July 2007 - Eagle (INACTIVE) - mailman.amsat.org

Receiver Spec vs. ATP, a few Suggestions and a Question or Two
by Juan Rivera 06 Aug '07

06 Aug '07

John, I took a few minutes to look over your new specs and compare them against the Acceptance Test Procedure. I've got a number of tests in the ATP for which there are no specs: * Image rejection * Internally generated spurs * Local oscillator leakage * Input and Output VSWR Items that need to be addressed that aren't in either document: * EMI conducted susceptibility * EMI radiated susceptibility * Short and long-term frequency stability I also take issue with the -60C minimum power-down temperature. I think this is unrealistic just from a CTE mismatch perspective. The reliability of anything subjected to that wide a temperature spread is going to suffer. A way must be found to raise that temperature. I have a few thoughts... The CAN-Do switching step-down converter is only supplying 11 milliamps. If we take a slight efficiency hit we could just go to a simple linear regulator and completely eliminate the radiated and conducted EMI emission problem from CAN-do. That eases the EMI filtering and shielding requirements for every single payload. That seems like a good trade-off to me. Rather than worry about trying to conduct heat through a PCB why not just go to externally mounted regulators for the CAN-Do and the Receiver right on the case itself. We're not that pressed for space. That eases the heat sink and the associated thermal gap filler issues. EMI will still be an issue, but only for external sources instead of one that is inside the enclosure itself. That strikes me as a huge bonus. Why not design a single-sided PCB with the regulators hanging over the edge and the whole assembly, PCB and regulators, mounted directly to the enclosure. Stick it in with the CAN-Do module in a separate cell. Filter all the signal and power through the common bulkhead. I'm also curious as to why you are specifying two different types of SMA connectors. 73, Juan - WA6HTP

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This weekend at Central States VHF Society
by Tom Clark, K3IO 02 Aug '07

02 Aug '07

This year's CSVHFS meeting wound up tonite in San Antonio. Among the many AMSAT folks in attendance were W4MO, W7LB, W5IU, W3XO, N4HY, K5SDR, W5SXD, N6TX, KL7UW and K3IO. There were no satellite specific papers presented this year, but the world of DSP and SDR was very much present. K5SDR presented his new SDR5000 radio. KL7UW (with the SDR-IQ) and W5LUA (with the Softrock-40) reported on the use of SDR receivers for various VHF/UHF/Microwave tasks. AMSAT highlights of the meeting came at Saturday Night's banquet. K3IO accepted a financial contribution from CSVHFS for AMSAT. And then the crowning glory: Bob McGwier, N4HY was presented the 2007 John Chambers Memorial Award for technical achievement, recognizing his many SDR and AMSAT activities. Bob joins previous AMSAT Chambers Award recipients W0LER, W0PN, W3GEY & K3IO. Congratulations to Bob -- 73 de Tom, K3IO

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Re: N4HY wins prestigious award
by Robert McGwier 29 Jul '07

29 Jul '07

Thanks Dale, Tom, and others. I have had great partners in all of my work. I am grateful for all of the ideas, support, trust, complaints, advice etc. that have flown freely from the SDR,Flex groups, TAPR, ARRL, and of course, AMSAT. It has been amazing fun to try out new ideas here and to work with Frank, Eric, and many others on our joint endeavors. There are too many people in AMSAT to thank but one must be singled out. Tom Clark talked me into doing technical work in AMSAT when I was still in college and later talked me into doing the DSP project with TAPR and AMSAT. That advice and encouragement had a tremendous impact on my life, defining its trajectory almost completely. My close relationship with Tom has gone on for over 25 years. Tom often does not seem to see that of all his contributions, the most important of all by far is the impact he has had on others through his friendship, mentoring, and leadership. In my mind, it is the one of the most accomplished lives in amateur radio and beyond if you completely subtract all of his technical work. Tom talked me into joining Central States who gave me the award. My wife and I love it so much we go every year not unlike most of its members. Dale, your friend was the runner up in the big CSVHFS operating award again with an eye toward going for first. I know you are proud of that friendship. I do not covet awards and I certainly don't seek them but the John Chambers award is one I am extremely proud to have as all of my engineering mentors in amateur radio have received it including, but not limited to, Tom and Jan King. This was a complete shock. 73's Bob Dale Boresz wrote: > Congratulations on the award Bob - and thanks for your continuing work > to advance the state of the art of radio communications. > > Great times for amateur radio. > > Dale > WA8SRA > -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson

