Re: [time-nuts] Which HP Frequency Counter?
Jean-Christophe, I would like to second Dan's opinion. Despite of owning some HP counters and a SR620 from Stanford Research i regulary use my good old RACAL DANA counter. The model 1992 is a standard even at European based surplus dealers. An even better buy than the 1992 is the not so often seen model 1996 for example at http://www.rainer-foertig.de/Zaehler.htm because it has an increased number of measurement facilities. The trouble with the pushbutton switches is the same with this model. RACAL DANA has used push buttons over a period where the color ingredients of the switch body would gas out over the time and ruin the elasticity of the plastic part closing the switch contact. This is very easy to diagnose: If you press the button and it does not come back you have a ruined pushbutton that must be exchanged. I did already exchange the complete set of of buttons on my 1996 for two times. You can imagine that I would not have done this if the device itself were bad. The last switches that i built in are completely white and do not have additional color ingredients. This seems to have sold the problem! Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Dan Rae Gesendet: Samstag, 8. Marz 2008 18:36 An: Discussion of precise time and frequency measurement Betreff: 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 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.
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.
