|
From: | John Ackermann N8UR |
Subject: | Re: moving to 8 digits of lat/lon (gpxlogger, maybe elsewhere)? |
Date: | Thu, 3 Sep 2020 15:46:03 -0400 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
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
[Prev in Thread] | Current Thread | [Next in Thread] |