Wirt, et al:

I was thinking in terms of the detector circuit in a radio, now I understand
what you were saying:  Undetectable except for equipment designed to receive
the RF.


Jim Phillips                            Manager of Information Systems
E-Mail: [log in to unmask]     Therm-O-Link, Inc.
Phone: (330) 527-2124                   P. O. Box 285
  Fax: (330) 527-2123                   Garrettsville, Ohio  44231

----- Original Message -----
From: Wirt Atmar <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 19, 2000 3:30 PM
Subject: Re: [HP3000-L] A death in the family


> Jim asks:
>
> > Okay, I'll ask the obvious question:  What good is a radio transmission
that
> >  is undetectable?  I mean, isn't that the point of a radio
transmission - to
> >  be detected?
>
> It wouldn't be detectable unless you had a matching receiver, just as you
> wouldn't be able to read an encrypted message unless you had a suitable
> decoder ring.
>
> A standard AM radio receiver isn't able to make much sense out of an FM
> signal, if you were to tune it to the same frequencies. An extremely
> wide-band FM transmitter (more broadband than the 250kHz deviation
> transmitters currently in use) would definitely be essentially
undetectable
> to a standard AM receiver, except as a series of chirps. But a properly
> constructed receiver would have no trouble with the signal.
>
> Wirt Atmar