Symmetricom help and advice please... - Page 1
Forum section: electronics / general

author: Mike G
author_rank: Regular Contributor
timestamp: October 23, 2019, 02:43:35 pm
content: Hi, a few months ago I decided I needed a reference 10Mhz source in the workshop, the rabbit hole then opened! Any how three months later I have a pair of Symmetricom 4370A units and an Extron DA proudly mounted in the rack with a pair of Maxrad antannas up on the top roof. It seems to work ok but I have read the manual for the 4370A and it appears to have it's own webserver which allows access to more information and options. I can find it on the LAN and when connected it asks for username and password. I have tried the standard ones from other models with no success and the manual says to contact Symmetricom for the information. Sadly Microsemi appear to not be as helpful as Symmetricom so I have come up against a brick wall. If any of you experts could help a novice volt/time nut I would be very grateful.As a beginner in this area could anyone suggest the level of accuracy that might be obtained from this type of reference. I have two so I can compare them. I am using a frequency counter using one receiver as the reference while the other as the input, is this a valid test to find the error between the two? According to a timing reading on a scope there is a phase diference between the two outputs and this appears to be very slowly changing. They have been running for a couple of days so far, how long would they take to finally stabilise?If I am making gross mistakes I apolgise but am keen to learn more. Thanks.

author: awallin
author_rank: Frequent Contributor
timestamp: October 23, 2019, 02:49:41 pm
content: this paper has some numbers that you can compare your measurements against:https://www.nist.gov/publications/use-gps-disciplined-oscillators-primary-frequency-standards-calibration-and-metrology

author: Mike G
author_rank: Regular Contributor
timestamp: October 24, 2019, 12:52:17 pm
content: Thanks for that link, looks as though that will keep me busy for a while, some will be over my head at the moment but there is a lot of useful information there.Still stuck for any advice regarding the username and password, any Symmetricom experts who may be able to help please?

author: martinr33
author_rank: Frequent Contributor
timestamp: October 28, 2019, 07:34:19 am
content: I think if you take your gate up to 60 seconds, the difference will disappear. My GPSDOs show similar variation.

author: Drewbie
author_rank: Contributor
timestamp: October 29, 2019, 11:46:47 am
content: Have you tried admin:symmadmin ?

author: Mike G
author_rank: Regular Contributor
timestamp: October 29, 2019, 02:52:41 pm
content: Hi Drewbie, thanks for the idea, no I hadn't but I have now, unfortunately with no success. It may not be using the default user name/password so I am struggling. There is an SD card inside, for the firmware I believe, so I don't know if the password etc is in there or eeprom. I have ordered a Bus Blaster to try to get in through JTAG and have a look what's going on. I feel sure Symmetricom must have a back door user/password for when people mess up. There is, apparently also a "community" password to allow use of there GUI software which is downloaded from the 4370. Looking at the screenshots in the manual I think this may be "tsc" but I have to get that far first. Other than that the two units seem to be settling in, running them 24/7 for a week then check out the accurcy. After two days with 10 second sampling they are averaging within 1uHz of each other but I am not sure if the accuracy of a £100 FA2 frequency counter is to be trusted at that level. I am using one unit as the external reference and the other as the input, is this a valid test?