Repeater mapping travel search, terrain analysis

Discussion in 'Amateur Radio News' started by K5EHX, Dec 18, 2008.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: K3QNTad-1
ad: Subscribe
ad: L-rfparts
  1. K5EHX

    K5EHX Ham Member QRZ Page

    The K5EHX repeater mapping project is a collaboratively edited and maintained database of repeaters displayed using Google Maps. All data can be freely downloaded in multiple formats. You can get there by going to

    For your Christmas traveling pleasure, the website now supports searching along a route. Just enter the From and To locations (next to "Directions") and google maps figures out the best route and searches for repeaters along the route. The Google Maps API doesn't yet support changing routes, so if you are taking the scenic route just split it into multiple searches. Printing should work, and there is a CSV data export "hack" in place - you have to copy and paste into a text editor for now (most browsers don't support saving files in Javascript).

    Please note that the directions search has to be done by AJAX, and so it may take a few seconds (or minutes) to display the repeaters after displaying the route. It actually performs a search every twenty miles, then sorts them in the browser and removes duplicates. For long trips, this could mean more than a hundred separate searches!

    Thanks to KD2BD's excellent (and open source) SPLAT! terrestrial RF path analysis software coupled with elevation data from the USGS and NASA, terrain analysis is now integrated into the website. If you want a repeater analyzed, set the position correctly along with the receive antenna height and it will be added to the queue. Other parameters are currently ignored, but may be used in future analysis or used by other projects such as AB9RF's repeater footprint project. Terrain analysis is compute intensive, and currently runs at about 50 per day.

    For some repeaters, viewing terrain analysis along with google maps' new "terrain" feature can be enlightening, or at least interesting. The shuttle radar topography mission is detailed enough to predict some radio shadows caused by large buildings. Refraction, however, is not taken into account so the two meter coverage is usually better than predicted, while the seventy centimeter coverage and above is fairly close. An example: The WA5LVT 146.94 repeater near Sand Springs, OK

    The analysis used is Splat!'s simplistic line of sight / coverage model. Longley-Rice (which is supported by Splat!) turns out to require more computing horsepower than I have available. I have several computers available for analysis, hopefully between them all I can keep up with the demand. If you do set the location and receive antenna height, please be patient as it could take a day or more before yours makes it into the queue. That should only apply for a short time after a large announcement (for instance, an article on, so normally it will only take a couple of hours before an analysis is available. AB9RF's project, when available, uses Longley-Rice to compute repeater availability by gridsquare.

    As before, this data is downloadable for free so you can use it in google earth or radio programming software. I do that so nobody can hold the data "hostage", including me. I'm been busy adding more export formats to make the data easier to use in different applications. I've added an export format that is compatible with the Travel Plus export file, a beta export for Xastir to do persistent repeater objects, and GPS and radio programming formats. Export formats are fairly easy to do, so detailed suggestions are welcome.

    73 and Happy Holidays,

    Tom White, K5EHX
    Tulsa, OK
  2. N7DIC

    N7DIC Ham Member QRZ Page

    Thank you for a very promising program system!

    I shall sashay over there today and check it out.

    Dick Murphey N7DIC
  3. N0MSA

    N0MSA Ham Member QRZ Page


    What a fantastic tool! Looks great and we'll keep spreading the word.

    Matt - N0MSA
  4. K8ERV

    K8ERV Ham Member QRZ Page

    Sounds good, but link not working for me.

    TOM K8ERV Montrose Colo
  5. WA4TM

    WA4TM Ham Member QRZ Page

    Same here... no workie....
  6. N1RKW

    N1RKW Ham Member QRZ Page

    Great tool with lots of promise. I quickly identified two out of state repeaters that I had previously overlooked. However, some of the repeater data is either out-of-date or inaccurate. For example, the WA1UNN repeater in Greenfield NH is actually on 147.060 not 147.135. Not a deal breaker, but certainly a fly in the ointment. My suggestion is to use this tool in conjunction with other repeater directories.
  7. AB9RF

    AB9RF Ham Member QRZ Page

    May I suggest that if you find data that is out of date, that you update it? K5EHX's site has a mechanism for providing updates. Grousing that the data is out of date doesn't help others; correcting the out-of-date data does.
  8. KC2UGV

    KC2UGV Ham Member QRZ Page

    This is nice, especially helpful for a elmer-less new ham who is looking for things in the area :)
  9. K5EHX

    K5EHX Ham Member QRZ Page

    Hmm... maybe my hosting provider got a bit overloaded. Or something. They've been dependable in the past, if a bit slow at times. If anyone has experience with a solid hosting company (Linux based, with shell access / PHP / MySQL, not too expensive) please send me an email.
  10. K8ERV

    K8ERV Ham Member QRZ Page

    It is working now, will check it out.

    I can't raise the Vernal station on 147.1 with 50w and a Ringo, but not surprising, lotta dirt in the way. Or, I can't find the PL.

    TOM K8ERV Montrose Colo
Thread Status:
Not open for further replies.

Share This Page