Re: [time-nuts] Mounting GPS Antenna on Steel Roof
In a message dated 08/03/2008 03:57:02 GMT Standard Time, [EMAIL PROTECTED] writes: The inverter is required because the Motorola GPS receiver uses TTL and the PC serial port uses RS232. RS232 uses a positive voltage of +3 to +25 volts to indicate a logic zero, and a negative voltage of -3 to -25 volts to indicate a logic one. --- My Motorola Oncore test rig uses a Max232 to interface the RS232, no inverter, and works fine. regards Nigel GM8PZR ___ 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] Mounting GPS Antenna on Steel Roof
The MAX232, like all RS-232 interface chips I have ever come across, inverts the signal. Didier KO4BB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Saturday, March 08, 2008 2:48 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Mounting GPS Antenna on Steel Roof In a message dated 08/03/2008 03:57:02 GMT Standard Time, [EMAIL PROTECTED] writes: The inverter is required because the Motorola GPS receiver uses TTL and the PC serial port uses RS232. RS232 uses a positive voltage of +3 to +25 volts to indicate a logic zero, and a negative voltage of -3 to -25 volts to indicate a logic one. --- My Motorola Oncore test rig uses a Max232 to interface the RS232, no inverter, and works fine. regards Nigel GM8PZR ___ 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. No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.21.6/1316 - Release Date: 3/6/2008 6:58 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.21.6/1316 - Release Date: 3/6/2008 6:58 PM ___ 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] SkyLab/SkyNet USB Demo Board
I purchased a GPS/USB demo board from Sure Electronics using e-bay. It seems to do an OK job of receiving. Can anyone suggest how to flash the unit to produce the 1 PPS output? I bought this to use as a driver for a Disciplined Quartz Oscillator. The board uses the u-Nav 8130 baseband chipset. ___ 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] Mounting GPS Antenna on Steel Roof
In a message dated 08/03/2008 13:29:42 GMT Standard Time, [EMAIL PROTECTED] writes: The MAX232, like all RS-232 interface chips I have ever come across, inverts the signal. That'll explain it then:-) ___ 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] Which HP Frequency Counter?
Dear group, I consider buying a used lab frequency counter / timer --preferably HP/Agilent-- covering from few mHz to perhaps 400 MHz. I'm worried that models handling high frequencies seem to be limited to under 100 mV input signal max. I don't want to destroy an input channel each other day when calibrating/repairing some instrument. Also are there instruments with high impedance input? 50 Ohm is not quite right for investigation in the guts of most designs. Is it possible to find a not-too-old model under $800? I would like to find something in France or UK or Europe, but it seems hopeless in this budget. I would favor a repairable model (with available service docs schematics). Your expert advises are more than welcome! -- mailto:[EMAIL PROTECTED][EMAIL PROTECTED] ___ 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] Which HP Frequency Counter?
The HP 5334A or B with the C channel option has a sensitivity spec of -30dBm (from memory) up to 1 GHz or so. The C channel has 15mV rms sensitivity at 1 GHz. The C channel option is rare, but it only requires 3 parts (a diviser and two dual-shottkys) and a connector (and a hole in the front panel) to add it to a 5334B for instance. I have two 5334Bs (one is broken) and both have the other parts required for the C channel except for these three. There is a socket for the diviser, the shottkys have to be soldered in. The C channel input is activated on pressing the '9' key. Unfortunately, the MB506 diviser (Fujitsu) seems a little hard to find. If anyone has a spare, let me know. A surface mount equivalent should not be too hard to put in. The HP 5316 has similar characteristics and also has a 1 GHz option, which is also rare. I also have an Advantest TR5823 counter which has the 1.3 GHz input with 20mV rms sensitivity at 1.3 GHz. The HP models have reciprocal counting, so they work MUCH better for low frequency signals. Didier KO4BB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jean-Christophe Deschamps Sent: Saturday, March 08, 2008 10:49 AM To: time-nuts@febo.com Subject: [time-nuts] Which HP Frequency Counter? Dear group, I consider buying a used lab frequency counter / timer --preferably HP/Agilent-- covering from few mHz to perhaps 400 MHz. I'm worried that models handling high frequencies seem to be limited to under 100 mV input signal max. I don't want to destroy an input channel each other day when calibrating/repairing some instrument. Also are there instruments with high impedance input? 50 Ohm is not quite right for investigation in the guts of most designs. Is it possible to find a not-too-old model under $800? I would like to find something in France or UK or Europe, but it seems hopeless in this budget. I would favor a repairable model (with available service docs schematics). Your expert advises are more than welcome! -- mailto:[EMAIL PROTECTED][EMAIL PROTECTED] ___ 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. No virus found in this incoming message. Checked by AVG. Version: 7.5.518 / Virus Database: 269.21.7/1319 - Release Date: 3/8/2008 10:14 AM No virus found in this outgoing message. Checked by AVG. Version: 7.5.518 / Virus Database: 269.21.7/1319 - Release Date: 3/8/2008 10:14 AM ___ 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] Which HP Frequency Counter?