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Re: This weekend at Central States VHF Society
by wb4gcs＠wb4gcs.org 29 Jul '07

29 Jul '07

CONGRATULATIONS BOB!!!!!!! Very 73, Jim wb4gcs(a)amsat.org This year's CSVHFS meeting wound up tonite in San Antonio. Among the many AMSAT folks in attendance were W4MO, W7LB, W5IU, W3XO, N4HY, K5SDR, W5SXD, N6TX, KL7UW and K3IO. There were no satellite specific papers presented this year, but the world of DSP and SDR was very much present. K5SDR presented his new SDR5000 radio. KL7UW (with the SDR-IQ) and W5LUA (with the Softrock-40) reported on the use of SDR receivers for various VHF/UHF/Microwave tasks. AMSAT highlights of the meeting came at Saturday Night's banquet. K3IO accepted a financial contribution from CSVHFS for AMSAT. And then the crowning glory: Bob McGwier, N4HY was presented the 2007 John Chambers Memorial Award for technical achievement, recognizing his many SDR and AMSAT activities. Bob joins previous AMSAT Chambers Award recipients W0LER, W0PN, W3GEY & K3IO. Congratulations to Bob -- 73 de Tom, K3IO _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle(a)amsat.org http://amsat.org/mailman/listinfo/eagle

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CAN-Do 3-second Glitches
by Juan Rivera 29 Jul '07

29 Jul '07

Stephen, I've mentioned this to you before and you've been kind enough to try to explain it to me several times, but I wanted to document these CAN-Do three-second glitches for posterity. After you look over my log and listen to the recording please feel free to add to my log. Just send me your comments and I'll include them. Here's the link --> http://www.juanr.com/pages/hobbies/ham_radio/Eagle/3-Second_Glitches.htm 73, Juan

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DC Input Test
by Juan Rivera 28 Jul '07

28 Jul '07

John, I'm in the process of reconciling your requirements document with the ATP. The first test in the ATP is a receiver power supply test. Requirement Actual Result Minimum voltage with no loss of signal level 10.8 10.35V 312.1 mA Pass Minimum voltage with 1 dB loss of signal No spec 10.14 N/A Maximum voltage 16.8 16.8V 230.7 mA Pass Juan

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[Fwd: HFSS Training, Burlington MA, August 2-3]
by Tom Clark, K3IO 26 Jul '07

26 Jul '07

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Status update
by Jim Sanford 25 Jul '07

25 Jul '07

Team: It's time for me to draft the next Journal article. Please send me your update by Wed, 1 August. If you have no progress to report, please send me that. (And let me know what's coming in the near future.) Thanks & 73, Jim wb4gcs(a)amsat.org

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70 cm Passband at -1 dB and -60 dB
by Juan Rivera 25 Jul '07

25 Jul '07

All, I re-ran the -1 dB passband test of the 70 cm receiver for my presentation. Here's another look at a 500 kHz span at 0.5 dB/Div: Here's a look at the -60 dB passband with a 2 MHz span and 5 dB/div. I increased the input Level to get the skirts out of the noise. It's 1.248 MHz wide at -60 dBc. Juan - WA6HTP

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A new opportunity (Phase 4 lite?)
by Robert McGwier 23 Jul '07

