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

Kiwisat Status
by Rafael Valdez G. 08 Jul '08

08 Jul '08

For all interested in kiwisat, there is a very nice update in their webpage... http://www.kiwisat.org.nz/status.html 73's & Dx's Rafael Valdez Jr. XE2RV @ DL55 10X-52716 QRV V/U Sat EX-XE2PWF P Before printing, please think about your responsibilityand commitment with the ENVIRONMENT. Antes de Imprimir, piensa entu responsabilidad y compromiso con el MEDIO AMBIENTE

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Re: IC-W2A as sat rig?
by John Mock KD6PAG 08 Jul '08

08 Jul '08

> I tried this rig (IC-W2A) out tonight on AO-51 and it seemed deaf. I > had a very good pass right over my head, but I could barely hear the > bird. My IC-32AT with the same antenna setup works FB (Arrow > Antenna). Anyone else used the W2A and found that it was lacking in > the sensitivity dept.? I used the W2A on AO-27 (which is harder to hear) for several years and it worked just fine. An Arrow should be good (and is comparable to what i used). I wonder what was going one... -- KD6PAG (Networking Old-Timer, Satellite QRPer)

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Re: IC-W2A as sat rig?
by Chris Maness 08 Jul '08

08 Jul '08

> > Thanks, John. On further investigation, it seems that > the W2A will not fully suit my needs, due to an odd > issue with this rig. It seems that the W2A will work > cross-band in full duplex mode only, not in half > duplex (in contrast, the W32A allows you to choose > between full duplex and half duplex). This means that > a W2A can only be used for sats with headphones, or > else there will be feedback. Full duplex with > headphones is of course the best way to work the sats, > but sometimes it's just too inconvenient and I'd > prefer to at least have the option of using the HT on > half duplex with the speaker. And if the W2A desenses > as badly as the W32A, then full duplex with headphones > will be a total waste. > > I'll test it out as soon as the charger arrives. > > 73, Bill NZ5N > I tried this rig (IC-W2A) out tonight on AO-51 and it seemed deaf. I had a very good pass right over my head, but I could barely hear the bird. My IC-32AT with the same antenna setup works FB (Arrow Antenna). Anyone else used the W2A and found that it was lacking in the sensitivity dept.? Thanks, Chris KQ6UP

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Fw: Re: NASA's American Student Moon Orbiter...
by i8cvs 08 Jul '08

08 Jul '08

----- Original Message ----- From: G0MRF(a)aol.com To: nss(a)mwt.net Cc: domenico.i8cvs(a)tin.it ; kl7uw(a)acsalaska.net Sent: Saturday, July 05, 2008 1:21 AM Subject: Re: [amsat-bb] Re: NASA's American Student Moon Orbiter... Hi Joe. Looking at 70cm up and 2m down, Dom has shown the 2m path can be achieved with a 13dB gain antenna on the ground and 10 Watts on the satellite. That's a very small bandwidth transponder For the uplink, it's not quite as easy. I've just run a link budget calculator and it looks like you need about 80 Watts and 20dB of antenna gain on 70cm. That produces around 5000 Watts ERP (allowing for losses) As Dom pointed out, you dont just need a signal thats just above the noise level at the satellite. Up there you need enough of a signal at the receiver so that the satellites transmitter can generate a decent amount of power on 2m. The 5kW ERP generates a signal around 16dB above noise at the satellite. With luck, that will be sufficient to produce enough power on the 2m downlink. Of course there are a lot of variables and 'detail' . but 5kW ERP up and a 13dB gain antenna on the downlink are 'In the ballpark' for a minimal working U/V system. Thanks David Hi David, G0MRF Looking at the specifications of AO40 I found that at 435 MHz the equivalent noise temperature of the RX is TN (k) = 500 kelvin The Prx (23) i.e. the power needed by the receiver to develope a signal of 23 dB over the noise is -145 dBW The 435 MHz satellite antenna gain is 14 dBi It is not specified the transponder output power with a S/N=23 dB because it depends on what transponder is intended to be used for the downlink. Probably -145 dBW at the RX input is the power needed to get a S/N = 23 dB at the IF input before to be switched by the matrix to different transponders. By the way the attenuation earth to moon at 435 MHz for 400.000 km is 197 dB and going back to calculations we get : TX power at 435 MHz on earth........................ + 20 dBW (100 W) 435 MHz antenna gain on earth ....................... + 18 dB ----------------- EIRP of the ground station................................ + 38 dBW ( 6.3 kW) Attenuation 435 MHz for 400.000 km .............. -197 dB ------------------ Power received on a 435 MHz isotropic........... - 159 dBW antenna at a distance of 400.000 km Satellite antenna gain ......................................... + 14 dBi ------------------ Received power at RX input for S/N=23 dB.... - 145 dBW It seems that both calculations match and 5 kW to 6 kW EIRP up on 70 cm and 13 dBi antenna gain on the 2 meters downlink are a minimum necessary provided that the satellite antennas orbiting around the moon are constantly directed toward the earth but this is a very difficult task. 73" de i8CVS Domenico

