I would appreciate feedback on the question of the ill effects (if any) of mounting two GPS antennas in proximity to one another. I am intending to mount a 58532A L1 antenna and a L1/L2 antenna on the same mast on my roof separated by around 1-2 feet. I have attached a photo to show the intended installation. (Mast is clamped into the right side aluminum channel.) My concern is “shading” of one antenna over the other. Thanks for the consult. Jim Robbins N1JR

Hi Most of what you see suggests > 10’ / 3M between GPS antennas. They seem to be concerned about a variety of things. Exactly how those concerns translates into the magic distance has always been a bit obscure. Bob > On Nov 23, 2019, at 7:07 PM, JAMES ROBBINS <jsrobbins@earthlink.net> wrote: > > I would appreciate feedback on the question of the ill effects (if any) of mounting two GPS antennas in proximity to one another. I am intending to mount a 58532A L1 antenna and a L1/L2 antenna on the same mast on my roof separated by around 1-2 feet. I have attached a photo to show the intended installation. (Mast is clamped into the right side aluminum channel.) My concern is “shading” of one antenna over the other. Thanks for the consult. > > Jim Robbins > N1JR > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

I have two identical GPS antennas mounted side by side about a foot apart feeding two different receivers with no observed problems. Jeremy On Sat, Nov 23, 2019 at 4:12 PM JAMES ROBBINS <jsrobbins@earthlink.net> wrote: > I would appreciate feedback on the question of the ill effects (if any) of > mounting two GPS antennas in proximity to one another. I am intending to > mount a 58532A L1 antenna and a L1/L2 antenna on the same mast on my roof > separated by around 1-2 feet. I have attached a photo to show the intended > installation. (Mast is clamped into the right side aluminum channel.) My > concern is “shading” of one antenna over the other. Thanks for the consult. > > Jim Robbins > N1JR > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > -- Jeremy Nichols Sent from my iPad 6.

On 11/23/19 5:23 PM, Bob kb8tq wrote: > Hi > > Most of what you see suggests > 10’ / 3M between GPS antennas. They seem to be concerned about > a variety of things. Exactly how those concerns translates into the magic distance has always been a > bit obscure. 3m/10 ft is "round number phenomenon". For identical receivers, there's always the issue of LO leakage back through the antenna, and into the other receiver. The LOs/clocks aren't going to be exactly the same (the crystals are probably 1ppm or something like that), so you wind up with a 1kHz tone on top of your PN code. I suppose the same is generically true of any receivers. I have experienced this both with disparate and identical receivers, back in 1993 with handheld receivers (Trimble, Magellan) side by side, and newer ublox NEO-7 > > Bob > >> On Nov 23, 2019, at 7:07 PM, JAMES ROBBINS <jsrobbins@earthlink.net> wrote: >> >> I would appreciate feedback on the question of the ill effects (if any) of mounting two GPS antennas in proximity to one another. I am intending to mount a 58532A L1 antenna and a L1/L2 antenna on the same mast on my roof separated by around 1-2 feet. I have attached a photo to show the intended installation. (Mast is clamped into the right side aluminum channel.) My concern is “shading” of one antenna over the other. Thanks for the consult. >> >> Jim Robbins >> N1JR >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >