Hi Greg, KO6TH
In my opinion one lesson the satellite community can learn from this, is that if we want to communicate a satellites should be designed with only one mode and with redundant transponders i.e. "strong and stupid"
BTW after working few orbits it seems to me that the indian transponder was less subject to be overloaded in comparison to the Dutch transponder.
If the EIRP is too high and there are many station in the passband the Dutch transponder is FMing and get distorted while the indian transponder was more linear and less subject to be overloaded.
If the uplink power is in the order of 10 to 20 watt into a 10 dBi RHCP antenna than the Dutch transponder is not overloaded.
I agree with you that it will be very interesting to know from ISRO if the difference in linearity between the above transponders is due to the actual battery conditions or to a different performance of the AGC
73" de
i8CVS Domenico
----- Original Message ----- From: "Greg D" ko6th.greg@gmail.com To: "Mani VU2WMY" wmy@isac.gov.in Cc: "RANGAN" tprangan@istrac.org; "AMSAT-INDIA" amsatindia@yahoogroups.com; "VUHAMS" vuhams@yahoogroups.com; "PE1RAH" pe1rah@yahoo.com; "BB,AMSAT" amsat-bb@amsat.org; "VU3TYG" vu3tyg@yahoo.co.in Sent: Thursday, March 15, 2012 4:05 AM Subject: [amsat-bb] Re: Dutch Transponder on-baord HAMSAT VO-52 'Turned On'
Hi Mani,
Congratulations on the recovery of VO-52; it's great to have our friend back.
I am curious if ISRO will be issuing some sort of report on what happened. I understand that they will have limits on what they can say, but if there is something the satellite community can learn from this, it would be good to not miss the opportunity.
Greg KO6TH
Mani VU2WMY wrote:
Dear HAMSAT VO-52 users, The commands to 'Turn On' the transponder # 2 (Dutch transponder, made by Williams PE1RAH) on-board HAMSAT VO-52 was successfully sent during 14:00 UT 35 deg ascending Node pass over Bangalore, India.
The sent commands were successfully received, acknowledged and confirmed by the telemetry. Subsequently, the transponder # 2 is now 'ON' and Williams CW message beacon was heard again after a gap of approximately 6 years & 4 months.
The beacon signal was heard loud and strong here at Bangalore.
A detailed Initial reports addressed to: tprangan@istrac.org and a copy to wmy@isac.gov.in would be greatly appreciated.
73 de
Mani, VU2WMY Secretary & Station-In-Charge Upagrah Amateur Radio Club VU2URC ISRO Satellite Centre HAL Airport Road, Bangalore-560 017. Phone:(O)91-80-25082054/2598/2192 Mobile: 91-80-98803 41456 E-mail ID: wmy@isac.gov.in vu2wmy_mani@yahoo.com isrohams@yahoo.com
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