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AO-40 experimental transponder operation started on Saturday morning, May 5th, when the U-band and L1-band uplinks were connected to the S-2 transmitter passband downlink via the matrix switch. Operation has been extremely successful with many reports of AO-40 operation received by ANS.
ANS has also received the following from AMSAT-DL:
After a very successful week of S-band transponder operation, the announced test of the 10 GHz X-band downlink was not successful. Michael Fletcher, OH2AUE, along with command station W4SM tested the X-band (both the solid state and TWT) systems, and, unfortunately, the test was not successful.
The IHU-1 telemetry indicated the proper commands were received, but no power is getting to any of the X-band modules. Nothing happened and even the status of the temperature sensors in the X-band modules did not change. The values did not change when the module was commanded on, thus the conclusion that there is no electrical power within the module.
The problem must be either in the 28-volt supply or in the module power control line from the IHU. This problem was never observed during all the testing in Orlando and Kourou. A software problem is very unlikely. It is planned to investigate this further in the next few days and another X-band attempt will be made soon.
S-band transponder operation will continue.
The LEILA system on AO-40 has been turned on for the first time! Recently, some very strong signals appeared in the passband, several dB louder than the middle beacon. At this time the AGC on the U-band receiver was suppressing up to 16 dB, clearly in sync with the strong transmissions. LEILA was switched into the U-band passband, (as seen by the MATRIX configuration). LEILA was configured for a SCAN/JAM/NOTCH mode and it worked like a charm! The threshold was set to a level which is approximately equal to the general beacon signal, which means any stronger signal will be detected by LEILA and a "police siren" sound will first be heard to give the offending station a chance to reduce power, otherwise the notch will do its best. Initial reports are that users in the passband loved it! This is the first time that such a system has been used in space for a transponder with uncoordinated multiple access.
Meanwhile, the RUDAK team has reported good progress with both CPU's running for more than 10 days. Jim, WD0E, finished loading the GPS task into RUDAK-A and also loaded the CEDEX task. Both tasks are running but commands to begin their operations have not yet been transmitted. Jim also reported that RUDAK-A telemetry continues to look normal and the SmartNode temperature sensors on the CAN bus seem to work fine.
Peter, DB2OS, for the whole AO-40 team
AO-40 users are reminded that +/- 5 kHz around the Middle Beacon (MB) must be avoided. If the beacon cannot be copied due to interference with users in the passband, transponder operation may be stopped.
ANS Principle Satellite Investigator Mike, N1JEZ reported that he has been testing uplink conditions with AO-40 as he watched the AGC action on the passband. His recommendations have been posted on the AMSAT bulletin board. Mike reports that he "can't wait until AO-40 is stabilized and pointing right at us! I see great DXpedition potential for a small U/S system!"
Stay tuned to ANS, the official source for news and information about AMSAT OSCAR 40.
[ANS thanks AMSAT-NA, AMSAT-DL and the ARRL for this information]
The ARRL is reporting that it has again asked the FCC to create a primary, domestic amateur radio allocation at 2300-2305 MHz. ANS notes that amateurs now are secondary here.
The League first asked the FCC in 1996 to upgrade the allocation to primary, but the Commission has never acted on the request. "The segment 2300-2305 MHz is of extreme importance to the amateur service, especially for weak-signal communications and propagation research, including beacon operation, due to the low noise levels in that band," the ARRL said.
The renewed petition was prompted by increasing demands on that portion of the spectrum due to development of new telecommunications technologies. The amateur service has primary allocations in this part of the spectrum at 2390-2400 MHz and 2402-2417 MHz. The ARRL last year also sought to have the segment 2400-2402 MHz elevated from secondary to primary. AO-40 has been successfully using this part of the band for downlink telemetry and transponder operation.
Amateurs "need and should be afforded protection from" commercial users between 2300-2305 MHz, the ARRL concluded. It also requested the FCC to not introduce any other users to the band "in view of the necessity to protect the expanding amateur uses in the band which involve sensitive receivers."
[ANS thanks the ARRL for this information]
As ANS reported in last week's bulletins, the Dayton Hamvention is quickly approaching. In addition to information noted last week, ANS has the following data:
AMSAT-NA Vice-President of Field Operations, Barry Baines, WD4ASW, is requesting additional volunteers to serve for a "tour of duty" at the AMSAT booth during a portion of the Hamvention. Volunteers will help handle the myriad of activities that typically occur at an AMSAT booth, handle transactions, deal with memberships and renewals, answer questions and serve as a representative of AMSAT. Prior experience in representing AMSAT at (any) hamfests is helpful but certainly not required. If you are attending Dayton and have not contacted Barry to tell him you can help, please do so immediately.
Barry can be reached at: firstname.lastname@example.org.
AMSAT will also offer S-band equipment. To assist AMSAT with raising funds, SSB Electronics USA has graciously agreed to contribute a portion of the unit price to AMSAT for each UEK-3000S mast-mounted S-band downconverter that is sold at the AMSAT booth.
AMSAT will also have available the Phillips-Tech SPG-24 "barbecue grill" style 2.4 GHz antennas at Hamvention. These units have been very popular with AO-40 users. A specification sheet will be available at the AMSAT booth. The UEK-3000S in combination with the SPG-24 will provide an outstanding combination for S-Band operations.
See you at Dayton!
[ANS thanks AMSAT-NA Vice-President of Field Operations, Barry Baines, WD4ASW, for this information]
ANS news in brief this week includes the following:
Link to the weekly report on satellite ...
ISS . RS-12 . RS-13 . RS-15 . AO-10 . UO-11 . UO-14 . AO-16 . DO-17 . WO-18 . LO-19 . FO-20 . UO-22 . KO-23 . KO-25 . IO-26 . AO-27 . FO-29 . TO-31 . GO-32 . SO-33 . PO-34 . SO-35 . UO-36 . AO-40 . SO-41 . SO-42
Please send any amateur satellite news or reports to the ANS Editors at email@example.com, or to ANS Editor Dan James, NN0DJ, at firstname.lastname@example.org.
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This week's AMSAT News Service bulletins were edited by AMSAT News Service editor Dan James, NN0DJ.