Re: [time-nuts] Spectracom 8140T Line Tap Schematic
On 14/06/18 23:31, gandalfg8--- via time-nuts wrote: > Earlier replies that discussed removing the DC supply from the 8140 outputs > gave me the impression your requirement was to connect directly the outputs > of the 8140 without line tap modules, which is what I was addressing with my > recent suggestion of a series capacitor, but can see now that's not the case. I think that was a digression from my post, I'm planning to use the 8140 as-expected by Spectracom. > The VersaTaps phase lock an internal crystal, any frequency between 4 and > 20MHz, to the 10MHz input and then provide an output at the crystal frequency > or the crystal frequency divided by a fixed integer between 1 and 8,192, so > in that sense yes they're a synthesiser but the few I've seen were still > supplied preset for a specific frequency. Ah, yes, that design would make a lot of sense. I was imagining a more modern design you might do these days. > However, "versatile" does not necessarilly mean quick or convenient to > reprogram. > Aside from perhaps needing to change the crystal the division ratio needs to > be set by adding or removing links across pairs of holes in the circuit > board. Those holes are on a standard 0.1inch pitch so fitting headers that > would take shorting links should be straightfoward enough, and I suspect what > was originally intended, but the units I have were supplied preprogrammed > using resistor style wire ended zero ohm links mounted above the circuit > board and soldered from below. Reprogramming one of these would involve > unsoldering and perhaps removing all the connectors etc in order to remove > the circuit board, so I'd certainly make darn sure they had headers fitted > before being returned to the box! I'm going to have to do something very similar to the 8140 when it arrives, as I bought one set for 1MHz input, and I'm going to (initially) be feeding it 5MHz from an FRK. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Spectracom 8140T Line Tap Schematic
I'm somewhat tempted to take the schematic and see if I can fit it in the comparatively tiny Pomona boxes, although I have far too many side projects already, enough 10MHz taps, and I still need to do the terminators. The VersaTaps are supposed to be an actual synthesizer IIRC. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Source for DC-blocking 50-ohm terminators? (Spectracom 8140)
Making my own that fits in either the mini Pomona boxes (which has BNCs)[1] or the nice really tiny Crystek SMA housings[2] with a BNC to SMA looks like it's probably the sensible option. 1: https://www.pomonaelectronics.com/products/boxes/boxes-with-connectors 2: http://www.crystek.com/microwave/spec-sheets/enclosure/SMA-KIT-1.3MF.pdf On 04/06/18 22:52, Bob kb8tq wrote: > Hi > > DC blocked 50 ohm terminations are indeed a bit odd. One answer is to simply > use the > 75 ohm version and move on. The gotcha there is that they may / may not have > a block > that works well at 10 MHz ( = the cap is to small ). The one thing *not* to > do is to run the > device with no termination on the cable. The gizmo will be perfectly happy. > Your lab will > be a mess. The coax will normally be long enough to make a great antenna at > 10 MHz. > Leaving the end un-terminated puts it in “antenna mode”. You will have RF all > over everything. > I have a lot of experience with this specific problem ….. > > Bob > >> On Jun 4, 2018, at 12:09 AM, Julien Goodwin >> wrote: >> >> I'm looking at using a Spectracom 8140 for 10Mhz distribution, and they >> specify using a DC-blocking 50-ohm terminator on each run. >> >> These seem to be odd enough that none of my usual sources have them >> (75-ohm DC-blocking terminators yes, 50-ohm, no). >> >> While it's easy enough to chain a DC block and a terminator, I'd prefer >> a single module I can more obviously label as the line termination. >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Source for DC-blocking 50-ohm terminators? (Spectracom 8140)
I'm looking at using a Spectracom 8140 for 10Mhz distribution, and they specify using a DC-blocking 50-ohm terminator on each run. These seem to be odd enough that none of my usual sources have them (75-ohm DC-blocking terminators yes, 50-ohm, no). While it's easy enough to chain a DC block and a terminator, I'd prefer a single module I can more obviously label as the line termination. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Commercially available empty ovens for oscillator testing?
