Dutch Transponder on-baord HAMSAT VO-52 'Turned On'
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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Mani C O N G R A T U L A T I O N S !!!!!!!
73 Zeljko 9A2EY
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Mani VU2WMY Sent: Wednesday, March 14, 2012 3:11 PM To: BB, AMSAT; AMSAT-INDIA; VUHAMS Cc: RANGAN; PE1RAH; VU3TYG Subject: [amsat-bb] Dutch Transponder on-baord HAMSAT VO-52 'Turned On'
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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_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
VO-52 is sounding very strong. I just had a quick QSO with K8YSE, KC7MG,and W7JPI.
Dave - KB1PVH
Sent from my Verizon Wireless DROID X
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
Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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
----
Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient,
please
contact the sender by reply e-mail and destroy all copies of the
original
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On Fri, March 16, 2012 09:33, i8cvs wrote:
Hi,
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 experience the same, last night during the pass from 7:22 p.m. UTC there was an overload on the uplink and therefor it was impossible to use the passband efficient. I also experienced linearity problems.
So please reduce power to a minimum - if the transponder is clogged no one benefits.
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
73 Jan PE0SAT
Hi all, The two transponders are not built exactly the same way.
The Indian transponder has an AGC - but according to my memory Williams transponder has a diode limiter.
I think that can be the difference.
In theory the AGC will regulate the gain down so that the "stronger" station "drowns" the ones with a lower uplink signal.
The diode limiter will of course limit the signal for the strong stations - but also create distortion in a broad frequency range for all stations. That is if there is a very strong signal - or many stations at the same time.
Whatever the reason KEEP THE POWER DOWN
73 OZ1MY/Ib
Hi Ib, OZ1MY and William, PE1RAH
Thank you for the information about the diode limiter into the William's transponder.
I got the link of PE1RAH describing the block diagram of indian and Duch transponders but without information about AGC or diode limiter.
http://www.qsl.net/pe1rah/HAMSAT-info.htm
I hope that William will informe us on this matter.
73" de
i8CVS Domenico
----- Original Message ----- From: "Ib Christoffersen" oz1my@privat.dk To: pe0sat@vgnet.nl Cc: amsat-bb@amsat.org Sent: Friday, March 16, 2012 11:36 AM Subject: [amsat-bb] Dutch transponder versus the Indian transponder.
Hi all, The two transponders are not built exactly the same way.
The Indian transponder has an AGC - but according to my memory Williams transponder has a diode limiter.
I think that can be the difference.
In theory the AGC will regulate the gain down so that the "stronger"
station
"drowns" the ones with a lower uplink signal.
The diode limiter will of course limit the signal for the strong
stations -
but also create distortion in a broad frequency range for all stations. That is if there is a very strong signal - or many stations at the same time.
Whatever the reason KEEP THE POWER DOWN
73 OZ1MY/Ib
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi Domenico
I think we have also another problem: In the last few years, the OP's growing up without fullduplex TRX (Ic-706 and similar) and use the ssb sat. They can't hear her own downlink signal from the bird.
73's de Michael
HB9WDF, Michael Lipp, JN47AE
Am 16.03.2012 um 12:14 schrieb "i8cvs" domenico.i8cvs@tin.it:
Hi Ib, OZ1MY and William, PE1RAH
Thank you for the information about the diode limiter into the William's transponder.
I got the link of PE1RAH describing the block diagram of indian and Duch transponders but without information about AGC or diode limiter.
http://www.qsl.net/pe1rah/HAMSAT-info.htm
I hope that William will informe us on this matter.
73" de
i8CVS Domenico
----- Original Message ----- From: "Ib Christoffersen" oz1my@privat.dk To: pe0sat@vgnet.nl Cc: amsat-bb@amsat.org Sent: Friday, March 16, 2012 11:36 AM Subject: [amsat-bb] Dutch transponder versus the Indian transponder.
Hi all, The two transponders are not built exactly the same way.
The Indian transponder has an AGC - but according to my memory Williams transponder has a diode limiter.
I think that can be the difference.
In theory the AGC will regulate the gain down so that the "stronger"
station
"drowns" the ones with a lower uplink signal.
