AO-40 Amateur Satellite  


UPDATE: (Apr. 7, 2003)

AO40 is in the dumps again. It is so useless to even try and get excited about this bird. As soon as the condx are good for a couple of months and activity starts to pick up it is time to rotate the bird. WHAM! there go the signals. As of this writing the ALON/ALAT is 35/0. In other words the squint angles are horrible and only a small portion of the pass has low enough squints to be workable with even a great setup. Oh well it will be this way until at least June so here we go again. It is a real shame the control operators have chosen not to even attempt to use the momentum wheels. If they had tried them and god forbid they worked we would have a really useful satellite. Unfortunately they feel this piece of space junk that is useable for maybe MAYBE a quarter of the pass every week or so is better than nothing. I disagree. I will not even continue to write this anymore. I am disgusted. I will check AO40 from time to time and see what is up but not again until at least the end of June. I am so very much looking forward to the possibility of the new AMSAT DL satellite. Do a google search and check out their plans. Very nice. As for the new AMSAT Eagle, or whatever stupid codename they are using, it will be a dud. Another low orbit piece of crap. They should call it an AMSAT.bomb because it will bomb just like most of the dot-coms. Enough.

UPDATE: (Dec. 1, 2002)

Well I am happy to finally report that the satellite is finally in better condition. Now this does not mean that the satellite is in good shape but it is better. Though I suppose to be a bit better than AWFUL is not that hard. I have also made some improvements to my station that have helped. The AMSAT crew have finally gotten the ALON/ALAT to 0/0. What this means is that the squint angles are now low enough for at least half the pass to be useable. The squint angle indicates how the antennas on the satellite are pointing. A squint angle of 0 is what we are shooting for obviously this will not be possible without the momentum wheels being fired up. 

Now I decided that the 2' by 3' BBQ grill dish was just useless and that we had been suckered into believing would work just fine. Sure this is true if your idea of fine is S2-4 signals. This can be achieved when the squint angle is less than 10deg. Otherwise expect S1 signals. (this is 1 s-unit above the noise) Now this just does not equate to fine or "armchair" copy which many will have you believe is how you will be hearing the satellite. 

So what I have done is gotten a 4' MMDS dish (for free being scrapped by the local cable co). This is a grill type dish but it is round. This has provided me with a 1-2 S-unit increase in signal. Next I added a 3db attenuator because the K5GNA preamp/downconverter has too much pre-amplification. So an easy fix is to attenuate it. This is no problem as I knew this before I bought it. Thanks to Bob for a fine piece of equipment that performs as advertised. What the attenuator has really done is drop my noise and this in and of it self makes signals more intelligible. When added to the additional S-unit from the dish and the fact the orientation of the satellite is better it makes for a useable satellite. 

The satellite is not going to be in this orientation for very long. So this of course is a major disappointment. This means to me that the AMSAT people are content to have a operational satellite than to try and get it to work better just in case something else happens. God forbid we lose AO40. Now even to me this would not be good. Seriously even after all my berating of this bird. However this opinion only applies to AO40 in it current condition which will last until spring 2003. When the ALON/ALAT increases again and knowing it will probably be another year until the bird is back in this kind of shape. 

So there you have it. AO40 is workable FINALLY! Just don't bother to go get any equipment because it will not be this way for long. And if for some strange reason you do go out and buy equipment for AO40 then please, please, please, did I say please, get at least a 1 meter solid dish with a patch or helix feed. This will at least equal the gain of my 4 footer. If you get the 2x3 BBQ dish you will be disappointed in the near future.

 I am going to build a patch feed and put it onto my dish this should give me another S-unit which will make AO40 quite workable. What this basically means is that the 2x3 bbq dish is about 6 or 7 dBi less than is needed for easy copy of the satellite.

Finally, LEILA has got to be the worst invention ever imagined. Let me fill you in on this just in case you have not read the whole page. LEILA is supposed to 'police' the satellite and keep uplink signals to a reasonable level by warning stations with a siren that they are uplinking too strong. In addition the AGC is increased for a short period of time satellite wide and also there is a notch filter applied to the offending signal. This was thought to be the way to stop a couple of stations worldwide from uplinking with too much power and de-sensing (man made qsb) the satellite. What has in fact happened is that the satellite is constantly adjusting the AGC causing stations to constantly change their uplink power thus causing LEILA to 'police' them with up to 5 min sirens. This of course causes more AGC'ing by the satellite and around we go again. This does not take into consideration the problems the satellite is having with some other sources that causes LEILA to go off on unoccupied frequencies. It was designed to stop one or two stations from de-sensing the satellite (this usually only happened for a few minutes until some other ham kindly asked them to turn down their power) what has actually happened is that LEILA now constantly de-senses the satellite. So in sum, the solution to the problem (LEILA) is worse than the problem. HA! Now that makes me smile. Typical result of trying to over engineer the perfect society. 

The kicker is that L-band uplink has no LEILA so those stations using L-band uplink are consistently 1-2 S-units above the beacon. Where LEILA forces U-band uplink to be 2-3 S-units BELOW the beacon. The GHz geeks sure scored on this one. 

