[time-nuts] Spirent STR4500 GPS simulator

Bob kb8tq kb8tq at n1k.org
Wed Apr 5 12:46:29 EDT 2017


Just to clarify a bit:

These gizmos fall into two broad categories:

1) The single sat simulators like the GSS6100 that show up cheap.

2) The full constellation simulators that show up for a bit more money.

The single sat stuff is simple to run from a serial port and limited in function. They are
quite useful for checking things like GPS week rollover or sensitivity. They will often 
run in a fully autonomous mode ( = boots to full function) if desired. The target audience 
is / was production testing. 

The full constellation gear is a bit more complex. At least the boxes I have seen require
a computer with the proper “dongle key” to do much of anything. They will let you set up
all sorts of cool navigation processes. How long they will run those setups and with how
many satellites involved is a “that depends” sort of thing. 

Within both categories you have the inevitable “how many systems?” question. Early stuff
is generally GPS / SBAS only. Later stuff has various options to let you customize the 
systems it will simulate. In some cases it’s a pick them one at a time, pay for each sort of thing.
On other boxes it’s a “here they all are” license. Working out from the cryptic numbers 
on the typical box which options it is / was licensed for can be nearly impossible. 

Even with a support contract, getting info from the various outfits that make some of these
devices is a major hassle. Getting information without a support contract is even worse. 
It is not specific to one vendor. They all seem to be focused on selling you the latest and 
greatest rather than upgrading the box they sold you a couple of years ago. None of them
seem to be at all excited about supporting the surplus market. 

Before we all go off on a bender about lack of support, consider how small this market 
is and how fast stuff changes. The GSS6100 was brand new 10 years ago. Now it is 
past end of life. It was replaced roughly 5 years ago. Other vendors have similar 
cycles. There are industries out there that would consider 10 years to be a *really* long
support period ….

The big advantage to us of this process is that the value (to a real customer) of these boxes
goes to zero very quickly. When that happens, we get to buy them dirt cheap on the 
secondary market Rather than paying $4,000, they go for $200. The odds of getting 
a fully functional device are quite high even at the $200 level. 

Lots of fun.


> On Apr 5, 2017, at 9:46 AM, paul swed <paulswedb at gmail.com> wrote:
> Phil
> Welcome to the group.
> Funny you mention the Spirent. I see many available for semi reasonable
> pricing though for Ham/Time-nuts a bit pricey still at $295 for a tinkerer.
> And they do not come with the disk.
> But as was pointed out to me by a fellow time-nut you don't need it. You
> can directly control the unit by rs232 through quite simple commands. Use a
> USB to RS232 converter if you do not have a real port.
> You can create batch files of the comands on and on. I had downloaded the
> manual to look at.
> However I will not be buying a unit for quite a long time. Would need to be
> sub $100 for me at least.
> Good luck and have fun.
> Regards
> Paul
> On Wed, Apr 5, 2017 at 6:24 AM, Phil Parsons <phil at computerhotline.co.uk>
> wrote:
>> This is my first post after lurking for quite a while reading & trying to
>> get to grips with the technology. I just purchased a Spirent STR4500 GPS
>> simulator  along with a pile of other kit. Unfortunately the CD was missing
>> (no great surprise) & Spirent are not interested in selling me a
>> replacement disk. So, can anyone help me with software for this or should I
>> accept it is  a door stop & get rid? My plan was to use this to get
>> consistent signals to test a few GPSDOs I have acquired. Any advice
>> gratefully received.
>> Phil
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