[amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)
At 02:20 AM 4/22/2010, Stephen Melachrinos wrote: Ah, but this focuses on my question: Why is ERP referenced to a dipole? Why did someone assume that Arecibo's stated gain of 60 dB was dBd and not dBi? I've never seen the gain of a dish antenna used in satellite work quoted in dBd. All of the references for calculating gain are based on the isotropic reference. And all of the usages I have seen (in professional satellite work) use ERP and EiRP interchangeably, and the i in EiRP is used to explicitly state referenced to isotropic. In fact, the amateur community is the only place where there is a fascination with the dipole reference. The dBd specs are useless for any real calculation purposes. Satcom engineering is much simpler if everyone quotes isotropic, and all commercial/government/military satellite link budgets are based on isotropic references. Steve Melachrinos W3HF (Professional) Satcom Engineer since 1979 ERP is about 243 MW and that comes from the conversion from dBi to dBd. ___ Sent via amsat...@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 In fact the first gain number published over a month ago was 58 dBi. Then I suppose a bunch of hams complained that they didn't understand isotropic gain so the Arecibo folks kindly converted the number to 60 dBd. (i.e. unity isotropic gain, dBi=0, is what a true omni-directional antenna produces in free space) Does anyone on this reflector know the formula for calculating gain of a parabolic dish (Yes, I know-I'm asking if you know)? Did you know that Arecibo dish is spherical and not parabolic? So we can only use the gain number they provide (BTW the UHF line-feed corrects for spherical aberration of the dish surface at Arecibo). Arecibo can track a small amount of angle because the dish is spherical. It is my understanding (might be wrong on this) the line-feed can adjust for the amount of surface irradiated (which will change the gain). The formula normally used in radio astronomy and mw engineering is in terms of dBi. Most (not all) eme hams use dBi vs dBd. I am really amazed at this thread on amsat-bb. I thought the satellite community was more globally oriented (International). The different convention in expressing decimal numbers (aka using comma or period) is pretty well known (I thought). US/UK use period and most EU use comma. Most antenna analysis sw express gain in dBi 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)
At 07:46 AM 4/22/2010, Edward Cole wrote: At 02:20 AM 4/22/2010, Stephen Melachrinos wrote: Ah, but this focuses on my question: Why is ERP referenced to a dipole? Why did someone assume that Arecibo's stated gain of 60 dB was dBd and not dBi? I've never seen the gain of a dish antenna used in satellite work quoted in dBd. All of the references for calculating gain are based on the isotropic reference. And all of the usages I have seen (in professional satellite work) use ERP and EiRP interchangeably, and the i in EiRP is used to explicitly state referenced to isotropic. In fact, the amateur community is the only place where there is a fascination with the dipole reference. The dBd specs are useless for any real calculation purposes. Satcom engineering is much simpler if everyone quotes isotropic, and all commercial/government/military satellite link budgets are based on isotropic references. Steve Melachrinos W3HF (Professional) Satcom Engineer since 1979 ERP is about 243 MW and that comes from the conversion from dBi to dBd. ___ Sent via amsat...@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 In fact the first gain number published over a month ago was 58 dBi. Then I suppose a bunch of hams complained that they didn't understand isotropic gain so the Arecibo folks kindly converted the number to 60 dBd. (i.e. unity isotropic gain, dBi=0, is what a true omni-directional antenna produces in free space) Does anyone on this reflector know the formula for calculating gain of a parabolic dish (Yes, I know-I'm asking if you know)? Did you know that Arecibo dish is spherical and not parabolic? So we can only use the gain number they provide (BTW the UHF line-feed corrects for spherical aberration of the dish surface at Arecibo). Arecibo can track a small amount of angle because the dish is spherical. It is my understanding (might be wrong on this) the line-feed can adjust for the amount of surface irradiated (which will change the gain). The formula normally used in radio astronomy and mw engineering is in terms of dBi. Most (not all) eme hams use dBi vs dBd. I am really amazed at this thread on amsat-bb. I thought the satellite community was more globally oriented (International). The different convention in expressing decimal numbers (aka using comma or period) is pretty well known (I thought). US/UK use period and most EU use comma. Most antenna analysis sw express gain in dBi hmm dBi = dBd +2.15. Gain of dipole = 1.64 10Log(1.64) = 2.15 dB so what gives here? is it 58 dBd and 60 dBi? Sorry if I wrote that backwards. Or we just playing around with significant numbers and gain is approx 58 to 60 dB (somethings). Pat, Joe? can you please clear up this mess and state for everyone what the gain is for Arecibo on 432-MHz? 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Arecibo--MUCH louder today!
