[DSP-10] INFO - HP Z3801A GPS Receiver?

[Mike Pinault]

Hi all,
         Here is some information I have found on the Z3801A and Z3816A. I 
do have both of them
operating in the shack. This information pertains to the 2 units I have and 
some things are different ie..powered by -48vdc
or -24vdc on the units available.

First the Z3801A.( -38to-60VDC, I'm using -48VDC power). This excellent 
site by K8CU has loads of info on the unit, interfacing
and documentation via a PDF file. The PDF docs explain how to install the 
unit and what type of antenna to use as well as
coax type and length required. It also explains the SatStat program and its 
commands. I printed the manual out and it is
98 pages long and most info pertains to both type units.

http://www.realhamradio.com/GPS_Frequency_Standard.htm

The Z3801A uses a RS-422 input for the computer port and K8CU has provided 
a couple of options for interfacing to RS-232.
I chose the surface mount chip as I couldn't find a source for the dip 
chips. The whole converter fits in the case of the
25 pin connector. The software program is the SatStat program. The 
parameters are listed in the PDF manual.
Read all of his notes and you'll re-invent the wheel a few less times. This 
unit uses a HP High Stability osc
about twice the size of the HP 10811osc. Most of your questions will be 
answered on the web page and PDF doc.
Unit puts out 1PPS and 10MHZ.


The Z3816A (-24VDC power) appears to be a  generation ahead or at least a 
different approach to the time standard. The basic unit ie..
power supply type but not voltage and GPS receiver are the same. This unit 
uses RS-232 input and came with a SatStat software
package modifed to auto connect to the unit via serial port and monitor the 
unit. It doesn't have the part of the software to configure
the unit and make software requests and changes. I found the Satstat from 
K8CUs site worked fine with both units but you have to
change the connection protocols in the "open com port" section when 
switching between the 2 different units. The difference in osc
standards is this unit uses a "MTI 260 Series OXCO Ultra Stable Atomic 
Standard Replacement"  This is MTIs description of their
OXCO replacement for Rubidium standards. Check out 
http://www.mti-milliren.com/260.html  for complete information on this OXCO.

I have had them running for about 3 weeks and have not really compared them 
to each other yet except for looking at the time it took
to stabilize the 1PPS and 10 MHZ outputs. The Z3816A did come up a little 
earlier but both were ready after 18 hours. The learning
receivers still get better at compensating for drift as the days go on. I 
will do some comparison of the 2 signals with some of the
software available over the summer. I will be using the them as my external 
time and frequency standards for the DSP-10 project and
as a cal standard for the HP test gear as the external source.

I'll answer any questions you may have and can describe how I hooked up the 
power for the RS-422 connector inside the GPS unit
if you need it. I've noticed the price coming down on the Z3801A on ebay 
and this makes it a real bargain at under $300. For the antenna
search for the Symmetricom 58532A on ebay. It is the Motorola antenna but 
now taken over by Symmetricom. A bargain at under $30.

Hope this helps, Mike W7GHz formerly N3CEV/7







At 05:34 PM 4/28/2002 Sunday , you wrote:

>I have a friend who is looking at a HP Z3801A GPS Receiver, but there 
>isn't any technical data.
>
>Does anyone have technical information about these item? Or a web site?
>
>Does anyone know the diferences between Z3801A and Z3816A?
>
>Any help would be greatly appreciated.
>
>
>Jimmy  Oldaker   W7CQ
>      Eugene, Oregon
>            CN83jx
>
>a DSP-10 ready station
>
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