Hi Dave,
What Ethernet transformers are you looking for, UTP or Coax? I'd guess coax for
the distribution amp. These are best scavenged from old Thin Ethernet cards.
Look for cards with a BNC connector. Best place is either a electronics surplus
place, computer repair shop or shop that sells
Old scrap PC network cards?
The DC-DC isolated converters are useful to pull too.
Dave Baxter.
--- Original Message ---
Message: 6
Date: Thu, 30 Jul 2009 00:16:12 -0400
From: Dave M masond...@comcast.net
.
. Trimmed !
.
Also, looking for a source of low cost 1:1 and
Old network cards are an excellent source of isolating transformers, filters
and small DC-DC converters. If you need to distribute sinewave 10MHz signals
(some items accept or even need a square wave) then the filters that can be
recovered from the cards are very useful - they include
Top Posting, Mid Posting or Bottom Posting,
I agree to not discuss it extensively.
But why it is necessary to fill up the archive space with twice, triple or even
more times of:
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
I've been hanging around and reading long enough to understand that when
measuring the differences between oscillators the preferred methods are the
HP 5370A Time difference counter or the dual mixer method. I want to
evaluate some ocxo's and Rb sources against either a Tbolt or Z3801 and I
don't
Hi:
I think the power transformer got cooked. Have a look at the Vac and Ohms
data: http://www.prc68.com/I/HP3458DVM.shtml#T1
Force a browser refresh to see the latest schematic.
Have Fun,
Brooke Clarke
http://www.prc68.com
___
time-nuts
You really need to mix down to a low frequency beat note as in the
HP5390 system. There is a huge increase in sensitivity by doing
that. It is not difficult to make a mixer circuit.
Rick Karlquist N6RK
John Green wrote:
I've been hanging around and reading long enough to understand that when
Looks like it. Does the transformer draw much current with the PCB
removed? If it has shorted turns, as it appears, it likely will. Does it
get hot?
-John
=
Hi:
I think the power transformer got cooked. Have a look at the Vac and Ohms
data:
Dave M wrote:
I haven't been able to find schematics for the Extron DA, but according to
the author's discussion, it seems to be very similar to the DA circuit
schematics at http://www.ko4bb.com/~bruce/IsolationAmplifiers.html. I
haven't had time to reverse engineer the circuit in my
Hi John:
It's hard to say. With the A4 Inguard p.s. board removed when powered up the
fan comes on and the display lights up with the error message.
So, measured on the primary side, there's 25 ma AC current going to the
transformer then to the Outguard p.s. and fan.
Have Fun,
Brooke
Seems low for shorted turns. How physically big is the transformer? It
still might be shorted turns, if the transformer is small (say under a 1
cube) and has a high primary resstance..
Shorted turns or an open winding are single point failures. Other failures
(two point)are much less probable.
Try putting a light load on the transformer when you measure the output
voltage (maybe 1K). You may find that terminals 2-3 are open circuit
rather than short. Maybe that's why CR10 survived - the transformer
blew first.
Ed
Brooke Clarke wrote:
Hi John:
It's hard to say. With the A4
Look at the Ohms readings. It's not open, if the readings are right.
-John
=
Try putting a light load on the transformer when you measure the output
voltage (maybe 1K). You may find that terminals 2-3 are open circuit
rather than short. Maybe that's why CR10 survived - the
You're right. Sorry.
Brooke, now that you know the source of at least this problem, have you
considered powering up the system by applying DC to the inputs of the
regulators? This would allow you to limit the current in case there's
been some damage further in.
Also, is the Outguard p.s.
Hi Ed:
Yes, all the supply voltages are within spec, but the error message stays the
same.
The Outguard supply visually looks OK and the voltages are centered in the spec.
Yes the transformer has seven wires feeding the outguard p.s.
See: http://www.prc68.com/I/HP3458DVM.shtml#Bot
You may
Brooke Clarke wrote:
Hi Ed:
Yes, all the supply voltages are within spec, but the error message
stays the same.
The Outguard supply visually looks OK and the voltages are centered in
the spec.
Yes the transformer has seven wires feeding the outguard p.s.
See:
Hi Stan, (and time-nuts because this may interest someone).
Well I've made good progress. The 1000 uF capacitor fixed a lot of things.
After letting the unit warm up for 24 hours it has settled down to become
quite an accurate unit. Current drift (after calibration with a screwdriver)
is 2 nsec a
The voltages are correct even with a half-fried transformer. Sounds
like typical HP overdesign. :-)
Did you check for ripple or noise on the outputs?
