Re: [time-nuts] TymServe TS2100 dead power supply

Many thanks for the replies on this one. Before I made the first post, I'd pulled the supply, given it a visual and nasal inspection, checked the outputs for shorts, and powered it up on the bench. Dead (and dead quiet, not even the tick-tick-tick of a switcher with a shorted output). In my

[time-nuts] TymServe TS2100 dead power supply

We had a brief power outage a few days ago. My TS2100 didn't power up afterwards. Fuses are fine, AC power delivered to power supply, which is producing nothing. Nothing looks/smells fried on the power supply. Couldn't find data on what the power supply output voltages should be; not in the

Re: [time-nuts] Designing an embedded precision GPS time

One can minimize temperature change which affects things like regulated voltages, CMOS transition points for those converting sine to TTL with gates, etc. in addition to the oscillators. The November issue of Nuts and Volts Magazine has an article on an Arduino based PID controller which might

Re: [time-nuts] I've been thinking about a GPS receiver experiment

. The exception to that rule are oscillators that have a large TC or a very high drift rate. In most cases those are not the ones you pick for a GPSDO. Bob On Oct 25, 2017, at 7:46 PM, Bob Martin <aph...@comcast.net> wrote: The holdover state is a DAC set to the last value of the analog control v

Re: [time-nuts] I've been thinking about a GPS receiver experiment

Sorry, my mistake, change that to the former! I have used DACs that were monotonic with decent results but prefer analog loops when the time constants are short enough. Bob M On 10/25/2017 5:46 PM, Bob Martin wrote:   The holdover state is a DAC set to the last value of the analog control

Re: [time-nuts] I've been thinking about a GPS receiver experiment

The holdover state is a DAC set to the last value of the analog control voltage that adjusts the oscillator frequency. Some designs use an analog control loop and switch the DAC into the control loop. Others use the DAC to set the control voltage at all times. This can result in a steps in

Re: [time-nuts] Spice simulation of PSRR and phase noise

I never had much luck with current feedback amplifiers such as the LMH6702. Their input current noise (at the time) was too high for my needs and their output peaks at higher frequencies if the feedback resistors aren't optimal for the part. I had the best results with voltage feedback op

Re: [time-nuts] Need advice regarding rubidium oscillator

Roman-- You'll find a lot of information on the care and feeding of rubidiums such as the LPRO-101 on the list, and referenced websites. A specific reference for the LPRO-101 is: http://www.ka7oei.com/10meg_rubidium1.html that page has links to a

[time-nuts] FS: ThunderBolt

U.S. only, will ship in well packaged USPS Priority Mail box. $220. E-mail me off-list if interested. This is my back-up Trimble ThunderBolt with rev 3.0 firmware. It's been sitting unused in a box for too long; it should be in some time-nut's lab listening to birds. Obviously used with tape

Re: [time-nuts] UPS, battery backup, and connectors

A lot of ham radio operators, particularly those in involved in emergency services use Anderson Powerpole connectors. Easy to install, reliable, available. A standard configuration exists for 12 VDC emergency communications and mobile work. bob k6rtm

[time-nuts] End of the World, or beginning of a new one?

As I look at my Tymserve 2100 sitting in the rack to my left, the date it's displaying is JUL 02 2015. So the week rollover bug was coupled to the leap second? No wine to drink today (it's still early)... Anyone else with a TS2100 that's suddenly acting strange, er, correct for the first time

[time-nuts] Tymserve 2100 thinks it's 1995?

My Tymserve 2100 gps unit (Rev 4.1) thinks it's 1995 -- September 17, 1995. But a restart (connect via telnet and give the commands util restart) brings it back to the correct time and date -- for a while? I haven't caught it dropping back, so i don't know if it's doing this on the hour, after

Re: [time-nuts] Tymserve 2100 thinks it's 1995?

Additional information -- Power cycling (leaving it off for about 5 minutes) didn't do any good. Once at the correct time/date, it bounces back to 1995 at about 30 seconds after the hour (now to Sep 18, 1995). My Tymserve 2100 gps unit (Rev 4.1)

Re: [time-nuts] TS2100 thinks it's 1995...

Middle of the night I had a worry this was a rollover bug... And that seems to be confirmed, 1024 weeks. As I mentioned in an electronic conversation with another TS2100 user, I have the feeling our TS2100s have turned into turnips. Well, I can use the 1U space in that rack... Don't recall

Re: [time-nuts] Off topic project sort of heart rate monitor

Being left-handed, I'll offer a left-handed suggestion -- Ditch the direct connection. Go with a commercially available heart rate sensor, such as a transmitting chest strap heart rate monitor from Polar. You can buy receivers for this (low carrier frequency) signal that connect up to

Re: [time-nuts] Embedded NTP server ideas and feature - POE

Full-blown 802.3af POE (IEEE 802.3af-2003 for example) is not a simple beast. The Arduino world uses a standard module, the Silvertel Ag9000-S. Silvertel shows them as $10.64 each for a module that puts out 9W max and is 802.3af compliant. Bob K6RTM

Re: [time-nuts] Nifty MINI TIC for DMTD work

SIgn me up for one! Bob K6RTM in sunny Silicon Valley -- Message: 3 Date: Mon, 19 Nov 2012 14:53:16 -0500 (EST) From: ewkeh...@aol.com To: time-nuts@febo.com Subject: Re: [time-nuts] Nifty MINI TIC for DMTD work Message-ID: 2822f.5cd0eab7.3ddbe...@aol.com

Re: [time-nuts] XL-DC Antenna Requirements

Chris-- The 58532A is somewhat higher gain (30dBi or better) than most mag-mount antennas (26dBi typ IIRC). The pointy nature of the 58532A also serves as an avian deterrent, reducing the accumulation of attenuating deposits... Running two receivers, I would highly recommend a real GPS

[time-nuts] About that Leap Second...

After all the waiting... I set up a video camera to capture the LCD on my Datum/Tymserve 2100 GPS NTP box, and another camera to watch a different GPS-slaved IRIG-B display. But for all the build-up, no 60 to be seen -- the video of the 2100 clearly shows the 23:59:59 hanging around for wy

[time-nuts] The Elusive 74AC175PC

Summary: I found some, 50 or so, 20 cents each. Contact me off-list (at k6...@arrl.net) if you are interested. The longer version: My travels had me near a surplus place I hadn't visited in a while. Wandering the aisles, I thought to myself, Self, there's a part we need for the PICTIC II --

Re: [time-nuts] Opinion Of Attached - Possible HPSDR GPSDO

John-- Who do we make the checks to? Having been reasonably successful at today's flea market, would small bills be preferable? (This is an expression of interest!) 73, Bob K6RTM On Apr 14, 2012, at 18:11, time-nuts-requ...@febo.com wrote: