Re: [HCDX] Re: [HCDX]: R.F. NOISE

["Robert Montgomery" <RMonty3@xxxxxxxxxxxxxxxx>]

Sorry, that is not true.  They run on r-f energy and not microwave freq.
NASWA did a write up about them 2 yrs ago.  The box says r-f energy.
Bob Montgomery
----- Original Message -----
From: "Vittorio De Tomasi" <vdetomasi@xxxxxxxxxxxxx>
To: <hard-core-dx@xxxxxxxxxxxxxxxx>
Sent: Monday, July 10, 2000 6:13 PM
Subject: [HCDX] Re: [HCDX]: R.F. NOISE


> Patrick Martin wrote:
> >
> > Does anyone know what the noise sounds like from the new RF light bulbs?
> > For the past month I have been getting a "buzz" from just before LSS to
> > about LSR. Once in a while thenoise has been on all day. I main affects
> > my Northern beverage, but it also gets into my EWE antenna. With the
> > Drake R8 this evening after it popped on I checked the band from 100 kHz
> > on up. I lost it at about 3-4 mHz. It isn't bad on many places on the
> > dial. I hear varied  tones from 100-200 kHz, and as you go higher,the
> > harmonics seem to be more of a "buzz". One strong one at 760 kHz and
> > others 1000-1200 kHz.
> >    At first I thought it was powerline noise, but with the timing it
> > would not be that and the varied tones, it much be something else.
> >    Anyone have any ideas?
> > 73s,
> >
> > Patrick
> > http://community.webtv.net/BobAndPatrick
>
>
> Hi Patrick,
>
> as far as I know, RF light bulbs (sulphur lamps) are powered by
> microwave energy, and they have probably little to do with the noise
> affecting you.
>
> Are you sure that the noise is not coming from a faulty HID lamp (High
> Intensity Discharge - not to be confused with halogen lamps) ? They are
> often used for street and industrial plant illumination, and they are
> basically arc lamps, whose arcing is controlled by a current limiter
> (ballast). Together with the power lines they can behave as a spark-gap
> transmitter, if the current limiter is faulty. Besides radiating on the
> frequencies where the power lines resonate (the "buzz" emission), they
> emit also plenty of noise (some months ago one of these faulty lamps
> close to my QTH emitted a noise spectrum till to 1.1 GHz !). The "buzz"
> they generate is usually in the range of LW-MW bands, and can drift in
> frequency due to arc voltage variation, or if power line length varies
> (it is often enough to open/close a mains switch connected to the power
> line, to have the "buzz" drift of several kHz).
>
> To approximately locate the source, you can use a MW receiver with a
> loopstick ferrite antenna. You will probably not be able to find exactly
> them, because the low-frequency "buzz" is usually spread everywhere by
> power lines.
>
> To circumvent this problem, and to exactly pinpoint the position of the
> faulty lamp, I used succesfully a portable scanner with AM/SSB detector,
> and a small dipole antenna (but a TV VHF yagi could work too). The VHF
> noise emitted by the lamp is not "captured" by power lines, and locating
> the faulty lamp becomes a straightforward fox-hunting game...
>
> WARNING: do not ever think to repair the faulty HID lamp by yourself,
> unless you exactly know what you are doing. The lamp ballast delivers at
> start up a voltage pulse of about 1 kV, that can instantly kill a man.
>
> More on HID lamps (and RFI emitted by them) at http://www.misty.com/~don
>
> vy 73
>
> Vittorio IK2CZL
>
> --
> *************************************************************************
> Vittorio De Tomasi         ik2czl@xxxxxxxxx
> Home page:                 http://space.tin.it/scienza/vdetomas
> My DSP page:               http://www.freeyellow.com/members/padan
>
> "Wir muessen wissen; wir werden wissen" (David Hilbert)
>
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