Fred - I will be specific, with the ESE 185 series, for education — understanding what you see on the Surplus / Used market — to make informed a purchased. As noted earlier, many surplus resellers are clueless about technology under covers. — Whenever possible, acquire detailed documentation and “era” when the GPS device was designed / sold as new. The clock mfg. we’re forced to update their products due to external regulations; technology changes/new GNSS constellations; WNRO obsolescence; OEM discontinuing products or entire marketplace over the past 30 years. == ESE MASTER CLOCKS These are the standard ESE models sold, BUT ESE offers a variety of options AND performs custom work for clients. Over the years, I have found custom ESE clocks for the former Harpo Studios (Oprah Winfrey) after Chicago studios closed (now McD Corp HQ) as well as custom ESE clocks for Latter Day Saints (Mormon church) media production facility. https://www.ese-web.com/masters.htm The ESE ES-185F GPS Master Clock is current production, it has a “K” option for providing 10 MHz and 1 PPS outputs (rear panel). ESE 185A GPS MASTER CLOCK Currently for sale on eBay. This earlier model (A) was designed in Late 1990s, PC boards silk screened 1999. It used a Motorola Oncore 8-channel receiver (VP or UT). 23-page Manual (PDF) with schematics and parts listings. https://bama.edebris.com/download/ese/es-185a/ese_es-185a_manual.pdf You will note the CPU for the ES-185A is the Intel 8051 series, showing the foundation of their original clock designs / firmware (1970s). The “K” option schematic diagram is shown on page 23 (last page), with part number ID, BUT without PC board layout or specific listing of “K” parts — SO, you will see that the ES-185A is a “first generation” product (1995-2003), thru-hole construction — lacking TCXO, OCXO, and other features taken for granted. RoHS Regulations (2003) and President “W” Bush (43) rule changes for Daylight Savings Time (2005-2007) ** ESE current model ES-185F, uses a 12-channel rcvr & different (design / tech updates), BUT without schematic or photo — a specific comparison can not be made. greg w9gb === Date: Sun, 22 Dec 2024 14:25:31 -0800 From: fwbray@mminternet.com Subject: [time-nuts] ESE GPS Clocks To: Time Nutes <time-nuts@lists.febo.com> I've noticed that some of the ESE GPS master clocks have optional 10 MHz and 1 KHz outputs. I'm curious how accurate and stable these are. I assume that at best they use a TCXO and not an oven. Has anyone worked with these units? Thanks and happy holidays. Fred Bray KE6CD

Hi Greg, Thanks for all the info. I, too, have a number of the ESE products including one of the early ES-911E/GPS units that I use to drive the slave clocks, including an analog unit. The ES-911E/GPS has the NTP option, which doesn't seem to work. Someday, I might try to trouble shoot it but it isn't a function that I need. I occasionally look at the eBay offerings and became curious about the ones that have the 10MHz output. I have a HP Z3801A (which I should update with a modern receiver) so I wasn't thinking of acquiring the ES 185 as a frequency standard. I appreciate the comments and suggestions. Fred KE6CD On 2024-12-28 13:18, Gregory Beat via time-nuts wrote: > Fred - > > I will be specific, with the ESE 185 series, for education — > understanding what you see on the Surplus / Used market — to make > informed a purchased. > As noted earlier, many surplus resellers are clueless about technology > under covers. > — > Whenever possible, acquire detailed documentation and “era” when the > GPS device was designed / sold as new. The clock mfg. we’re forced to > update their products due to external regulations; technology > changes/new GNSS constellations; WNRO obsolescence; OEM discontinuing > products or entire marketplace over the past 30 years. > == > ESE MASTER CLOCKS > These are the standard ESE models sold, BUT ESE offers a variety of > options AND performs custom work for clients. Over the years, I have > found custom ESE clocks for the former Harpo Studios (Oprah Winfrey) > after Chicago studios closed (now McD Corp HQ) as well as custom ESE > clocks for Latter Day Saints (Mormon church) media production > facility. > https://www.ese-web.com/masters.htm > > The ESE ES-185F GPS Master Clock is current production, it has a “K” > option for providing 10 MHz and 1 PPS outputs (rear panel). > > ESE 185A GPS MASTER CLOCK > Currently for sale on eBay. This earlier model (A) was designed in > Late 1990s, PC boards silk screened 1999. It used a Motorola Oncore > 8-channel receiver (VP or UT). > > 23-page Manual (PDF) with schematics and parts listings. > https://bama.edebris.com/download/ese/es-185a/ese_es-185a_manual.pdf > > You will note the CPU for the ES-185A is the Intel 8051 series, > showing the foundation of their original clock designs / firmware > (1970s). > > The “K” option schematic diagram is shown on page 23 (last page), with > part number ID, BUT without PC board layout or specific listing of “K” > parts > — > SO, you will see that the ES-185A is a “first generation” product > (1995-2003), > thru-hole construction — lacking TCXO, OCXO, and other features taken > for granted. > RoHS Regulations (2003) and President “W” Bush (43) rule changes for > Daylight Savings Time (2005-2007) > > ** ESE current model ES-185F, uses a 12-channel rcvr & different > (design / tech updates), BUT without schematic or photo — a specific > comparison can not be made. > > greg > w9gb > === > Date: Sun, 22 Dec 2024 14:25:31 -0800 > From: fwbray@mminternet.com > Subject: [time-nuts] ESE GPS Clocks > To: Time Nutes <time-nuts@lists.febo.com> > > I've noticed that some of the ESE GPS master clocks have optional 10 > MHz > and 1 KHz outputs. I'm curious how accurate and stable these are. I > assume that at best they use a TCXO and not an oven. > > Has anyone worked with these units? > Thanks and happy holidays. > > Fred Bray > KE6CD > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com