Hi Remember - a number of these boxes go *way* back in time GPS wise. Often the basic guts were a mix and match affair and this or that sub-system was frozen for a decade or more. At this late date, figuring out why they did that, or why they had multiple sub-systems is going to be tough. I suspect that it goes something like - this one works with 1500’ of RG-58, that one works with 300’ of RG-58.
In answer to your basic question - I’d bet it has the IF to a GPS receiver and the tuned front end is up at the antenna. I have never seen one of these that was an either or as installed. If you wanted a downconverter, that’s what they built into the box. If you wanted a full receiver, that went in instead. They flipped a few dip switches on the main board to tell the firmware what it had and moved on. Bob > On May 2, 2015, at 12:10 AM, Al Wolfe <alw.k...@gmail.com> wrote: > > Does this AL-AK have a real GPS receiver in it? Does the unit have a board > with a crystal of 16.368MHz. that is multiplied by 96 up to 1571.328, the > mixing frequency to get to the GPS freq of 1575.42? > > Since the down convert-up convert is offered as an option perhaps TrueTime > used an actual GPS receiver in all their units. It stands to reason (at least > to me) using a stock off-the-shelf GPS receiver in all their boxes would be > simpler than having to do a custom kluge to work at 4 mhz. > > If this user can find out if his box has an actual GPS receiver then the > converter section could probably be bypassed. > > FWIW, the TrueTime XL-AK used an external up converter and down converter, > model 142-6150. Says it's good for up to 1500 feet of RG58. Its manual is on > line. It uses the above mixing scheme. > > Al, retired, mostly > AKA k9si > > >> 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 ... > <snip> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
