Mike
Understand the mechanics of how the transmitter works which surprises me considering your usual good understanding of the subjects you comment on, the quoted output at 70 watts is peak power, not average. The average based on a 112us message, which has about 50% only containing either a .5 or 1us pulse, averages out at only a few watts. Boeing have conducted tests on EMR from these devices and concluded that after a distance of 2 inches no appreciable levels are of any concern. You can obtain a free space calculator for calculating losses from a transmitted antenna off the net, you will need to convert watts to Dbm. My company was the one who got up at the ABIT meeting and proposed the lower output power so I have the information first hand. The Boeing data was supplied by Boeing, who were also at the meeting. So was Bob Hall, albeit uninformed and a wasted his time as he had done no preparation or research into ADS-B, although I think he now has a better understanding of what is going on, he also had a look at our handheld ADS-B unit, which runs on 4 AA batteries for 4 to 5 hours - sort of discounted his belief that to power ADS-B you needed a small nuclear reactor. Remember Mike I am at the coalface, so to speak so working on Pulse L band transmitter design is what I do daily. Cheers Nigel Nigel Andrews Managing Director RF Developments Pty Ltd "A Queensland Company devoted to Research and Development in aviation electronics" Email [EMAIL PROTECTED] Web www.rf-developments.com Ph: (61) 7 54635670 Fax: (61) 7 54635695 **************DISCLAIMER************ The information contained in the above e-mail message or messages (which includes any attachments) is confidential and may be legally privileged. It is intended only for the use of the person or entity to which it is addressed. If you are not the addressee any form of disclosure, copying, modification, distribution or any action taken or omitted in reliance on the information is unauthorised. If you received this communication in error, please notify the sender immediately and delete it from your computer system network. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Borgelt Sent: Sunday, June 19, 2005 11:09 AM To: Discussion of issues relating to Soaring inAustralia. Subject: Re: [Aus-soaring] 200 feet separation Take a look at this: http://astra.aero/ABIT/index.aspx ADSB implementation stuff. Note the mid air collision paper. Also one other paper does discuss the possible concerns about the effect of high power rf pulses on the pilots of composite aircraft. The proposal is that they will halve this for GA aircraft below 15000 feet and the pulses at the antenna will only be 70 watts. Oh joy! Mike Borgelt Instruments - manufacturers of quality soaring instruments phone Int'l + 61 746 355784 fax Int'l + 61 746 358796 cellphone Int'l + 61 428 355784 Int'l + 61 429 355784 email: [EMAIL PROTECTED] website: www.borgeltinstruments.com _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
