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[TenTec] Re: Omni VI+ QSK Thump and Click Mod

To: <tentec@contesting.com>
Subject: [TenTec] Re: Omni VI+ QSK Thump and Click Mod
From: troy_wideman@eee.org (Troy Wideman)
Date: Mon, 07 Sep 1998 10:08:11 -0700
 Thanks for the mod info. You got my attention
when you mentioned " other modifications" to your
Omni VI. Would you care to share those with the
rest of us? Thanks in advance.
 73, Troy, W6HV

Paul Christensen wrote:

>  There were far too many replies to answer each
> one individually. The mod consists of unplugging
> connector 52 on the I.F./A.F. Board.  That's
> it.  Plug 52 should have only one wire attached
> to it.  Those of you with more recent Omni Sixes
> should verify this as some of the circuit boards
> have been changed to SMD types.  Once connector
> 52 is unplugged, use a nylon tie-wrap to keep it
> safely out of harm's way. The theory behind the
> change:  Plug 52 activates a 4066 CMOS quad
> bilateral switch which is configured as a
> sidetone wrap-around circuit.  The audio click
> and thumps one hears is generated by the CMOS
> chip.  These chips are used in the broadcast
> audio world and are known to cause the same
> effect when switching audio on complicated audio
> mixers and routers. You will note after the
> change that you still have sidetone control and
> the ability to control its mix relative to
> incoming received audio through the front
> panel's "ST" button. Use a set of headphones to
> listen to your QSK audio before the mod and make
> a mental note of what you're hearing.  Then,
> using your headphones, critically listen to the
> QSK after the mod.  There should be a marked
> difference. Disclaimer: This is not a Ten-Tec
> approved modification.  I discovered this while
> making other modifications to my Omni Six Plus.
> Use care in making this change if you attempt to
> make it. 73, -Paul, W9AC
>      -----Original Message-----
>      From: Paul Christensen
>      <paulc@mediaone.net>
>      To: tentec@contesting.com
>      <tentec@contesting.com>; Chester
>      Alderman <chestert@pressroom.com>
To: <tentec@contesting.com>
>      Date: Sunday, September 06, 1998 9:15
>      PM
>      Subject: Re: [TenTec] Re: [CW] Kachina
>      vs. Omni VI+
>       Since I own the Kachina 505DSP, Yaesu
>      FT-1000MP and the Omni 6+, I can say
>      that Kachina's QSK comes with a noisy
>      relay (not a reed type) and the T/R
>      turnaround time is much too long.  You
>      can hear the receiver between most
>      characters, but nothing between dits
>      and dahs.  Another abnormality is that
>      when you use their excellent CW
>      keyboard interface, QSK is
>      automatically turned OFF and it cannot
>      be changed.  Why? Anyway, I continue
>      to enjoy my Omni 6+ for real CW work,
>      particularly since I made my keyed
>      waveform and chirp mods back in June,
>      and eliminated the slight QSK "thump"
>      altogether.  The last mod makes a
>      tremendous improvement and requires a
>      non-invasive mod to only one wire on
>      the I.F./A.F. Board.  Everyone should
>      at least try this since it can be
>      restored simply with the push of a
>      connector. By now, I thought the W1AW
>      20-meter signal would have improved.
>      While listening tonight, the leading
>      edge chirp is clearly evident.  I
>      don't mean to start another raging
>      discussion on this, but it's evident
>      that some Omnis manifest this slight
>      chirp.  Hint: the source can be traced
>      to the 9 MHz @ 2.4 kHz crystal filter
>      circuit.  This is the only filter that
>      shares the TX and RX function.  Those
>      radios with chirp are the same radios
>      that exhibit a truncated trailing CW
>      waveform, particularly when adjusted
>      to the most "soft" setting.  The new
>      Omni 6+ SMD Control Board no longer
>      allows you to make this adjustment.
>      Instead, a fixed resistor is now
>      located where a pot used to reside and
>      guess what?  The fixed value
>      corresponds to what used to be the
>      most "hard" setting.  Here's another
>      hint for Ten-Tec: The source of the
>      chirp is what also causes the USB
>      receive audio to sound a bit thinner
>      in low-end response and less "full"
>      than in LSB.  Has anyone else noticed
>      this?  The good news is that the chirp
>      is correctable.  Anyway, compare the
>      20-meter signal against the
>      simultaneous 40-meter
>      transmission. Back to the Kachina:
>      The I.F. DSP is at least as good as
>      the Omni 6+.  The only drawback is
>      that there is some audible digital
>      distortion on transient-rich signals,
