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Re: Black Box Crystal Set

On Nov 18, 10:30 am, Ian Jackson
<ianREMOVETHISjack...@g3ohx.demon.co.uk> wrote:
> In message <he0e2e$bc...@news.eternal-september.org>, Yeti
> <y...@ayrshore.com> writes
>
>
>
>
>
> >Brian Reay wrote:
> >> "Mike Hunt" <imac.h...@baldsheep.com> wrote in message
> >>news:RlGMm.63854$TK7.35553@newsfe18.ams2...
> >>> How do these operate anyone ?
> >>> None radiating, is it a posh crystal detector :) ?
>
> >>>http://tinyurl.com/y85pkmr
> >>   Probably a TRF.
> >>  It is the local oscillator(s) which radiate in a superhet which is
> >>the  normal configuration of receivers. Of course you can have a
> >>direct  conversion or a regen but these both tend to radiate.
> >>  The bit about receiving several transmissions at a time suggests it
> >>is  "as wide as a barn door", another feature of a TRF.
> >>  You can read up on the basics of rx design in the current range of
> >>books for the RCE exams or an old RAE manual.
> >>  --  73
> >> Brian G8OSN/W8OSN
> >>www.g8osn.net
>
> >It's a crystal set with a preselector and audio amp, basically.
>
> >I've never heard of a LO on anything causing problems on a plane,
> >including my old Alinco DJ-G5E.
>
> What power do Air Traffic Control transmitters typically run? For
> 'local' communications, probably at least 10W, and more like around 50W.
> Unless a radiating receiver was very close indeed to the receiving
> aerial, I doubt if it would stand any chance of interfering.

I guess it depends on the age of the equipment concerned and what emc
qualification testing was applied.
Without this info any comment must surely be speculative.

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