VK Logger Ham Radio Forum Archive

Hi all

Just wondering if anyone has any documentation for the Hp GPSDO model Z3616a

There are other models with Z38xx numbers

I have one on test here with an external antenna but "alarm" led is not going off and the GPS Lock "LED" is not coming on

Kevin VK4UH

Hi Kevin

Do you have the right antenna, I don't remember what the 3816 is but you can have either 3 volt or 5 volt antenna's and sometimes (but not always) a 5 volt antenna won't work with a 3 volt source. Quite often there is a jumper link internally to select the antenna voltage.

When I got my 3816 it took hours for first time to lock but now only takes around 20 minutes since the almanac has updated.

Rex

Thanks Rex

I have just checked and the 3816 is putting 5volts on the antenna

Ill set it up again with a mains PSU, its currently on 2 12v gel-cells in series, and let it run for some hours

Thanks KJ

Thanks Rex

I have just checked and the 3816 is putting 5volts on the antenna

Ill set it up again with a mains PSU, its currently on 2 12v gel-cells in series, and let it run for some hours

Thanks KJ

Hi Kevin,

The best thing to do is connect a RS232 terminal to the unit and query what is going on. I believe the command is:

:system:diag:log:read:all?

and

:system:status?


Some of the HP units (not sure which one, there are many GPSDO models) have issues with the GPS date. The underlying issue is the GPS year is a small range of bits and it cannot hold 2016. Depending on the age of the GPS receiver it gets confused and you have to manually set the date to get it correct - this normally happens if the receiver has been put into storage and did not witness the GPS rollover. It is a common problem and you can find more details on the timenuts mailing list.
This can cause it to have the wrong idea of time, and finding the sats using the Keplerian elements gives the wrong result, and the GPS has a lot of trouble locking.

Once you have basic terminal working you can run something like GPSCon which might tell you what is amiss.

No doubt you have already discovered this website: http://realhamradio.com/GPS_Frequency_Standard.htm

73,
Wayne

Following on from Wayne's advice I use some software called Z38xx which may work for you.

http://www.ulrich-bangert.de/html/downloads.html

Download the software and there's a debug window that lets you see whats happening including the survey times and sat data

Rex