Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)?

[John Ackermann N8UR]

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...

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.

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.

John