Does anyone know if there's anyone who sells essentially just the oven & casing for an OCXO on its own? I have a project for which I'm currently using a VCTCXO, but I'm wondering if enclosing a plain VCXO, plus the control DAC & voltage reference in a single small oven would end up more stable, and possibly not even much more expensive. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Microsemi 3120A sold on eBay
On 28/01/18 09:38, John Miles wrote: > So, who's the lucky winner? Anyone on here? That's the first one of these > I've seen in the "secondary market," so to speak. > > https://www.ebay.com/itm/332531180078 While we're at it, whoever picked up the SGC-1500 from the same seller[1], if it actually boots I'd be interested in talking to see if the one I picked up a while back can be recovered. Given that Microsemi discontinued them back in 2013[2] I doubt much will come from them. 1: https://www.ebay.com.au/itm/Symmetricom-Microsemi-090-01630-102-Rev-L-SyncServer-SGC-1500-Smart-Grid-Clock/332532177945 2: http://www1.symmetricom.com/media/files/support/tsd/pd/SGC-1500%20PDN%20Dec%202013.pdf ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Symmetricom SGC-1500
Can anyone from Symmetricom/Microsemi help me with a firmware image for an SGC-1500 for personal use? I picked this thing up on eBay over a year ago, but only just got around to getting the needed serial adapter bits to talk to it (should anyone else need it, it's rolled from the standard Cisco convention, and 115200 8N1). It seems like this unit must have been running some form of experimental image based on the variety of boot errors it has. I tried the default password I could find (admin/symmetricom) which let me log in but then kicked me right back out as it couldn't find the shell. Relevant version strings from the boot logs: Linux version 2.6.32.46.cge (r...@cbuf15.symmetricom.com) (gcc version 4.3.3 (Cavium Networks Version: 2_1_0 build 110) ) #5 SMP PREEMPT Tue Mar 12 14:57:59 MDT 2013 MontaVista Linux CGE 6 .dev-snapshot-20120201 SGC-1500 console ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Exact power connector for Symmetricom TimeProvider 100
I'm wondering if anyone knows exactly which power connector the Symmetricom TimeProvider 100 uses as as the manual doesn't have it (word of advice people, describing a connector as simply Molex style is fairly useless), and a trawl of mouser seems to indicate it's a MiniFit Plus series but I'm not about to order one of everything to figure out which one. (Yes I could mail Symmetricom, but I bought it used without PSU) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Symmetricom Launches CSAC Product for Precise Timing and Synchronization
On 19/01/11 02:35, Pierpaolo Bernardi wrote: Though this could be of interest... http://www.insidegnss.com/node/2446 The SA.45s reportedly provides ... short-term stability (Allan Deviation) of 2E-10 @ 1 sec, long-term aging of 3E-10/month From the data sheet of the bigger Rubidium micro-clocks: SA.33/35m: 1 Sec stability- 3E-11 1 month aging - +/1 1E-10 Neat, but only really of benefit to *really* space/weight/power critical devices. The cesium atoms are “excited,” or heated to a vapor state by a beam generated from a vertical-cavity surface emitting laser (VCSEL) that passes between upper and lower polymide heater/suspension strips. The VCSEL was designed by Sandia Labs, one of Symmetricom’s partners on the CSAC team. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Happy New Year from Melbourne UTC+10
On 01/01/11 00:16, swingbyte wrote: First New Year at home ( 20 week old baby ) fortunately the neighbours have let off a few fireworks. Melbourne is, of course UTC+11 at the moment being AEDT not AEST for the summer. We had idiots with fireworks here too, as apparently did much of Melbourne. In a more on-topic note I grabbed a video of my XL-DC (well, a TrueTime 2ru IRIG-B LED display) rolling over to the new year and it'll be on YouTube in the morn. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] how to open a Trimble mushroom ?
On 26/12/10 06:47, Hal Murray wrote: Seem to recall they may be rs422. Trimble has/had at least 2 units like that: Palisade and Acutime. There have been several variations of the Acutime. So I can't just plug a Palisade into an Acutime rack? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Symmetricom SA.3Xm series
Does anybody have a source for purchasing these in quantity one? I've been looking for a few for a variety of projects (mainly the software radio GSM stuff where something better then then a *XO is needed), but actually I'm doing a talk to a bunch of developers about managing time and would love one to show off the pace of technology, I also have an old (lab) caesium tube as well. Thanks, Julien ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Datum TS-2100 Rubidium
On 21/07/10 02:41, Greg Dowd wrote: Hey Rob! Yeah, there was a LPRO Rb option on that board and you are remembering correctly. The main thing was a dc-dc converter to get the right voltage (24vdc?). Then, I believe we just selected the external So some more probing with a meter this time showed that there *is* 24v available, albeit in -12 and +12 components, but the LPRO isn't designed (well, according to the spec) for GND != -VE clock and cranked the filter constant up to 1000 and I think that's it. I can't quite remember how it was hooked up, I think maybe a couple SMB mounts inside, one for clock and one for control voltage. Let me know if you want more info. Any more info would be great. I think the Rb version went in a taller case? As for the reboot, probably depends on where you are probing :-) Not that I've seen. One that actually *says* rubidium on the back was on ebay and it was the same 1ru case. I wonder if it wasn't a deeper case though? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Datum TS-2100 Rubidium
On 28/06/10 21:36, Julien Goodwin wrote: Up next is to convert the darn thing to Rubidium, like it was meant to be when I purchased it (insert rant here). OK so the pinout vaguely matches, the TS-2100 is *very* twitchy on the alarm circuits, even a 1Mohm scope (well, it's 1M in theory, cheap Rigol[1]) tripped it to reboot a few times. But where in the world are you supposed to *put* the darn LPRO oscillator, it's too tall to fit above the board, and there doesn't look to be enough room between the back of the front panel and the main board. I'm also not sure about the power supply thing, seeing only the single post to time-nuts about it. I'd love photos, but I'd assume that most people that have one it sits in a rack running. Thanks, Julien 1: Actually 'tis one of the 50Mhz units hacked to 100Mhz operation, a very nice Tek 11k analog scope was reserved, but the seller appears to not want my business going silent after several prods. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Datum TS-2100 firmware updating
As a first post I thought I'd share a success story. After a lot of flailing about the magic combination to upgrade a TS-2100 from old/ROM firmware appears to be to ensure the line endings on the file match that of the TFTP host. While it is twitchy about ethernet as long as there's no contention it's probably fine. Serial updates I just couldn't make work. Up next is to convert the darn thing to Rubidium, like it was meant to be when I purchased it (insert rant here). Other toys are a TrueTime XL-DC and Trimble Palisade, along with a TrueTime IRIG-B display. Thanks, Julien ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
