Hi Bob,
Thanks for your response which is starting to focus on the pitch you really need to make, and which you can defend (it's down toward the end!).
You state another "what if" and not a "fact."
"What will happen if the Galileo goes up is that no European airport will allow a commercial jetliner to land without the Galileo system. This will inevitably lead to this basic system being in world wide use for navigational purposes."
But consider the "fact" that all commercial airlines are currently using the US GPS system and a MLS (microwave landing system) that uses around 5 GHz. Our GPS system is also going through additional studies regarding issues with potential interference and these are NOT Amateur transmissions. Since the Galileo is intended to focus on "personal" and "for profit" applications, (check out their web site and mission statements), I can't see commercial airlines scraping their current working systems in favor of an uncertain Galileo system. If they do - it will be many, many years down the road. So I can't buy your commercial airline "fear" scenario. Again an argument based on "fear" not "fact".
Again, I keep repeating that Galileo recognizes the potential for interference (again - see their web site). We are but one of many potential sources of interference. In "fact" to date they have not even included us in their list of potential interfering sources (again see their web site).
You state "The receiver manufacturers will not want to build high quality, expensive front ends to filter out powerful emissions that could bring an airplane down. They will choose the path of "clean the bums out" and they will win."
You can't be serious Bob? You know darn well any airborne receiver used for aircraft navigation will be designed to be as bullet proof as possible. Again read the Galileo web site for their comments about interference where they state their system will "detect, identify and mitigate" potential inference. Is this lip service to sell the system or a real desire to build a solid system?
You state:
"So your idea is that we should spend $10,000,000 of donated money on the back of prayer that Galileo will not force us off our band when we KNOW it will be viewed as a safety of life service and that we will overload the front ends of the receiver in the (admittedly very rare) cases where the airplanes are in our emitter beams? No one can be that naive to believe that even the slightest possibility of interference will be allowed."
No Bob, I'm saying that your reason for dropping L-Band should be based on technical considerations not "fear" of what might happen.
You state:
"We cannot use L band for the advanced communications package anyway because we do not want to increase the antenna size for the ground user. We want to accomodate CC&R restricted users with a 60cm (2 foot) dish. The L band feed required, being dual band with C band (say) makes this infeasible."
Bob - now you talking the RIGHT ARGUMENT! Given a variety of technical considerations, available money, available current, space etc., these are the justifications you need to emphasize.
Get this "weak" (in my opinion) Galileo argument off the table and focus on we what we know to be the "real science" that you are already bringing to the project.
You stated another good technical "fact" when you said:
"Here is a fact you have not taken into account. The advanced communications package needs 10 MHz not a few tens of kHz but I have already discussed why L band is not usable for the system (ground and space) we are attempting to accomodate. That has nothing to do with Galileo or the loss of L band. In fact, if we can fit the antennas on the spacecraft, I see no reason we shouldn't include an L band receiver and we should drop it into the Galileo null. The issue will be coordination with our AMSAT-DL friends and partners to mitigate interference issues. These should be rare indeed if we achieve our target orbit for Eagle and they achieve their target orbit for P3E. The birds will be many degrees apart almost always when L band will be appropriate."
Way to go Bob. Technical arguments! That's what I want and your hitting on them now.
Bill - N6GHz AMSAT #21049