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[TenTec] Precision in Frequency displays

To: <tentec@contesting.com>
Subject: [TenTec] Precision in Frequency displays
From: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Wed Mar 5 13:04:24 2003
>From my perspective, that's why the manufacturers put a KNOB on a radio.  I
turn the knob until I hear what I want to hear.  On the other hand, some
folks set the frequency with the KNOB and then complain that other stations
don't sound correct.  Isn't this like putting the cart before the horse?

To that end I run a lot of AM and  I have a receiver that has true
synchronous detection for AM.  It does not have a digital readout either.
If the BFO or HF oscillator drifts, I turn the knob.  This is one advantage
to not having a digitally controlled radio.  There is no such thing as
frequency steps.

At to accuracy, I know what band I'm on and that I am in the correct
sub-band for the mode I operate.  If I want to know what frequency I am on,
I use a real frequency counter.  One that will measure to better than
0.01Hz.

73
Bob, K4TAX




----- Original Message -----
From: "Ken Brown" <ken.d.brown@verizon.net>
To: <tentec@contesting.com>
Sent: Wednesday, March 05, 2003 11:26 AM
Subject: Re: [TenTec] Precision in Frequency displays


> Dennis,
>
> When selective fading causes the carrier to drop far below the amplitude
> of the sidebands, reinserting a carrier with a BFO is a way to improve
> detection of the AM signal. This is not erroneous. The local
> oscillator(s) and BFO must be stable for this to work. They do not have
> to be accurate. It would be really nice if they could be controlled with
> a smaller resolution than 1 Hz for those of us who can hear the
> difference between a 1 Hz flutter (beat) and a slower beat. For most
> amateur operation this does not matter. I was only using this as an
> example of how most people CAN in fact tell the difference if the BFO
> cannot be adjusted in smaller than 10 HZ steps.
>
> Yes a real syncrhronous detector is a better way to detect an AM signal
> with selective fading.
>
> Ken N6KB
>
>
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