[TenTec] [Norton AntiSpam] Re: Corsair vs. Orion (weak signal)
Bill Tippett
btippett at alum.mit.edu
Wed Aug 3 10:04:11 EDT 2005
5B4AGN:
>Utter nonesense. (sic)
Correct, but isn't it actually nonsense <grin>.
>If the incoming signal is on 14025 and the IP product is zero beat with it,
then that will be on 14025 too. If the wanted signal is CW and the IP is a
carrier, then whatever audible tone you choose to listen to the CW at, the
interfering signal in the form of the IP carrier will produce the same tone.
If one understands that zero beat is a relative term then one would readily
understand this and how interference between the IP product and the wanted
signal will be caused.
I suspect K4TAX is thinking about zero
beating on AM, where you actually look at
the S-meter for no fluctuations. The simple
definition of "zero beat" means zero beat note
or "zero difference" between two frequencies.
When listening to a 400 Hz CW note, zero beat
occurs when the other signal is also 400 Hz,
resulting in 400 - 400 = 0 Hz difference. My
ears can easily detect zero beat without meters
or other tuning aids, but I know others have
problems doing this.
Of course the other problem with zero
beat IMD birdies is that they are the product
of two keyed signals, which produce a resulting
birdie only when BOTH are on. The birdie will
sound like keyed CW in something other than
Morse code, making it even more impossible
for the ear to sort from a Morse signal on
the same frequency.
73, Bill W4ZV
P.S. When I see things like this on the Internet
I know some of us have too much time on our hands.
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