May 2008 - AMSAT-BB - mailman.amsat.org

FS Bias Tee
by Ronald Long 11 May '08

11 May '08

I have a new unused commercial bias tee for sale. http://www.teletronics.com/Accessories.html#24ghzbiastee They call it a Bias Tee/dc injector. Part 17-101 on the above page. It is in a cast-type box, female N connectors. Rated at 2.4GHz. DC connector is type normally used with wall warts. This might be what you want if you don't want to build and want guaranteed specs. ron w8gus

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WANTING TO KNOW PASSES USA FOR SEEDS
by Mr Jeffrey L Ross 11 May '08

11 May '08

Hi folks, would anyone be nice enough to send the USA Passes here to the bb for seeds. Just a close call would be ok to have. have set up for 437. down with left hand polar. wanting to copy the cw or even 9600 baud or sstv pic but no way to set up the sat for the pass at this time. thanks in advance Sitting in the Midwest, Michigan USA. KC8GKF

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Re: P3E Microwave Frequencies
by Michael Fletcher 11 May '08

11 May '08

>Hello The Net: > >Was just at the WWW.KEPS.IT website and saw a proposed frequency >plan for P3E. > >I am starting to plan for Microwave receive only down converters >and transmit only up converters. > >How firm is the frequency for the X band downlink at 10,490 MHz ? > >Ditto for the L2 uplink of 1,263 MHz and S band uplink at 2,447 MHz ? > >I am starting to look at possibilities of a common Local Oscillator >(LO) for some of the bands, but I am having no luck. Having a commonLO > or at least parts of a LO multiplier chain, would economize and maybe >lend themselves to being PLLed to the station 10 MHz reference. > >Has anyone come up with common LO and IF schemes for multiple P3E >bands ? > >My IC-910H will cover 1,263 MHz nicely, but it looks like all of the >other higher bands will have a unique LO for the band, at least for >X band and below. > >Time to get ready.... > >Stan, W1LE FN41sr Cape Cod There is some contradicting information around regarding the S band receiver and X band transmitter, but here are the frequencies the engineering and flight models are being synthesized and crystalled for as per our efforts to get at least the X band downlink to a more "standard" frequency: Center Frequencies for the IF center frequency of 10.700 MHz: U/D Mode Center Frequency Bandwidth Uplink Coherent 2438.567 MHz ~2 MHz Uplink Linear 2439.000 MHz 38 kHz Downlink Coherent 10451.000 MHz ~2 MHz Downlink Linear 10451.000 MHz ~2 MHz Beacon BPSK 10451.030 MHz NB, Modulation dependent These frequencies were last published in the AMSAT-DL Journal Nr.4 Jg.33, any other public sources may be unreliable. 73's Michael, OH2AUE -- "Life is too short for Sudoku"

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AO-16 2110z 5/11/2008
by John Marranca, Jr 11 May '08

11 May '08

Job well done, Mark, on returning AO-16 to service-again!!! At the beginning of the pass, I had Warbler running...but heard N8MH and K3SZH as the bird was commanded on. Excellent pass...worked Allen N5AFV, my neighbor Jeff WB2SYK, and Mark N8MH...all using my IC-2AT at 1 watt (with the AA alkaline battery pack) as the uplink. 16 does sound a bit different running half the power she usually does...but still...it's great to have her back-again! John KB2HSH -- _______________________________ John Marranca, Jr PBX Technician/Shop Steward CWA Local 1122 BN Systems, Inc Orchard Park, NY (716)972-2006

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CUTE and COMPASS heard
by andy thomas 11 May '08

11 May '08

Interesting! Two distinct satellite CW transmissions on the CUTE-1.7 frequency: 1) A very chirpy CW: 00(both zeros) compassuf 00 (zeros)m then 5 zeros (several times) b) second cw signal: 38 26 25 -- 64 -1 cute 87 c6 a- a- 4- 17 cute 8-....8 26 24 ....12 1- with cc in there somewhere. 2035-2042 utc approx, 437.275 CW slightly downtuned to 437.274.789 to get a good cw tone, doppler corrected with Ham radio DeLuxe on yesterday's Cute 1.7 keps. Rig - ICOM IC-910, WiMo 70cm helix, no preamp. Locator - IO02NL, UK I will qsl to the COMPASS satellite office address ( on their website) and copy this report to CUTE-1.7 and COMPASS teams. 73 de andy G0SFJ __________________________________________________________ Sent from Yahoo! Mail. A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html

