Bear with me on this Ken....It's long but hopefully I can explain.:
By the same token....I can see no reason why the center frequency of DATA A
and AFSK A should be different.
Most advanced digital mode programs such as MixW have something similar to
an "Align" macro. You tell the macro what you filter's center frequency is
then whenever you click on that macro it instantly tunes your K3 so that the
desired trace on your waterfall is exactly centered in the IF passband. You
can then choose your most narrow filter and that signal will still be in the
IF's center. I have a macro for the filter selection too so everything is
really fast and easy.
Here's how it works for me.
1. K3 filter set on very wide....3+ KHZ.
2. See signal on waterfall.
3. Click on signal.
4. Begin to copy data on screen.
5. Signal is weak, QRM, need narrow filter.
6. Click on "Align" macro. Signal is now centered in passband.
7. Click on filter macro, choosing 200Hz filter.
8. QRM gone...Signal now easy to copy.
Now this was all in DATA A mode. I use DATA A for PSK31, MFSK and anyother
digital mode.
So what if I want to operate RTTY? Well I can go ahead and do so in DATA A
mode however that DUAL FIL feature will not activate. Is this a flaw?
So I got to AFSK A....Now DUAL FIL works but now my ALIGN macro won't work
because my IF Center is different. It should not be....1500 HZ should be the
default. If I wanted to use 910 HZ and enjoy that low pitch sound, I would
have to either change my Align macro or try to manually tune the RTTY signal
which is terribly difficult, especially in a contest when transmissions last
for only a few seconds.
Steve Ellington
[EMAIL PROTECTED]
----- Original Message -----
From: "Ken K3IU" <[EMAIL PROTECTED]>
To: "n4lq" <[EMAIL PROTECTED]>
Cc: <elecraft@mailman.qth.net>
Sent: Sunday, May 18, 2008 3:37 PM
Subject: Re: [Elecraft] RTTY filter for K3
As far as I know, the reason for having the capability of changing the
Mark freq is for personal preference in what you like to listen to. The
Dual PB filter works at whatever frequency you select. I can think of no
reason why AFSK A and DATA A modes would necessarily have to be the same.
I'm not sure why you want to change the center frequency to specifically
1500 HZ in AFSK A mode. I sure wouldn't... that's too high for my ears.
I prefer the lower mark frequency of 915 Hz. The software that is
decoding the signal sure doesn't care and it doesn't make any difference
to what you are sending.
But as they say here ofter.... YMMV.
73,
Ken K3IU
~~~~~~~~~~~~~~~~~~~~~
n4lq wrote:
Yes but it won't change the center fq. to 1500Hz so it will be like
DATA A. I'm not sure what the purpose of changing the pitch is.
Steve Ellington
[EMAIL PROTECTED]
----- Original Message ----- From: "Ken K3IU" <[EMAIL PROTECTED]>
To: "n4lq" <[EMAIL PROTECTED]>
Cc: <elecraft@mailman.qth.net>
Sent: Sunday, May 18, 2008 2:43 PM
Subject: Re: [Elecraft] RTTY filter for K3
You can change the MARK freq in AFSK A mode to one of four values
ranging from 915 Hz to 2125 Hz by pressing PITCH and rotating the VFO A
knob which, of course, will change the center frequency accordingly.
73,
Ken K3IU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
n4lq wrote:
To use the DTF, I changed to AFSK A mode. This allows the DTF to work
however the center frequency of the IF changes from 1500Hz to 1356Hz.
I will notify Elecraft about these.
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