At 10:31 AM 4/17/2010, Edward Cole wrote: At 09:41 AM 4/17/2010, Mark L. Hammond wrote: Hearing test carriers MUCH better today! Give it a listen, they are saying 350W output today (rather than 30W yesterday ;) 73! Mark N8MH Mark L. Hammond [N8MH] ___ Sent via amsat...@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 Nothing heard here, but the M2 11-element yagi (11.3 dBd/13.4 dBi) cannot be elevated (Moon is now 18-deg) so probably Moon is out of the beam. I am using a Gasfet preamp on this antenna whose normal use is for terrestrial 70cm SSB/FM. Back to work on getting the dish ready (perhaps tomorrow?): hooking up 432 antenna, preamps for 432 1296, and 432 TR relay, plus getting az-el system calibrated. Got the 432 1296 Pa's installed yesterday and some things that didn't work out and will have to be done after the weekend. All wiring to the dish have to be tested, yet. Yeah, a bit behind the curve for working Arecibo ;-) 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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 Briefly heard voice on 432.044.500 about 1920 when Moon was 24.5 deg.elevation; maybe the Moon traversed a sidelobe of my yagi? I checked with KL7XJ who is also trying to hear Arecibo to see if he might have been transmitting - he was not. No other 432 SSB stations within 70-miles so that rules out QRM. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Arecibo
In march they set up the radios in the antenna structure at the feed; now probably have some feedline loss since relocating to a more amenable operating room. I cannot watch the TV stream since something has turned off my active-X on this computer. 73, Ed - KL7UW At 11:27 AM 4/16/2010, Bill Dzurilla wrote: I'm at work and not QRV, but I had no problem copying them with a single 12 el. yagi leaned again the chair when they did the test a couple of weeks ago, and most everyone else gave them good reports. At the time, they were running 50w, a barefoot Kenwood TS-2000. They must have changed rigs if now they only have 20w. And something else must be wrong, because even folks with big antennas are having trouble copying them (more so than the 50w vs. 20w would suggest). There's a live feed at http://www.ustream.tv/channel/kp4ao-eme Good luck and 73, Bill NZ5N From: Sebastian w...@bellsouth.net Subject: [amsat-bb] Re: Arecibo To: Mark L.Hammond marklhamm...@gmail.com Cc: AMSAT BB AMSAT-BB@amsat.org Message-ID: 4141f900-265d-4987-b3be-59b3834be...@bellsouth.net Content-Type: text/plain; charset=us-ascii I can hear very faint CW from them. I'm surprised as I have just a single yagi, and apparently their amp isn't working. 73 de W4AS ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Arecibo
At 08:23 AM 4/15/2010, Bob- W7LRD wrote: Hello Should I be so lucky as to connect with Arecib o this weekend, what is the proper protocol for a QSO? 73 Bob W7LRD Seattle ___ Sent via amsat...@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 Bob, A good question since they will be using SSB, initially. I do not operate eme on 432+ but I believe that normal calling is done on 2-1/2 minute sequences. I suspect that will not be done with Arecibo (but they should say what their operating protocol will be). Normal eme protocol goes like this: CQ de KP4AO calls for 2.5 minutes KP4AO de KL7UW means KL7UW copied KP4AO call sign (not calling in the blind); calls for 2.5 minutes KL7UW de KP4AO signal report (May be RST or OOO); also means Arecibo copied both KP4AO and KL7UW's call sign; gives report for 2.5 minutes KP4AO de KL7UW roger your report (RO) and/or RST; for 2.5 minutes KL7UW de KP4AO RRR means I copied your report; for 2.5 minutes KP4AO de KL7UW 73 and SK; end of successful contact; for 2.5 minutes total time 15-minutes So with 2:45 hours of operation 11 QSO's could be made; so I do not expect the usual 2.5 minute time sequence. That is usual for CW and digital eme, but I do not know what is likely to ensue with the expected pile up on SSB. But for proper eme both calls must be given and confirmed (unlike HF were only one call is stated and the other station, assumed). 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Arecibo and circular polarization using cheap yagis
