[RTTY] Audio filters

[Jon Harder]

Ed, for in-line filtering I found the MFJ-784B tunable DSP filter to be the
best of any I ever tried over several years of contesting.  N1RCT, Dick
Stevens, felt the same way about it.

You can easily use it to create a very sharp double bandpass combo filter so
tight that nothing gets through the middle between mark and space.  I owned
three of these at one time, and ran them following a TS-850 with 250hz/500hz
crystal filtering, a TS-570 with 250 hz crystal in the IF to tighten its
audio DSP, but when I moved to the TS-870 pair, I found those DSP filters
built-in to be quite adequate.

Look on eBay's ham listings under MFJ, and see what you can find.  You can
almost always come up with one in the $120 range.  They do go pretty fast.
Be sure and look for the "B" model.   The built-in audio amp, speaker and
earphone jacks were also a great way to adjust and use the audio levels
coming out of the fixed ACC connections in the Kenwoods, going to and from
the soundcard.  Infinite adjustments, as the downloadable manual at the MFJ
Enterprises site will show.  That was hard to beat, used with a P38, Kam
Plus, etc. or direct under MMTTY and WriteLog.

These boxes really worked well, in spite of what some say of MFJ's "mighty
fine j....."

73,   Jon         K1US

----- Original Message ----- 
From: "K4SB" <k4sb at earthlink.net>
To: <rtty at contesting.com>
Sent: Wednesday, January 14, 2004 10:54 PM
Subject: Re: [RTTY] Audio filters


>
> I'm wondering how many of you guys use in line audio filtering? And if
> so what type unit.
>
> Can't seem to find one on the internet..maybe because I don't know the
> right "key word".
>
> And yes the OMNI VI+ has more than adequate DSP and Noise reduction
> filters already installed. As well as CW filters down to 250 cycles.
>
> What I want is is a filter which would go in line with the P38 or the
> output of the rig to the sound card.
>
> 73
> Ed
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