23 Jul '07

In the last few weeks we have been presented with a new opportunity to launch RF platforms into space. This note will necessarily be cautious because we do not wish to do or say anything that will throw a monkey wrench into the works. More specific details than are given here will come from one voice, and that is from Rick. This is a major development. One which will refocus some of the energy of the organization should it come to pass. That said, no one in management has proposed we stop Eagle and Jim Sanford will remain its project manager irrespective of what goes forward on the new project because we are still looking for rides for it. The following is adapted from Rick's note to the board of directors, with comments from me (and edits). We are being asked to propose that we ride on someone else's satellite with our RF gear and antennas. The primary is not a small satellite. It will go to geosynchronous orbit. There are MULTIPLE rides being discussed but we have to get our act together for round one. The planned lifetime of the large satellite is over a decade and they have a track record of exceeding it. At the beginning of life it produces 1 kw of excess power and we are trying to ask for at least 1/3 of that because at the end of life, after years of solar degradation, that is what the primary expects it to produce as excess power. They do station keeping to maintain their subsatellite point. They provide the ride. Thus, we do not need a motor, fuel tanks, hydrogen bottles, propellant flow assemblies, or liquid ignition units. They provide the electricity, thus we do not need solar cells or a battery. We will not need an attitude control system at all or even attitude sensors except for "gee whiz" like cameras or experiments. They could easily provide us about as much space and mass as the Eagle would have consumed, BUT WE DO NOT NEED IT. Rick suggested to them that we would probably need as much antenna space as we have proposed for Eagle, and they did not blink. Mechanical constraints (moment of inertia ratios) allowing for a motor are completely out of the picture. We will be rigidly mounted to their frame and they do the work. They will be asked to provide some thermal control for our RF modules, which will sit on the Nadir pointing side of their spacecraft, which is 3 axis stabilized, and will of course be subjected to hours in the sun and hours in the dark. A careful thermal design is required. We will never need to point another antenna on the ground after the very first time should their payload behave. We will not need to despin a phased array at 3 rpm. WE WILL need a phased array but it will be adjusted in tiny increments on a daily basis at most. No more spin modulation unless there is some failure on their bird. We need our very high efficiency power amplifiers, both the proposed linear and hard limiting design to be, as much as possible, producers of RF and not heat. They are offering this opportunity because they have discovered that if a goodly portion of the heat that is dumped from their solar arrays at the beginning of life is consumed in RF, light, etc., it saves them a considerable number of resources. This was one clever study by an in house engineer. They have been given some basic technical information on our proposed payload. We, AMSAT, must get together now and provided them with real answers on our proposed payload in a formal written proposal, but they were given these rough estimates. We need to provide the follwing which includes but is not limited to: 1) Size & Mass [less than 50kg, probably closer to 20kg, no batteries, ] Antenna Configuration (space required) [they were told the same as Eagle, a 60cm per side hexagon or some equivalent] Frankly, it needs no symmetry at all. It can be completely determined by the needs of the antennas and the envelope restricting us. 2) Given that, there is no need for a very thick spacecraft since it has NOTHING in it but RF modules and computer(s). 3) Power requirements [they were told about 300 Watts] 4) Efficiency (how much power becomes heat) [we agreed to choose 0% to start thermal design] (sic, from Rick. I don't understand what needs to be calculated if we agree that we produce 300w of heat, then our body will quickly rise to a very high temperature and melt. I think they want to upper bound the thermal control needed for us. ;-) . ) 5) Need for some of their on board resources to be specified and more details follow after our study. 6) They must be told a REALISTIC schedule that we can meet. That will determine what launches will be available to us and where the multiple payloads will be placed. We do know their power bus is many times our planned voltage, and we need to decide if we or they build the power converter. This is pretty obvious because they don't want to power TWT's, etc. from 5 or 14V!!! If we do multiple payloads with them, as is currently proposed, they would consider providing a "LAN" for us to communicate between satellites to our payloads (think direct, bird to bird interlinking). If the design study says we will not impact them greatly, they can provide us this link. For Eagle, we have planned to use 3400-3410 MHz for Earth->Space and 5830-5850 MHz for Space->Earth. It may be necessary to switch these to be compatible with their transponders which are on nearly identical frequencies BUT IN THE OPPOSITE DIRECTION. We don't want to transmit near their receive frequencies. This raises a serious problem as Region 1 does not permit us to radiate signals from the satellite in the 3400-3410 MHz band if they can see it. So it is clear, I will need to call engineering meetings, and more than one, in the next couple of months. We are prepared to spend the money on these meetings and bet this will be pulled off. If it looks like we really will close this deal (as in signing an MOU) then we will definitely bet the farm on it. Right now, we probably should think we are basing the payloads initially on what has been thought of for Eagle and we need to rethink this because one thing should be crystal clear. THESE ARE NOT ADEQUATE. Think about what it will mean to have a very loud transmitter, either analog or digital, available 7/24/365.25 at the same spot in the sky. We do not have sufficient capacity in our current design, period. We would not want to do the SMS text messaging in the linear transponder, but would likely move it back to Microwave for example. This relieves the phase noise demands on the system for SMS (maybe not other considerations TBD). Also, the user antennas on the ground are fixed. We need some redesign starting from our basic payloads and then building them out to meet what capacity we think we can support but this will be the first time we have ever spent all of our power on the RF and very little on anything else! I hope you can see that we must be both bold and professional with a dash of caution. A dash only because the probable time schedule will not allow us to pontificate for half a decade. If we pull this off, there is very little doubt in my mind that this will change not only AMSAT, but amateur radio in general, and if we do our job well, in a big way. We must thank Lee McLamb profusely for finding out this opportunity was becoming available. Special circumstances allowed us, following his notice to us, to move VERY quickly to "go in at the top of the organization". That was done (MAN do I love low friends in high places and in this case, at the very top). More details will follow as the okay comes from Rick. Please refrain from speculation or much gossip. I know I would be heart broken if the wrong leak or wrong public statement caused us to lose this major opportunity. I will not be entertaining a thousand questions but I do want everyone to think about the redesign of the payloads carefully to support a geosynchronous bird. 73's Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson

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DICK JANSSON -- I NEED YOUR DIRECT EMAIL ADDRESS
by Jim Sanford 20 Jul '07

20 Jul '07

For whatever reason, my address book only has the old ones . . . Thanks & 73, Jim wb4gcs(a)amsast.org

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Help Needed
by Juan Rivera 19 Jul '07

19 Jul '07

Hello All, I'm trying to arrive at a reliable method of measuring phase noise for the testing I'm doing on the 70 cm Eagle Receiver. I recently purchased an SDR-IQ software defined radio. It makes a great spectrum analyzer below 30 MHz, with a very low noise floor and great resolution. I took it to work to show to my coworkers and the lab manager liked it so much he purchased the big brother of this unit, the SDR-14, which I borrowed and brought back to my shop. I also sent my Agilent 8566B spectrum analyzer out for calibration so now I have three pieces of test equipment that I can use to measure the phase noise of the 70 cm Receiver. My problem is that I cant get any two of them to agree... Ive fed the same 10 MHz 0 dBm signal into each unit, recorded all of their settings and created the attached PDF file. As you will see, they all differ. If we look at the 120 Hz power supply sidebands you get the following: SDR-IQ: -102 dBm SDR-14: -93 dBm 8566B: -84 dBm The 8566B automatically calculates RMS noise levels normalized to a 1 Hz noise power bandwidth by correcting for the analyzers log amplifier and detector response and compensating for the resolution bandwidth setting. Its capable of accurately measuring noise levels down to 10 dB above the spectrum analyzers noise level (-131.6 dBm) and reading out in steps of ±0.1 dB. At a 150 Hz offset it measures -104.0 dBc/Hz. Looking at the two SDR units its hard to reconcile this measurement with either of them, or to reconcile any of the power supply sidebands. Both SDR units measure power levels in a very linear way. Ive confirmed their accuracy at the levels Im interested in around -90 dBm. Can anyone shed any light on this? No combination of FFT block size, span, RF or IF gain, or filter bandwidth can make any two of these devices agree on the noise floor or the amplitude of the power supply sidbands. 73, Juan WA6HTP A man with a watch will always know what time it is - a man with two watched can never be sure.