At 12:16 PM 4/15/2010, Douglas Quagliana wrote: I heard Arecibo would be using circular polarization, but I haven't heard if it will be left or right-handed circular polarization. I also heard that there's a way to do circular polarization with the popular cheap yagis. Apparently the details are in an article in the April 1999 issue of CQ VHF Cheap Circular Polarization? It Can Be Done on pages 66-69. Is there anyone on the list that has this back issue that can tell me what the method is that is described in this article? Is it a physical quarter-wave displacement on the same boom? Two booms with a quarter-wave coax delay? Something else? How is the circular polarization done with the cheap yagis? Douglas KA2UPW/5 ___ Sent via amsat...@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 You are running out of time to build a CP antenna system for the Arecibo eme event, aren't you? I would not worry about it and just use a simple yagi in any polarity. Yes, you will lose 3-dB of the signal from Arecibo, but it probably won't matter much if your antenna is big enough. Arecibo will be transmitting an effective power of 441 Mw. But if you want to make a CP antenna from a yagi, you need two sets of elements perpendicular to each other (i.e. two antennas mounted on a single boom or two separate antennas one rotated 90-degrees in polarity from the other. If both are mounted so the antennas are in-phase you need to split the feedline and add 1/4 wavelength of cable to one antenna. Or you can split the feedline equally if one antenna is spaced 1/4 wavelength ahead of the other. The relation of the fed elements determine whether you get RH or LH CP. The center conductor is connected to one side of the fed element (this is called the + side). If the antenna to the rear (or not with extra feedline) is vertical with + straight up and the other antenna has its + element pointing to the right, you get RHCP. Reverse it and you get LHCP. For antennas in the X configuration (back antenna + up and to the left, front antenna = up and to the right for RHCP. Caveat: I f you have the antenna configured backwards for Arecibo then you will hear nothing. Little understood fact of eme: RHCP signals are reflected by the Moon as LHCP signals back to earth, and vice versa. We have no info on Arecibo, but for hams the convention is to Tx - RHCP and RX - LHCP for eme. So if you build a CP antenna and you plan to transmit, also, you will need a polarity switching system between Tx and Rx. I am building a simple two-element Quagi (linear pol) to feed my dish (24.5 dBi). VK3UM spreadsheet says Arecibo will hear me with a +20 dB signal on SSB. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: (no subject)
At 11:45 AM 3/16/2010, Jack Barbera wrote: Bob,with the AG25 preamp on I see s5/6. I do get the audio at a higher level ,it seems to me,. Just added to AO-51 the L/u to my doppler for satpac32 FM/FM to add for cross mode do I have to add a separate line or add to the info on the FM/FM string. If anyone can figure out what my ? is pls let me know what has to be done. ThanksJack WA1ZDV ___ Sent via amsat...@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 Jack, Sorry if this was covered, but do you have an internal preamp in the radio? If you do, turn it off. Even if there is not one, maybe you have an attenuator on the input ( a lot of the newer radios do nowdays). Try turning on the attenuator (probably 10dB) and see if that sounds better. If you have SSB see what S-meter rise you see in SSB. My preamps push my S-meter in FM a lot higher than when in SSB (typ S-5 vs S-2/3). I am running a 22-sB gain 432 preamp on my new Lindy antenna into a FT-847. The NF is probably approx 0.5 dB (Mgf-1302). The others gave you methods for testing it with local signals (measure S-meter rise on/off with a local rptr; compare S-meter with preamp connected with just the radio connected; moving antenna so that a local signal becomes near noise level and see if preamp pulls it up out of the noise (by ear)). Usually a rise in background noise is the sign of a healthy preamp - but not always. If signals are heard better without the preamp, then it probably is broken (always check dc power connections in this case). the AG25 is probably powered thru the coax by your radio (check that the radio is putting out voltage on the center pin). Since you are seeing noise rise these latter ideas are applicable (just covering the field for others that may be having preamp problems). GL 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Fractal Antennas?
