Friends,
We've had little information about the P4 opportunity since the Symposium. But reading between the lines and reading N4HY's message of today it seems that most of us are missing what they are trying to tell us ...
There aren't **any** easy/cheap/free rides to HEO to be had. That ship has sailed and everything that we ever knew about the launch business has changed.
I'm not trying to put words in anyone's mouth here, but I take it from Bob's message and the solicitation letter from President Hambly that there is really no apparent option to launch Eagle without doing something radically different.
Assuming that we could pay for even a cheap launch, it might cost a million dollars if we were just paying customers. Think about that -- a MILLION dollars. Maybe more. After two years of raising money for Eagle we are up to what, $70K?
At this rate it would take a decade or more to raise enough funds to launch Eagle if AMSAT continues on the published path. This isn't about digging a little deeper -- this is about reality.
I get the impression that if some agreement isn't worked out with someone -- like is being discussed with the P4 opportunity -- we won't get back to HEO. Ever. Unless the satellite business changes.
Those who think that the option is to EITHER finish Eagle and launch it, OR work on P4 seem to be missing the point -- the first option may now be more dream than a viable option.
I would be pleased to learn that I am reading this all wrong because my *only* satellite interest is in a high-orbit bird and my hopes for seeing another in my lifetime are beginning to fade.
It's now been over 11 years since we had AO-13 and it's becoming a fond, distant memory...
Jeff,
Just to clarify two points in your message. A cheap launch may cost over $6M, not just $1M.
The Phase 4 rideshare opportunity is a simplified Eagle, not a new project. Thus it is easier to build than Eagle and the only effect on the Eagle project is a realignment of project priorities, putting an emphasis on the communications modules. The overall Eagle project could still continue if we so desire.
Rick W2GPS AMSAT President
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Jeff Davis Sent: Tuesday, December 11, 2007 3:37 PM To: amsat Subject: [amsat-bb] Bob's Message
Friends,
We've had little information about the P4 opportunity since the Symposium. But reading between the lines and reading N4HY's message of today it seems that most of us are missing what they are trying to tell us ...
There aren't **any** easy/cheap/free rides to HEO to be had. That ship has sailed and everything that we ever knew about the launch business has changed.
I'm not trying to put words in anyone's mouth here, but I take it from Bob's message and the solicitation letter from President Hambly that there is really no apparent option to launch Eagle without doing something radically different.
Assuming that we could pay for even a cheap launch, it might cost a million dollars if we were just paying customers. Think about that -- a MILLION dollars. Maybe more. After two years of raising money for Eagle we are up to what, $70K?
At this rate it would take a decade or more to raise enough funds to launch Eagle if AMSAT continues on the published path. This isn't about digging a little deeper -- this is about reality.
I get the impression that if some agreement isn't worked out with someone -- like is being discussed with the P4 opportunity -- we won't get back to HEO. Ever. Unless the satellite business changes.
Those who think that the option is to EITHER finish Eagle and launch it, OR work on P4 seem to be missing the point -- the first option may now be more dream than a viable option.
I would be pleased to learn that I am reading this all wrong because my *only* satellite interest is in a high-orbit bird and my hopes for seeing another in my lifetime are beginning to fade.
It's now been over 11 years since we had AO-13 and it's becoming a fond, distant memory...
Quoting "Rick Hambly (W2GPS)" w2gps@cnssys.com:
Jeff,
Just to clarify two points in your message. A cheap launch may cost over $6M, not just $1M.
The Phase 4 rideshare opportunity is a simplified Eagle, not a new project. Thus it is easier to build than Eagle and the only effect on the Eagle project is a realignment of project priorities, putting an emphasis on the communications modules. The overall Eagle project could still continue if we so desire.
Gang:
It has been apparent to me for some time that the missing part of the equation has been launch opportunities. If the board has made progress toward securing some sort of HEO orbit for our payloads, this is not a diversion of their efforts; rather it brings us closer to our goal of communicating over wide distances using traditional (U/V SSB) and novel (advanced digital package) modes. I have to say that even though I've not attended the Symposium, I feel properly informed about these things.
Secondly, it should be noted that the team working with SSETI to provide S-band communications on SSETI ESEO have also found a means to launch amateur packages to HEO: namely, by supporting government-funded educational projects. Though the result will probably have a less-powerful signal than AO-13 et al., we should include this in our discussion of future HEO amateur capabilities and applaud them for their resourcefulness.
