Re: VLF: Inspire VLF-3 receiver

[Daniele Tincani <danieletincani@yahoo.com>]

OK, I will adjust both the spectrum scale and the B slider so that even -120dB are visible on the waterfall. The C slider will be kept untouched.

I will record 10 seconds this evening. Also I think I will be available for a long-term observation (over 12 hours or so) next saturday.

 

I don't want to annoy you and the LF/VLF group with all these detailed questions, anyway I noticed that bits/sample is set to 16, while my soundcard perform much better of course at 24 bits/sample. Must the 16 bits/sample setting be retained the for long-term observation?

Regards

Daniele

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From: Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.org
Sent: Wed, October 6, 2010 10:24:33 AM
Subject: Re: VLF: Inspire VLF-3 receiver

Hi Daniele,

Yes, adjust the B slider. But the QRM/QRN must be totally visible on all frequencies. You can increase the input level but it's better to leave it as you usually have it. It is better to change the range of the visible spectrum, so click: options => audio settings => ..(2) => increase the lower range to -120 dB if necessary. It's good to cover 60...80 dB totally so make the same changes on the other side, means if you have -80...-20 dB, go to -120...-60 dB. Additionally you can adjust the B slider.

Or you may record a wav file and send it to me. Just click: file => audio files => save input as audio file => (choose a directory and save about 10 seconds). Otherwise the size becomes to big. ;-)

73, Stefan



Am 06.10.2010 00:53, schrieb Daniele Tincani:

Hi Stefan,

 

> Adjust the color scale if necessary but don't change the 'C' (contrast) slider.

 

Do you mean I can adjust the Brightness control too? Or simply select a different palette?

I'm testing the .usr and it results almost in a blank screen (apart from lower frequencies) because of the fact that strongest signals I see (for example RDL on 18100Hz) are all below -80dB, with an overall noise floor around -110dB. In order to have some pixels emerging from the dark, I have to increase the brightness of the waterfall. Is it OK?

Otherwise, I could increase significantly the line input gain in Windows. What is the preferred method?

 

Regards

Daniele

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From: Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.org
Sent: Tue, October 5, 2010 7:37:52 PM
Subject: Re: VLF: Inspire VLF-3 receiver

Hi Daniele,

Am 05.10.2010 17:00, schrieb Daniele Tincani:

My reasoning is: I'm pretty sure :-) that I have hum at home affecting reception below 10KHz.

Attached you find an usr file. Just let it run for some hours, maybe so that the QRN minimum (in Gramany and Italy arround 8...10 UTC) is visible. Than take a capture maybe at arround 17 UTC and show it here. Adjust the color scale if necessary but don't change the 'C' (contrast) slider.

We will see your QRN/QRM situation and how strong the Alphas are and and and... Don't turn the antenna during the recording ;-)

Later (or before) you can check different antenna angles and check for minimum QRM. You can switch on/off everything that may cause QRM in your house. And you can try to find a quiter location...

73, Stefan