From memory, I believe the advantage that fractal antennas provide is very wide bandwidth and reduced size for performance. Desirable characteristics for hand-held communications. But as far as radiation efficiency??? 73, Ed- KL7UW At 07:08 AM 3/14/2010, Anthony Monteiro wrote: Dear friends, See the article by Steven Best in the June 2003 IEEE Antennas and Propagation magazine. His analysis shows that they do not work any better than any other small antenna. I attended a presentation on his findings at an IEEE antennas society meeting and he makes a very persuasive case. There are those who argue that his analysis is not perfectly fair (i.e. those trying to SELL these antennas) but I have yet to see any technical analysis that shows otherwise. 73, Tony AA2TX AMSAT VP Engineering At 09:18 AM 3/14/2010, Nigel Gunn G8IFF/W8IFF wrote: I beleive fractal antennas have been ignored because of patent issues. On 13-Mar-10 22:26, Dave Marthouse wrote: This seems almost too good to be true. Keep in mind that I'm not an engineer. Maybe this technology could be used for future amateur satellites, wider bandwidth, more gain, less space, etc. http://www.fractalantennas.com/ Dave Marthouse N2AAM dmartho...@gmail.com ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Membership Benefits
At 05:40 AM 3/7/2010, Joel Black wrote: AMSAT-BB, I realize what I'm going to get by asking this... If you were giving a presentation to amateur radio operators who know little or nothing of AMSAT, what would you list as some of the benefits of being a member of AMSAT? What would be the single most important reason? 73, Joel, W4JBB ___ Sent via amsat...@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 Supporting the launch of new ham satellites. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Membership Benefits
At 08:02 AM 3/7/2010, Bob- W7LRD wrote: Hi Joel and all -This is a timely question for me. Yesterday I organized and ran (with the help of Wayne-W9AE) a AMSAT table at a local hamfest. I had the opportunity to meet many local hams both satellite ops and the curious. I extolled the virtues of AMSAT and the satellite community in general. A few points I noticed as an undercurrent in some of the conversations. We hams are generally a frugal bunch and in some cases just plain cheap. I had several antennas on display as well as several pictures, one was of an astronaut on a EVA installing one of our  antennas on the outside of the space station. Some of the questions went like this, one guy asked, do you have to belong to AMSAT to operate satellites?, can I get this software (Satpc32) free on line? are these books available any where else? My response to these and similar queries was, see this picture? what do you think the shipping cost is? What we do, is rocket science, and rocket science is not cheap.  How many active satellite operators do not belong to AMSAT? How many use pirated tracking programs. How many do not contribute something to AMSAT. Maybe some aspect of of AMSAT ticks you off, so you cut the cord. I'm sure some part of the government ticks you off, you don't move to Canada. In order for AMSAT and our efforts to succeed it takes money, and yes probably lots of it. This event was a learning process for me and in the future I hope to hone my abilities and create more dues paying and contributing members. Finally- this is rocket science and rocket science is not cheap. 73 Bob W7LRD Washington State AMSAT area coordinator - Original Message - From: Joel Black jbblac...@gmail.com To: AMSAT amsat-bb@amsat.org Sent: Sunday, March 7, 2010 6:40:33 AM GMT -08:00 US/Canada Pacific Subject: [amsat-bb]  Membership Benefits AMSAT-BB, I realize what I'm going to get by asking this...  If you were giving a presentation to amateur radio operators who know little or nothing of AMSAT, what would you list as some of the benefits of being a member of AMSAT?  What would be the single most important reason? 73, Joel, W4JBB ___ Sent via amsat...@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 ___ Sent via amsat...@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 Re: being a member of Amsat: That is the minimum we can support amateur satellites with. I am proud of my low Amsat membership# as that shows I have been a long-standing member. If I could afford more I would become a life-member, but in my retirement we will manage to come up with our annual dues. Cheap? I know, considering the cost of rocket science! I have been a field-op since about 1998. I have handed the torch off (sponsored) to four others in Alaska to become field-ops (they do a superb job). I now try to support with technical advice, if I can. I have fond memories of the early years in ham satellites (AO-6). Looking forward to more with Amsat in the future. My hat is off the volunteers that make it all possible (and to the members that support them). 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Wish List, The Ideal VHF/UHF Sat Rig
