On 2012-02-25, David J Taylor <david-tay...@blueyonder.co.uk.invalid> wrote: > "unruh" <un...@invalid.ca> wrote in message > news:qfS1r.13334$pc2.3...@newsfe13.iad... >> On 2012-02-24, David J Taylor <david-tay...@blueyonder.co.uk.invalid> >> wrote: >>> "unruh" <un...@invalid.ca> wrote in message >>> news:cmQ1r.3572$py5.2...@newsfe09.iad... >>> [] >>>> The graphs of the signal strengths at the edges of these dropouts is >>>> in >>>> ftp://theory.physics.ubc.ca/outgoing/drop{out,in}.pdf >>> >>> Could not access this page in Firefox. >> >> These pages. >> dropout.pdf and dropin.pdf sorry if my use of the bash syntax confused >> you. > > Thanks. > > [] >> It has. I plotted the location of the satellites in the sky using S/N >> bands. I can see the whole sky (ie sattelites are tracked across the >> whole sky-- except for a hole in the northern sky where I guess the >> satellites never go as viewed from Vancouver.) There are some trees to >> the east, and they seem to reduce the S/N by about 10dB but they are >> still visible and tracked even through the trees. (Cedars) > [] >> Mine are stuck to the iron flashing around the top of the building-- >> about 1/2 a meter wide. But that flashing is not attached to any >> microwave noisy source AFAIK. > > The correct URLs are: > > ftp://theory.physics.ubc.ca/outgoing/dropout.pdf > ftp://theory.physics.ubc.ca/outgoing/dropin.pdf
Yes, that was what I hoped I was saying. Obviously I was wrong. Sorry. > > You should not be seeing a gap like that. You could get down to a small Agreed. I have now managed to get the GPGSV from a Garmin 18 located about 5 m away on that same rooftop, and this morning I got a dropout from the Sure again for about 5 min. while I was also recording the messages from the Garmin. The garmin shows that during this time, the weakest sattelites (35-40dB S/N) did show more dropouts, but for brief times ( a few to about 10 sec) but the stronger (>40dB) showed no change in their S/N during those times. (When working, The Gamin's minimum useable S/M seems to be about 35dB, while the Sure goes down to below 20dB and still tracking Of course when not working the Sure sees nothing)). The Sure again completely died over a time span of 3 sec, with all signals (including the 50dB prior level signals) completely dropping out. It is still dropped out 6 hours later. > number of satellites, but not none. What was the duration of the outage? > The scale is in seconds. The outages have run from about a minute to 17 hours. > I did mean to ask whether the receiver board itself was in a well-screened No the receiver board is still just the bare board, located inside the building. The antenna line goes out the window and up to the roof. The antenna puck itself is in a plastic bag magnetically fastened to the flashing along the top edge of the roof. > box, and the whole assembly properly sealed for outdoor operation. I take > it that you have not extended the lead from the antenna puck to the > receiver board? No, I have not extended the lead. I would like to to get more options as to where to locate the antenna puck, but am not sure what the specs would have to be for an extention cable. I am becoming convinced that either the antenna or the receiver is defective-- leaning toward the antenna. > > My gut reaction is that if the antenna puck is outdoors you should be OK Yes, it is outdoors, on the edge of the roof. of a three story old building ( Ie, at about 12-14m above ground.) There are two tall cyprus trees to the east, but looking at the signal strengths, these cost less than 10dB in the strength of the sattelite signals if the sattelites are behind the trees for the antenna. The Gamin is located about 5 m further onto the top of the roof mounted on an air fan unit-- I could lead the line from the Garmin through the roof vents for that fan. And no, I have never seen any evidence of interference from that fan on the Garmin signals. > (unless you were at ground level and blocked by skyscrapers). I hope you > can locate the source of the problem. > > Cheers, > David > _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions