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

W9VNE input on transceiver question
by Jim Danehy 27 Nov '08

27 Nov '08

I was in a similar situation several months ago. I had a pair of M Square antennas along with the elevation rotor and a Ham M to turn the antennas. What to do for a rig. Well I bought a brand new Icom 910H. A great rig. I use SatPC32 software which interfaces to the Icom via Icom's interface accessory (plug and play). You forget about your doppler shift once set up. I still control antennas manually with both rotors. The Icom 910H is a top of the line satellite transceiver. The only thing I would improve on it would be the RIT control. It only offers a 1 khz range but that is no big deal. It sounds like you are going to setup for the SSB satellites. They can become very lonely. AO7 is used but by a handful of USA stations (you will not work Europe from CO. It suffers from some stations using excessive power and generating trash up and down the band too. FO 29 and VO 52 (both SSB/CW) also have a handful of operators. No hashy trash because they are newer birds. AO7 is 34 years old and easy to trash it with hash if you use excessive power. If you live on the East Coast of the USA you could work Europe. QRZ.COM shows your location is in Colorado. Forget about working Europe. The FM satellites are very popular with AO 51 being the most popular. It suffers too from some poor operating at times. Most of the time it is OK. That early evening pass can be bedlam. SO 50 is useful but not used very often enough. It works well in my opinion. AO 16 is interesting but will be off the air very soon. The reason I mention all of the above is because it impacts your selection of a rig. If you want to work a lot of grid squares which many of us do, the FM satellites are where the action is located. You do not need an Icom 910H and the money it represents to work the FM satellites well. You can do that with a HT (hand held). There are other dual band 440/144 FM rigs available for a fraction of the cost of an Icom 910H. The Kenwood TS2000 is a good rig but it has a birdie on SO 50's downlink making it impossible to use that FM satellite. There is a big difference, in my opinion between the FM and SSB/CW satellites. FM being used to its capacity on AO 51 and the SSB/CW birds suffering from inactivity. Just a fact of life. Some may disagree with these observations. I was on the satellites back in the 1970s and came back in August 2008. I have made QSOs with 15 countries and 200 Grids and 45 states in that time. I think my intense 3 months of operating provides me with enough observations to make these statements. I am often asked why not more activity on non-FM satellites. My answer has always been : 1) Doppler shift and 2) equipment. Unless you have software to manage the doppler shift on 435 mhz your signal will travel quickly across the band. Some experienced ops can do it manually but they are pros. Equipment for SSB/CW is relatively (emphasis) scarce compared to FM only rigs. You do not need software to control Doppler shift on FM. . . . you can control it in other ways. To choose a transceiver depends on how you want to spend your time. If you are preparing for the HEO (German venture) then go with the Icom 910H type rig. If you just want to get on the satellites for the satellite experience you may find an FM only rig is more suited for you. Of course since you are not currently on the satellites ( my inference ) you would not have the benefit of personal knowledge. I hope my observations are helpful. Selection of the gear depends on how you are going to use it. If you do not know that there are really two different roads to currently travel you could be wasting your money. Just my 2 cents and probably not worth even that amount of money.

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AO-51 mode L/U
by almetco＠comcast.net 27 Nov '08

27 Nov '08

I heard a few passes of AO-51 in L/U mode. Most stations came in strong. I tried to get into the bird using about 8 watts out into a 23cm horizontal yagi on an elevation rotor. It was to no avail, though the bird was at 50 degree's and higher. I am working on a CP antenna for mode L. Can those that worked this mode give me an idea of wattage, EIRP or antenna for Mode L that you are using. I was sure 7-10 watts would do from the Icom 910. However, it may have been the yagi and the lack of CP. Thanks Greg N3MVF

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whole pass AO-51 tlm RX
by nader omer 27 Nov '08

27 Nov '08

Hi all A whole pass of AO-51 TLM RX at KK65GP ORBIT # 23,195 16:24 16:38 UTC signal was very strong from AOS to LOS using here only a soundcard with AWGPE and UISS! link to data RX in a text format http://www.st2nh.com/AO-51TLM27112008.zip http://www.st2nh.com/satellites 73 Nader ,st2nh www.st2nh.com

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[Fwd: Re: AMSAT Orbit Magazines 1-4]
by Dee 27 Nov '08

