With regards to the western Nebraska hole, I've been trying to get some hams interested out that way.
Roger - KC0MWM Grand Island, NE On Wed, Dec 23, 2009 at 6:16 PM, gecko_ph <[email protected]>wrote: > Hey Guys, > > Thanks for all the great info. I understand, and WILL NOT set up the > airborne digi. > > My aprs setup is documented here : > > http://www.mnwing.org/ > > click the powerpoint, skip the geeky LED stuff, and there is an overview of > my setup. > > I fly a lot of rescue dogs and APRS is great for coordinating pickups! > > Thanks again guys hope you all have a good holiday!! > > PS there is a big APRS hole over western Nebraska as well! > > Pete > > --- In [email protected], James Ewen <ve6...@...> wrote: > > > > On Wed, Dec 23, 2009 at 7:34 AM, Peter Howell > > <pete.how...@...> wrote: > > > > Hey Keith, Pete's callsign is KD0CVN-1 > > > > > I have the a Nuvi350/tracker2/Yaesu mobile setup running in my > > > experimental airplane. It works great - super tracking - easily > > > updated status messages, and the envy of my flying friends - > > > the email from 10,000 ft! > > > > It looks like you might have done some homework... From what I can > > see, you are using a single hop path at most. As you have observed, > > you can get into the APRS network from an airborne platform very > > nicely. > > > > As you are probably aware, in the realm of VHF communications, antenna > > height is where it's at. When you are flying, you have some of the > > best antenna height available. Running long paths, or very fast beacon > > rates from an airborne platform can cause a lot of problems across the > > APRS RF network. With just 500 feet AGL, you're probably going to get > > into a LOT of digipeaters for many miles around. The APRS-RF network > > can handle getting hit like that, but it's all your earth bound > > neighbors that might feel a little miffed by you hogging the network. > > > > > I'd like to set up the digi function(mini awacs), but I am not well > > > versed in how to set up the parameters. Is there a good guide I > > > can access? The tracker2 manual makes it seem too easy - > > > maybe it is. > > > > Okay, so... remember how you can hit a whole bunch of digipeaters from > > 500 feet AGL? Well, the reverse is true as well, but it's not only the > > digipeaters on the ground that you can hear, but every other station > > on the ground. If you run an airborne digipeater that acts like a > > ground based digipeater, you're going to be causing quite a bit of > > noise. Every ground based station asking for a hop from a digipeater > > will not only bounce through the regular digipeater network, but will > > also be handled by your airborne digipeater. You'll be adding to the > > noise factor in areas already covered by digipeaters. Also, due to > > your altitude, you will be increasing network loads because you will > > be causing stations located well outside the ground based digipeater > > footprint to be included in the local digipeater network. > > > > Think of it this way, if you can hear a station 200 miles away, and > > you digipeat him, another digipeater 200 miles the other direction > > will most likely hear your digipeated packet. That means that the > > original station which is 400 miles away from the ground based > > digipeater is now effectively a local station, and will be seen in > > that area. Now multiply that by a couple hundred times, to include all > > the ground based stations you'll be able to hear... and you thought > > that the earth bound peons were grumpy when it was just you making > > noise from the sky... > > > > To get an idea of what traffic you might be bouncing around the local > > RF network, try this... > > > > Go to the page linked below. > > > > http://aprs.fi/?call=kd0cvn-1&mt=m&z=7&timerange=3600 > > > > This will show the last hour of packets from your station, from the > > last time you were up flying. Now without touching anything else, > > click on "Show All" in the upper right side of the screen where it > > says Track Callsign: [Clear / Show All] > > > > Hold on for a bit, and watch all the stations that you could > > potentially be digipeating show up on the map. That's quite a few > > stations, and an awful lot of airtime being used. > > > > Now, if you were flying around Saskatoon, Saskatchewan, things might > > be a bit different. > > > > http://aprs.fi/?call=VE5RHF&mt=m&z=7&timerange=3600 > > > > Again click on the "Show All" link, and you'll see why you wouldn't > > cause such grief. > > > > You can still run an airborne digipeater, as Bob by running it on a > > frequency other than 144.390. If there is an alternate experimental > > APRS frequency in your area, an airborne digipeater might be welcomed > > as an interesting adjunct to the network. The other option is to run a > > non-standard digipeater alias. Digipeating on just your callsign, or > > an alias such as TEMPn-N would not cause problems, as the ground based > > stations would need to specify using your airborne digipeater > > explicitly. > > > > Yes, we are indeed raining on your parade. Think of it this way > > though. Would you drag a VHF repeater up in the plane on 146.85 and > > run it while flying? Of course not, you would interfere with the > > repeater on the east side of St. Paul, and probably a couple others > > depending upon how high you were flying. > > > > The APRS network runs on a single frequency, and there are literally > > thousands of people using that resource. While amateur radio is > > experimental by nature, we already know what the results of these > > types of experiments will produce. > > > > Now, if you have a special event of some kind that could benefit from > > having a long range digipeater available, feel free to fly one, but > > just be aware of the issues outlined above. Set up a sked with some > > buddies that are far flung, get the plane up at 9000 feet, and see if > > they can bounce signals through you using a special digipeater alias. > > You can still play and have fun, but you're not going to drag everyone > > else in the world into the fray. > > > > I hope this makes sense to you, and gives some reasoning behind why > > you would NOT want a flying digipeater on 144.390 acting upon WIDEn-N > > packets. Maybe a little easier to live with than just getting your > > fingers slapped and told NO! > > > > James > > VE6SRV > > > > > > > ------------------------------------ > > Yahoo! Groups Links > > > >