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Payload Adapters and excess launch margins
by Lee McLamb 19 Jul '07

19 Jul '07

As Bob mentioned I attended the NASA/NRO Rideshare conference again this year. I've just uploaded a file to Eaglepedia with one of the presentations which shows the current and some proposed secondary payload adapters presented by United Launch Aliance (ULA - the new Boeing & Lockheed-Martin partnership). Especially interesting is the 1000 and 1500 lb propellent margins for the AEHF and WGS missions on slide 11. While we won't be ready for their first flight, both of these are the beginning of a constellation build-up which means there will be multiple re-flights for each. Now I'm looking for an angle to get Eagle into an IPC for one of these missions. http://www.amsat.org/amsat-new/eagle/EaglePedia/uploads/a/aa/Keath_Karuntzo… 73, Lee-KU4OS

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Re: [Advisors] A new opportunity (Phase 4 lite?)
by RaySoifer＠cs.com 18 Jul '07

18 Jul '07

In a message dated 7/17/2007 2:53:03 PM Pacific Daylight Time, rwmcgwier(a)gmail.com writes: > This raises a serious problem as Region > 1 does not permit us to radiate signals from the satellite in the > 3400-3410 MHz band if they can see it. Bob et al, This might overstate the problem just a bit. The ITU RR allow any country to put any station on any frequency, as long as no harmful interference is caused to stations operating in accordance with the Table of Frequency Allocations. So, depending upon the orbital station(s), it may be possible for us to design an antenna whose footprint would result in a PFD low enough in the Region 1 land mass so as not to cause harmful interference there. One more design issue for the engineering team.... 73, Ray

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Source of 70 cm Microphoncs Found
by Juan Rivera 17 Jul '07

17 Jul '07

John, The microphonics is caused by C19, C27 and C28 (.047uF 25V) and C50 and C51 (.022uF 25V). I found the best way to isolate this is to inject a CW signal into the receiver, tune the signal in at the IF output using my TS-2000 in AM mode, and then listen to the audio output while lightly tapping each component one at a time. According to my research, barium titanate, the base ceramic material for most ceramic SMD capacitors is inherently microphonic. Juan

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2M High Efficiency PA
by Tom Clark, K3IO 15 Jul '07

15 Jul '07

In case you missed it, the following EAGLE item appears in today's AMSAT NEWS SERVICE (ANS) bulletins: > SB SAT @ AMSAT $ANS-196.04 > High Efficiency RF Linear Amplifier Design Proposed for Eagle > > AMSAT News Service Bulletin 196.04 > >From AMSAT HQ SILVER SPRING, MD. > July 15, 2007 > To All RADIO AMATEURS > BID: $ANS-196.04 > > AMSAT members Allen Katz, K2UYH and Marc Franco, N2UO have > designed a VHF, high-efficiency, class-E, RF power amplifier > with a DC to RF efficiency of 86.8%. Their innovative > design is based on silicon carbide (SiC) metal-semiconductor > field effect transistors, or MESFETs. > > The design was presented in a paper at the IEEE International > Microwave Symposium in Hawaii. It is now available on-line: > http://www.cree.com/products/wireless_docs.htm titled > "Class-E Silicon Carbide VHF Power Amplifier" (June 5, 2007) > > The final amplifier efficiency was measured at around 86 to 88% > with this number holding quite well at almost any drain voltage > or output power. This type of amplifier is under consideration > for the envelope elimination and restoration linear amplifier > planned for the AMSAT Eagle satellite. > > [ANS thanks Marc, N2UO for the above information] > > /EX > Marc has promised to have a presentation with more details on this work for the October AGM in Pittsburgh. (BTW -- Marc & Patty are expecting their first 2nd harmonic)