Finally, it's time to start getting excited about Delfi-C3. The PSLV launch window is 7 - 10 January for this large cubesat whose comm package will, after it completes its experiments, be turned over to amateur use in mode U/V. If you miss the challenge of HEO communication, why not apply your station to collecting data for Delfi-C3 and then enjoying the QRP satellite communication through this bird? By doing so, we will prove to those who are developing educational birds that by collaborating with amateurs they stand to gain a great deal in data collection.
73, Bruce VE9QRP
Rick,
I hope the original Eagle project will also continue albeit delayed slightly (the original hopes were of course for two Eagle satellites, I guess we're now talking about one).
I recognise there isn't a limitless pool of money or volunteers.
The opportunity that currently exists with Intelsat is simply too good to miss.
Even if the eventual orbit of the first Phase 4 payload doesn't cover the British Isles I still believe that AMSAT-NA should press ahead with it as the first priority.
If the first payload is successfull it will open the way for others in the future. If we pass on the Intelsat option we will not get a second chance.
73 Trevor M5AKA
--- "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Jeff,
Just to clarify two points in your message. A cheap launch may cost over $6M, not just $1M.
The Phase 4 rideshare opportunity is a simplified Eagle, not a new project. Thus it is easier to build than Eagle and the only effect on the Eagle project is a realignment of project priorities, putting an emphasis on the communications modules. The overall Eagle project could still continue if we so desire.
Rick W2GPS AMSAT President
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Jeff Davis Sent: Tuesday, December 11, 2007 3:37 PM To: amsat Subject: [amsat-bb] Bob's Message
Friends,
We've had little information about the P4 opportunity since the Symposium. But reading between the lines and reading N4HY's message of today it seems that most of us are missing what they are trying to tell us ...
There aren't **any** easy/cheap/free rides to HEO to be had. That ship has sailed and everything that we ever knew about the launch business has changed.
I'm not trying to put words in anyone's mouth here, but I take it from Bob's message and the solicitation letter from President Hambly that there is really no apparent option to launch Eagle without doing something radically different.
Assuming that we could pay for even a cheap launch, it might cost a million dollars if we were just paying customers. Think about that -- a MILLION dollars. Maybe more. After two years of raising money for Eagle we are up to what, $70K?
At this rate it would take a decade or more to raise enough funds to launch Eagle if AMSAT continues on the published path. This isn't about digging a little deeper -- this is about reality.
I get the impression that if some agreement isn't worked out with someone -- like is being discussed with the P4 opportunity -- we won't get back to HEO. Ever. Unless the satellite business changes.
Those who think that the option is to EITHER finish Eagle and launch it, OR work on P4 seem to be missing the point -- the first option may now be more dream than a viable option.
I would be pleased to learn that I am reading this all wrong because my *only* satellite interest is in a high-orbit bird and my hopes for seeing another in my lifetime are beginning to fade.
It's now been over 11 years since we had AO-13 and it's becoming a fond, distant memory...
-- 73 de Jeff AMSAT-NA AMSAT-DL
___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure thing so the Eagle project will be the backup. In either case we are looking at multiple launches. I have discussed this with Intelsat making it clear that two or three satellites over the Atlantic, Pacific and over the Americas would be good for AMSAT. We could then consider ways to link them, probably by using AMSAT assets on the ground.
If it turns out that we get a P3 launch we will pursue multiple launches as described in our strategy statements from the past three years. Ether way the goals are the same - 24 hour/day wide area coverage for our members.
Finding these opportunities is a huge job and closing a deal for any launch can take years of hard work. It is also largely behind the scenes work due to the sensitive issues involved so the membership only see a fraction of the work. I ask people to be patient and trusting as we are doing our best with limited volunteer resources.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Trevor Sent: Tuesday, December 11, 2007 7:18 PM To: AMSAT BB Subject: [amsat-bb] Re: Bob's Message
Rick,
I hope the original Eagle project will also continue albeit delayed slightly (the original hopes were of course for two Eagle satellites, I guess we're now talking about one).
I recognise there isn't a limitless pool of money or volunteers.
The opportunity that currently exists with Intelsat is simply too good to miss.
