Re: [DSTAR_DIGITAL] Mobile High speed data
On Mar 15, 2009, at 4:11 AM, Don Russell wrote: > Anyone try the 128K high speed data while mobile? Due to the fact that it's a much wider signal than 1.2 DV, and the receiver at that width is not as sensitive, it takes a very solid signal into the Access Point/DD system to work well. With our high site, we see that it works great over a large area when non-moving, but motion/multipath tears it up. A continuous ping by one of our folks with a 1.2 GHz radio would start working at every stop light, and stop as soon as he was moving. > I mean in a vehicle above say at a constant 30-45 mph. > What about at higher speeds? Would it work > to say a helicopter or airplane orbiting over the city > where the access point is? Or would the Doppler shift > be too much? I am wondering if it could be used to > feed data to/from a CAP spotter heli/plane should the > proper equipment be installed in the craft? The harder part in an aircraft would be getting the 1.2 GHz signal outside the airframe. 1.2 GHz antennas for aircraft are in short supply, I'd say. Remember also that it's 128K HALF-duplex... -- Nate Duehr, WY0X n...@natetech.com
Re: [DSTAR_DIGITAL] Mobile High speed data
Our limited experience so far has required directional antennas to go 3 to 4 miles on ground level up to 2 stories. Higher elevation with a clear path got 17 miles with omnidirectional gain antennas (4 segment colinear). The cases were: 12 element Yagi at 5ft to omnidirectional at 35 ft, 3 miles. Omnidirectional at 15ft to omnidirectional at 35 ft, 5 miles. 12 element Yagi at 45ft to omnidirectional at 20 ft, 4 miles. Omnidirectional at 7ft to omnidirectional at 35 ft, 17 miles. High point to high point clear path. Buildings and trees have a significant effect at ground level and we are sticking with non-mobile operation. We are also doing WiFi access, data transfer which tends to be stationary. Air mobile might have a chance subject to rotor/propeller multipath effects. Mike KD6GWO Don Russell wrote: Anyone try the 128K high speed data while mobile? I mean in a vehicle above say at a constant 30-45 mph. What about at higher speeds? Would it work to say a helicopter or airplane orbiting over the city where the access point is? Or would the Doppler shift be too much? I am wondering if it could be used to feed data to/from a CAP spotter heli/plane should the proper equipment be installed in the craft? Also would like to know of anyone successfully using VOIP. Is it possible to send voip over the high speed link. I am thinking asterisk box with a standard pstn connection at the AP and some kind of IAX client running ILBC or GSM. That way a served agency could make a real TX call via a d-star connection. The only other way could like of being able to do this is via a DVDongle and some creative audio patching. The concept is to be able to get a call to PSTN via D-star. Thanks, Don W9DRR _ Windows Live Groups: Create an online spot for your favorite groups to meet. http://windowslive.com/online/groups?ocid=TXT_TAGLM_WL_groups_032009 [Non-text portions of this message have been removed] Please TRIM your replies or set your email program not to include the original message in reply unless needed for clarity. ThanksYahoo! Groups Links [Non-text portions of this message have been removed]
Re: [DSTAR_DIGITAL] Mobile High speed data
Today, 07:47 -0400, iw2...@iq2gm.com wrote: >Quoting Don Russell : > >> >> Anyone try the 128K high speed data while mobile? >> >> I mean in a vehicle above say at a constant 30-45 mph. >> What about at higher speeds? Would it work >> to say a helicopter or airplane orbiting over the city >> where the access point is? Or would the Doppler shift >> be too much? I am wondering if it could be used to >> feed data to/from a CAP spotter heli/plane should the >> proper equipment be installed in the craft? Doppler shift is negligible. The real problem with mobile operation (especially at 1,2GHz) is the constant change RF path due to reflections on ground structures (eg. buildings). We have used with success a webcam mounted on a moving vehicule. At the push of a button, it was transmitting one jpeg image. It was working fine at highway speed in the open field, i.e. in plain view of the repeater site that was some 35km away. We have not done yet any experiment from a plane or helicopter, but we have all reasons to believe it would work. >> >> >> Also would like to know of anyone successfully using VOIP. >> Is it possible to send voip over the high speed link. As for VoIP, the half-duplex nature of this beast (and it's rather long turn around time), makes it virtually impossible. '73 - Pierre __ Pierre Thibaudeau VA2RKA/VA2RKB/VE2RIO/VE2RVR/VE2RQF/VE2RTO/VE2LKL/VE2TXD sysadmin
Re: [DSTAR_DIGITAL] Mobile High speed data
Quoting Don Russell : > > Anyone try the 128K high speed data while mobile? > > I mean in a vehicle above say at a constant 30-45 mph. > What about at higher speeds? Would it work > to say a helicopter or airplane orbiting over the city > where the access point is? Or would the Doppler shift > be too much? I am wondering if it could be used to > feed data to/from a CAP spotter heli/plane should the > proper equipment be installed in the craft? > > > Also would like to know of anyone successfully using VOIP. > Is it possible to send voip over the high speed link. > I am thinking asterisk box with a standard pstn connection > at the AP and some kind of IAX client running ILBC > or GSM. That way a served agency could make a > real TX call via a d-star connection. > The only other way could like of being able to do this is via > a DVDongle and some creative audio patching. > > The concept is to be able to get a call to PSTN via D-star. > Hi Don, when you drive normally you cannot able to navigate to internet, is very dangerous. But when you are in parking that's sound good. So a second operator in car with me have good delay of ping around 63ms to car speed of 80Km/h near the AP...about 15Km in LOS. For VoIP we use Teamspeak, with 3/4 users in the server connected the streaming is good. 73 de Antonio IW2OAZ
[DSTAR_DIGITAL] Mobile High speed data
Anyone try the 128K high speed data while mobile? I mean in a vehicle above say at a constant 30-45 mph. What about at higher speeds? Would it work to say a helicopter or airplane orbiting over the city where the access point is? Or would the Doppler shift be too much? I am wondering if it could be used to feed data to/from a CAP spotter heli/plane should the proper equipment be installed in the craft? Also would like to know of anyone successfully using VOIP. Is it possible to send voip over the high speed link. I am thinking asterisk box with a standard pstn connection at the AP and some kind of IAX client running ILBC or GSM. That way a served agency could make a real TX call via a d-star connection. The only other way could like of being able to do this is via a DVDongle and some creative audio patching. The concept is to be able to get a call to PSTN via D-star. Thanks, Don W9DRR _ Windows Live Groups: Create an online spot for your favorite groups to meet. http://windowslive.com/online/groups?ocid=TXT_TAGLM_WL_groups_032009 [Non-text portions of this message have been removed] Please TRIM your replies or set your email program not to include the original message in reply unless needed for clarity. ThanksYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dstar_digital/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dstar_digital/join (Yahoo! ID required) <*> To change settings via email: mailto:dstar_digital-dig...@yahoogroups.com mailto:dstar_digital-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: dstar_digital-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
