Brian - Synergy (San Diego, CA) has a solution for your WNRO, as well as additional benefit for new GNSS receiver capabilities over past 20+ years (Sensitivity, “Best in View”). When Motorola had their GPS/Oncore division (here in Chicago area), Synergy was one of their largest distributors. There is MORE to this process than just “plugging in a newer GNSS receiver”. HP/Symmetricom GPSDO solutions originally used Motorola Oncore 6 and 8 channel receivers. As I remember, Motorola binary was used between the HP and GNSS receiver (not NEMA). Page 3 shows the comparison of Motorola Oncores to uBlox based replacements. Page 6 of brochure, you see the Z3805A listed (6-channel Oncore). https://synergy-gps.com/wp-content/uploads/2022/05/SSR-VP-UT-and-GT-Drop-In-ReplacementsTN484-B030624.pdf The UNKNOWN is what changes (firmware) MAY have been made by Samsung GPSR for commands/responses (“@@“ or NEMA?) from GNSS receiver (Furano). My late model Symmetricom 58503B Reference had production changes made that Synergy engineers tested/verified with their replacement solutions. During testing, Commands were discovered that required firmware adjustment (translation of ublox to Motorola binary). greg, w9gb == Date: Sun, 10 Nov 2024 22:45:00 -0600 From: bryon <kd4fm@aol.com> Subject: [time-nuts] Samsung-Symmetricom GPSDO Rollover Problem To: time-nuts@lists.febo.com I have a Samsung GPSR, which is a Symmetricom Z3805A. It looks like a Z3801A, except it has a front panel power switch. On the rear panel it shows its made by Symmetricom and it has stickers inside on the PCB showing Symmetricom Z3805A, etc. Runs off of 28 volts DC. It also uses the MTI-260 5 Mhz oscillator on a 5 MHz doubler board to get back to 10 MHz. The unit runs, but it has the March 2004 rollover date problem. The unit uses a Furuno GT-8031B GPS receiver. The GPS receiver has the form factor of a Motorola M12+ receiver and then the Furuno receiver is mounted on an adapter board that has the form factor of the elder Motorola PVT/Oncore VP receivers. The Furuno runs 9600 BPS and the basic data sheet states it runs NMEA like protocol. I attempted to put a LEA-6T and a M12+ into NMEA mode at 9600, but they will not do it. I think its because they are timing only receivers and only run binary. I also tried to put a Motorola Oncore VP in the unit that was set to the 6 channel mode and binary and the Samsung unit gave a front panel fault about 30 seconds after power up. Does anybody have any experience with a replacement GPS receiver for this unit ? Thanks, Brian.