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OSCAR-10 & OSCAR-13 video on the web
by Peter Guelzow 07 Jul '08

07 Jul '08

Hi, I uploaded some videos about Integration and Launch of OSCAR-10 and OSCAR-10 in full-length: http://en.sevenload.com/search/amsat/videos You will also find there a video from the SDX demonstration during the HamRadio 2008. Unfortunately the videos are in german language, but I hope you will still enjoy them.. 73s Peter DB2OS

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Review of FD ST1 computer interface to Yaesu 5400/5500 rotators
by Ronald G. Parsons 07 Jul '08

07 Jul '08

I just completed testing of a Fox Delta ST1 computer interface for Yaesu G5400 and G5500 antenna rotators. I purchased this kit as a backup to our GS-232 interface for our ARISS school contact on July 4. http://www.foxdelta.com/products/st1.htm The kit was delivered quickly and kit completion took only a couple hours. It is available with either an RS-232 interface (which I purchased) or a USB interface (not tested). The only connections required are a serial port on the computer and a DIN-8 cable to the Yaesu controller. I used SatPC32 software but it is said to work also with Nova for Windows. The only calibration required is setting the "OUTPUT VOLTAGE ADJ." for both Az and El on the Yaesu controller. The instructions say to set this voltage to 4.5V, but with this setting, the controller tried to rotate the antenna beyond its limit. I got a hint from WA8SME who programmed the PIC firmware to try increasing the calibration voltage slightly. I found a value of 4.7V worked properly. The Az and El rotators are moved sequentially rather that simultaneously as does the Yaesu GS-232 controller. This slows down large movements in both Az and El, but since incremental movements are usually small, this should not matter much. The unit performed as specified. The price sure beats the Yaesu GS-232 price. Ron Parsons W5RKN

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F.S.
by Anna Osborn 07 Jul '08

07 Jul '08

Yaesu 5400 rotor & control box, fiberglass mast mounted thru rotor, rotor has mounting bracket, both units mounted togather. Have manual. $350.00 2 mtr 2m-cp22 only 1 circularity. manual. 60.00 KLM 420-450-18c relay & relay box bad. It works in 1 circularity position. manual, 50.00 Antennas are dismounted, and in 3 sections. NO SHIPPING, contact off Amsat bb Pick up in Bushnell, Fl. Abt 60 miles N of Tampa, fl just off I 75. Anna Osborn,ws4z NA Amsat 1298A ws4z1(a)yahoo.com Ph.352-793 3439. .

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Best type of coax to use between preamps and antennas
by Ronald Nutter 07 Jul '08

07 Jul '08

After problems I had on Field Day in trying to operate the satellites, I am looking to upgrade the coax I use between the preamps and the antennas. I am using 9913FX from the IC-910H and the preamps. I had been using RG Mini 8/U for the connection between the preamps and antennas. Should I also use 9913FX between the preamps and the antennas? The run between the radio and the preamp is 50 ft. The run from the preamp to the antennas is about 10 - 15 ft depending on where I set the antennas up. I am concerned about how flexible the 9913FX would be in terms of the antennas rotating back and forth. I was planning on ordering the cables pre-made from CableXperts since working with N connectors isnt my strong point and dont want to worry about my soldering and having a good connection on both ends of the cable. Any suggestions appreciated. Thanks, Ron KA4KYI

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NASA's American Student Moon Orbiter...
by Dave hartzell 07 Jul '08

07 Jul '08

http://www.spaceref.com/news/viewpr.html?pid=25839 http://asmo.arc.nasa.gov/ Wouldn't it be fun to have a transponder on this! ;-)

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Re: Fw: Re: NASA's American Student Moon Orbiter...
by i8cvs 07 Jul '08

07 Jul '08

----- Original Message ----- From: "D. Mynatt" <dave(a)mynatt.biz> To: "i8cvs" <domenico.i8cvs(a)tin.it> Sent: Monday, July 07, 2008 3:48 AM Subject: Re: [amsat-bb] Re: Fw: Re: NASA's American Student Moon Orbiter... > Where can one even find a 33ft dish? > > Dave/KA0SWT/Pueblo, CO Hi Dave, KA0SWT For big EME dishes in USA look here http://www.signalone.com/kb2ah/ and then here http://www.nitehawk.com/rasmit/gallery.html 73" de i8CVS Domenico

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