27 Nov '08

All involved... Thanks for the run down memory lane. I recognized most of you but I would be torn to recognize some. The organization needs to remember its "roots!' 73, Dee, NB2F -------- Original Message -------- Subject: [amsat-bb] Re: AMSAT Orbit Magazines 1-4 Date: Thu, 27 Nov 2008 07:35:08 -0800 (PST) From: Glen Zook <gzook(a)yahoo.com> Reply-To: gzook(a)yahoo.com To: amsat-bb(a)amsat.org, "Ralph Wallio, W0RPK" <W0RPK(a)netins.net>, "Phil Karn Jr, KA9Q" <karn(a)ka9q.net> Are you interested in the original bulletins? "Somewhere" I should have all of the original bulletins except for the very first. I have been a member of AMSAT since the first couple of months of its formation and, being a "pack rat", I keep things like organization bulletins. It is just a matter of locating them! If I can find them, I can loan them to you for scanning. Of course I would like them back when you are through. Glen, K9STH AMSAT 239/LM 463 Website: http://k9sth.com --- On Thu, 11/27/08, Phil Karn Jr, KA9Q <karn(a)ka9q.net> wrote: From: Phil Karn Jr, KA9Q <karn(a)ka9q.net> Thanks to Ralph, W0RPK, the first four issues of AMSAT Orbit magazine are scanned and online. ORBIT began publication shortly before the ill-fated Phase III-A launch in 1980. http://www.ka9q.net/newsletters.html _______________________________________________ Sent via AMSAT-BB(a)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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AMSAT Orbit Magazines 1-4
by Phil Karn Jr, KA9Q 27 Nov '08

27 Nov '08

Thanks to Ralph, W0RPK, the first four issues of AMSAT Orbit magazine are scanned and online. ORBIT began publication shortly before the ill-fated Phase III-A launch in 1980. http://www.ka9q.net/newsletters.html 73, Phil

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Re: Help for Humber College Students with ISS Contact
by AJ9N＠aol.com 27 Nov '08

