Way off topic, but what antennas are you guys using for this? Vertical monopoles have a null in the downwards direction. I'm sure it's been thought out throughly, just curious.
-Dan N7NMD On Oct 12, 2009, at 15:31, Scott Miller <[email protected]> wrote: > Well, this is annoying... aprs.fi has one packet (with no pulseox > data), > findu has none, aprsworld.net's history search is broken, and > openaprs.org doesn't show anything. I just wanted to see how the > pulseox worked. > > Scott > > James Ewen wrote: >> >> >> On Mon, Oct 12, 2009 at 3:09 PM, Keith VE7GDH <[email protected] >> <mailto:ve7gdh%40yahoo.com>> wrote: >>> Scott N1VG wrote... >>> >>>> I'm not seeing it on the site - the only link I see is for the >>>> forums. >> >> It's tough to know what they are up to without knowing the callsigns >> used... I see AF6IM-7 around the Byron Airport on Sept 19th and 20th. >> This station was using a path of RELAY,WIDE3-3. That would make it >> effectively a zero hop path unless some stations around were >> mis-configured. >> >>> The forum makes a mention of WIDE3-3 but also mentions some >>> alternate >>> frequencies as well as 144.390. I understand they are using either >>> a T2 >>> or OT2m so they could vary the path and beacon rate based on >>> altitude. >>> It would be nice to use a short path (or no path) while at 24,000 >>> feet, >>> but something like a two hop WIDE2-2 below a few thousand feet. The >>> last post indicates they will be on 144.330, so no path would be >>> needed >>> unless they set their own digis up. Regardless of the frequency, I >>> can >>> see that recovering the payload would be of prime importance! >> >> Everyone has to go through the same process... 10,000 feet of antenna >> height and 3 hops paths, and still seeing holes in the tracking, so >> the next obvious step is to take an amplifier up to get more power... >> maybe a 13 element yagi too! >> >> For a project like this, in an area of dense APRS activity, you HAVE >> to move off 144.390. Zero hop paths work just fine. With a low >> altitude drop like this, and a manned payload that is going to be >> actively returning to the drop zone, a zero hop path is the logical >> choice. If there should be an issue with an incapacitated skydiver, >> then your recovery teams should be already deployed down range into >> the anticipated recovery area. >> >> As they have suggested, if they are going to be moving to a separate >> frequency, then they will need to provide their own receive stations, >> and if desired i-gates. It is pretty easy to set up a mobile i-gate >> on >> any frequency using a cellular telephone with a data plan, and a >> laptop connected to your receive equipment. The open trackers could >> easily be set up on a single simplex frequency with a 5 second >> reporting rate each, and use time slotting to keep from clobbering >> each other. >> >> I would not plan on using the APRS-IS as my main source of data >> recording, and especially not for tracking and recovery of manned >> payloads. >> >> If those involved in this project are interested, we have a similar >> project happening around here that we are involved in. We are doing >> experiments with high altitude balloons using unmanned payloads, with >> the BEAR and SABLE projects, but will be primary tracking and >> recovery >> crews for Le Grand Saut, a manned expedition to 40 km (131,000 feet) >> above the earth with a world record skydive/parachute recovery jump. >> >> Of the many tracking systems on board, only one will be on 144.390. >> Critical telemetry from Michel which includes physiological sensors >> will be done on a licensed frequency. Other trackers for the 1 ton of >> balloon, and 1 ton of gondola will be on distinct frequencies as >> well. >> >> Le Grand Saut has been many years in planning, and attempts to get >> off >> the ground, and hopefully next May will see a successful launch and >> recovery. >> >> Le Grand Saut >> http://www.legrandsaut.org/ <http://www.legrandsaut.org/> >> >> BEAR >> http://bear.sbszoo.com/ <http://bear.sbszoo.com/> >> >> SABLE >> http://bear.sbszoo.com/sable/ <http://bear.sbszoo.com/sable/> >> >> We're always more than happy to share experiences and lessons learned >> with others. I know I can't afford to make all the mistakes made by >> others again... I'm happy to learn from others and modify my >> experiments to suit. >> >> James >> VE6SRV >> >> > > > > ------------------------------------ > > Yahoo! Groups Links > > >