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EMI Control & PCB Analysis - Aug. 22, Boston
by Tom Clark, K3IO 14 Jul '07

14 Jul '07

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Phase Noise Calibration
by Juan Rivera 13 Jul '07

13 Jul '07

All, I've written up my efforts to understand the SDR-IQ and to use it to measure phase noise on the 70 cm Receiver. You can read it HERE <http://www.juanr.com/pages/hobbies/ham_radio/Eagle/Phase_Noise_Calibration. htm> . 73, Juan - WA6HTP

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P3E SDX Design Levels take 2
by Howard Long 12 Jul '07

12 Jul '07

Folks Sorry I will try again with some formatting. Following the Teamspeak meeting, the pertinent levels for P3E: V Tx Phase +10dBm @ 145.895MHz into 50 ohm; V Tx Envelope 2Vp-p into 1kOhm baseband; U/V AGC I/O: 2V full gain, 5V full compression (output capable of ~2.5mA drive); U band IF in -15dBm @ 10.7MHz into 50 ohm; L band IF in -15dBm @ 10.7MHz into 50 ohm; S band IF out -15dBm @ 10.7MHz into 50 ohm. 73, Howard G6LVB

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Re: 10 MHz Phase Noise
by Juan Rivera 12 Jul '07

12 Jul '07

Bill, I'm sending you my preliminary phase noise results. As you recall, I constructed a battery-powered 10 MHz oscillator by grabbing a junked reference oscillator from an old HP signal generator and mounting it in a box with two 9-volt batteries, a switch, and a BNC. That allowed me to bring it into work and use the Agilent ES5500 Phase Noise Measurement System on it. Then I brought it home as my poor-man's phase noise source. Here's the test results on the oscillator and the first look at the SDR-IQ: Phase noise of the battery-powered oscillator Here's the same oscillator captured with the $400 SDR-IQ. The SDR-IQ drifts in relation to the device under test so the signal average is artificially low. It's really at 0db on the scale. With the IF and RF gain set to their lowest settings I think this lines up pretty well until the level drops down to the SDR-IQ baseline noise level at about the 100 kHz point. The 120 Hz bump has to be coupling from the PC via the USB port where it gets its power. I was able to rid the SDR-14 of that by tossing the wall wart and using a lab bench supply. For now I'll just ignore this one. What do you think? Juan -----Original Message----- From: Bill Ress [mailto:[email protected]] Sent: Tuesday, July 10, 2007 7:27 PM To: Juan Rivera Subject: 10 MHz Phase Noise Hi Juan, Really sorry you couldn't transmit this evening. I always enjoy your keen comments. Thanks for the 10 MHz phase noise data. What is the model number for the HP oscillator? It's probably a version of the one I use. Now - - - - I'm really interested in what you read on your SDR. On the 8566B you'll just be looking at its internal LO's phase noise floor but it will be very interesting to see what your SDR phase noise floor is. Your test results will be the key data point in my decision to buy one. Again - much thanks for you fine work. Regards...Bill - N6GHz

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P3E SDX Design Levels
by Howard Long 11 Jul '07

11 Jul '07

Folks Following the Teamspeak meeting, the pertinent levels for P3E: V Tx Phase +10dBm @ 145.895MHz into 50 ohm V Tx Envelope 2Vp-p into 1kOhm baseband U/V AGC I/O: 2V full gain, 5V full compression (output capable of ~2.5mA drive) U band IF in -15dBm @ 10.7MHz into 50 ohm L band IF in -15dBm @ 10.7MHz into 50 ohm S band IF out -15dBm @ 10.7MHz into 50 ohm 73, Howard G6LVB

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Re: P3E SDX Design Levels
by Howard Long 11 Jul '07

