Re: Mobile or Portable Grids


Stephen Melachrinos
 

Paul -

That's precisely the approach I was going to take. Excel makes the math easy (at least for me), and each of those steps would result in one character. Then it's a simple concatenate.

Steve
W3HF


-----Original Message-----
From: Paul Butzi (W7PFB) <w7pfb@...>
To: 070Club <070Club@groups.io>
Sent: Sat, Jan 19, 2019 6:54 pm
Subject: Re: [070Club] Mobile or Portable Grids

For those that are interested, this thread:

gives a fairly concise description of how to convert from latitude/longitude to Maidenhead Grid.  It appears to be correct to me but I’ve not examined it closely.

Be aware that the datum for Maidenhead Grid is WGS84, so if you are using a GPS set to some other datum (e.g. NAD27) then you’ll get wrong answers when you’re close to a grid boundary!


-p W7PFB
73, Don’t forget to smile and have fun!

On Jan 19, 2019, at 2:02 PM, Stephen Melachrinos <melachri@...> wrote:

Hey, hold on a second, folks. Let's not make this harder than it has to be.

Yes, smartphones are amazing, and mobile connections to the Internet are wonderful. But not EVERYTHING you need to do requires an Internet connection. And calculating a grid square from Lat/Lon coordinates is extremely simple. (I'm not a programmer, but I'll bet I could write a set of equations in Excel in less than half an hour to do a calculation that would be good anywhere in the world.) So I went to prove that I could find an app that would calculate a grid square without using the Internet.

Of course, your phone still has to have its GPS function enabled. I have an Android phone, and I know location services are still active when in airplane mode. I'm not sure about iPhones, but you might have to do something special.

I went to the Google Play Store and downloaded the first Maidenhead grid application I found. It's called Grid Square Locator and it's written by Boris, US1PM. (It actually has very good reviews, rated 4.8 out of 5.) Then I put my phone in airplane mode (to simulate a lack of any external connections) and went driving around. 

My home is in FN20ge. By the time I got to the pharmacy (my destination), I had watched the app tell me I'd moved to FN20gf, and then FN20ff. Then I headed back, taking a longer route that took me back into FN20ge, then FN20he, then FN20hd before coming back to FN20ge.

So you really don't need anything special other than a smart phone and an app that does the calculations onboard. (I'd actually be surprised if any app really used server-side calculations for something this easy.) The only hiccup might be an app that won't run unless it can show you advertisements, and those will require an Internet connection. So if you run into that, find another app.

Steve
W3HF



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