Hi Ben, Symmetricom/Microsemi/Microchip has delivered NTP boxes with 12VDC antenna voltage only a few years ago.
Looking at Antcom antennas most of them run on anything between 2.5 and 24V, iirc. /Björn Sent from my iPhone > On 8 Jul 2021, at 14:20, Ben Hall <kd5...@gmail.com> wrote: > Good morning all, > > Spotted one of these on the e-place for $50 plus shipping and couldn't > resist. I've got four other GPS-NTP servers already, so this really fits > into the "nuts" portion of time-nuts. ;) > > Looking in the archive, only found one post on it dealing with firmware. I > know it's a very old unit, might have GPS week roll-over issues, but curious > if anyone on the list has any hints or hacks on this unit? > > The 12 volt antenna is a bit unusual to me, but seems as if 12 VDC was the > standard for these type of products before the 5 VDC became common. I've got > an open DC-blocked port on my GPS antenna splitter, so it's really a > non-issue for me, I hope. Per the manual, the unit can sense antenna port > open, antenna port shorted, but really doesn't say how it reacts to these > conditions. I'd imagine if it still sees RF, it will use it, as that seems > to be the norm for everything else, but I could be surprised. > > Worst-case, I've got some rather old vehicle-mounted GPS patch antennas that > I believe I could modify with an internal regulator of some sort to handle > the 12 VDC. Really worst-case, I use the NTS-150 to provide 12 VDC to the > TOPGNSS "mushroom" antenna. It *says* it can handle 15 VDC maximum...but I > seem to recall someone here having issues running that unit above 5 VDC and > burning it out? Looking in the archives, it seems at one time that TOPGNSS > spec'ed these at 15 VDC max, even though the one I looked at yesterday was > spec'ed to 12VDC max, so perhaps there were issues and they backed that down > to 12 VDC? > > If I get really adventurous, I might modify the unit to include a load > resistor so it sees a load all the time. If I get super-adventurous, I might > modify it for a 5 VDC output instead of 12 VDC. I'd assume they've got an > isolated, linear-regulated supply for the antenna, so could be just replace a > 7812 with a 7805. Again, this is embracing my inner time-nut, as who else > would even think of doing this? hahaha ;) > > I've got the manual downloaded, seems as if one needs to set it up from the > front-panel RS-232 then can remotely administer it from telnet. I quickly > scanned to see if telnet could be disabled, as while I do run behind a NAT > router and will put the unit on the isolated "Internet of Targets" network on > which nothing important resides, it seems like a bad idea to have an open > telnet port if I really don't need it. Or perhaps I'm just paranoid. > > Anyways, looking forward to what wisdom the group may have on this unit. :) > > Thanks much and 73, > ben, KD5BYB > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