Even if the eventual orbit of the first Phase 4 payload doesn't cover the British Isles I still believe that AMSAT-NA should press ahead with it as the first priority.
If the first payload is successfull it will open the way for others in the future. If we pass on the Intelsat option we will not get a second chance.
73 Trevor M5AKA
--- "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Jeff,
Just to clarify two points in your message. A cheap launch may cost over $6M, not just $1M.
The Phase 4 rideshare opportunity is a simplified Eagle, not a new
project.
Thus it is easier to build than Eagle and the only effect on the Eagle project is a realignment of project priorities, putting an emphasis on the communications modules. The overall Eagle project could still continue if
we
so desire.
Rick W2GPS AMSAT President
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Jeff Davis Sent: Tuesday, December 11, 2007 3:37 PM To: amsat Subject: [amsat-bb] Bob's Message
Friends,
We've had little information about the P4 opportunity since the Symposium. But reading between the lines and reading N4HY's message of today it seems that most of us are missing what they are trying to tell us ...
There aren't **any** easy/cheap/free rides to HEO to be had. That ship has sailed and everything that we ever knew about the launch business has changed.
I'm not trying to put words in anyone's mouth here, but I take it from Bob's message and the solicitation letter from President Hambly that there is really no apparent option to launch Eagle without doing something radically different.
Assuming that we could pay for even a cheap launch, it might cost a million dollars if we were just paying customers. Think about that -- a MILLION dollars. Maybe more. After two years of raising money for Eagle we are up to what, $70K?
At this rate it would take a decade or more to raise enough funds to launch Eagle if AMSAT continues on the published path. This isn't about digging a little deeper -- this is about reality.
I get the impression that if some agreement isn't worked out with someone -- like is being discussed with the P4 opportunity -- we won't get back to HEO. Ever. Unless the satellite business changes.
Those who think that the option is to EITHER finish Eagle and launch it, OR work on P4 seem to be missing the point -- the first option may now be more dream than a viable option.
I would be pleased to learn that I am reading this all wrong because my *only* satellite interest is in a high-orbit bird and my hopes for seeing another in my lifetime are beginning to fade.
It's now been over 11 years since we had AO-13 and it's becoming a fond, distant memory...
-- 73 de Jeff AMSAT-NA AMSAT-DL
___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/ _______________________________________________ Sent via AMSAT-BB@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
At 08:54 PM 12/11/07 -0500, "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure thing so the Eagle project will be the backup.
Like how the BOD put Eagle on the back burner and instead built Echo so people could pass more Grids?
KB7ADL
Vince,
Where did you get that idea? There was no Eagle project then. Get your facts straight.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Vince Fiscus, KB7ADL Sent: Wednesday, December 12, 2007 1:03 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Bob's Message
At 08:54 PM 12/11/07 -0500, "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure
thing
so the Eagle project will be the backup.
Like how the BOD put Eagle on the back burner and instead built Echo so people could pass more Grids?
KB7ADL
_______________________________________________ Sent via AMSAT-BB@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
Vince,
I may have misspoken. There might have been an Eagle IDEA then but there was certainly no PROJECT.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: Rick Hambly (W2GPS) [mailto:w2gps@cnssys.com] Sent: Wednesday, December 12, 2007 2:07 PM To: 'Vince Fiscus, KB7ADL'; 'amsat-bb@amsat.org' Subject: RE: [amsat-bb] Re: Bob's Message
Vince,
Where did you get that idea? There was no Eagle project then. Get your facts straight.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Vince Fiscus, KB7ADL Sent: Wednesday, December 12, 2007 1:03 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Bob's Message
At 08:54 PM 12/11/07 -0500, "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure
thing
so the Eagle project will be the backup.
Like how the BOD put Eagle on the back burner and instead built Echo so people could pass more Grids?
