First experience with do-61 (DELFI C-3) this morning here.
1-No body was on the satellite only me calling CQ 2-From AOS to TCA signal was very good about +-3 DB above noise level 3-At TCA signal dropped below noise level too week for SSB but week for CW 4-From TCA to LOS signal remain below noise level and became too weak even for CW
I suspect the satellite antenna configuration show some directivity or it is the satellite attitude who seems to favour some part of the orbit pass? I was never able to received my SSB dowlink on the eastern pass only a week CW carrier one time. There is some audio AGC as increasing the audio level make's not a big change on the dowlink. I was able to uplink with the FT-847 RF gain control completely turned off (about 1 or 2 watts).
I don't know if my results are in line with what the team planned but when the sat was on data mode i was able to copy it from AOS to LOS but i think the TX power is reduced in transponder mode?
It make's another one to experiment with and a preamp is imperative to be able to work it with ease. Just have to get some folk's on it here to be able to check it again. "-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE
Hi Luc,
Thanks for your report here on the BB, Did you try to switch your polarization between LHCP and RHCP? As Delfi-C3 goes over the earths poles, it flips itself 180 degrees in Z axis (perpendicular to earth). Otherwise one side will be always exposed to sunlight and things might run hot / degrade in time. Due to this flip, the polarization sense changes depending on which pass you are tracking (ascending from south to north, or descending from north to south) If you do not switch polarization sense, you can observe big differences between those two. Please bear in mind that Delfi does not have any active attitude control system and solely relies on passive stabilization. During a pass, polarization might change due to slow rotations. You could try to switch polarization within a pass and see whichever is stronger.
Delfi-C3 does have an RF AGC within the IF-stage, so uplinking more power than necessary only limits other weaker stations and does not improve your own signal.
We received some reports about people uplinking using a FT817 with abt. 5 Watts into an arrow antenna, so your 1 or 2 watts with a good antenna could do miracles...;) Reports of Delfi-C3 (DO-64) transponder operation are greatly appreciated and can be sent to info at delfic3.nl or via the BB.
On behalf of the Delfi-C3 team,
Best 73's
Wouter Weggelaar PA3WEG Delfi-C3 Command Team
On Sun, Aug 10, 2008 at 5:58 PM, Luc Leblanc [email protected] wrote:
First experience with do-61 (DELFI C-3) this morning here.
1-No body was on the satellite only me calling CQ 2-From AOS to TCA signal was very good about +-3 DB above noise level 3-At TCA signal dropped below noise level too week for SSB but week for CW 4-From TCA to LOS signal remain below noise level and became too weak even for CW
I suspect the satellite antenna configuration show some directivity or it is the satellite attitude who seems to favour some part of the orbit pass? I was never able to received my SSB dowlink on the eastern pass only a week CW carrier one time. There is some audio AGC as increasing the audio level make's not a big change on the dowlink. I was able to uplink with the FT-847 RF gain control completely turned off (about 1 or 2 watts).
I don't know if my results are in line with what the team planned but when the sat was on data mode i was able to copy it from AOS to LOS but i think the TX power is reduced in transponder mode?
It make's another one to experiment with and a preamp is imperative to be able to work it with ease. Just have to get some folk's on it here to be able to check it again. "-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE
Sent via [email protected]. 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
On Aug 11, 2008, at 06:12:56, wouter weggelaar wrote:
As Delfi-C3 goes over the earths poles, it flips itself 180 degrees in Z axis (perpendicular to earth). Otherwise one side will be always
Are you saying it has an active attitude control that it uses to change orientation right as it crosses the poles? Or is the satellite rotating with a period equal to that of its orbit?
TIA,
Rick - I think that they use a permanent magnet aligned with the long axis of the satellite. When it goes over the magnetic poles, the permanent magnet (an the satellite) flip to follow the magnetic field lines. Say the North end of the magnetic is the leading end of the satellite as it ascends from equator to the pole. WHen it goes over the pole, the north end of the satellite becomes the trailing edge as the satellite descends form the pole to the equator. Slick. - Duffey On Aug 11, 2008, at 12:50 PM, Rick Mann wrote:
On Aug 11, 2008, at 06:12:56, wouter weggelaar wrote:
As Delfi-C3 goes over the earths poles, it flips itself 180 degrees in Z axis (perpendicular to earth). Otherwise one side will be always
Are you saying it has an active attitude control that it uses to change orientation right as it crosses the poles? Or is the satellite rotating with a period equal to that of its orbit?