The diode limiter will of course limit the signal for the strong
stations -
but also create distortion in a broad frequency range for all stations. That is if there is a very strong signal - or many stations at the same time.
Whatever the reason KEEP THE POWER DOWN
73 OZ1MY/Ib
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi Michael, HB9WDF
I think we have another problem too: Since the Dutch transponder is very sensitive someone will attempt to use it in FM using an HT and arrow antenna.
73" de
i8CVS Domenico
----- Original Message ----- From: "Michael Lipp, HB9WDF" hb9wdf@bluewin.ch To: "i8cvs" domenico.i8cvs@tin.it Cc: "Ib Christoffersen" oz1my@privat.dk; pe0sat@vgnet.nl; pe1rah@yahoo.com; "Amsat - BBs" amsat-bb@amsat.org Sent: Friday, March 16, 2012 2:47 PM Subject: Re: [amsat-bb] Re: Dutch transponder versus the Indian transponder.
Hi Domenico
I think we have also another problem: In the last few years, the OP's growing up without fullduplex TRX (Ic-706 and similar) and use the ssb sat. They can't hear her own downlink signal from the bird.
73's de Michael
HB9WDF, Michael Lipp, JN47AE
Am 16.03.2012 um 12:14 schrieb "i8cvs" domenico.i8cvs@tin.it:
Hi Ib, OZ1MY and William, PE1RAH
Thank you for the information about the diode limiter into the William's transponder.
I got the link of PE1RAH describing the block diagram of indian and Duch transponders but without information about AGC or diode limiter.
http://www.qsl.net/pe1rah/HAMSAT-info.htm
I hope that William will informe us on this matter.
73" de
i8CVS Domenico
----- Original Message ----- From: "Ib Christoffersen" oz1my@privat.dk To: pe0sat@vgnet.nl Cc: amsat-bb@amsat.org Sent: Friday, March 16, 2012 11:36 AM Subject: [amsat-bb] Dutch transponder versus the Indian transponder.
Hi all, The two transponders are not built exactly the same way.
The Indian transponder has an AGC - but according to my memory Williams transponder has a diode limiter.
I think that can be the difference.
In theory the AGC will regulate the gain down so that the "stronger" station "drowns" the ones with a lower uplink signal.
The diode limiter will of course limit the signal for the strong
stations -
but also create distortion in a broad frequency range for all stations. That is if there is a very strong signal - or many stations at the same time.
Whatever the reason KEEP THE POWER DOWN
73 OZ1MY/Ib
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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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.
Yes, it's important not to run too much power to prevent overloading. I have found that just 300 mW into a 16 dBi vertically polarized antenna works beautifully through most of the pass, during the last few days. Not much power is needed at all.
73 de Dave KB5WIA
Dear Greg,
You are very right in all your aspects.
1. We are still in the process of documenting the recent HAMSAT VO-52 Anomaly Analysis and Transponder-2 Switch ON Report.
2 The report will not be complete without the feedback from the user (HAM) community. Hence, we have decided to circulate, very soon a feedback format, at least to all those who have sent us their initial reports.
3 Right now, we are not in a position to share anything with the users.However, once the formal analysis report is approved and released, your request , will be forwarded (justifying that such information will help in future amateur radio satellite ventures) to the Management for further advise.
Dear Greg, we hope you understand our position and limitations.
73 de Mani VU2WMY
Quoting Greg D ko6th.greg@gmail.com:
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
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Hi Mani, VU2WMY and All on the list
Beacon and transponder of VO-52 were not heard over Europe to day 4 May 2012 during the ascending orbit 37853 at 17:44 UTC and it was in full Sun light.
Yesterday 3 May VO-52 it was not heard over South America by PY5LF and over USA by K5OE as well not heard over Europe by IW6OVD
Please let us know the actual situation.
TNX
73" de
i8CVS Domenico
participants (9)
-
Dave Webb KB1PVH -
David Palmer KB5WIA -
Greg D -
i8cvs -
Ib Christoffersen -
Mani VU2WMY -
Michael Lipp, HB9WDF -
PE0SAT -
Ulip Željko