There have have been pirates on just about every bird in orbit for years. The old environmental units sent up and used by agencies like the Wildlife Service were famous for being "wide open" if you knew what you were doing. They had unencrypted "order wire" channels which were infested, so to speak. We had intruders on the unencrypted order wire channels of military satellites back in the 1970's and early 80's -- one guy called himself "Professor Universe" and hacked into some voice channels. Played music, gave anti-war (Vietnam War at that time) rants, etc. As for Professor Universe, as they used to say back in the day: Qui cum recessisset ab scena - fortasse vita cum NSA adprehensa lacinia (he was toast) Cheers, Dave N4CVX ex-DA1BB, ex-VP2EHF, ex, ex ex, etc.
Canada to Argentina, it covers a hemisphere not just the parts north of the equator. And the ground terminal will be functional with not just this satellite, but the others that AMSAT is working on. That spreads the cost of the equipment out over many years, just like any other new radio.
I don't plan on using a hub/ground terminal ... I plan on using my own microwave satellite equipment .... right now 5Ghz would be harder for me to use than 10Ghz ...
the 10 gig downlink is cheap and easy now , a $20 usb SDR and a $10 avenger LNB on any dishnetwork reflector.
I stopped supporting AMSAT when they kept launching satellites that were technically difficult to use on higher and higher bands that require expensive LNA's. Now 5 GHz and 10 GHz links and will probably require new more difficult modes. I am moving towards moon bounce since it is easier to achieve. I know 10 meter downlinks wouldn't be good for a geo-stationary sat but please not 10 Ghz. I remember years ago how much money it took to buy a 10Ghz "Gunplexer". I used to work all the Radio Sputnik sats (RS-7, RS-11/12 etc.) because they were 2 meters up and 10 meters down with simple transponders using the standard modes. Easy, simple and cheap to access with easy antennas and no LNA's, down converters and exotic antenna arrays. I could literally pull a tripod, and a mobile radio out of my car, set up the antenna on the tripod and manually point at the sat and work stations. I think we need a mix of simple sats as well as challenging ones. Yes, I know there are a couple of FM transponders but they are 1 frequency not a wider band transponder. When I look at the satellite map on my computer and sort through all the existing sats for an easy to use transponder type and there are none. Well , maybe FO-29, but AO-7 only works part of the time with random mode settings. Dave NA7V
So, what would you suggest they do/use for a geosynchronous bird? Do you think the same link frequencies that work for LEO's would be OK for a geosynchronous sat? Should we be doing things the same way we did 40 years ago just because? Or should we be taking full advantage of the opportunity to do bigger things serving a greater audience, and have some relevance to the younger generation out there? 5GHz and 10GHz was more difficult 10+ years ago, but it's not so bad today with DTV and surplus consumer stuff like the HughesNet equipment. Doing something new is OK for me - looking forward to pulling something together! Steve KV6O
Yeah. We sure wouldn't want to do anything that might be technically challenging, use new modes, new antennas, and use those weird frequencies above 440MHz. If I can't do it with a Bao Feng HT then it's unfair and should not be allowed .
AMSAT has never launched satellites designed to require the use of "higher and higher bands." Every satellite that AMSAT-NA has been involved in has incorporated 10m, 2m, and 70cm uplinks and downlinks. Unfortunately, AO-40's 2m and 70cm downlinks failed, requiring the use of the 2.4 GHz downlink, but the downconverter and dish required were simple and low cost and the U band uplink was still available. Yes, Phase 4B (and some other satellites in the future) will be 5 GHz up and 10 GHz down (for reasons previously explained in this thread), but those frequencies are relatively easy to use with modern equipment. You can put together a decent 10 GHz receive station for under $150. The trick is generating RF at 5 GHz and by launch, that problem should be solved. As far as easy to use LEOs with linear transponders: FO-29 works great. AO-7 works almost all of the time, except on morning passes. It's usually in Mode B, except when it's in constant sunlight (next time, Oct-Dec 2016) Plus: AO-73 XW-2F XW-2A XW-2C All have 2m/70cm linear transponders that are very easy to use. No Mode A satellites have been launched in many years due to the antenna size required for a good 10m downlink and the availability of launches. Lots of us work all of these satellites with simple equipment (such as a pair of FT-817s) and a handheld Arrow pointed at the antenna.
I suppose if they gave you the gear and installed it at your house you'd feel better? I'm not sure where you got the notion that AMSAT kept launching satellites that required expensive LNA's on higher and higher bands.
