[time-nuts] Re: Symmetricom NTS-150 Network Time Server

[Björn]

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 <kd5byb at 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 at lists.febo.com -- To unsubscribe send an email to time-nuts-leave at lists.febo.com
> To unsubscribe, go to and follow the instructions there.