[ARC5] externally generated noise from switching controllers.

[Leslie Smith]

Hello Group,

I went to Sydney yesterday.  In the 1930's the Australian government instituted a public broadcasting system called The Australian Broadcasting Commission - ABC.  The ABC got favoured parts of the broadcast spectrum, (for radio and TV) and while some of their transmitters have modest power output, they are generally the best.  

ABC Radio National, broadcasts on 576kHz from a transmitter of 50kW to the Sydney area.  I was surprised and shocked to hear the unmistakable buzz & grumble of network interference in the background under 576 yesterday.  

I can't say whether it was BPL or some other souce, just that it was digital/"internet" noise.  

I'm off-topic, so I'll end here

Les



> ----- Original Message -----
> From: "J. Forster" <jfor at quik.com>
> To: "Discussion of AN/ARC-5 military radio equipment." <arc5 at mailman.qth.net>
> Subject: Re: [ARC5] externally generated noise from switching controllers.
> Date: Wed, 9 Jun 2010 06:19:28 -0700 (PDT)
> 
> 
> Soapbox Mode On:
> 
> IMO, the spread spectrum switchers are EVIL. They are, philosophically,
> equal to "Dilution is the solution to pollution" in the chem engineering
> business. They are a way of evading the law and getting away with it. What
> you wind up with is a raised noise floor everywhere.
> 
> Soap Box Mode Off.
> 
> -John
> 
> =============
> 
> 
> 
> > My company is a leading maker of LED drivers.  The switching style
> > controllers have to pass FCC Part 15 just like everything else.  The bad
> > news is that passing does not insure RFI low enough to satisfy hams or
> > other
> > so-called "weak signal" spectrum users.  Part 15 did not contemplate such
> > ubiquitous use of "unintentional radiators" when it was first drafted.
> > The
> > good news is that some manufacturers are trying to get below FCC limits by
> > using sophisticated spread spectrum techniques which are less onerous to
> > narrow band users like ourselves.  But overall, it is kind of a losing
> > battle we hams wage as switch mode controllers of all types invade our
> > homes
> > and offices in the form of lighting, HVAC, solar arrays, and flat screen
> > TV's to mention just a few.
> >
> > Dennis AE6C
> >
> > On Tue, Jun 8, 2010 at 9:03 PM, Brian Clarke
> > <brianclarke01 at optusnet.com.au>wrote:
> >
> >> OK, Les,
> >>
> >> It's just that this email stream started off with concern about the
> >> amount
> >> of RFI generated by household lamp dimmers, not that generated by the
> >> new
> >> CF
> >> lamps. That's why my question about dimming LEDs. My lad wants to dim
> >> LEDs,
> >> too, and I have told him the dynamic range is very small - perhaps 3:1
> >> at
> >> most.
> >>
> >> 73 de Brian, VK2GCE.
> >>
> >> Les said:
> >>
> >> > Hi Brian,
> >> > These lights are on or off.  There is no control over intensity -
> >> except
> >> > by changing the series resistor.  If I was going to control the
> >> intensity
> >> > I would do a very nasty thing.  I would connect an X2 rated cap (or
> >> series
> >> > of X2 rated caps) in series with the primary of the power transformer.
> >> > (Or alternately a big fat inductor).>
> >> > Les
> >> >
> >> >
> >> In response to Brian's:
> >> >>
> >> >> What dynamic dimming range do you get with these LEDs?
> >>
> >>
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> 
> 
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