This brings up some interesting questions: If sharing an active GPS antenna, do you have to DC block all but one receiver port to prevent multiple receivers trying to supply current to the antenna?
On say a 26dB antenna (ignoring line loss, power divider insertion loss, et al), what is the effective gain to each receiver? (Sorry, having a senior moment) Should ALL unused ports have 50 ohm +/- 0j terminators on them? I assume so... Thus, it would be "better" to always use the divider with the minimum required ports? I am assuming since this is a receive only situation, it will follow approximately the same rules of physics that dealing with satellite antenna installations. I would LIKE to share one PC-TEL 26dB GPS antenna mounted at the top of my 38 foot horiz.loop mast right at the shack entrance, using LMR-400-DB from antenna to Narda 2-way and thence to my current hacked Nortel GPSDO and my soon to be complete RPi 2/3 w/ Adafruit Ultimate GPS Hat NTP Server. On that mast, the antenna would have a near 360 degree view of the sky completely unobstructed. (Eventually, I expect both of those units to be replaced with commercial units). I'm assuming that I DC block whichever unit is capable of providing the LEAST current at 5VDC... I suspect the Nortel unit can supply more current than the RPi, but that's not a guarantee... And I guess I could block/turn off DC delivery on BOTH units and add a voltage adjustable, current limiting DC injection unit into the line. Thanks. 73, ______________________ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 6/16/2017 7:26 PM, Tim Lister wrote: > On Fri, Jun 16, 2017 at 4:40 PM, Gregory Beat <w...@icloud.com> wrote: >> I have reached the point that I need a 4-port splitter for my GPS antenna >> (outdoor 5 volt). Any recommendations of models (HP/Symmertricom/Microsemi) >> to acquire OR to avoid?? > As we recommended to me when I asked a similar question, the Narda > 4372A-4 was a brand I had not heard of before and didn't come up in > 'gps splitter' searches. I got one on ebay for $24 plus a bit extra > for DC blocks on the n-1 other ports and it seems to work well and it > was handy to have an SMA-based solution as most of the gps receivers > and the antenna pucks seem to use SMA. This meant I only needed 1 N to > SMA converter cable for an external antenna (which has yet to be > externalized...). I found it smaller in real life than it looks in a > lot of the pictures, about the size of a modern smartphone but about > double or more the thickness (the connectors are on the ends). > >> greg >> --- > Cheers, > Tim > _______________________________________________ > 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.