Jean-Christophe Deschamps wrote: Dear group, I consider buying a used lab frequency counter / timer --preferably HP/Agilent-- covering from few mHz to perhaps 400 MHz. I'm worried that models handling high frequencies seem to be limited to under 100 mV input signal max. I don't want to destroy an input channel each other day when calibrating/repairing some instrument. Also are there instruments with high impedance input? 50 Ohm is not quite right for investigation in the guts of most designs. Jean-Christophe, I know you said HP, but the one instrument that I have on my bench and use all the time that is not by HP is a Racal-Dana 1992 counter. It has three inputs, the A input can be set to 1 MegOhm impedance and will count up to 160 MHz at good sensitivity, 50 Ohm loads and attenuators and filters also available. The C input goes to 1.3 GHz, 50 Ohm only. The A and B inputs can be used for phase comparisons. Most of them have a very good quality Ovened timebase, Option 04E. There are a lot available in the US and not so many in Europe, prices for what they are seem very reasonable; in the US $200 to $300, working. Some have trouble with the push button switches, these can be replaced, but it is a big job to do, there are a lot. Apart from that I know of no other common failure modes. Not a lot of other components inside that cannot be found easily enough. Manuals are freely available. And it is quiet. No fan noise. My HP counter sits in the garage... Good luck, Dan ___ 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] Handar 541 WWV receiver project update
Have dumped the EPROM and made several passes with the dissembler to separate the data and code. Total code and data is 0x1823 bytes. Some text decoded thus far : ; L0216: DB '.5 MHZ RECEPTION SELECTED.' ; L0240: DB '.10 MHZ RECEPTION SELECTED ..15 MHZ RECEPTION SELE' DB 'CTED ..ALL COUNTS HAVE BEEN CLEARED..P' DB 'RESS CLEAR AGAIN OR OTHER KEY TO ABORT ..WWV TIME MEASUREMENT IN' DB ' PROGRESS..WWV' DB ' TIME CORRECTION RECEIVED..NO ' DB 'WWV TIME CORRECTION WAS RECEIVED .' ; break ; L104B: DB 'TRIES=.' ; L1052: DB '5M=.' ; L1056: DB '10M=.' ; L105B: DB '15M=.' ; My next step will be to hook up a terminal to see these status messages and maybe the TIME is also produced in ascii readable form. Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping ___ 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] TiNI Time Server
On Fri, Mar 7, 2008 at 2:28 PM, Matthew Smith [EMAIL PROTECTED] wrote: Hi Does anyone have or has anyone come across the Dallas TiNI evaluation module (DS80C400) being used as a GPS-connected time server? I've found references to something called 'tinitim', but whatever it was seems to have gone away. I just rather like the idea of an ultra-low power device that works as an NTP server, nothing else. Googled for the part number, got this: - http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3609 Looked for TiNI module: - http://www.tstik.com/tstik72nb_data.html - http://www.maxim-ic.com/products/microcontrollers/tini/ Also found this: TiniTim - A TINI Time Server - http://automationfaq.com/cgi-bin/fom?amp=editCmds=compactfile=259 -- GDB has a 'break' feature; why doesn't it have 'fix' too? ___ 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] Which HP Frequency Counter?
Jean-Christophe, I have had a very good experience with my Fluke PM6681 (aka Pendulum CNT-81). They show up on eBay 2 or 3 times each quarter, selling for US$600-800. Since they are designed produced in Sweden, I would expect them to available more easily in Europe. The PM6681 advertises 50ps single shot TI resolution, but the GPIB data returns 25ps data. The frequency mode produces 11 digit/s readings. Pete Rawson ___ 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] Which HP Frequency Counter?
A lot depends on the resolution you need and what all you want to use it for, but it might also be worth looking at some recent Fluke counters. The PM6681 has a nominal rating of 300MHz on it's main input, although it may read rather higher. It has 1M or 50R input res, and can tolerate up to 12V rms. Also, its nominal time interval resolution of 50ps single shot and 1ps averaged can be quite useful. The PM6680B is only rated at 225MHz, but it's cheaper, and sometimes turns up with a high frequency channel at a reasonable price. GPIB was an option with this one, so if you want that, you would have to check that it's fitted. It might also be worth checking if a separate prescaler would be ok for your high frequency use, rather than having to find (and pay for) a counter with a high freq input. An active probe could be used to reduce the loading, but they tend to be expensive to buy. Sometimes an HP53131A also turns up at a decent price, but probably not with a high frequency channel. Input damage level is quoted at 5V rms for it. Personally, I really like the PM6681 since it's so capable, and I find it much easier to use if the settings have to be adjusted much - but the HP has an RS232 port which makes logging the data very simple on any computer. Angus. On Sat, 08 Mar 2008 17:49:02 +0100, you wrote: Dear group, I consider buying a used lab frequency counter / timer --preferably HP/Agilent-- covering from few mHz to perhaps 400 MHz. I'm worried that models handling high frequencies seem to be limited to under 100 mV input signal max. I don't want to destroy an input channel each other day when calibrating/repairing some instrument. Also are there instruments with high impedance input? 50 Ohm is not quite right for investigation in the guts of most designs. Is it possible to find a not-too-old model under $800? I would like to find something in France or UK or Europe, but it seems hopeless in this budget. I would favor a repairable model (with available service docs schematics). Your expert advises are more than welcome! ___ 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] Isotemp OCXO118-12 pinouts?
Does anyone have the hookup information for the foloowing 10MHz oscillator Isotemp OCXO118-12 P/N 674-0012-000) 7 pins in a row plus 1 more pin below on the bottom 12v operation Only the more recent ones datasheets are on the Isotemp web site The only web search hit is a post for pinouts on this reflector by W9FZ back in 2005, which appeared to go unanswered Thanks Dave Robinson ___ 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.