KB7ADL
_______________________________________________ Sent via AMSAT-BB@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
Vince,
I need to apologize. A review of old messages shows that you are right; the Board had an Eagle project as far back as 2001 that was put on hold for Echo. The reason I thought otherwise is that the real Eagle project had it genesis at the Orlando design meeting in February 2004.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: Rick Hambly (W2GPS) [mailto:w2gps@cnssys.com] Sent: Wednesday, December 12, 2007 2:08 PM To: 'Vince Fiscus, KB7ADL'; 'amsat-bb@amsat.org' Subject: RE: [amsat-bb] Re: Bob's Message
Vince,
I may have misspoken. There might have been an Eagle IDEA then but there was certainly no PROJECT.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: Rick Hambly (W2GPS) [mailto:w2gps@cnssys.com] Sent: Wednesday, December 12, 2007 2:07 PM To: 'Vince Fiscus, KB7ADL'; 'amsat-bb@amsat.org' Subject: RE: [amsat-bb] Re: Bob's Message
Vince,
Where did you get that idea? There was no Eagle project then. Get your facts straight.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Vince Fiscus, KB7ADL Sent: Wednesday, December 12, 2007 1:03 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Bob's Message
At 08:54 PM 12/11/07 -0500, "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure
thing
so the Eagle project will be the backup.
Like how the BOD put Eagle on the back burner and instead built Echo so people could pass more Grids?
KB7ADL
_______________________________________________ Sent via AMSAT-BB@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
At 08:54 PM 12/11/07 -0500, "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure thing so the Eagle project will be the backup.
Like how the BOD put Eagle on the back burner and instead built Echo so people could pass more Grids?
The reason for Echo (a two-user FM voice) escapes me also, Greg.
To me, money down the tubes...
When I fought it to begin with, one of the reasons given was to increase membership quickly to increase contributions....I have never seen proof of either increase since.
Profit motives?? I'm sure it sold a bunch of 2 M handhelds. Increase interest in ham satellite radio?? I doubt it, it has the same degree of difficulty as a cell phone....Can't imagine that weak challenge would hold anyone's interest for long, or induce them to contribute to a HEO.
There was obviously a reason to go the Echo route, but that reason still escapes me...
Another Oscar 7 or 8 would have been infinitely better...But I was told, prior to building of Echo, at several conventions, that my opinion had not been requested, by several powers that were and still are...
But I am still a member and still have a vote!!!
73, Dave, WB6LLO dguimon1@san.rr.com
Disagree: I learn....
Pulling for P3E...
Dave Guimont wrote:
The reason for Echo (a two-user FM voice) escapes me also, Greg.
To me, money down the tubes...
I'll agree with that one also, a whole bird with one "Channel" seems like a HUGE waste. Cool? Yeah,, but single user uh,, nah.
I'm old skool oscar 6 & 7 and the old russian birds, FUN!
In preperation to a long distance balloon flight coming from Arizona soon, I experienced PSK31 for the first time the other day, and what a cool mode!
Just now I was listening for the test beacon for the balloon, with a "Online" reciever, not even my own, that has a generaic all band antenna so it can listen from 500Khz to 50 Mhz, imaging the efficiency of that antenna!? Anyway with this rig tuened to the beacons freq of 14070.45KHz it's amazing, using Digipan as the software, i was watching and reading 16 QSO's happening all at the same time on the one audio passband! People can be like 50 cycles away and have perfect QSO's,
is this mode used on the birds much? what a bandwidth saver.
Joe WB9SBD
Joe wrote:
Dave Guimont wrote:
The reason for Echo (a two-user FM voice) escapes me also, Greg.
To me, money down the tubes...
I'll agree with that one also, a whole bird with one "Channel" seems like a HUGE waste. Cool? Yeah,, but single user uh,, nah.
I'm old skool oscar 6 & 7 and the old russian birds, FUN!
In preperation to a long distance balloon flight coming from Arizona soon, I experienced PSK31 for the first time the other day, and what a cool mode!
You think that's good... grab the most recent copy of QEX, and look over the technical testing of PSK31 vs. all of the newer modes that have popped up in the last four to five years, and try those modes out.
PSK31 is well into the "peak of popularity" portion of the bell curve, and obviously because it's popular, it's also fun.
But if you're into experimenting on the leading edge of the technology curves, try out some of the others mentioned in the article.
PSK is very popular because it has been around quite a long time at this point, and it's easy to do with a soundcard and a bog-standard HF rig. Luckily most of the follow-on modes are also that simple to set up, too.
According to the QEX article, PSK31 also has the *worst* performance in bad HF conditions -- and you've already seen how well it DOES perform.
So imagine modes that survive various forms of noise and fading even better than PSK31, and then know that they're here today.
