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.