Hi Peter, >> you should > > never drop the coax down the middle of your support-pole, as the conducting > pole will mess up the characteristics of the cable by affecting the > currents in the outer braid.
Well, that is true for ’twin-lead’ (“TV antenna wire”), but is not an issue for coax. (You _don’t_ want signals on the outside of the coax anyway :) Depending on what meets your budget for time, $, esthetics, and specifics of that installation, one or more of these might help: - attach the coax to the mast with tie-wraps (loosely, so as not to ‘pinch’ the coax) - as above, use “20 cm” of “14 AWG” insulated solid conductor instead of zip ties - electric tape is tempting, but will degrade (UV), and can cause the mast to rust - other ideas from group Also, depending on how much lightning / storms you get locally, add suitable lightning arresting equipment Good luck, Scott W7SLS > On Jul 4, 2019, at 1:43 PM, Peter Vince <petervince1...@gmail.com> wrote: > > Hello all, > > A new contact, whose background is in computer programming rather than > RF, is getting into accurate GPS positioning, and has been tapping me for > any knowledge I might have. I persuaded him to get the new Ublox F9P > receiver and also a "proper" dual-band antenna - albeit from China, so > affordable! This seems to be going quite well, and he sent a photo today. > He has mounted said aerial on what looks like a six-foot pole which is > good, but currently the coax down-lead is just hanging - flopping about in > the breeze. Now that is bad for so many reasons :-) However, I am not > sure of the best advice to give him. I'm sure I heard that you should > never drop the coax down the middle of your support-pole, as the conducting > pole will mess up the characteristics of the cable by affecting the > currents in the outer braid. And so similarly, you presumably don't really > want to tie-wrap it tightly to the outside of the pole for pretty much the > same reason. So my gut instinct would be to put some (half-inch??) > insulating spacers between the coax and the pole where the tie-wraps go. > Now when I worked in a TV shop in my youth, they didn't bother with any of > that - a) they probably didn't know about any such effects, b) they > certainly couldn't have been bothered, and c) TV signals are strong, so it > wouldn't have made a significant difference. GPS signals, however, are NOT > strong, and need to be treated with much more respect - especially if you > are after some seriously good positional accuracy. Is my idea right, or am > I barking up completely the wrong tree? > > Thanks in advance, > > Peter (London, England) > _______________________________________________ > 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.