Message-ID: <378966D9.366@xtra.co.nz>
Date: Mon, 12 Jul 1999 15:54:01 +1200
From: "vernall" <vernall@xtra.co.nz>
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To: rsgb_lf_group@blacksheep.org
Subject: LF: Low radiation?
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> > I had assumed when I bought my Hyundai Low Radiation monitor that the
> > Low-rad
> > refered to ionising radiation, i.e.X-rays from the faceplate, but it seems
> > not, the low rad refers to electromagnetic radiation. It is certainly
> > livable with on 136, whereas the other VGA and SVGS monitors I use,
> totally
> > destroy the band for listening. This might be a help for anyone
> > contemplating Spectrogram listening.

It is my understanding that "low radiation" is mostly concerning the CRT
magnetic flux (necessary for CRT spot deflection).  Low radiation means
that as far as is practicable the sweep flux is internal to the case?

Whatever, the sawtooth sweep can cause bad harmonic interference in the
LF band.  Even though I am mostly receiving around 181/182 kHz, a strong
emission from a PC monitor close to 188 kHz effectively paralyses my
noise blanker (which has a wider IF than the main receiver IF).  Playing
around with refresh rates can shift the scan frequencies, however when
it shifted, the harmonic fell below the wanted signal by about the same
amount and still paralysed my noise blanker.  My QTH had fairly bad
pulse noise from a high voltage power line and the noise blanker, when
working, significantly improves weak signal reception.

Bob