Re: LF: OT - RF noise from PC display: LCD vs CRT

[Daniele Tincani <danieletincani@yahoo.com>]

Hello Stefan,

Thank you for your reply.

Yes I think you are right. So probably I will let time take the decision :-) As long as the CRT survives, I will stay with it (at least I know I can switch it off while the received signal is recorded on the hard disk e.g. at nigth). Then I suppose I will move to an LCD one to save space and power.

Cheers

Daniele

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From: Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.org
Sent: Sat, August 21, 2010 2:12:45 PM
Subject: Re: LF: OT - RF noise from PC display: LCD vs CRT

Hi Daniele,

The older CTR monitor seems to have a "real" switch that yust disconnect the mains from the supply (like it should be!). As you said, there is QRM near the both monitors. The SMPS in the LCD monitor is active all the time, so there is QRM all the time but it should be just detectable in some 10 cm.

The question is, if and how the noise is (hopefully) decoupled from the cables going in and out from/to the monitor. This is essential since your RX antenna will not be placed in the near of the monitor, i suppose ;-)

For example, i have very good experience with my tiny netbook as a VLF RX although it has a LCD display near the internal soundcard and the keyboard as well. So the LCD monitors are not worse in principal. EMC is an issue at all monitors so you have just to check the difference in your case.

73, cu, Stefan

Am 21.08.2010 13:16, schrieb Daniele Tincani:

Hi LF, VLF,

currently I have a CRT monitor which of course is a bit cumbersome compared with a slim LCD one. On the other hand, I have done a very simple RF noise test with an LCD TV/monitor I had in another room and I have found the LCD is significantly noisier than the CRT. I have simply checked the noise using a portable radio close to the screen on LF (abt 300KHz) and MF (abt 900KHz).

The LCD generates RF noise even when powered off (because of an internal power supply, I suppose), while the CRT doesn't.

As I plan to use my SDR in LF/MF in the vicinity of the PC (and my poor VLF loop antenna usually sits only five meters apart), the RF noise from monitor could be an important factor.

Did you find similar or different results in your experience?

Best regards
Daniele