[HamWAN PSDR] HamWAN portable
apolloeme at gmail.com
Sat Oct 5 10:38:52 PDT 2013
I have been following the threads from the eaves here, with interest,
because I do/have done this intervisibility/path loss kind of stuff a lot.
I recently discovered a very powerful program that can assist in this
pursuit. Check out: http://www.heywhatsthat.com . This program will
construct, file and store a skyline horizon from any location on the
planet, looking in any direction. And it will identify nearby intervening
terrain peaks. It will answer questions such as range, and elevations,
intervisibility profile plots, bearings, distances, fresnel zones, path
loss, etc.. Make your viewshed maps, and file them, in a library of such,
on-line, or send them to your colleagues.
. Try it out. Enjoy..
Best, 73, Pat
On Sat, Oct 5, 2013 at 9:41 AM, Tom Hayward <esarfl at gmail.com> wrote:
> On Sat, Oct 5, 2013 at 9:26 AM, Jeff Francis™ <jeff at gritch.org> wrote:
> > http://plane.gritch.org/plane/tn/2013-09-08%2014.18.42.jpg.html
> > If you look in the back of the truck, you can see precisely the same
> > antenna setup that Tom is using laying on top of the spare tire (next to
> > stool). From the park, I was close enough I just propped the antenna up
> > did it that way. No need for the tripod (and the strange looks from
> > park-goers).
> From that photo, I can tell you that it won't work. You're aimed at
> the sky. The beamwidth of these dishes is very narrow and they must be
> aimed precisely in both azimuth and elevation.
> Here's my algorithm for aiming:
> - First, I calculate the bearing from my current location to a HamWAN
> site (your APRS client should be able to do this for you with the
> HamWAN* objects).
> - Then I sight that bearing with my compass.
> - With the Poynting on the tripod mast, I sight down the feedhorn of
> the Poynting and line it up with the same landmark I spotted with the
> compass, being sure to keep the feedhorn level in the elevation axis.
> - At this point the signal LEDs on the modem have usually registered
> something (I'm connected) and I can pan and tilt slightly in each
> directly to maximize signal.
> This works really well for me because I have a sighting compass
> accurate to 1 degree and I know how to use it. Another technique is to
> plot the path on Google Earth and look for landmarks along the path.
> I've done this and sighted "between the two water towers." This
> technique requires more patience and panning.
> This is microwave. It's a lot harder to get a signal than VHF, but
> it's really satisfying when you do (and faster than 1200 baud!).
> Tom KD7LXL
> PSDR mailing list
> PSDR at hamwan.org
Best, Pat Barthelow
apolloeme at gmail.com
Google Lunar X prize Team, SYNERGY MOON
pat.barthelow at synergymoon.com
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the PSDR