Circulating air will reduce the temperature rise and the total warmup
drift (and maybe prolong your rig's life), but you will still have
drift from changes in ambient temperature. The "better" way is to
stabilize the temperature with some kind of oven, preferably one that
stays on even when rig power is off. That should not be too hard to
make, if we have any real experimenters here!
Even better is to stabilize the TCXO against an external precision
frequency source (e.g., 10 MHz). That can't be done (IMO) with the
existing TCXO. You need a voltage tuned unit. If you aren't careful,
you could degrade the VFO phase noise.
An opportunity for the right garage engineer!
73 Martin AA6E
On 2/7/06, Toby Pennington <toby423@earthlink.net> wrote:
> I have noticed this problem and installed a CPU fan to blow across the top
> on the Orion and this keeps the heat build up down considerably. I hung the
> fan under the shelf above the Orion attached with velcro strips from Radio
> Shack. The top of the rig stays very cool and the rig does not drift nearly
> as much. This may not make much sense cause the master osc. is in the bottom
> of the rig.
> But it works!
>
> Toby W4CAK
>
>
> ----- Original Message -----
> From: "Ron Castro" <ronc@sonic.net>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Tuesday, February 07, 2006 7:42 PM
> Subject: Re: [TenTec] Orion firmware statistics and drift info
>
>
> > Martin:
> >
> > Thanks for posting that information. I have uploaded the new version, and
> > AM works fine now, with 100% power equaling 40 carrier as measured with a
> > Bird 43 and dummy load. I also checked the CW output since someone had
> > mentioned that on the list recently, and found that key-down output power
> is
> > dead-on 100 Watts all bands. I have no way of measuring PEP.
> >
> > BTW, I read your posts about the slight Orion drift problem, and found
> > similar results on the O2, although the O2 seems to stabilize within about
> > 35 minutes. Mine still is 10 Hz high on 15 MHz (reads 10 Hz low on zero
> > beat), so I'll probably set it right on soon. I put a temperature probe
> > from a Protek 608 DVM inside the chassis near the master oscillator module
> > and it shows a total warm-up of 45 degrees F over the shack temperature,
> > nearly exactly what you had estimated. I'm looking at the meter now and
> > it's reading 114.8 F in a 69 F shack after running about 90 minutes. Last
> > night, I tracked the frequency drift against the temperature and found a
> > correlation of around +.7 Hz per degree F (again with zero-beat
> reading -.7
> > Hz/degree) on 15 MHz. Once warmed up, the radio stays rock stable, within
> > +- .5 Hz at 15 MHz.
> >
> > This information leads me to believe that this minor issue may be cured by
> > simply putting a small fan on the chassis partition just in front of the
> > oscillator module and blowing cool air across it. This should
> substantially
> > reduce the temperature build-up in that part of the chassis, and if my
> > theory is right, after about 10-15 minutes of warm-up time, the frequency
> > should stabilize with no perceptible drift. Should make the components
> last
> > longer and could slow long-term oscillator drift as well.
> >
> > I'll report back to the list what I find.
> >
> > Ron
> > N6AHA
> >
> > ----- Original Message -----
> > From: "Martin, AA6E" <martin.ewing@gmail.com>
> > To: <tentec@contesting.com>
> > Sent: Tuesday, February 07, 2006 3:03 PM
> > Subject: [TenTec] Orion firmware statistics
> >
> >
> > > Here is a graph showing the documented TT firmware versions for Orion
> > > and Orion 2 versus months since introduction:
> > > http://www.aa6e.net/images/oristats.gif . Versions for the first
> > > Orion were running one a day for a while at the beginning! (Most were
> > > not released.)
> > >
> > > The numbering methodology may have changed with Orion 2. I.e., not
> > > every recompilation gets numbered? I can't tell. Maybe they've
> > > learned something in 3 years!
> > >
> > > 73 Martin AA6E
> > > --
> > > martin.ewing@gmail.com
> > > http://blog.aa6e.net
> > > _______________________________________________
> > > 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
>
> _______________________________________________
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> http://lists.contesting.com/mailman/listinfo/tentec
>
--
martin.ewing@gmail.com
http://blog.aa6e.net
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