[Elecraft] unequal power output per tone in FSK

[Wayne Burdick]

Hi Hank,

The difference in amplitude is due to the small amount of ripple in  
the crystal filter. The effect on transmission bandwidth is  
negligible, and it's also extremely unlikely to affect copy.  
Nonetheless, we're planning to provide a way to tune out the difference.

73,
Wayne
N6KR

On Jan 10, 2011, at 3:26 PM, Hank Garretson wrote:

> Mark and space switch between two frequencies 170 Hz apart.  There  
> should be
> no change in amplitude between mark and space.
>
> With my K3 the difference between mark and space is about 1 dB.  Too  
> much.
> Elecraft is aware of the problem, and the sooner it gets fixed the  
> better.
>
> Side note.  There were some pretty wide RTTY signals in the  
> Roundup.  It
> would be interesting for someone smarter than me to calculate the  
> bandwidth
> of a 0-dB-difference-between-mark-and-space signal and the bandwidth  
> of a
> 1-dB-difference signal.  I sure hope my signal wasn't one of the  
> wide ones.
>
> 73,
>
> Hank, W6SX
>
>
> On Mon, Jan 10, 2011 at 8:54 AM, <nr4c at widomaker.com> wrote:
>
> I may be all wet here, but I seem to think this is understandable.
>> FSK uses two tones, one is the MARK and one is SPACE.  There are only
>> two states, you will have one or the other tones on the air all the
>> time.  One tone is the base, and if the signal is un-modulated, it
>> would be transintted 100% of the time.  The other tone is a pulsed
>> deviation from the base, so is only "ON" for short pulses when needed
>> to form a character.  Since there is hardly ever an even distribution
>> of MARK/SPACE, the power out will not be the same.
>>
>
>
>
>
>
> Ski Exuberantly,
>
> Hank
>
> Mammoth Lakes, California
>
> Elevation 8083 feet in John Muir's Range of Light
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