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Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?
From: |
Gary E. Miller |
Subject: |
Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)? |
Date: |
Thu, 3 Sep 2020 13:03:07 -0700 |
Yo John!
On Thu, 3 Sep 2020 15:46:03 -0400
John Ackermann N8UR <jra@febo.com> wrote:
> On 9/3/20 3:29 PM, Gary E. Miller wrote:
>
> >> I'm using the u-blox ANN-MB-00-00 dual-freq mag mount antenna,
> >> which seems a bit touchy. It absolutely wants a ground plane (I'm
> >> using a metal pie tin) and the solution often dropped to float
> >> when there were sky obstructions.
> >
> > Uh, wait a minute. If the pie tin is > 50mm it is not doing what
> > you think it is doing. See Section 5 of this u-blox doc:
> >
> > 'GPS-Antenna_AppNote_(GPS-X-08014).pdf'
>
> Thanks for the pointer to that. Interestingly they don't talk about
> the effect of ground planes bigger than about 100mm square -- and a
> vehicle-mounted mag mount is likely to have a much larger metal
> surface. I wonder how a several-wavelength ground plan impacts
> things...
gpsprof can answer those questions.
> Anyway, the pie tin was a temporary expedient, adopted when I found
> that without something under the antenna, I could get only a FLOAT
> soluton; adding the pie tin got me a FIX solution within a few
> seconds.
I'm not saying it does not work, just not the way you think it does.
Over-large ground planes limit reception from sats nar the horizon.
I suspect setting the elevation cutoff to a large value (30 degrees?)
may yield similar results.
> Once I figure out the best way to feed more than 3.3V down the
> cable, I have a nice Ashtech survey antenna available for field use.
Easy, I use cheap chinese bias teess. Like this one:
https://www.ebay.com/itm/10-6000MHz-Bias-Tee-DC-Blocker-RF-Microwave-DC-Feed-50V-SMA-K-For-Active-Antenna/124130508678
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can't measure it, you can't improve it." - Lord Kelvin
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- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, (continued)
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Greg Troxel, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Greg Troxel, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, John Ackermann N8UR, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, John Ackermann N8UR, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, John Ackermann N8UR, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?,
Gary E. Miller <=
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, John Ackermann N8UR, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Bernd Zeimetz, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/03
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Greg Troxel, 2020/09/05
- Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?, Gary E. Miller, 2020/09/05