Paul,
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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