27 Nov '08

Hi all, Let me clear up a little bit of what ARISS wants for a school ground station. What you do for your own home contact is your business but here is what we want for an ARISS school contact: 1. We require two complete radio stations, each one 75 watt class or better (we actually prefer over 100). RF amps are OK. The radios should have the ability to go in frequency steps smaller than 5kHz so that the Doppler shift can be corrected (at 2 meters it goes about +/-3.5 kHz). 2. The primary radio is to have a circular polarized beam with azimuth and elevation control rotors. We prefer computer control of the rotors. 3. The backup radio is to have a vertical and/or eggbeater style antennas. Now for a short explanation of why for each: 1. The need for two complete radios is so that if one radio fails for any reason, the school contact can carry on (it is recommended each radio be on its own 120VAC circuit and UPS if possible). The reason for the 75 watt class is that we want to have as much signal to reach the ISS as possible. The ISS is actually pretty noisy and the radio footprint is very big and it picks up all sorts of interference. So it helps to have as much signal get to the astronaut. Throw in the fact that the ISS superstructure is so big now that we have had schools have the signal dropout to almost nothing and you can see that every little bit helps. 2. The circular polarized beam helps because the signal to and from the ISS can be bouncing off of the superstructure itself and in some cases the surrounding ground terrain. As I mentioned above, we have had some schools where the signal dropped out almost to zero. Luckily the signal (sometimes about a minute later) came back up as the ISS changed its orbital position relative to the ground station and thus some of the blockage was reduced. I have done 4 school contacts as control op and I use 5x2 LHCP and 10x2 RHCP circular polarized beams with an antenna switch. Most of the ARISS telebridge stations are using something similar. The ISS antennas are basically vertical antennas but the signal can be deflected all over the place because of the superstructure. I tend to run my contact on the RHCP beam (but I am ready to switch) but we at ARISS have had some reports where the signal did come up a bit when using LHCP. Those who are really into satellite work know that the RF pattern does change during a contact so it makes sense to be able to switch polarity. And don't forget the ISS radio is running maybe 25 watts (or maybe 5 depending on the radio used) and can not do any Doppler correction. 3. The backup radio is to have a non-directional antenna so that in case of rotor or computer failure, the contact can carry on although it will be with a shortened contact time and the quality may suffer. I have an antenna switch to switch between the 2 antennas during a pass as the RF pattern between the 2 antennas is completely different. The biggest reason for doing what some may think is overkill is this. The hams involved with a school contact are just the messengers. The school kids, teachers, and parents are the ones we have to satisfy and they don't understand this ham radio business. They do understand good audio and no screw ups on the part of the ham crew. I always tell the schools that I mentor to plan on 600 to 800 people-hours for 10 minutes of contact time. They usually think I am nuts until they do the contact and they often tell me that my estimate was too low. Think of a school contact as your worst case Field Day; not so much because of the equipment issues but because of the 600 or so kids watching. Hope this helps a little. 73, Charlie Sufana AJ9N One of the ARISS mentors In a message dated 11/26/2008 4:15:52 A.M. Central Standard Time, gordonjcp(a)gjcp.net writes: Ken Owen wrote: <snip> > From: Paul Je [mailto:paul_je@hotmail.com] > Sent: Monday, November 24, 2008 1:17 PM > To: Ken Owen > Subject: RE: ISS contact > > Say Ken, we've set up our primary station just fine, but I was wondering if > I could ask for your advice. Well, you see, we've tested the transceiver > that we have (the ICOM IC-V8000), and we can transmit and receive just fine > with it on our circular-polarized HyGain 2m antenna. Also, we did a VSWR What kind of antenna? Anything more than a 3-element Yagi will be more trouble than it's worth. Bear in mind that I've successfully sent and received APRS with the ISS using a homebrew vertical. The higher the gain of your Yagi, the more directional it is, and the more accurately it needs to be pointed. I find that a 3-element beam is okay for handheld use when working portable, and has more than enough gain to hit the amateur satellites with 5W from an HT. > test and our loss is minimal with the 75W transceiver that the ICOM 75W sounds a bit much, especially into a very directional antenna. You're trying to talk to the ISS, not etch your name on the side. > produces. Ok, so here's the problem. Even with all the proper testing > done, we still can't seem to pick up or hear the 166MHz beacon that the ISS > produces. Are you using a 166MHz aerial for this? Are you sure the beacon is even transmitting when you think it is? Your high gain Yagi might well be very very deaf outside its intended band. Try making a simple dipole or even a two-element beam for 166MHz. With two elements, it will have a more-or-less cardioid pattern, so you shouldn't really even need to steer it much ;-) > My classmates and I are a bit worried/stressed out. I mean, just on last > Friday, we did a test and someone drove at least 5km away from out college > and heard us fine with the handheld radio he had. We had a signal strength > of 3+ out of 5. He could've drove out even further, but we felt that we did > enough testing to know that any attenuation losses were very minimal. The ISS is pretty much the classic case of line-of-sight. There's nothing in the way, and it's only 200 miles away. There's nothing to stop the signal anywhere. > Well, do you know what the problem could be? Have you heard the beacon? > What does it sound like? Maybe we should delay or advance the rotor by a > few seconds? We're using NOVA software, and it allows us to send our > transmission a few seconds ahead or behind. Use a wider beamwidth. > Ok, so we have a circular polarized HyGain antenna hooked up to our Yaesu > G5500. Uhm, this might sound dumb but do you know whether we should be > right hand circular polarized or left hand circular polarized? Is the ISS > right hand or left hand on 144.490MHz? This I'm not sure about. I thought about building a circular polarised antenna for ISS and amateur satellite work, but it seemed more trouble than it was worth. If you've got the polarisation wrong, it will be incredibly deaf! > I'm trying to research this, but I'm having the hardest time to find this > information out. Oh, also, since our antenna is circular-polarized, does > the way we set our antenna have an effect on our transmission? I know this > sounds confusing, but let me explain: > > If you looked at our antenna from the front so that you could see all the > dipoles/elements both vertically and horizontally to your view, well, should > they be perfectly aligned with one set horizontal and one vertical? Both > the vertical and the horizontal are perfectly 90degrees to each other, > however, instead of being a perfect cross to your view, the elements are > more like an "X" to your point of view (even though both are perfectly > 90degrees to each other). That shouldn't make much of a difference. Imagine the signal arriving like a big corkscrew - the key to the circular polarisation is that the signal arrives at one set of elements and then a quarter wavelength later arrives at the second. Now, let's imagine we've made our circular-polarised aerial by putting two dipoles on a boom, 1/4 wavelength apart, and connected them by two equal-length lines. The vertical one is at the "front" of the boom and the horizontal one is to the "back", and the up and left elements of the dipoles are "hot". Let's pause reality just as a "vertical" peak hits the vertical dipole. That dipole now has some signal. Using the single-Planck-time advance button on our Worldivo (it's like a Tivo for the fundamental nature of the Universe), we'll step through - tick, tick, tick, tick - until a quarter wavelength has passed. Now the vertical peak is somewhere above the centre of the horizontal dipole - it's picking up no signal - and there's a horizontal peak about the centre of the vertical dipole - no signal there either. Step forwards another quarter wave, and there's a vertical dip at the cold end of the vertical antenna, and the horizontal peak we just saw came in is at the hot end on the horizontal antenna. We now have a negative signal on the cold side of the antenna connection (remember, both dipoles are effectively in parallel) and a positive signal on the hot side of the antenna connection - loads of signal! If we reversed the direction of the corkscrew, or reversed the phase of *one* of the dipoles, then the two signals would cancel out almost completely. You can have two signals transmitted in left and right circular polarisation on the same frequency, and have *phenomenal* rejection between the two. I should point out that there's quite a lot in that explanation that's not entirely true, or at least terribly inaccurate. It's still a useful model for getting your head around what seems at first to be a very confusing polarisation mode. HTH, Gordon _______________________________________________ Sent via AMSAT-BB(a)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 **************Life should be easier. So should your homepage. Try the NEW AOL.com. (http://www.aol.com/?optin=new-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000…)

