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Re: LF: Spectrum Lab & VLF

To: [email protected]
Subject: Re: LF: Spectrum Lab & VLF
From: wolf_dl4yhf <[email protected]>
Date: Mon, 25 May 2015 11:59:12 +0200
In-reply-to: <[email protected]>
References: <AC666FAFFAF340258B396B3B6D0949A6@AGB> <[email protected]> <[email protected]>
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Hello Joe,

I will check the QRSS120 configuration soon, maybe I had copied the settings from a computer where the input level (soundcard) was rather high, and the signal in your case is much weaker. When turning on the "input monitor" (scope-like gadget), does it show a flat green line, or a noisy-looking waveform ?

Flat line -> not good (wasting dynamic range of the soundcard's A/D converter)
Green waveform -> ok
Red waveform -> not good (not much headroom before clipping)

Details: http://www.qsl.net/dl4yhf/speclab/circuits.htm#monitor

Cheers,
  Wolf DL4YHF .


Am 24.05.2015 15:01, schrieb [email protected]:

Dear Group,

A QRSS60 detection at 5.2 km is the best DX for yours truly to date.
Although there was a detection at 7 km, this was probably via conduction
from a nearby mains line. The RX is a DK7FC VLF probe and Spec Lab
on a laptop.

The next logical step is to try QRSS120 to get past the 5.78 km boundary.
To my abject dismay, when doing: Quick Settings/ Slow Morse Reception(QRSS)/ Slow CW, 120 s/dot/ Enter
AUDIO centre frequency (8277 entered) / OK/no;
the spectrum screen scrolls across completely blank and the real time
spectrum on the right shows a flat line.

Going back to QRSS60, all is just fine.

Am I or the computer malfunctioning again?

Many thanks
Joe VO1NA





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