2012 8:42 PM

To: rsgb_lf_group@blacksheep.org

Subject: LF: Problem with generator to VLF transmitter

Hi All!

We’re building an 8,970kHz VLF transmitter at SP2KDS club.

We almost have everything in place:

• transmitter (on IGBT transistors – diagram attached)
• antenna coil 76mH http://www.sp2kds.pl/136khz/303-klubowa-cewka-vlf-na-897khz
• 4 capacitors 4nF/30kV
• 100m long, 20m high antenna
• supply 60V 50 A

 

What we still need is a generator to feed the transmitter. Required parameters are the following:

• 8,970kHz frequency
• regulating range +-0.05Hz
• adjusting duty cycle of 5 to 45%, at 5% for two signals at the same time
• two signals shifted by 180 degrees

A friend of mine has promised to build it but it’s been over a year now and nothing has happened.

Is there a software which would use a soundcard with the aforementioned parameters?

 

73! Marcin SQ2BXI