As a non-TT user, I have gathered from the list postings that the Scout
problem with drift is basically one of task priority and inadequate CPU
speed.
My understanding is that the CPU tends to the keying task at a higher
priority than the task of stabilizing the transmit/receive frequency, since
keying is happening almost constantly and frequency changing is done less
often.
At speeds up to about 25 wpm, the cpu is fast enough to handle the keying
and to find time to work the frequency support to correct any frequency
drift. At speeds above 25 wpm or thereabouts, the cpu is unable to service
the frequency stabilization task often enough and so the frequency
continues to drift slightly. When keying slows down or stops, the cpu is
able to service the frequency control and "snaps" back to the
preset/desired frequency which many interpret as a jump in frequency.
I get the idea that internal heat is the cause of the slow drift which the
cpu operation is intended to periodically correct. As long as the cpu can
find the necessary cycles to do this, the radio is stable. But when
required to service fast CW keying, it fails to correct frequency drift
often enough with the results described above.
So, taking the keying task away from the cpu by using an external keyer
allows the cpu enough time to deal adequately with drift control.
I agree that this is a problem that probably arose when a cost vs
performance decision was made on the side of cost + <good enough>.
I suspect that like many of the TT rigs, the cost of manufacturing the
Scout had gotten out of hand. I will not be surprised to see that the Orion
is a fully SMT, auto-board-assembled radio as that seems to be the only way
that today's circuit complexity and density can be realized in the space
available and within labor cost constraints. Along with that comes
specialized ASIC designs that further render any effort at home repair
unlikely.
72/73/oo, George W5YR - the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121 Kachina #91900556 IC-765 #02437
All outgoing email virus-checked by Norton Anti-Virus 2002
Steve Ellington wrote:
>
> Tell me how an external keyer stops the Scout from Jumping frequency?
>
> I thought the manual said that when operating higher speed cw that you were
> supposed to stop, pause and give it a chance to recover, cool off or
> whatever, which is a rather strange thing to be doing during a qso. I must
> admit though: It's a one-of-a-kind-rig.
> I worked on one for a guy once. I liked the sound of the receiver and the
> QSK was very smooth. I would probably have one in my car now if it weren't
> for the jumping problem they all have. And yes, any rig that jumps
> frequency,for any reason in 2002 does indeed have a problem regardless what
> the manual says.
> Did they quite making them for some reason?
> Steve
> N4LQ
> ----- Original Message -----
> From: "robert k stephens" <bstephens1@mindspring.com>
> To: <tentec@contesting.com>
> Sent: Friday, March 01, 2002 7:52 AM
> Subject: [TenTec] Scout instability-was Orion direction
>
> > Every now and then someone mentions the Scout "instability problem".
> > What problem ?
> >
> > I agree with Stuart. If the Scout is operated according to directions the
> > frequency stability is more than adequate for the ssb and moderate speed
> cw
> > operation it was designed for.
> >
> > The problem is that the internal keyer caused instability at speeds higher
> > than about 25 wpm or so. Tec Tec said that right in the manual. Use an
> > external keyer and the problem goes away.
> >
> > 73 Bob KB1CIW
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
--
72/73/oo, George W5YR - the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121 Kachina #91900556 IC-765 #02437
All outgoing email virus-checked by Norton Anti-Virus 2002
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