To rx this bird you will need a <$15 LNB for FTA sat and a <$20 RTL-SDR and a DTV or DishNetwork dish likely free. No tracking system required set it up and you are on 24/7/365. I would not call that expensive. Yes transmitting up on 5hgz wont be cheep, but not the price of a new HF radio either. The ability of this bird to not only provide two way communications, but the ability to disseminate bulletins, wx, solar wx info and short msging will be a great asset.
DX-Peditions today show us their operations to desolate unfriendly and downright dangerous locations, and deliver contacts approaching the 100K mark, before mounting successful efforts to get paid. AMSAT has IMO had many unfortunate failures which turned a lot of experimenters who had made substantial donations off. They now need to show us the success of the working birds they promised, and then mount their campaign to successfully get paid. Some background: I was QRV for several years on High Elliptical Orbit birds (ao 10/13) which had linear SSB/CW transponders that were 435 up/145 down and 1269 up/435 down. I built power amplifiers, antennas, LNAs, and sophisticated antenna positioning systems to operate those birds. I participated in the ZRO receiving tests and still have the plaque on my wall for the phenomenal receiving systems I built. I could generally hear the noise floor of the transponder some 12 dB or more above my own noise floor. AMSAT pushed a heavy fund raising effort and I donated substantially back then to see another such replacement satellite, but saw nothing but dopey little fly-bys so kids/lids could use HTs. These "successes" were of no interest to me. As to data communications, I did packet with a Commodore 64 and yes it was interesting then, but so 80's now. Short messaging (SMS) is currently done too easily with everyone on my iPhone to even be of interest anymore. Frustrated with the lack of satellites to work DX on, I got into EME with what I had learned and made lots of initials on 144 and 432 EME, including many DX stations on the other side of the world. That later became boring as CW was being replaced with computer to computer processing. I successfully worked the MIR space platform as it flew by, but after one initial contact saw that as boring because of the capture effect of FM and the unruly pileup on a single "channel". I still fondly look back at the conversations I had on ao 10/13. I am not at all against building up gear for the higher microwave frquencies, and have previously built up gear thru 10 GHz for VHF/UHF contesting. However, I'm not going to make that investment in time and expense until there is actually a successful bird to make SSB and CW contacts on. Then, and only then, would I be willing to donate again, since I still consider myself in the hole on my prior investments with AMSAT. I would be remiss if I didn't mention that HF has been reliable since I was a kid in 1974! Sorry for the hard truth and my long memory...
I noticed that one ham made some scary commentary about the extreme dangers of microwaves and 5 GHz operation, walking in front of such a dish, etc. I also saw commentary from some folks in the know about this satellite that the earth station uplink required on 5 GHz was suggested as 1 Watt feeding a small offset feed TV dish. Since I do know a little about power density analysis and maximum permissible exposure, I would like to clarify that if you decide to put your finger into the open 5 GHz waveguide feed while transmitting with 1 Watt of power, you would indeed exceed the safety MPE - so don't do that. However, that 1 Watt or 1000 Milliwatts of power is intended to feed and thus be spread over the surface of a dish that is 1.5 feet in diameter or larger, and reflected in a plane wave towards the satellite. You would NOT exceed the safety MPE if you stood or walked in front of this dish and encountered that plane wave energy. You would block the signal though. In fact the larger the dish being fed, the more square centimeters of surface area those Milliwatts of power being fed are spread over, such that while a larger dish does have a higher ERP because of its larger aperture, it is actually safer from an MPE perspective than a smaller dish, or open waveguide, because of that larger aperture. The safety standard to not exceed at this frequency is 1 Milliwatt per square centimeter, for the general public with no time limit and no knowledge of exposure. Using the worst case of the smallest TV dish of 1.5 feet (45.72 cm) diameter, those 1000 Milliwatts are spread over a surface area of 1641 square centimeters resulting in a power density of 0.61 Milliwatts per square centimeter on the actual surface of the dish, which is within the safety MPE on the actual surface of the dish. The actual surface of the dish represents the worst case exposure as there is additional path loss attenuating the signal as one moves further out in front of the dish. I trust this clarifies that there is no MPE threat here to anyone knowingly or unknowingly walking in front of such a dish, based on the standards that we must follow.
http://www.downeastmicrowave.com/category-s/1841.htm If that isnt cheap enough then go back to knitting Carl
I for one would love this to have activated emergency channels that for the most part would be monitor only relaying selected comms about a certain declared emergencies... Much like BROADCASTIFY does over the internet with its ham radio links... This is obviously not going be one open circuit with ten thousand hams trying to check-in... I used to checkin with orbiting SAT for hams where you had a good 15 minutes before it disappeared over the horizon... Looking forward to it... Roy Ken K9PHT - King George VA
