Hello Guys, 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@gmail.com> wrote:
On Sat, Oct 5, 2013 at 9:26 AM, Jeff Francis™ <jeff@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 the stool). From the park, I was close enough I just propped the antenna up and did it that way. No need for the tripod (and the strange looks from other 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@hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org
-- Best, Pat Barthelow apolloeme@gmail.com Google Lunar X prize Team, SYNERGY MOON wwww.synergymoon.com pat.barthelow@synergymoon.com
So looking at that profile I see a small rise close by that is probably less than my tower. But I have a lot of fir and ceder all around me that are higher than the tower. How well will 5ghz pass through the fir and cedar? 73, Allen ----- Original Message ----- From: Patrick Barthelow To: Puget Sound Data Ring ; esarfl@gmail.com ; Patrick Barthelow ; jeff@gritch.org Sent: Saturday, October 05, 2013 10:38 AM Subject: Re: [HamWAN PSDR] HamWAN portable Hello Guys, 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@gmail.com> wrote: On Sat, Oct 5, 2013 at 9:26 AM, Jeff Francis™ <jeff@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 the > stool). From the park, I was close enough I just propped the antenna up and > did it that way. No need for the tripod (and the strange looks from other > 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@hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org -- Best, Pat Barthelow apolloeme@gmail.com Google Lunar X prize Team, SYNERGY MOON wwww.synergymoon.com pat.barthelow@synergymoon.com ------------------------------------------------------------------------------ _______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org
We don't have good data on trees. We should certainly develop some. How much attenuation does a trunk of X diameter present? Is there a variation between trees? How does it scale with diameter? What about branches/needles? I can tell you that I shoot through trees about a mile away, but the fresnel zone helps me out there. I can also tell you that rain affects me, but not because of the rain itself! On a clear shot with rain, there's hardly any signal degradation. It's the fact that the rain coats the trees in a film of water, and that seems to be the killer of signal. In my case, I think I lose about 8dB, but we don't have good data on this either. It's gonna take a while to build it since we don't control the weather...yet. :) Where are you located? We can do a path analysis and see if we can help you do a site survey. --Bart On 10/5/2013 6:09 PM, Allen wrote:
So looking at that profile I see a small rise close by that is probably less than my tower. But I have a lot of fir and ceder all around me that are higher than the tower. How well will 5ghz pass through the fir and cedar? 73, Allen
----- Original Message ----- *From:* Patrick Barthelow <mailto:apolloeme@gmail.com> *To:* Puget Sound Data Ring <mailto:psdr@hamwan.org> ; esarfl@gmail.com <mailto:esarfl@gmail.com> ; Patrick Barthelow <mailto:apolloeme@gmail.com> ; jeff@gritch.org <mailto:jeff@gritch.org> *Sent:* Saturday, October 05, 2013 10:38 AM *Subject:* Re: [HamWAN PSDR] HamWAN portable
Hello Guys,
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@gmail.com <mailto:esarfl@gmail.com>> wrote:
On Sat, Oct 5, 2013 at 9:26 AM, Jeff Francis^(TM) <jeff@gritch.org <mailto:jeff@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 the > stool). From the park, I was close enough I just propped the antenna up and > did it that way. No need for the tripod (and the strange looks from other > 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@hamwan.org <mailto:PSDR@hamwan.org> http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org
-- Best, Pat Barthelow apolloeme@gmail.com <mailto:apolloeme@gmail.com>
Google Lunar X prize Team, SYNERGY MOON wwww.synergymoon.com <http://wwww.synergymoon.com> pat.barthelow@synergymoon.com <mailto:pat.barthelow@synergymoon.com>
------------------------------------------------------------------------ _______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org
_______________________________________________ PSDR mailing list PSDR@hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org
participants (3)
-
Allen -
Bart Kus -
Patrick Barthelow