[TowerTalk] tool to retrieve data and build HFTA profiles

[David Aslin]

Jim, this will be hugely valuable. As someone else has posted, maybe the
profiles should have data restricted to just sufficient to feed HFTA.
I'll add my congratulations on a great idea and what will be a great
service to this group; and I'll raise you a further congratulations for
working with the SRTM data so non-US based users can enjoy the fun too!

Even with the 90m resolution limitation of SRTM it will be much better
than no guidance or using flat terrain antenna data for obviously hilly
ground; we could always stare at a map and manually interpolate the
profile numbers, I guess.
73
Dave   G3WGN   WJ6O

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Message: 1
Date: Sun, 04 Mar 2012 21:26:10 -0800
From: Jim Lux <jimlux at earthlink.net>
Subject: [TowerTalk] tool to retrieve data and build HFTA profiles
To: towertalk <towertalk at contesting.com>
Message-ID: <4F544E72.7060107 at earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I've been fooling with some shell scripts and the like..

I think I can automatically retrieve the right 1x1 degree chunks of SRTM
data fairly well and then do the interpolation to build the profiles.

The big question for all of you potential users..

I use cURL as a command line tool to retrieve pages/files from websites
(it has Windows, mac, and Linux versions).
There's also wget aria2c and httrack, which I've not used, but which
appear do the same thing.


Any preferences out there?

What I intend to do is write a batch file (for windows) and shell script
(for MacOS X/Linux) that retrieves the square where you are, and the
surrounding 8 (guaranteeing that we've got 50-60 miles of data in every
direction), then fire off a C program that generates the .pro files.

I'll publish source and executables..

I'm thinking you'll start it with something like  >> makepro <N lat in
decimal> <W lon in decimal> <profile angle increment in degrees>

so makepro 34.21874 118.81626 15

would generate a profile for every 15 degrees of azimuth for my QTH


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Message: 2
Date: Sun, 04 Mar 2012 21:34:42 -0800
From: Jim Lux <jimlux at earthlink.net>
Subject: Re: [TowerTalk] tool to retrieve data and build HFTA profiles
To: towertalk at contesting.com
Message-ID: <4F545072.3020104 at earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 3/4/12 9:26 PM, Jim Lux wrote:
> I've been fooling with some shell scripts and the like..
>
> I think I can automatically retrieve the right 1x1 degree chunks of 
> SRTM data fairly well and then do the interpolation to build the
profiles.
>
> T

BTW, it won't be fast or small.

the raw zip files are about 12Mbyte each and expand to about 26MB, so it
will eat about 400 MB of your disk. (although you can delete the files
when it's done)

You're going to want a fairly speedy internet connection for the 108
MByte download. That's a good 20 minutes at 1 Mbps.