[time-nuts] Lucent 40 dB Antenna
Charles P. Steinmetz
charles_steinmetz at lavabit.com
Wed Apr 11 12:20:42 UTC 2012
Chris wrote:
>Where are you placing your antenna? I'm curious because you say the
>choke ring helps. Is it close to the ground, near a building? What
>might be the cause of the muiltipath that the choke ring is helping
>with
I've been working with RF long enough not to expect easy answers when
it comes to multipath. It's pretty much always there, sometimes in
sufficient quantity to be really troublesome, other times (as with
GPS at my location) enough to notice but not to be really troublesome.
Typical suburban neighborhood, 2-story brick houses on ~80-foot
lots. The antennas have been tried (i) on the second floor (under a
plaster ceiling + asphalt shingle roof); (ii) in the attic (under the
roof only); and (iii) on a mast about 15' above the roof peak (~45'
AGL). The c/n improves ~ 7 dB going from (i) to (ii) and another ~2
dB going from (ii) to (iii) for all antennas, while the relative
advantage in positioning and deviation of the choke ring is
essentially unchanged. After experimenting, I installed the choke
ring antenna in the attic peak.
A ground plane placed under the mag mount and the Bullet 3 did not
improve the positioning or deviation.
Best regards,
Charles
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