Re: LF: Generating 8970 Hz carrier with Spectrum Lab ?

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

Hi Wolf,

Am 25.04.2012 18:02, schrieb wolf_dl4yhf:

Much easier and more reliable to build a dedicated hardware, clocked by a 10 MHz reference, using a PLL, DDS, or similar.

Really easier?
I have very good results, using the SL frequency error compensation. For example my local VLF transmission in November has not had a single glitch over more than 12 hours. Remember Paul's report: http://abelian.org/vlf/ss111126/
Here i used a more than 10 year old notebook.
Also if people like to use the digimode termninal or also the frequency generator, not beeing limited to frequencies given by the steps of a divider, SpecLab is much more comfortable. Also on the receive side i remember to have received DF6NM's first tests in a 47 uHz window, with a stable trace.

:-)

73, Stefan

All the best,
  Wolf .

Am 25.04.2012 11:38, schrieb Roger Lapthorn:

Peter,

I hope the experts like Wolf and Stefan can help.

Another question for Wolf etc: how would one use a single PC with two instances of SL running to (a) lock the soundcard to an 18-22kHz MSK signal like GBZ one one instance and then (b) generate a (frequency stable and locked)  output signal for an 8.970kHz TX?

It is some months since I have used SL and I was never what might be called an "expert user".

73s
Roger G3XBM

On 25 April 2012 10:12, PA1SDB, Peter <pa1sdb@amsat.org> wrote:

Hello VLF,

I like to do some local test here with Spectrum lab setings (and who knows, High ERP transmissions later  :-)

I have here a notebook that generates a signal with the Signal generator in Spectrum Lab at 8970.1 Hz.

It has a Loop connected at the input and thats how it is locked to a GDO (HWU, FTA, what is available)

I tried several, and that Lock wondow gets green, but output looks terrible.

To radiate the signal I use a pice of wire at the notebook LS output.

 

Below two grab's over the same periode of time.

My localy generated signal at 8970.100 Hz and for comparison the signal of DJ8WX at 8970.022 Hertz.

 

Both grab's are made with the same Spectrum Lab task.

 

Why does my signal look like a widband FM transmission ?

 

 

 

Best 73's, Peter - PA1SDB

 

 

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