Re: [TenTec] omni v short dits

[Ken Brown <ken.d.brown@verizon.net>]

Duane A Calvin wrote:

> That's only because the K1/K3 don't do weight properly.  Weight should be
> the ratio between the dit and dah length, not "on vs off" time in each
> element.  
>
>        73,  Duane
>  

I have always heard the "weight" adjustment of CW timing adjusts only 
the length of the dits. If a transmitter has a fixed delay time between 
key down and RF power output on, then in order to maintain the proper 
timing of the output RF on/off envelope, the obvious thing to do is 
incorporate into the transmitter an equal delay for key up to RF power 
off. If the radio does not do that, and we are compensating by 
lengthening the key down times (at the key input to the transmitter), 
then both the  dits and the dahs need to be lengthened, whether this is 
called weight adjustment or something else does not matter.

If the radio adds delay to the 'key up to RF output off timing', at 
higher speeds the RF output will still be on all the way through the key 
up (at the keying input) time, and the receiver will be muted all the 
way through the interelement spaces. The CW RF output envelope will 
accurately represent the keying input, just delayed. And at higher 
speeds QSK reception will only be working between character spaces and 
not between interelement spaces.

If the radio does not add delay to the key up to RF output off timing, 
The RF output times for both the dits and the dahs will be shortened. At 
higher speeds the dit/dah timing ratio will be noticably off. The dits 
could get really short ("light"). The receiver hears more during 
interelement spaces at the expense of unfaithful representation of the 
keyed input by the RF output envelope.

Compromises are made. Different radios undoubltly make the compromises 
differently. The 'key down to RF output on' delay is unavoidable. The 
smaller that delay is the less we need to compensate for it by 
increasing the 'key up to RF output off' delay, either inside the radio 
or externally with keyer adjustments. The amount of compensation needed 
ought to be equal for both dits and dahs, in order for the dit and dah 
lengths the be correct relative to each other AND to interelement and 
intercharacter spaces at the overall CW speed. Again compromises are made.

DE N6KB


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