Chris What Bob was mentioning is true of the older units circa 1990s. I have homebrewed down converters for two older units. Essentially everything gets multiplexed onto the one jack so you can't really tell by looking if it needs a downconverter or just an antenna. A bit of a hint. If there is something like 12-15VDC on the jack then it needed a down converter. But its just a hint not a rule. Its funny how you find great receivers for $0 only to find out a key component is missing. Thats how I ended up with my Austron. Good luck Paul WB8TSL
On Sat, Jul 20, 2019 at 9:00 PM Chris Quayle <[email protected]> wrote: > Hi > > > It’s a pretty good guess that a device from that era ran a > “downconverter” head end. > > They had a full RF front end out at the antenna and fed some sort of IF > frequency > > back to the unit. Various outfits had approaches to how to do it. The > net result is that > > the head end is pretty specific to this or that box (or at least series > of boxes). > > > > Since it’s an entirely different approach to getting things done, > directly replacing the > > head end with a modern module is going to be tough. The normal > alternative is to > > build up a downconverter. Some do it from scratch, others find a similar > unit > > somewhere and modify it to do the job. The big trick is to find out > exactly what the > > main box is looking for …. > > > > Bob > > > I had wondered about that, but if you look at the antenna input, it > looks like pretty high frequency, with a track inductor. Would > assume that a downconverter from gps frequency would > translate to baseband, but may be wrong. > > Took a few pics of the board, in case it looks familiar to > anyone, but it must have been used on other, perhaps marine or > avionics kit of the time. Problem is finding such an item, say > on Ebay, without taking the lid off to verify contents. Have a > feeling this quest may take some time :-). > > Here are the pics anyway: > > https://www.flickr.com/photos/182770787@N05/ > > Regards, > > Chris > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
