There have been so many thoughtful comments on the S band question that it's been fun to follow the thread. I'd like to chime in.
I bought S band gear just before AO40 went south. Not a lot of equipment, just a W7LRD dish with helix, a K5GNA converter, and a few odds and ends. Unfortunately, I never got to put them on the air. Now I try out the converter on AO-51when the mode is right. I live in Manhattan, operate portable, and have a fairly decent QTH to get maybe a 100 degree window. Mode V/U on AO-51 is a breeze with an HT, and FO-29 provides the occasional DX QSO using a pair of FT817s and an old 20 watt 2 mtr. amp.
S-band here is nearly hopeless. I live in a census tract that contains 10 city blocks. There are 15,000 people in 9,000 households. I would not be surprised to find that 75% of those households had some sort of 2.4 Ghz device! The bird can be directly overhead, but only the rare station pops up out of the noise for a few syllables at a time. Using an Arrow ant. for 435 Mhz., by contrast, much is heard on both FO-29 and AO-51.
That is my experience. It is an anecdote, to be added to the many others that have been shared. I would be shocked if a satellite designer paid much attention to it if he had some more aggregate data on which to base a design decision. It's a shred of evidence, no more, no less. Even a cub reporter shouldn't write about it without doing some research into what others are experiencing and whether my experience squares with what informed people and the data suggest. For one thing, my QTH probably isn't typical, to say the least. The designers of Eagle probably aren't hung up on making sure that users in my position should be able to use all the bird's modes. They probably don't design for the superstations either. The job is to make the bird useful to the greatest number of possible users given the budgets they face (money, power, size, etc.).
The evidence I've seen in these exchanges seems to favor the designers by a large margin. They have cited their evaluation of the available data regarding the present and future use of S band. Are there data to the contrary? The fact that some stations can make it through a tough QRM situation isn't very convincing. It is the great majority of stations that should be able to use the bird.
I have a couple of concerns. Is the emphasis on making the bird accessible to very modestly equipped stations (like mine?!) going too far? The bird's potential use in emergencies sounds farfetched to me. Maybe if we're down to a choice between the bird and a semaphore!
I'd also like to know much more about the ground equipment required for S/C mode. How will it interface with existing equipment in the shack? Are these new pieces of gear add-ons to existing transceivers or do they stand alone? What functions to they perform? Sorry, but I'm not up on digital SSB and CW as you can see.
Finally, is enough known about U/V to tell us now what ERP and receive capability will be needed? That is, how big will the antennas need to be?
Thanks for all the work being put into this by the design team. If Eagle is going to fly any time soon, we've got to let them get on with it.
73, Tony, N2UN LM 183
On 12 Sep 2006 at 17:18, ANTHONY JAPHA wrote:
Hi Anthony
Your actual setup is OK on LEO but with an HEO even in V/S mode i doubt it will be enough. By definition to be able to work an HEO you need more than a portable station. Your setup can be doing the job when the satellite will be at close range but it will be much more harder near apogee.
I don't know what you have to receive the IF of your AIDC downconverter? here i have the same downconverter and ALL the QRM on S band disappears as soon as i switch the noise blanker on. With a S-9 noise level on 2.4ghz mainly from cordless phone frequency hopping type and Wi-FI the noise blanker reduce this noise level to half a s unit with the antenna over 5 degree elevation and 1 or 2 s units from 0 to 2 S units.
The bird can be directly overhead, but only the rare station pops
up out of the noise for a few syllables at a time.
The fact that some stations can make it through a tough QRM
situation isn't very convincing. It is the great majority of stations that should be able to use the bird.
I am sorry to tell you you need more than a portable setup to be able to work an HEO and its not because you have a marginal setup you should concluded that the rest of the world is in the same situation. It is unfortunate that you cannot work on AO-40 you probably will have a very different argumenting. I unnderstand your lack of experience working on HEO but if you rely solely your opinion without having any experience on HEO work and based on less than desirable setup for an HEO i understand why you are making thoses statements!
Here another commenting made by an "EXPERIENCE USER" :
Excerpt.
If local noise was a problem for you it was not a problem for the world wide majority of S-downlink users
Best 73" de
i8CVS Domenico
Here is a note about the Mode B requirements on Eagle
"The Mode B transponder will require no more than AO-13 required unless you want to use the new text messaging service and that will require a sound card and a computer."
Bob N4HY
Do you have an idea of what he mean about an AO-13 setup?
I have a couple of concerns. Is the emphasis on making the bird accessible to very modestly equipped stations (like mine?!) going too far? The bird's potential use in emergencies sounds farfetched to me. Maybe if we're down to a choice between the bird and a semaphore!
The S/C mode will be experimental and the idea behind making an HEO in this mode an emergency ready sat is not realistic of the condition who prevails in an emergency situation. In my 30 years of hamming i learn if you live in an apartments building at the 10th storey you will have a lot of restriction in your type of operation.
At the risk of repeating myself "again" you will have an S band on P3E and the Eagle main builders openly admitted they don't want to build "another AO-40" and they are hiding behind the AMSAT-NA "vision" where they contribute to implement to do what they want "as usual" going to a point to blackmail the whole amateur community.
HEE HEE.
I suspect P3E will fly the intended payloads if the microwave developers deliver their modules.
I am not interested in flying a carbon copy of P3E when I know it makes no sense whatsoever. I am 52 years old and one of the most active technical contributors in all of amateur radio. I will not waste my time doing what I know in my heart and my head is not in the best interests of amateur radio even if it is currently perceived to be for the good of the shrinking aging membership of AMSAT
I can added a lot more here but for the sake of what we called here civilities i let the AMSAT-NA membership with the conclusion.
And i hope you can see things differently now...i said i hope!
"-" The medium is the message...The content is the audience...;)
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe
participants (2)
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ANTHONY JAPHA -
Luc Leblanc VE2DWE