Re: [time-nuts] Z3801A OCXO manual trimming

What is the rail to rail EFC voltage on the Z3801A?  Is it different than the single oven 10811?  My 10811 manual says that the EFC is -5V to +5V, while the EFC voltage on my ailing Z3801 is ~-2.0V with LH reporting the DAC at 99.996902%. Haven't had time to dig any further - been

[time-nuts] Z3801A OCXO manual trimming

Since the Z3801A is being discussed, I thought I'd ask about an issue I'm having with my unit.  I use my Z3801 as my working lab standard for the usual pieces of RF test equipment.  In the past year or so I've had the unit drop out of lock and go into standby mode.  Resetting/cycling power

Re: [time-nuts] HP 4815 Vector Impedance Analyzer repair

The first thing I would do is replace all the power supply electrolytic capacitors on the internal boards.  If I remember correctly, the boards are plugged in and the replacing the capacitors is quite easy.  In my unit, at least one capacitor was shorted and was pulling down a power supply. 

Re: [time-nuts] TAPR TICC boxed (input protection)

You need to be careful how you paint the package black.  My first electronics job was in a place that made, among other things, mass spectrometers.  We made very high input impedance electrometers for the mass specs using TO-5 can mosfet transistors.  One batch was found to be very photo

Re: [time-nuts] OT: Eagle PC CAD now Autodesk, $500/year

KiCad is an open source pcd cad package that looks interesting.  Has some microwave/RF features, 8 layers (I think),  both schematic capture and layout.  Just started to look at it.  Doesn't have the libraries that Eagle does, but you can create your own.  Worth looking at. Considering how

Re: [time-nuts] Thunderbolt Harmonics

I'm not sure what the Thunderbolt specs state for harmonics, but -60 dB seems quite good to me. From: Rhys D To: Discussion of precise time and frequency measurement Sent: Tuesday, January 17, 2017 6:40 PM Subject: [time-nuts] Thunderbolt

Re: [time-nuts] Using GPSDO as a Refrence for Protable Amateur Radio Microwave Operations

I used one of the Jupiter GPS receivers that has a 10 KHz output to control my 10 GHz LO to discipline one of the common "brick" type of microwave oscillators.  These oscillators have an internal crystal oscillator (106.6 MHz  for a 10.224 GHz LO) that is multiplied up to the needed microwave

[time-nuts] Trimble UCCM survey results

A couple of questions: I've just started using  LH 5.0 with my 2  GPSDO units (Thanks Mark!) - a Trimble UCCM and a Z3801A.  Oddly, I'm very getting different survey altitude values.  The Z3801A is around 81 M, which agrees within 1 or 2 meters with Google maps (not a perfect source, but

Re: [time-nuts] FRK-L Rubidium

I'll add my own FRK-L failure story.  I have a FRK that suddenly stopped locking.  The 10 MHz was there, but off frequency so much that I couldn't adjust it to sweep over 10 MHz.  It suddenly occurred to me that the crystal oven housing should be hotter than just barely warm to the touch (it's

Re: [time-nuts] HP 10811 Tuning Diode

I'll second the interesting part. I have a problem with a 10 GHz brick oscillator LO that I converted to GPS lock.  I don't remember the instantaneous frequency jumps (around 200 - 400 HZ at 10 GHz) before I did the GPS lock (although it's possible).  Please note that this is NOT any type of

Re: [time-nuts] Why the fuss - GPS Interference...

I've also had some odd dealings with Rich Bailey.  Some time in the mid 1990's I was a contractor at a USN cal lab.  We had sent out a Datum time code generator for repair, and when it came back, one of the functions didn't work.  I called Datum and after describing the problem, the tech

Re: [time-nuts] Oh dear

Instead of making fun of the web site, we all need to be more entrepreneurial so that we can fleece, errr, that is, offer a superior product to the audiophiles out there.  Think of the add copy: You don't want to rely on a drifty, low accuracy, secondary rubidium standard for your audio

Re: [time-nuts] Service manual or schematic for Option 21 DVM in HP5328?

Chris: The theory of operation, along with the usual block diagrams, schematics, etc, for the OPT 021 for the 5328B is in the 5328B service manual.  It may be the same, or at least close enough to, the 5328A.  It's worth a try.  You can download the 5328B manual here: 

Re: [time-nuts] Building a GPSDO trouble using Jupiter-T

Ray: I used a similar circuit to lock my 10 GHz LO to GPS.  I used a similar Jupiter GPS board receiver (not the 'T' version).  My 10 GHz LO is one of the older Microwave Associates brick type of oscillators.  It has an internal 106.5 crystal oscillator that is in a crude oven.  The 106.5 is

Re: [time-nuts] synch for pendulum clock....

Check the Scientific American Amateur Scientist index for clocks here:  http://amasci.com/amateur/sciamdx.html#52-CC  It looks like the September 1974 issue has the article on using discrete cmos logic to synchronize a pendulum clock to a quartz crystal. Tom  WB6UZZ --- On Sun, 12/11/11,