Re: Why no IF shift?

[zl1aih-2]

Jim N2EY wrote :-

>Most "other" rigs implement IF shift by an extra
conversion step after
the first fixed IF. This means there's a lot of gain and
stages
between the antenna and the sharp selectivity
"knothole". No thanks.

IMHO, IF shift is of limited use in a CW receiver ...>

More so in a contest situation.
Our CW contest club (ZM1A) presently uses an
ICOM 781 and a K2 in a Multi-One or Multi-Two
category in many contests.   These are rigs of choice
because of problems with other rigs in the shack -
phase noise etc.
   
As the host I get to pass the sandwiches, pizza
wedges and pour the drinks, so I have the
opportunity to closely observe class operators like
Jacky F3CW (ZL3CW) and Aki ZL1GO (JA4EKO) in
action when they are running at 200+ per hour.
They seldom touch the transceivers - very
occasionally adjust the RIT and very seldom reduce
the filter width, only because there is some adjacent
and temporary QRM.  
The 781 has IF Shift - unused.   Our K2s have KAF2
filters (sometimes used) .   These ops have filters in
their ears.<G>

73, Ken ZL1AIH
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[Bill Coleman-2]

On Aug 8, 2006, at 5:59 AM, [hidden email] wrote:

> I have the
> opportunity to closely observe class operators like
> Jacky F3CW (ZL3CW) and Aki ZL1GO (JA4EKO) in
> action when they are running at 200+ per hour.
> They seldom touch the transceivers - very
> occasionally adjust the RIT and very seldom reduce
> the filter width, only because there is some adjacent
> and temporary QRM.

I think the key here is the filtering they get from the 200+ per hour  
pileup. With all those stations calling them, it is less likely that  
someone will settle in on an adjacent frequency, or if someone is  
there, it is more likely to drive them away.

QRM-fighting features like IF Shift are more likely to be used on the  
other end of the pileup -- to try and hear the responding station  
from amoung all the callers. It's more powerful a tool when S & Ping  
during a contest, or when DXing.

IF shift seems like a feature that could be accomplished with a  
"simple" firmware change. Perhaps its a possibility for a future  
upgrade.

Of course, Elecraft has those pesky amplifiers they'd like to ship  
first....

Bill Coleman, AA4LR, PP-ASEL        Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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