I would be very interested in participating, and yes, I believe the
"original" Orion used the same oscillator. While the mod on my website
mitigates the problem considerably, it can't really cure it. Looking at the
spec sheet of the AOCJY, it appears to be available in the correct operating
voltage, excellent phase noise. The sine wave output is shown at +2 dBm @ 50
Ohms output load while the original shows 1 V P-P into 10 k Ohms. This
should probably be looked into. Here are the specs of the Siward (I just
noticed my website link needs to be changed):
http://www.datasheetarchive.com/TXO32-datasheet.html
Another minor problem is that the AOCJY appears to be an SMT device, so some
sort of PC board would need to be designed to convert the architecture.
That would be good though since the AOCJY accommodates an external
adjustment pot that should make calibration a breeze. Also because since
its an oven-controlled device, an external 5 or 3.3 VDC regulator/filter
will be needed along with a direct connection to 13.6 VDC so the oven stays
on when the power switch is off.
BTW...did you ever notice that most new Orions are 20 Hz off frequency on 20
Meters? I heard that regularly on the TT Sunday net when I first started
checking in. That's apparently because when they are adjusted at the
factory, the radio is upside down with the cover off and the compartment is
at room temp. Normally that compartment gets to over 100 degrees F without
the fan mod!
A friendly call to TT might be in order to see if these specs will work, and
once done, you should have no trouble finding ten folks who want go in.
Ron N6IE
www.N6IE.com
----- Original Message -----
From: "Linwood Davis" <linbdavis@earthlink.net>
To: <tentec@contesting.com>
Sent: Wednesday, December 30, 2009 7:16 PM
Subject: [TenTec] High stability frequency reference oscillator for theOrion
II
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
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|