Some of the work done by the WSJT and variants crowd for weak-signal work is rediculously good -- signals no human can copy are pulled out of the noise and show up on the screen.
To keep the post on-topic, 100W and a single Yagi for moon-bounce!
I remember reading about the Amateurs lucky enough to be able to work moon-bounce prior to the advent of the PC-as-analyzer type technology... Folks used enormous ERP and huge antenna arrays to work moon-bounce via CW, before these recent advancements. Now anyone with a tri-pod in a backyard and a "brick" amplifier on 2m can work the moon, from what I've been reading online. It's probably time I give it a try, but I haven't yet.
Amazing stuff. Lots of neat work going on in the digital modes these days.
Nate WY0X
The reason for Echo (a two-user FM voice) escapes me also, Greg.
To me, money down the tubes...
I'll agree with that one also, a whole bird with one "Channel" seems like a HUGE waste. Cool? Yeah,, but single user uh,, nah.
Amazing stuff. Lots of neat work going on in the digital modes these days.
Nate, I could not agree more re: digital modes....I support them all the way....My criticism was FM voice vs ssb and cw(a digital mode)......
An FM voice mode vs the OLD AO7 (ssb/cw) is infinitely pleasurable to work....And enables many SIMELTANEOUS qso's.
Merry Christmas to all...
73, Dave, WB6LLO dguimon1@san.rr.com
Disagree: I learn....
Pulling for P3E...
At 10:05 AM 12/18/2007, Nate Duehr wrote:
To keep the post on-topic, 100W and a single Yagi for moon-bounce!
I remember reading about the Amateurs lucky enough to be able to work moon-bounce prior to the advent of the PC-as-analyzer type technology... Folks used enormous ERP and huge antenna arrays to work moon-bounce via CW, before these recent advancements. Now anyone with a tri-pod in a backyard and a "brick" amplifier on 2m can work the moon, from what I've been reading online. It's probably time I give it a try, but I haven't yet.
Amazing stuff. Lots of neat work going on in the digital modes these days.
Hmm, you give me hope I might be able to work moonbounce on 2m. :) I have the power and the all mode radio, just have to dust off the antenna and setup the PC. :)
73 de VK3JED http://vkradio.com
At 03:34 PM 12/17/2007, Tony Langdon wrote:
At 10:05 AM 12/18/2007, Nate Duehr wrote:
To keep the post on-topic, 100W and a single Yagi for moon-bounce!
I remember reading about the Amateurs lucky enough to be able to work moon-bounce prior to the advent of the PC-as-analyzer type technology... Folks used enormous ERP and huge antenna arrays to work moon-bounce via CW, before these recent advancements. Now anyone with a tri-pod in a backyard and a "brick" amplifier on 2m can work the moon, from what I've been reading online. It's probably time I give it a try, but I haven't yet.
Amazing stuff. Lots of neat work going on in the digital modes these days.
Hmm, you give me hope I might be able to work moonbounce on 2m. :) I have the power and the all mode radio, just have to dust off the antenna and setup the PC. :)
73 de VK3JED http://vkradio.com
Realities of digital EME:
Yes, a single yagi can make contacts via eme. You need a reasonably good computer with a soundcard interface to your radio (PSK-31 types work). You need a RS-232 interface to your radio's PTT (and CW key for CW). This can be as simple as some 2N2222's or better done with opto-isolated transistors. Most computer grounds are incompatible with your radio gnd, so keep them separated.
When running a single yagi with low power (for eme) like 100-400w. I will likely take a four yagi station to receive you. You can be heard quite well if you run 1000w and a single yagi, but you will not find receiving a station similar to you, very easy. This is because your receiving gain is inadequate. Single yagis MUST have the preamp located at the antenna to hear anything.
I run 4 yagis but only 185w in the shack. 125w makes it to the array. Single-yagi stations can be worked but it is very difficult taking sometimes several hour+ attempts to accomplish. On the other hand I can copy a single yagi station quite well.
So if you can only get one yagi up, get the biggest you can handle (Cushcraft 13B2 is the very minimum). And try to get more power so that more stations can be worked. Eight yagi or more stations can be worked pretty regular by a single yagi station.
The goal is to achieve a minimum of 16 kW EIRP.