11 Jul '07

Sorry I will attempt a re-format... Following the Teamspeak meeting, the pertinent levels for P3E: V Tx Phase +10dBm @ 145.895MHz into 50 ohm V Tx Envelope 2Vp-p into 1kOhm baseband U/V AGC I/O: 2V full gain, 5V full compression (output capable of ~2.5mA drive) U band IF in -15dBm @ 10.7MHz into 50 ohm L band IF in -15dBm @ 10.7MHz into 50 ohm S band IF out -15dBm @ 10.7MHz into 50 ohm Howard -----Original Message----- From: Howard Long [mailto:[email protected]] Sent: 11 July 2007 02:59 To: 'AMSAT Eagle' Subject: P3E SDX Design Levels Folks Following the Teamspeak meeting, the pertinent levels for P3E: V Tx Phase +10dBm @ 145.895MHz into 50 ohm V Tx Envelope 2Vp-p into 1kOhm baseband U/V AGC I/O: 2V full gain, 5V full compression (output capable of ~2.5mA drive) U band IF in -15dBm @ 10.7MHz into 50 ohm L band IF in -15dBm @ 10.7MHz into 50 ohm S band IF out -15dBm @ 10.7MHz into 50 ohm 73, Howard G6LVB

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Password change part 2
by Robert McGwier 11 Jul '07

11 Jul '07

I have changed the password back to Eagle. It is now consistent with the Eaglepedia web page. Sorry for the confusion. Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson

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Can't Log Into Conference
by Bill Ress 11 Jul '07

11 Jul '07

Hi Guys, For some reason "Eagle" doesn't log me in. Did the channel password change?? Regards...Bill - N6GHz

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TeamSpeak Password Changed
by Tom Clark, K3IO 11 Jul '07

11 Jul '07

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TS channel recreated
by Robert McGwier 10 Jul '07

10 Jul '07

I have no idea what happened. I recreated it AMSAT Engineering, password eagle1 and since it is fortunate I cannot remember what day of the week it is, I will see you folks tonight. 73's Bob -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson

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Teamspeak
by Dick-rr 09 Jul '07

09 Jul '07

With the bringing of the new computer on line, I discover that I do not have the information needed to bring up the Teamspeak connection. Can someone help me today so that I can be available tonight? Dick, KD1K

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TeamSpeak conference for 10 July
by Jim Sanford 09 Jul '07

09 Jul '07

Team: Reminder, our next conference is next Tuesday at 2100 EDT, 1800 PDT, and 0100Z. I will write the agenda (much) later tonight. If you have inputs, pls get to me, or feel free to modify mine, once I load it on EaglePedia. Thanks & 73, Jim wb4gcs(a)amsat.org

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First Temperature Run on the 70cm Receiver
by Juan Rivera 06 Jul '07

06 Jul '07

Greeting! I hope you are all having a great 4th of July! And as Jim says, please give a kind thought to the folks over in the Mid East. The temperature over there in the summer gets up to about 135 in the sun. It's a miserable environment just trying to walk from one place to another in a tee shirt. I can't imagine how anyone can grunt 40 or 50 pounds of equipment and have to worry about getting blown up. Believe me. They all earn their pay! Early this morning I started setting up for the first temperature run on the prototype 70cm Eagle Receiver. Unfortunately I believe that the master oscillator has got to go. I'll verify my suspicion this evening when the temperature in the shack drops back down to survivable levels... Please take a look and my report by clicking HERE <http://www.juanr.com/pages/hobbies/ham_radio/Eagle/Temperature_Run.htm> and look for the three audio wav files towards the end. 73, Juan - WA6HTP

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70cm Receiver Temperature Run in External Reference Mode.
by Juan Rivera 05 Jul '07

05 Jul '07

All, I ran a Temperature Run on the 70cm Receiver in External Reference Mode. Click HERE <http://www.juanr.com/pages/hobbies/ham_radio/Eagle/Temperature_Run.htm> for details... 73, Juan

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70 cm Frequency Stability Tests Results
by Juan Rivera 04 Jul '07

