Hi Stefan, LF

 

For the coil, I’m using the MF coil + variometer, and then adding two more coils to reach resonance

This links to a picture with inductance values

https://www.dropbox.com/s/tqzu5wxu3tfvnsv/MF%20and%20LF%20coils.jpg?dl=0

 

I’m using an Ultimate3 with DDS (The old version) running at 2 x frequency to feed the D-Class PA

 

EbNaut in LF is also in project. But I’m puzzled at how to modulate the carrier at LF. I’m not sure if the D-Class PA

would work for phase modulation. The driver is not a typical one, but a PWM controller SG3525A. It is a modified

“Ropex the First” which was designed as Xtal CW TX. So it will ruin any try to transmit with coherent signal, I’m afraid L

 

Working also in a  Class-E PA. Whcih will be much easier to  drive with coherent signals

 

73 de Luis

EA5DOM

 

 

Hello Luis,

Very well! Not a bad result for 30W :-)
Which L does your loading coil have?

2017-10-11 08:48:19 EA5DOM  1398km 137457.954Hz 163mHz -36.8dBOp  88% 20.7dB

2017-10-11 07:48:19 EA5DOM  1398km 137457.960Hz 106mHz -38.3dBOp  65% 17.5dB

2017-10-10 04:48:19 EA5DOM  1398km 137488.938Hz 177mHz -38.2dBOp  65% 19.0dB

2017-10-09 15:48:19 EA5DOM  1398km 137509.949Hz 174mHz -38.7dBOp  88% 20.6dB

Unfortunately my LF RX is overloaded by the local VLF transmissions (20m diatance between the antennas) but we can see that i can receive you beginning in the late afternoon until the morning :-)

How do you generate your frequency? Is it a coherent signal? Looks like the bandwidth is relatively high...

You could use one of the recent discussed NEO-7 GPS modules to generate the frequency directly. This would give you an ultra stable and precise carrier...
It would even work for EbNaut which is BTW a very good idea to try anyway :-)

73, Stefan




Am 11.10.2017 10:09, schrieb VIGILANT Luis Fernández:

Hi LF

 

I keep running Tx Op32 every hour at 30W to antenna