I have worked 115 stations on eme most using JT65. Soon I will have a 8877 PA so my power will increase from 16.8 kW EIRP to about 65-70 kW. Don't be put off by what I have said, though. EME is within reach of any AO-10/13/40 equipped station.
Oh and yes the CW standard station is four yagis with 19-20 dBi array gain and 1000w.
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
On Dec 17, 2007, at 10:12 PM, Edward Cole wrote:
Realities of digital EME:
Great detail Ed, this will help me plan my setup here for trying this.
-- Nate Duehr, WY0X nate@natetech.com
At 11:12 PM 12/18/2007, Nate Duehr wrote:
On Dec 17, 2007, at 10:12 PM, Edward Cole wrote:
Realities of digital EME:
Great detail Ed, this will help me plan my setup here for trying this.
-- Nate Duehr, WY0X nate@natetech.com
I hope it helps understand that eme no longer means huge antenna arrays and lots of power, though it does require some good construction with low noise receiving in mind.
Something I forgot to mention: EME signals are subject to polarization shift when they pass thru the ionosphere. EME is linear polarization so if your 2m satellite antenna is circular pol you should consider rewiring so that either the horizontal or vertical elements can be used. This a little more complication if you want to retain circular pol for satellite use. My eme antennas have crossed elements just like many satellite antennas but the vertical elements are all connected thru a 4-way divider and brought to a T/R coax relay at the tower-top where the preamp is located. The horizontal elements are similarly connected in another 4-way divider. Thus I have two feedlines coming to separate coax T/R relays. The Tx side of each relays goes to a third coax relay that selects whether I use H or V polarization. The preamp has a fourth smaller coax relay (since it does not handle high RF power) so that the receiver can independently chose H or V polarity. One could simplfy this with less coax relays but then the TX and RX would always be the same polarity.
EME signals are not necessarily the same pol at the other station you are working so often I may transmit in one polarity and receive in the opposite polarity. Having them separately controlled makes this easier.
The point of telling you all this is that if you are running a QRP eme station (less than four antennas) you want to be able to shift polarization or your signal may not make it due polarization mismatch losses as high as 20-dB. EME signals are almost always in the noise. If you run a small one or two antenna station that is your condition all the time on eme. JT65 makes this all possible by enabling signal decoding of signals 10-dB weaker than what one can copy on CW. The signals can often be not audible under the noise, yet fully copyable with JT65 due to its superior narrow band digital processing. JY65 occupies 4.3 Hz bandwidth.
Two cross-pol satellite antennas (KLM-22C or the M2 2mCP22) will make a pretty good eme stations, today. If you can add a 400w PA to that you will work hundreds of eme stations using JT65. My M2 2m-xpol-20 are quite similar to the 2mCP22 except not wired for circular pol.
You do not need the antennas mounted high on a tower for eme (same as for satellites) since the moon is often high in the sky. AZ-EL antenna rotation is needed to do much eme, but that is standard on most satellite antennas setups. NOVA and many other satellite trackig programs have the Moon listed so that is all you need to point your antenna. Keeping on the moon requires moving the antennas about every 20-30 minutes so no need for auto-tracking.
There is a lot of help for those that are interested in trying eme.
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
Have you EVER, even ONCE, posted a POSITIVE message to the BB?
Volunteered to represent AMSAT at a hamfest?
Contributed anything (other than criticism) to the design or construction of any satellite?
----- Original Message ----- From: "Vince Fiscus, KB7ADL" vlfiscus@mcn.net To: amsat-bb@amsat.org Sent: Wednesday, December 12, 2007 12:03 PM Subject: [amsat-bb] Re: Bob's Message
At 08:54 PM 12/11/07 -0500, "Rick Hambly (W2GPS)" w2gps@cnssys.com wrote:
Trevor,
The Intelsat opportunity is just that, an opportunity. It's not a sure thing so the Eagle project will be the backup.
Like how the BOD put Eagle on the back burner and instead built Echo so people could pass more Grids?
KB7ADL
participants (11)
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Bruce Robertson
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Dave Guimont
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Edward Cole
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George Henry
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Jeff Davis
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Joe
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Nate Duehr
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Rick Hambly (W2GPS)
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Tony Langdon
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Trevor
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Vince Fiscus, KB7ADL