04 Jul '07

All, I should have gone to work today but I ended up working on the 70 cm Receiver all day instead. Today marks a milestone for me -- my first use of audio files. You'll find two in my write up if you click HERE <http://www.juanr.com/pages/hobbies/ham_radio/Eagle/Stability.htm> . I think they work much better than descriptions and graphs. Now you can hear what I'm talking about... Have a great 4th! I plan to do a temperature run on the receiver tomorrow to celebrate! Let's see what that internal oscillator does when it's not at room temperature! P.S. to OSCAR guys... If you have time come on over and help me run this test. I'll probably start early to beat the heat. If you've never been gassed by CO2 before, now is your chance! 73, Juan - WA6HTP

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TeamSpeak conference for Tuesday 10 July 2007
by Jim Sanford 04 Jul '07

04 Jul '07

All: For whatever reason, I'm unable to update EaglePedia (it ignores my changes), so here's the agenda as I see it. Feell free to suggest additons to me, I'll keep a running total and publish just prior to the meeting. Topics: 1. Symposium 2. Requirements documentation ' 3. WBS and schedule development 4. Status reports UHF RX S2 Rx 5, EMI Please add topics. Thanks & 73, Jim wb4gcs(a)amsat.org

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70 cm Receiver Frequency Stability and One More Glitch
by Juan Rivera 03 Jul '07

03 Jul '07

All, Here's a plot of frequency drift in the 70 cm Receiver - first on internal reference, then on external reference: The first part of the plot is with the receiver and the signal generator set to 435.500000 MHz on internal reference. You can see the slow steady drift upwards of about 15 Hz over a period of about 5 minutes. Then I reinitialized the receiver for the external reference. It locked right up and the output was exactly 10.700000 MHz where it stayed. The most important thing I noticed is not on this graph. With internal reference selected, but while feeding 10 MHz into the external reference input, (as it might be configured in flight) the two reference signals are beating together. It wasn't until I started listening to the output of the receiver by patching it into a distribution amplifier so I can feed my counter, the SDR-IQ, the TS-2000, and the HP 8566B all at once that I noticed it. The result is that the input signal is FM modulated by the beat between the two reference oscillators. I also noticed some unexplained jumps in frequency that I have not yet been able to capture. I'll dig into this again when I have more time. 73, Juan

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CAN-Do Causing RF Frequency Jumps in 70 cm Receiver
by Juan Rivera 03 Jul '07

03 Jul '07

John and CAN-Do Team, I was in the process of checking some configuration files in preparation for my hunt for the 10.7 MHz spur. I initialized the receiver on 435.500, internal reference, and set up the SDR-IQ to display the IF output signal. Then I clicked the heartbeat button on the Can-Do Net Controller and was about to load the initialization file for external reference. As soon as I clicked the heartbeat button the IF output started jumping. I think it's the three second jumps that I have seen before, but I thought those were caused by a momentary loss of DC input power. In this case the receiver power is coming directly from the bench supply. I killed the CAN-Do module power and the IF jumping stopped. As soon as I applied power to the CAN-Do module again, the jumping returned. The duration of the jumps is very short and I am unable to capture a carrier - either with the SDR-IQ or using my TS-2000. They sound like clicks over a wide frequency range. Since the next revision of the receiver will be autonomous, perhaps this won't be an issue for us, but it will for others so it should be understood and documented in my opinion. 73, Juan

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10.7 MHz Spur
by Juan Rivera 03 Jul '07

03 Jul '07

John, I found the source of the 10.7 MHz spur. It's being generated inside the receiver itself. This is the first spur I have found that is not caused by switching power supplies. The origin appears to be in the 10 MHz reference area. I turned off and unplugged the SDR-IQ and fed the IF output from the 70 cm Receiver to my TS-2000. The spur is still there. Next I connected the RF input to my sniffer loop and moved it around the PCB surface. I get the strongest signal near the long trace between the two Freq inputs to U4 and U9, the two phased-locked loops. 73, Juan

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