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Re: bias tee circuits and components for 2.4 GHz downconverter
by G0MRF＠aol.com 11 May '08

11 May '08

Hi Michael. I see a lot of things written about bias tees, saying they are complicated or they need particular values of exotic inductor or coupling / decoupling capacitors.....but all the ones I've 'thrown together' have all worked perfectly with any converter with a VHF output. (The same is not true for UHF) General rule is to use a choke that is a minimum of 10 x the impedance of the line. So for 50 Ohm cable that's 500 ohms or about 700nH. Generally don't go above 2000 ohms as you can run into unwanted resonances in the choke. But that's a huge range, in practice 470nH to 4.7uH should be fine. - Your 1.5uH is within the limits. I've used iron dust cores from Amidon without problem. For the 2 capacitors required, the coupling capacitor and the decoupling cap to the DC supply, almost anything will do as long as it has a low impedance at 122MHz. The coupling cap can be 1n to 10nF ceramic. The decoupling capacitor can be the same value / type. Personally I always add an electrolytic as well for the DC connection. 1uF to 47uF will do. Regards David In a message dated 11/05/2008 18:23:12 GMT Standard Time, mat_62(a)netcommander.com writes: I have a Pacific Monolithics surplus MMDS downconverter here that I would like to get up and running on S-band. It has an 122 MHz IF and I want to whip up a bias -tee to power it. I've looked at the circuits in the Satellite Experimeters handbook and my problem is finding an rf choke of the right value that is readily available in my area. Shouldn't I be able to just wind something with an air core out of magnet wire or something similar that will do the trick? According to the circuit I have I'd need about a 1.5 uh choke for 146 Mhz and it isn't critical so that's probably close enough for my downconverters IF frequency. I hate to spend shipping charges to get one little choke or ferrite core for winding a choke on here. Most places have a minimum order and I don't need anything else at this time. I'd also welcome links to any other circuits that might be out there. Thanks, Michael, W4HIJ

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Re: Delfi Not Heard
by D R Mynatt 11 May '08

11 May '08

Interesting. Is the telemetry the same or would one be looking for modulated tones only? Dave

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AO-16 ON in voice mode 10May08 1020utc
by Mark L. Hammond 11 May '08

11 May '08

Hello All, This morning I turned AO-16 ON in voice mode around 1020utc. The output power is reduced a bit and is reported as 700 mW by the telemetry. It is possible that it will cease transmitting; any reports that help narrow down an approximate time for such an event will be helpful. Also, reports of its continued operation will also be appreciated. If you hear AO-16 in voice mode, free to use it. If you hear it "hummmming" in digital mode, please do not transmit to the satellite. AO-16 Uplink: 145.920 MHz FM AO-16 Downlink: 437.0260 MHz DSB (LSB and USB) On behalf of the command team, Mark L. Hammond [N8MH]

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Re: Delfi Not Heard
by k9jkm＠comcast.net 11 May '08

11 May '08

John mentioned ... > Nothing heard on 930 or 870 > Possibly a problem at my station, hope the sat is OK One quick way to test your delfi setup is listen for AO-7 on ~145.950 and VO-52 on ~145.900. Delfi operating on 145.930 is right in between. -- 73 de JoAnne K9JKM k9jkm(a)amsat.org

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Delfi-C3 information
by Nico Janssen 11 May '08

11 May '08

Hi all, For those of you who are monitoring the Delfi-C3 telemetry, here is some information on some of the abbreviations used in the RASCAL telemetry decoding software: - OBC On Board Computer - OBM On Board MORON - MORON Malfunctioning OBC Recovery OptioN - ComBo Combination Board - EPS Electrical Power Subsystem - MeBo Measurement Board - RAP Radio Amateur Platform - ICB InterConnect Board The average RAP 2 beacon frequency is around 145.9318 MHz. The actual frequency depends on the temperature of the transmitter. Just after leaving eclipse, when the transmitter is cold, the downlink frequency is 145.9323 MHz. While the transmitter warms up, the frequency drifts down to about 145.9313 MHz before entering eclipse again. So during an ascending pass, this downward drift adds some 500 Hz to the total observed doppler shift. I think by now everybody will agree that Delfi-C3 is object 32789, or 2008-021G. 73, Nico PA0DLO

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