UPDATE: (Nov 1, 2002)

Well I threw in the towel have gotten onto AO40 for a couple of passes starting in Sept 2002 and let me tell you its definitely NOT worth it!!! First of all the control operators are constantly changing the times when the (read: only) pass band is on. Another thing to consider is the fact that AO40 is basically unusable to all but the biggest (receiving) stations when on its way to and from apogee, an altitude of more than say 35km. This includes about half of the orbit, and god forbid this is when the pass band is on because AO40 is basically a wasteland. Sure you can hit the bird with 50W+ and 18db of antenna  Otherwise you have to listen to an S1 middle beacon for in general over half the pass. So combine the two things, first when higher than 35km not usable and second pass band off for half the pass, and you come up with a satellite that is useless for 3/4 of each and every orbit. 

Sure the GHz "geeks" will tell you the following: when you can use AO40 it is fantastic. Well I have an opinion on that too: BS! I consider my setup to be average for receive, i.e. a 3 ft BBQ grill and a AIDC down converter with plenty of gain, for transmit I may be above average with 2 432MHz antennas and 50w to sling my signal out there. Well the best I have ever heard the middle beacon (supposed to be loudest signal by 1-2 s-units) is 4 s-units above the noise floor. This is not fantastic, this is not even great, this is plain and simple mediocre at best. So you take away the built in advantage and that says the best I will ever hear myself is 2-3 s-units above noise. Now while this is no big deal when you add in the stupid, dumbass, ridiculous LEILA system you struggle a lot to hear signals. I still think LEILA is the stupidest thing I have ever seen in action, it lived up to all of my preconceived ideas of the most moronic invention known to exist in the ham world. LEILA basically produces some of the worst QSB that you will ever experience and discourages little. I hear all of the stronger stations working away and when LEILA kicks in they just stop transmitting for a couple of seconds/minutes and then continue. It is kind of funny because they are all so used to it that it no longer seems to bother them. Oh yeah did I mention that LEILA does not effect Mode L uplinks. Another win for the GHz "geeks". So do not bother to wonder why some people can be at or about the same level as the middle beacon but if you come within an s-unit or two LEILA kicks in and knocks you down. Did I mention how awful LEILA is?

I have a couple of questions: Why can't the AMSAT teams and all of their post graduate degrees not figure out what this "mystery" effect is? You know the force that is causing the satellite to be dragged off/out of its intended orbit. Next, Why can the AMSAT team not let the pass band stay on for longer periods of time? This is probably because they have decided not to unfold to solar panels and as a result the bird is being underpowered. Next, why can the AMSAT team not turn on the momentum wheels? You know the only useful addition to this satellite, these are "supposed to" keep the antennas pointed toward earth and the solar panels (once unfolded) pointed towards the sun. Next, Why does the AMSAT team insist on still doing anything with the satellite that is not completely necessary to keeping mode U/L on full time. Finally, Why does AMSAT not just accept the fact that this has been a big black eye and move on following a course something like: First test the momentum wheels, stop being afraid you cannot screw AO40 anymore. Second regardless of whether the momentum wheels operate, unfold the solar panels, you cannot screw up AO40 anymore than is already done. Third and finally scrap any thoughts of low orbit birds and dedicate all remaining monies toward a high altitude non-elliptical orbiting satellite that contains only Modes: B, L, S. Forget about anything higher than 2GHz. What most at AMSAT do not seem to understand is that just the GHz will intimidate people and the higher the number that precedes it the more intimidating it will be. Plus only the GHz-Geeks give a crap about higher frequencies and this will not change for at least another decade and more likely two decades. How many GHz-geeks do you think there are, maybe 100! Yeah there is a reason to spend a lot of money (and equipment in the mid to high GHz range is very costly, do not try and deny it).

Well that is enough for now as I am sure you get my drift..AO40 sucks! LEILA is a horrible invention! The AMSAT team while trying hard are not looking at the realities of the situation I sure hope this helps them see straight. I know the AMSAT team members are working hard but it seems they are thinking for whatever reason that AO40 as it stands is not bad, well let me reiterate IT SUCKS! So save your time and just go on with the wheels and solar panels if it screws something up well then the torture of hoping AO40 will eventually be OK will be over! If the panels work and the power levels can be turned up the torture of listening to a crappy signal from AO40 will be over too, and AO40 will usable by many more people. Then to cap it all off the batteries may be charged sufficiently so that the pass band can stay on for most of the orbit, if not the entire orbit. THE LATTER IS OF COURSE IS WHAT I WOULD LIKE TO SEE HAPPEN.

Of course I did not rant on about the eclipses because they are basically something that is unavoidable but should be greatly reduced when the solar panels are unfolded. Seems my earlier views were justified. 


On July 18th 2001 the satellite transponder was turned on again in Mode U/L1>S1.  So far in my opinion the satellite has been a complete failure. Here is any idea of what has caused me to think of the satellite as a failure:  

I know there are always people out there that will never take this sort of criticism as being constructive but to them I say piss off, most of it is not meant to be. This is a chronicle of the new satellite and no more.  I still thank those that put their time into the project because I know with all of its short comings there will be a segment of the Ham population that thinks this is the best satellite ever and the problems are being worked out.  That is not me. I think that this satellite should have been a lot more basic with a much lower orbit.  

So we will see if I am proved wrong and the workers/volunteers figure out some way to make this a successful satellite.  I am hopeful that the momentum wheels work properly (though I am not too hopeful as Murphy seems to be everywhere) after which the solar panels can hopefully be deployed successfully.  Until then I will not change my view. 

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