What is this 'GPSMAP76S'??? If I am understanding correctly, it plots grids on the GPS screen? If so, is this software or a separate GPS receiver? I have a Garmin Venture HC, would it be applicable to it? It would be a lot easier to look down and see what grid you are in on the display rather than calculate it using lat/lon.
73,
Zack KD8KSN
-------------------------------------------------- From: "Patrick STODDARD (WD9EWK/VA7EWK)" amsat-bb@wd9ewk.net Sent: Thursday, September 02, 2010 1:33 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: GPS for dx-expedition
Hi Rick!
The number of satellites isn’t the main factor in accuracy, it’s the sat geometry. A position fix with 4 birds spaced evenly and at a higher altitude will give a better position than 8 birds near the horizon bunched around the same area of the sky.
I understand that. I was only stating that about the VX-8GR as a reason why I don't use that device for establishing my location when working on grid boundaries etc.
When I drove out to the DM23/DM24 grid boundary a couple of weekends ago, I was able to easily get the VX-8GR and GPSMAP 76S to line up on the grid boundary line (34 degrees North). In fact, my VX-8GR was chirping away with APRS data on the boundary as I was taking the photos with the GPSMAP 76S sitting with my radios for the VUCC documentation (and the QSL cards). I also have a photo or two of the VX-8GR with 34 degrees North on its display, as additional proof I was out there.
That being said, once SA was turned off in 2000, I’ve rarely had a position error greater than 20 feet, even with my older Garmin II+. My HCx, easily get under 10’ most times.
You're right again. It should be easy to get that 20-foot accuracy, and this is stated in the VUCC rules. If the GPS is in good working order, and you're not concerned about having all the latest bells and whistles, an older GPS is certainly capable of meeting the VUCC documentation requirements. My GPSMAP 76S is 7 years old, and I don't have any need to replace it. Its firmware has been updated to the final version released by Garmin before it was discontinued, and the only thing I have to do with it is periodically replace the 2 AA batteries that power it.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/
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