TIA,
Rick
Sent via [email protected]. 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
-- KK6MC James Duffey Cedar Crest NM
On 11 Aug 2008 at 15:12, wouter weggelaar wrote:
Hi Luc,
Thanks for your report here on the BB, Did you try to switch your polarization between LHCP and RHCP? As Delfi-C3 goes over the earths poles, it flips itself 180 degrees in Z axis (perpendicular to earth). Otherwise one side will be always exposed to sunlight and things might run hot / degrade in time. Due to this flip, the polarization sense changes depending on which pass you are tracking (ascending from south to north, or descending from north to south) If you do not switch polarization sense, you can observe big differences between those two. Please bear in mind that Delfi does not have any active attitude control system and solely relies on passive stabilization. During a pass, polarization might change due to slow rotations. You could try to switch polarization within a pass and see whichever is stronger.
Delfi-C3 does have an RF AGC within the IF-stage, so uplinking more power than necessary only limits other weaker stations and does not improve your own signal.
We received some reports about people uplinking using a FT817 with abt. 5 Watts into an arrow antenna, so your 1 or 2 watts with a good antenna could do miracles...;) Reports of Delfi-C3 (DO-64) transponder operation are greatly appreciated and can be sent to info at delfic3.nl or via the BB.
On behalf of the Delfi-C3 team,
Best 73's
Wouter Weggelaar PA3WEG Delfi-C3 Command Team
Thank's Wouter for your comments.
The change in signal strength appears at TCA exactly at west and it was a southbound pass. I guess the antenna main lobe was directed at me and when the satelllite passed my TCA point the main lobe was not directed at me.
Half the pass was very good and the other extremely weak i'm using a 14 elem cross yagi stuck in right hand polarisation i know a 3DB difference due to polarisation change on a yagi but much more when using the wrong polarisation. This old KLM 2M 14C suffer numerous winters 2 crash down and the relay and the relay board where broken up to a point of no repair the only one solution is to make two separate antenna. I someone used to modified on of theses old beam it will be interesting to know what the impedance is at the end of the 2 4 to 1 balun? It will be nice if it will be 52ohms! But i guess it is 100 ohms as the 2 balun line are tied to a SO-239 connector.?
The audio quality is nearly as good as FO-29 by the way nice sat to experiment with.
"-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE
A few observations from down under. So far I have had 12 contacts through DO-64, mostly with VK. (With nothing to work out to the East or North there is no activity on the majority of passes.) The beacon is consistently strong on all passes and on a few passes has shown some distortion for about a minute as Delfi approaches 60 deg South. This was also the case in science mode. The transponder signal is somewhat variable. Some passes have very good downlink signals and some are apparently weaker. (S.C. orientation presumably.) I have not noticed much variability throughout a pass - strong downlink passes stay strong and weaker passes stay weak. In general the beacon is stronger than the transponder downlink. With no other stations on DO-64, increasing uplink power from 5 to 10 watts results in an increase in downlink signal. (All observations using 19 elements on 70cm and 10 elements on 2m with switchable polarization and Az/El tracking.) All in all an interesting and useful addition to the satellite options in this part of the world.
Alan ZL2BX
Hi Mike,
All commands sent and acknowledged at 2302 UT on Compass 8 deg pass.
Alan ZL2BX
Hi Mike,
Compass pass at 2004 UT. Sent commands at 2008 but only got response from ****13#200#. Resent commands at 2012 and all were accepted including the beacon test command but I did not hear any beacon.
Alan ZL2BX
Hi Mike,
Compass pass at 2139 UT. Sent commands at 2142 and all were accepted including the beacon test command but once again I did not hear any beacon. I have the command wave file if you want it but will have to send it later in the day as I am away for a couple of hours. Good to hear the beacon was heard in Hawaii.
Alan ZL2BX
participants (5)
-
Alan Cresswell -
James Duffey -
Luc Leblanc -
Rick Mann -
wouter weggelaar