[time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...

Sun Apr 7 16:45:12 UTC 2013

Hi,
IIRC the early Trimble Placer vehicle tracking GPS receivers used the SVee6 and SVee8. I think the Placer 400 used  the SVee6. These units turn up on ebay etc at very low cost.

Robert G8RPI.

________________________________
 From: "GandalfG8 at aol.com" <GandalfG8 at aol.com>
To: time-nuts at febo.com 
Sent: Sunday, 7 April 2013, 8:53
Subject: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...

The Trimble TNL 22880-B was indeed the original SV6, or SVeeSix as  Trimble 
chose to call it, I have just confirmed this from a photo I took some  time 
ago, and of which I can supply a copy if required.

The SVeeSix manual from 1992 is here.....
http://rapidshare.com/files/446743737/Trimble_SveeSix.pdf

and a much smaller, optimised version, here......
http://rapidshare.com/files/446744995/Trimble_SveeSix_Optimised.pdf

Thanks for these should be directed to Rob Kimberley on the list who  
provided the original printed copy.

This original SVeeSix was approx 4 x 3.5 inches and was  eventually 
replaced by the SVeeEight of similar appearance and  again the same size.
The SVeeSix Plus and SVeeEight Plus were the same modules mounted  in metal 
boxes.
The SVeeEight Plus manual from 2000 is available on the Trimble ftp  site.

I know of at least one application where an SVeeEight PCB module has been  
used as a drop in replacement for an SVeeSix, the Rapco 1804M GPS frequency  
standard, albeit using the opposite serial port, but don't know if this was 
an "out of the box" drop in or whether the port needed to be configured  
first.

The smaller, 1.8 x 3.3 inches, version of the SVeeSix is  the SVeeSix-CM3 
embedded module, and the 1997 manual for that is also on  the Trimble ftp 
site in the manuals/CM3 folder.

It's possible that an SVeeSix-CM3 could be configured as an SVeeSix  
replacement but I've not investigated this, both the SVeeSix and SVeeEight came  
fitted with 1 or 2 standard serial ports on DB9 connectors, the SVeeSix-CM3 
used  an 8 pin header with I/O at TTL levels.

Regards

Nigel
GM8PZR

In a message dated 06/04/2013 23:10:28 GMT Daylight Time, biwa at att.net  
writes:

(Note:  additional information about the receiver module has been  added.)

Burt

Gang,

You will remember several months ago I  had some stranges that I 
thought were related to a defective Vectron  oscillator in one of my 
DATUM 9390-52054.  That turned out to be a  the internal switching 
power supply so I replaced it with an external  Cisco unit.  I've done 
this in three units, two are mine and one  belongs to Stu, K6YAZ.

Well, I now have a different grief in one of my  units.  It had been 
cooking along swell with no problem ever since I  replaced the power 
supply.  This morning I notice that one of my  units had the lock and 
tracking lights out.  The display said that  the signal level was low 
and there were no usable satellites.  The 10  MHz output is also about 
20 or more dB low.  I assumed the power  supply is all right because 
the display was working and it said it was  9-E9, not so good, but 
working - sorta.  I swapped antennas and the  good Datum was happy so 
I know the antenna is ok.  when I got inside  I checked the power 
supply rails and they're within .05 Volts of where  they should 
be.  There is 5 Volts on the GPS module and there is 4.96  Volts on 
the antenna Type-N connector (measured with the antenna line  
disconnected.)  Power cycling the DATUM did not resolve the  problem.

Does anyone know if the symptoms above will occur if the 10  MHz 
oscillator is defective?  I can understand it not tracking or not  
locked, but could this cause the receiver to not see or indicate any  
satellites?  Since I only have two of these units on line, I'm very  
reluctant to start swapping modules because I would be without any  
working reference, so I need to keep one up and running.  Both of my  
units are on a UPS, and according to the clocks in the kitchen, the  
bedroom, and the old VCR, we've not had a power interruption.

I do  not recognize the GPS receiver module, but it has the following 
number on  it:  TNL 22880-B.  I have the schematics for the overall 
DATUM  9390-25054, but the GPS module in just a block.  By the way, 
the GPS  block on the DATUM overall schematic is marked, "SV6 / 
(TANS)".  I  suspect this means something noteworthy.

Any guidance would be  appreciated.

Thanks,

Burt

Burt I. Weiner  Associates
Broadcast Technical Services
Glendale, California   U.S.A.
biwa at att.net
www.biwa.cc
K6OQK  

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