[time-nuts] TrueTime AL-AK GPS receiver help

[paul swed]

Bob brings up all the additional details that are the reality of dealing
with teh older gear. Especially the date offsets because of the 1024 week
cycle. That is a real pain.
But the reason to spend time on something like this is to understand
something and to learn.
I picked up the austron 2000 gps because it was a useful rack mount box.
Then realized some of its unique qualities. That was the driver for
reviving it.
I was lucky that I was able to obtain some operational data and then later
schematics. BUT it was still a heck of a reverse engineering and adapting
process.
I am pretty sure I shared that on time-nuts and will guess that must be 5
years ago now.
Regards
Paul
WB8TSL

On Thu, Apr 30, 2015 at 5:58 PM, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> I guess the first question would be:
>
> Are we sure it’s an AL-AK and not an XL-AK?
>
> Past that it becomes a fairly involved process of, is it worth real money
> to get this up and running?
>
> If we are talking about a $20 eBay find that is worth another $5 to have
> somebody else get it running, the
> conversation is a real short one.
>
> If the AL-AK has some inherent value (it’s a working GPS disciplined Cs
> maybe) then putting a few hundred
> dollars into checking it out and getting it running might make sense. If
> it’s like most of the parts from that
> era, the delta between getting it checked and getting it running is pretty
> small.
>
> Once you *do* have it running, what do you have?
>
> 1) Leap second problems
> 2) GPS year rollover problems
> 3) Tracking issues
> 4) A noisy receiver with very few correlators
> 5) Software support issues
>
> This is an unusual box that is at least 20 years old. It *will* have at
> least some of the listed issues and
> may have all of them. Fixing them will be impossible.
>
> ========
>
> Why bring up all of the negatives? I for one have been sucked into this
> kind of thing a *lot* of times
> in the past. Just a few more this or that and it’ll be running fine. Much
> better to figure out the likely
> cost and outcome first. That’s *very* hard to do, and even harder to
> follow through on. If you can’t
> do the work yourself, the cost isn’t just lost time. This can cost real
> cash.
>
> Bob
>
>
> > On Apr 30, 2015, at 12:50 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
> >
> > I received this email. Anyone have a good answer?
> > Thanks,
> > /tvb
> >
> > ----------
> > Someone on ebay advised me to contact your website in hopes that someone
> in your organization can help me with my TrueTime model AL-AK GPS Receiver.
> I need to send it to someone so that they can check it to see if it works
> and can track Satellites.  This receiver has the onboard up/down convertor
> board that changes the receiver input frequency which is set at 4.092 MHz.
> I don't have the needed down converter at the antenna. I bought this
> receiver on ebay from someone who told me that he doesn't have the down
> converter as well and can't figure out how to get it to work at 1575.42
> MHz. He also didn't know if this receiver can be setup for a 1575.42 MHz by
> removing the onboard converter and changing some DIP switches. If one of
> your members can at least check out the receiver at 4.092 MHz for satellite
> tracking That would be a big help ...
> > ----------
> >
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