[TenTec] High stability frequency reference oscillator for the Orion II

[Martin Ewing]

Lin,

I'm all in favor of a higher stability oscillator.  Don't know if my
enthusiasm stretches to $135, though!

A couple of features I would be interested in for the oscillator:

1. Electrical trimming, so you can tweak the setting via an external
voltage (pot.) Unfortunately, the electrically trimmed oscillators
seem to have significantly worse phase noise, and that might be
unacceptable.

2. Phase lock to external (10 MHz) standard.  This is particularly
good for VHF / microwave folks.

I don't expect we're going to get all these features from a vendor at
a reasonable price.  I do think it's a shame that TT didn't pay a few
bucks more for a better TCXO as standard equipment.  Maybe someone
will home brew a solution?

73 Happy New Year

Martin AA6E

p.s. Thanks for the link to my blog post.  I checked it out and found
that all my figures had been wiped.  They are now restored for your
viewing pleasure!


On Wed, Dec 30, 2009 at 10:16 PM, Linwood Davis <linbdavis at earthlink.net> wrote:
> Hello folks,
>
> Primarily for the reason below, I've been considering drastically
> reducing the frequency drift over temperature that my Orion II
> experiences.  So I contacted Abracon Corp to see if they'll make a few
> 44.55 MHz high stability oscillators to replace the original one with.
> I'm interested in the AOCJY  series oven controlled crystal oscillator,
> which has remarkable stability. Try 5 parts per billion stability! (over
> 0 to 50C). That'd be three orders of magnitude better than the original!
> Anyway, I know they won't make just one for this mere hobbyist, but
> hopefully, they'll consider making 10.
>
> So I'm here to see if any Orion owners would be interested in also
> purchasing one. I got a informal quote of $135 a piece so far.
>
> Also, I don't know, but does the Orion (565) also use this frequency
> reference? Or any other Ten-Tec radio? I see from the O II schematic
> that the Sub Rx uses a divided-down signal from this same oscillator. If
> I remember right, the Sub Rx design is the same as the Jupiter Rx.
> (Please correct me if I'm wrong.) If so, are there any Jupiter owners
> that may be interested in joining this oscillator purchase?
>
> So here's where the drift becomes annoying:
>
> Recently, I begain "watching" meteors with my Orion II and DL4YHF's
> Spectrum Lab software. What I do, actually, is tune to 14.670 MHz (CHU
> Canada), and observe CHU's signal. Using Spectrum Lab's waterfall to
> display a 50 Hz swatch of spectrum around the carrier, I can see when
> micrometeors and not-so-micro meteors strike the ionosphere between
> here, NH, and there, Ottawa. Normally, the signal is fairly weak, so
> when a meteor ionizes a trail in between here and there, the signal
> strength significantly increases. What's more, the resulting spectrum is
> often composed of curves and lines above and/or below the carrier
> frequency. I believe these are created by the doppler shift due to
> ionospheric winds. (Why do I do this? Hey, I'm a curious guy, what else
> can I say?)
>
> The trouble is, especially just after turning the Orion on (and for the
> next 30 to 45 minutes), the frequency drifts by as much as 10-15 hertz.
> Normally, you probably don't notice this, but when narrowed down to a 50
> Hz display, it looks bad! (See AA6E's site,
> blog.aa6e.net/2005_08_01_archive.html, or N6IE's site, www.N6IE.com, for
> addition drift info.)
>
> Let me know,
>
> Thanks,
>
> Lin
> WB1AIW
>
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-- 
Dr. Martin S. Ewing, AA6E
Member IEEE, URSI, AAS, ARRL
Branford, Connecticut