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Re: BBsat Call for ideas
by Bob Bruninga 27 Nov '08

27 Nov '08

> One idea that hasn't been floated yet, > is a 10m or 15m transmitter aboard bbSat. We looked at that, but the problem is the order of magnitude fewer hams that have SSB transceivers. We went with a 10m uplink to an FM downlink so that any technician with nothing but an HT could hear it. But then, you have gained nothing over the typical FM satellite b ecause of single-use. So that is why we went with PSK-31 on the 10m uplink so that the single 2m FM downlink would have as many as 30 ussers simultaneously (all sharing the 10 m PSK-31 3 KHz wide uplink. > I therefore think a transponder that > downlinked on these bands would be > likely to 'broaden our base', > I recognize that transmitting on > such a long wavelength from a 10cm > cube represents a technical challenge Yes, the 4 foot whip deployment on our RAFT cubesat is what failed, not due to the antenna deployment but due to an ejection anomoly that spun the spacecraft out of contorl (80 RPM) from which the 4' whip antenna deployment could not work. Receiving 10 meters on a terribly small and inefficient antenna is no big deal, because users on the ground would be uplinking with 25 watts, and being on 10m is 14 dB better link too, so uplink on 10m is easy. So that is my preference, 3 KHz of PSK uplink on 10 meters with a single FM downlink with up to 30 users at a time... full duples too! We flew this on PCSAT2 and on RAFT (though both had other problems leading to a lack of any meaningful success). see: www.ew.usna.edu/~bruninga/pcsat2.html www.ew.usna.eud/~bruninga/raft.html bob, Wb4APR Bob, Wb4aPR >challenge of mechanical engineering, not something that would run up >against the limited power budget. I also vaguely have the impression >that amplifiers, etc. are more efficient in the lower frequencies, so >that might be a plus. (Not to mention reduced path loss.) Perhaps the >effective power out would be so low that a directional antenna would >be required on the ground. In which case, I'd say it was a no-go, >since that would preclude too many of the new experimenters that we'd >be hoping to snare on these bands. >_______________________________________________ >Sent via AMSAT-BB(a)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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AO7 log
by k3szh＠netzero.com 27 Nov '08

27 Nov '08

VE3DRT and K4JPC have the wrong date , it should have been 11/25/08 , see my log info for 11/25/08 and the sat was in mode "B". AO7 switched today at 20:58 utc to mode "A" They can correct it by deleting and start all over and put the correct info in for 11/25 you can change the date, time and mode in the log. Joe Amsat 3788 ____________________________________________________________ Don't risk your health! Click now for professional mold remediation! http://thirdpartyoffers.netzero.net/TGL2241/fc/PnY6rx8pbGBZiKmojWMReIgdSsH0…

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AO7 orbit 55749, possible problem?
by Mark Lunday, WD4ELG 27 Nov '08

27 Nov '08

According to my notes, the bird switches from MODE A to MODE B (or back to MODE A) at approx 2100 UTC every day. Today, it was supposed to be in mode A. According to the AO7 log, it made the switch to MODE A, but apparently switched back to mode B. http://www.planetemily.com/ao7/ao7log.php 26-Nov-08 23:37 55749 K4JPC EM73WU Mode B K3SZH, VE3DRT, W7LRD 26-Nov-08 23:33 55749 VE3DRT EN93RK Mode B WP4CNU, K4JPC, K3SZH, W7LRD 26-Nov-08 22:41 55748 EA8TX IL18QI Mode A K3SZH 26-Nov-08 22:41 55748 K3SZH FN10OG Mode A EA8TX 26-Nov-08 21:00 55747 AJ9K EN53EB Mode A 26-Nov-08 20:59 55747 AJ9K EN53EB Mode B DJ3AK 26-Nov-08 20:55 55747 DJ3AK JO52GJ Mode B F5APQ, K3SZH, G1WPR When the bird made a pass at my QTH around 0040 UTC, I did not hear a peep on MODE A or MODE B. Normally I hear LOTS of signals. Indication of a problem? Mark Lunday WD4ELG wd4elg(a)arrl.net http://wd4elg.net

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AO-51
by cpsvista 27 Nov '08

27 Nov '08

Does anyone know if the QRP frequency is operational right now, everyday, on AO-51, I tried it a few weeks ago twice with nothing heard, two days ago, I tried the regular voice frequencies and with my 5 watt HT on my arrow, could not seem to get a word in edgewise over the traffic and I hate to keep calling and putting out noise, I could hear most everyone loud and clear but could not get a response............... Rich KI6RRQ

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