>      like static crashes.  They'll get this
>      worked out in time.  Their rig is 90%
>      of the way to completely satisfying
>      me, but as we all know, getting that
>      couple percent improvement is the most
>      difficult to achieve. -Paul, W9AC
>           -----Original Message-----
>           From: Chester Alderman
>           <chestert@pressroom.com>
>           To: tentec@contesting.com
>           <tentec@contesting.com>
To: <tentec@contesting.com>
>           Date: Sunday, September 06,
>           1998 8:48 PM
>           Subject: Re: [TenTec] Re:
>           [CW] Kachina vs. Omni VI+
>            Jim...Unfortunately I can
>           only offer you what I was
>           told via email about the
>           Kachina. Someone was using
>           it at a special event
>           station and complained that
>           the QSK was very poor; mind
>           you, I don't know
>           personally.As for the Omni
>           6+ that resets to 14000kc
>           when it's turned on, I'm
>           sure your going to find when
>           that fellow reads the manual
>           and learns how to set the
>           menu selection, that the
>           Omni 6 will turn on at the
>           QRG that it was turned off
>           at. Mine does.I sure
>           disagree with the person
>           stating that "ultimately
>           IF/DSP filter performance
>           will surpass cascaded
>           crystal filters."  The
>           reason I disagree with that
>           statement is because digital
>           switching will probably
>           NEVER have the stop band
>           characteristics that a
>           crystal filter can have, if
>           designed correct. They will
>           probably make good strides
>           in using IF/DSP for SSB, but
>           I would almost (NOTE:
>           'almost') bet my Omni 6+
>           that it wont happen for CW
>           operation.As for TenTec's
>           final testing, I have not
>           witnessed it. However not
>           too long ago TenTec got a
>           military contract to build
>           receivers to MilSpec and I
>           think the result of that
>           contract is a lot of what we
>           see in the Omni 6. Meaning
>           the very good pc board
>           layouts, the excellent
>           cabeling routing, and the
>           overall significant
>           improvement in the design of
>           the Omni. I think most of
>           their testing is now
>           computer controlled, and
>           certainly with computer
>           controlled testing some
>           things can be missed. All
>           depends on the
>           communications between the
>           engineers and the computer
>           programmer!73,
>            >>I think the CW QSK/keying
>           performance was better with
>           the Omni also .>>Yes.  at
>           the Kachina web site,  they
>           say they 505 has QSK
>           "only>above 30 wpm",  at QRS
>           the "transmitter hangs",
>           whatever that>means.  They
>           go to say it is because the
>           Kachina completes>each CW
>           character for you!!  That is
>           different.>>>I'm sure that
>           ultimately all rigs will be
>           computer-controlled to the
>           degree>that>>the Kachina is,
>           and I'm sure that ultimately
>           IF/DSP filter performance
>           will>>surpass cascaded
>           crystal filters.  Give them
>           5 years or so!>>>But,  I
>           think I will need to order a
>           new rig next week!
>           However,  a bit>put off by
>           the fellow who just got his
>           new Omni+ from Ten Tec,
>           I>guess yesterday,  and it
>           would reset to 14000 and
>           1200 o'clock each>time he
>           turned in off  and later
>           back on!  Ten Tec says they
>           burn>each rig in for several
>           hours,  then check
>           performance again,
>           but>maybe they didn't/don't
>           turn them on/off a couple of
>           times as part>of the
>           check??>>73,   Jim,
>           KH7M>>73,  Jim,
>           KH7M>>>>-->FAQ on
>           WWW:
>           http://www.contesting.com/tentecfaq.htm>Submissions:
>           tentec@contesting.com>Administrative
>           requests:
>           tentec-REQUEST@contesting.com>Problems:
>           owner-tentec@contesting.com>Search:
>           http://www.contesting.com/km9p/search.htm>
>                Chester Alderman
>                   Tom - W4BQF
>              chestert@pressroom.com

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