G'Day All,
I have acquired a HP5065A standard. Sn 1840A000838 with option J19
fitted (whatever that is).
I am seeking a copy of the service manual and any advice on what to
look for or repair before I try to power the unit on. It has been
running on 24VDC I guess as it came with the DC plug and
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While the website is not explicitly about frequency
measurement, there is an interesting bit on improving
the stability of crystal oscillators with external
heater controllers. While it may not be suitable for
long term high
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Hi Tom:
That's a cleaver improvement to a non ovenized crystal. Usually crystals are
ground to have a temp vs freq turnover point occur at a specified temperature.
The common one is to be on frequency at room temperature.
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I support what Rick has said about crystal ageing. I also work for an
OCXO manufacturer, and will add my 2c worth.. Here are some points -
* Manufacturers do indeed have their own special techniques for
minimizing ageing and
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This is getting off topic (because it's far to practical!) but hanging
heaters on crystals is a time-honored activity for hams. Many of the
surplus FM rigs for VHF and UHF that we obtained from the likes of
Motorola, GE, RCA,
In a message dated 10/10/2007 11:13:21 Pacific Daylight Time, [EMAIL PROTECTED]
writes:
We first built a small proportional heater circuit that we could shove
in next to the crystal, and that worked OK. We finally found a source
for thermistors spot welded to a spring clip that would mount
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On Wed, 10 Oct 2007 07:34:30 +0200, Bernd Neubig wrote
There is much more to say, but I will stop here, hoping that this
contribution gave some time nuts a better understanding - and may kill
their firm believe into aging
[EMAIL PROTECTED] said the following on 10/10/2007 02:17 PM:
In a message dated 10/10/2007 11:13:21 Pacific Daylight Time, [EMAIL
PROTECTED]
writes:
We first built a small proportional heater circuit that we could shove
in next to the crystal, and that worked OK. We finally found a
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[EMAIL PROTECTED] said the following on 10/10/2007 02:39 PM:
BTW: I wonder how much effect thermistor and resistor-bridge aging as well
as opamp offset drift has on the long term aging of typical OCXO's since it
will
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In a message dated 10/10/2007 11:34:43 Pacific Daylight Time, [EMAIL PROTECTED]
writes:
heater design: http://www.febo.com/hamdocs/d4art.html. The quality of
the heater schematic isn't very good, but it's all I have.
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Try DigiKey pn: 235-1123-ND for a simple PTC Thermistor that can be
soldered to the xtal case if one were so inclined. Do so at your own
risk to the xtal!
-Brian
-- Original message --
From:
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In a message dated 10/10/2007 19:34:55 GMT Daylight Time, [EMAIL PROTECTED]
writes:
We bought them as a replacement part from Yaesu USA. This data is 10
years or more old, but here you go:
Part NameYaesu Part Number
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Hi Brian:
I used to use Balco (as far as I can remember) positive coefficient resistors
that had specs similar to the Digikey units you linked to. These were only
available in values under 200 Ohms and have a positive
From: [EMAIL PROTECTED]
Subject: Re: [time-nuts] Improving the stability of crystal oscillators
Date: Wed, 10 Oct 2007 14:17:24 EDT
Message-ID: [EMAIL PROTECTED]
John,
In a message dated 10/10/2007 11:13:21 Pacific Daylight Time, [EMAIL
PROTECTED]
writes:
We first built a small
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I bought 10kohm nominal NTC thermistors from Digikey, P/N 490-4653-ND. They
are very small, 1/10th of an inch long or so.
I have used those (or similar parts) in projects both at home and at work
(in military equipment...)
I have made several ovens for oscillators over the years.
The recipe is:
get a piece of aluminium big enough to contain the oscillator,
voltage regulator and first stage amplifier.
With a mill remove the shapes of each component.
Bolt a large power transistor, large power fets are best, to the
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Hi all,
I have been playing with a phase and frequency locked local oscillator in
my 3816A GPS receiver. The simple setup uses the OCXO output as an external
reference input to a HP 3325A and with a trivial mod to the VP GPS
Neville Michie wrote:
I have made several ovens for oscillators over the years.
The recipe is:
get a piece of aluminium big enough to contain the oscillator,
voltage regulator and first stage amplifier.
With a mill remove the shapes of each component.
Bolt a large power transistor, large
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