[time-nuts] Spring cleaning and antenna placement
magnus at rubidium.dyndns.org
Mon Apr 20 01:58:38 UTC 2009
Magnus Danielson skrev:
> bg at lysator.liu.se skrev:
>>> If you are in Scandinavia, the GPS birds will not spend much time (if
>>> any?) to the north of you. Slide 12 of
>>> suggests that the most northerly orbital point is at the latitude of
>> With a decent antenna siting you see plenty of SVs to the north. Magnus
>> problem is that there are lots of rather close by trees and stuff. These
>> trees are also much taller than the antenna position.
> Indeed. The southbound sats goes almost over the head, but I also get
> long tracking periods for sats way up to the north.
> Since the house sits partly in a valey and the neighborhood is rich of
> trees there is plenty of foilage. To the north is a building, two
> stories high and ground level for it is just above the upper of mine,
> which pick up the extreme north direction.
> The location also requires an antenna mast forr the TV reception. With
> modern digital transmission it is best to have a good margin for
> reception, or there is no TV at all.
> If I had a flat roof I might just put a ladder up to the antenna, but
> unfortunately not so.
> Sky-view of GPS antennas was not of concern when picking this house.
> Maybe it should be for the next.
To follow up on this... I have now received my LNAs and I have installed
one. The LNA gives me a 16 dB boost, but lack of a bias tee force me to
use a passive splitter to act as the bias tee, and that sets me back 6
dB, so I effectively only gets 10 dB of boost, but the effect is
certainly there, the Z-12 tracks significantly better.
Just goes to show that LNA may come to assistance. Thought this may be
useful to some. A second LNA could boost me up even more, but using a
proper bias tee should give me about 6 dB.
More information about the time-nuts