Re: LF: Coherent BPSK on LF using EbNaut

[IZ7SLZ <iz7slz.domenico@gmail.com>]

No Markus, i'm not sure now !

The power reduction that i'm now using is the built-in circuit of the PA (ex-marine reserve transmitter): one relais takes the output of the driver stage and
brings it directly to variometer.

To match my antenna it is necessary one transformer before the variometer.  I'm now checking if there is some impedance mis-matching when final stage is by-passed.
So, work in progress.

Domenico

On 10/24/2015 12:21 AM, Markus Vester wrote:

Domenico, 

 

the QRP carrier is not visible here. The attached spectrum shows a stored peak from a short 100 W carrier around 20:40 (green). The yellow trace is the latest spectrum from approx. 21:30 to 22 UT. The noise is about 20 dB below the old peak, and the QRP signal must be less than that.  Are you sure that 10 W are delivered to the antenna?

 

Best 73,

Markus

 

Domenico wrote:

 

Yes, Markus
      carrier is on now till next trasmission.

-----Ursprüngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 23 Okt 2015 11:41 pm
Betreff: Re: LF: Coherent BPSK on LF using EbNaut

 
Domenico,

 

nil from the 10 Watt transmission at 21:00 UT, only noise.

 

Could you perhaps leave the carrier on during the pause, to let me check signal level and frequency?

73, Markus

-----Ursprüngliche Mitteilung-----
Von: IZ7SLZ <iz7slz.domenico@gmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 23 Okt 2015 11:02 pm
Betreff: Re: LF: Coherent BPSK on LF using EbNaut

Hi all,

Markus, thank you for the report.
The small difference in QRG is due probably to the fact that i'm not using resample now.
Transmission of 6 char./3s with 10 W will start in few seconds.
GL

Domenico / iz7slz



On 10/23/2015 10:51 PM, Markus Vester wrote:

Hi Domenico, Paul,

 

good decode again from the first transmission which started accurately at 20:00 UT. I only noticed that I had to reduce the frequency offset by half a milliHz compared to earlier tests.

 

Best 73,

Markus (DF6NM)

 

-----Ursprüngliche Mitteilung-----
Von: IZ7SLZ <iz7slz.domenico@gmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 23 Okt 2015 9:47 pm
Betreff: Re: LF: Coherent BPSK on LF using EbNaut
 

Good evening Paul, Markus and all,        

thank you for your updates. 

I will start some EbNaut transmission at 22.00 each hour and hope that     Paul can make some measurement on my signal . Qrg is 137502.24 Hz 

Initial trasmission at 22.00 will contains 22 characters at 1 s/symbol     and will be sent with 100 W power output. 

Following transmissions will contains 6 characters at 3 s/symbol and     should be sent with 10 W.    Coding scheme: 8K19A.    

    GL. 

73, Domenico / iz7slz                

On 10/23/2015 7:00 PM, Paul Nicholson wrote:    >    > I have an E-field rx running on the 137 kHz band,    > GPS locked.    >    > Here is the 'first light' spectrogram    >    >  http://abelian.org/tmp/lf151023a.png    >    > which covers 137 kHz to 138.5 kHz.    >    > It's a bit shaky, everything held together with    > croc clips but hopefully will survive long enough    > to pick up an amateur signal or two.    >    > I'm recording 135 to 138.5 kHz.   I reckon the battery    > is good for about 60 hours.    >    > Maybe there will be some distant unmodulated carriers    > to measure, or even a coherent BPSK message.    >    > 137.5 kHz looks quiet here.    >    > --     > Paul Nicholson,    > Todmorden, UK.    > --     >    >