I'm intrigued by the fact that the error message is pointing you towards
the Outguard Controller, but the only apparent damage is to the
Hi Jim,
I'm glad you've made progress on it. The big old 106B is the
best quartz frequency standard hp ever made. I measured
more than one of them with short-term stability down around
1e-13. Left on for months, drift rate are on par with rubidium.
Some long-term plots of a hp 106b are shown
Tom Van Baak wrote:
Some long-term plots of a hp 106b are shown here:
http://www.leapsecond.com/museum/hp106b/
but I see that old page doesn't include any recent short-term
performance plots.
/tvb
That is awesome performance. Out of the hundreds or thousands
of 10811's and E1938's I've
The 107BR ain't no slouch either. Mine's been on for over a decade. I
check it against an Austron 2100F. Sorry, I don't have the data to hand at
the moment.
-John
===
Hi Jim,
I'm glad you've made progress on it. The big old 106B is the
best quartz frequency standard hp ever
Richard (Rick) Karlquist wrote:
Dave M wrote:
I haven't been able to find schematics for the Extron DA, but
according to the author's discussion, it seems to be very similar to
the DA circuit schematics at
http://www.ko4bb.com/~bruce/IsolationAmplifiers.html. I haven't had
time to
Len Cutler had a cylindrical oven assembly from a 106 on
display in his office. I wonder if he knew just how good these
were. I think he got to exercise his perfectionist tendancies
on this one, without any supervision from the usual suspects.
Rick Karlquist N6RK
Yes, I was able to share my
Hello Mark,
Looking at the sinewave output on a spectrum analyzer, I am getting 2nd
harmonic
suppression of ~46 dB and other spurious to 1 GHz at least 50 dB down.
I am using this10 MHz ref for a DEMI A32 synthesized LO board in a 10
GHz transverter.
So far no problems, but I am still
Does anyone have a good solution for monitoring 4-8 different voltages
at the same time? I only need a sample rate around 1-2 Hz, but would
need GPIB, serial, or ethernet support with protocol documentation.
Any help identifying a solution other than 8 voltmeters would be much
appreciated.
Hi Matt,
1.Is the voltage AC or DC ?
2.What is the voltage range ?
3.What kind of resolution ?
BillWB6BNQ
Matt Ettus wrote:
Does anyone have a good solution for monitoring 4-8 different voltages
at the same time? I only need a sample rate around 1-2 Hz, but would
need GPIB,
DC, 0 to 6V, 10mV or better resolution.
Thanks,
Matt
On Thu, Jul 30, 2009 at 9:08 PM, WB6BNQwb6...@cox.net wrote:
Hi Matt,
1. Is the voltage AC or DC ?
2. What is the voltage range ?
3. What kind of resolution ?
BillWB6BNQ
Matt Ettus wrote:
Does anyone have a good
National Instruments has been getting aggressive with their pricing lately:
e.g., http://zone.ni.com/devzone/cda/tut/p/id/8675 . I was actually toying
with the idea of getting into the DAQ business a few months ago, but I
changed my mind in a hurry when I saw their ads.
-- john, KE5FX
I've actually got some of their ethernet devices. The problem is that
the drivers are all closed. They give no info on how to talk to them
without LabView.
Matt
On Thu, Jul 30, 2009 at 9:34 PM, John Milesjmi...@pop.net wrote:
National Instruments has been getting aggressive with their
A good application for the Sanguino board?
www.sanguino.cc
-- FL
DC, 0 to 6V, 10mV or better resolution.
Thanks,
Matt
Trænger du til at se det store billede? Kelkoo giver dig gode tilbud på
LCD TV! Se her http://dk.yahoo.com/r/pat/lcd
Ah. Well, I guess that's the catch, then. :(
Unless they actively encrypt the data, I'd guess that a few minutes with a
variable power supply and a copy of Wireshark would open the proverbial
kimono.
Failing that, how about a bank of V-to-F converter chips with paralleled
outputs, driving a
Hi John and Mat,
The USB analog units seemed OK for the price ($169) and feature set. Another
one
to consider is http://www.dataq.com I tried one of their $25 starters that had
10
bit resolution.
I was going to suggest, depending upon Matts interests, that perhaps he could
use a PIC or ATMEL
Does anyone have a good solution for monitoring 4-8 different voltages
at the same time? I only need a sample rate around 1-2 Hz, but would
need GPIB, serial, or ethernet support with protocol documentation.
Any help identifying a solution other than 8 voltmeters would be much
appreciated.
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