At 10:47 AM 3/1/2010, Ken Ernandes wrote: I'm not normally one to throw cold water on creative ideas, but I will put myself in the position of the potential manufacturer. What any manufacturer would need to even contemplate this project is good answers to a few basic questions: 1. Can I come up with a design to these specifications that I can sell in the realistic price range of the typical amateur operator? 2. Is there a large enough market out there that I can make a profit on this exercise? My guess is the manufacturers wouldn't touch this one with 3.048-meter pole without at least one functioning high altitude satellite on orbit. I realize these are frustrating times, but I think you'll need to come up with more than just a wish list. Perhaps a group could get together and prototype portions to make a plausible case that this can be built economically. Can it be done? Probably... But those who really want it will probably need to invest a lot of sweat equity to prove it. 73, Ken N2WWD Ken echoes what I thought when I saw this thread. Note: the FT-847 has not been replaced by Yaesu/Vertex. I really think this should be reset to be a SDR radio. Then most of those niceties would be handled by software. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Wish List, The Ideal VHF/UHF Sat Rig
At 01:39 PM 3/1/2010, Alan P. Biddle wrote: When I retired 4 years ago, I had a long list of things to do, get, or build on my ham radio To Do list. After looking at the Flex 5K, I realized that well over half of them would be rendered moot by it. Since virtually none of my operating is on HF, I have been waiting (and waiting, and waiting,) for the V/U module to be ready. While waiting, I have gathered a few tools to go with it, including a GPS disciplined reference oscillator, so I will never need to wonder about what frequency I am really on. It looks as if that time is almost here, and I will be able to retire my venerable FT-847. Who knows, I may even start working HF again. And it will feel good to buy American again. The last purely US Rig I had was from Hallicrafters. Alan WA4SCA __ Sent via amsat...@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 Nice if you can afford it. My advice is do not wait until retirement to buy that dream radio. Living on social security and medicare does not provide for new toys! I am stuck with having to convince my wife to let me spend $3K of my 401K for ham radio...haven't worked up the courage, yet. We decided to withdraw $8K to payoff her new Toyota Sienna van so we are not having to come up with $600 car payments each month for another couple years. I have figured out that interest on my 401K will just be enough to pay my income tax on my social security...wow! What is my dream radio? Elecraft-K3 (dual-Rx) with new DEMI 2m 70cm xvtrs. I can't even think about a F5K (dual-Rx). I do have an SDR-IQ, FT-847, and FT817. Figured that selling the FT-847 would (maybe) pay for the new xvtrs. Reality...I probably will have to quit ham radio when the FT-847 dies :-( 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: drake 2880
At 02:26 PM 2/23/2010, Jim wrote: Has any one used the Drake 2880 downconverter on the air. I have 2 of them 1 I did the mod on and one that has not has any thing done to it. Jim K7UDG ___ Sent via amsat...@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 I have two Drakes that were used on AO-40. One is converted to 435-MHz IF and the second unmodified runs with 123-MHz IF. I feed both with a MKU-232A2 preamp directly connected to a 6-1/4 turn helical feed in front of a 85cm (33-in) offset feed dish. I have not re-installed my Drakes but the dish/preamp are ready for use. The Drakes do not have very good noise figure (~7 dB) so a low-noise preamp is mandatory. The db6nt preamp has 0.6 dBNF with 40-dB gain, easily able to feed both Drakes thru a coaxial tee. I also have a DEMI 2400-MHz preamp which I am thinking of feeding with a patch antenna. I am thinking that the patch should provide ample gain for S-band Leo satellites. The two antenna/preamps will be connected to the Drakes via a cross-over relay (not yet installed). I will need auto-tracking/tuning for S-band operation on Leo's. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Elk antenna as carry on luggage?
At 11:00 AM 2/20/2010, Mark L. Hammond wrote: Anybody know for sure if an Elk antenna is an acceptable carry on luggage item? Disassembled, and rolled up in a bag, for example. Or am I going to have to check it in? 73, Mark L. Hammond [N8MH] ___ Sent via amsat...@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 You have gotten several answers, already. The rule is one bag that will fit in overhead or under seat plus a personal carryon. I would guess your Elk is probably too long to qualify for fitting in the overhead. Check it inside a hard tube or box. I have flown with ham gear several times since 9-11 (one, two times/year) and never had any notice by TSA agents in Anchorage, Seattle, Minneapolis, Detroit, Cincinatti, Atlanta, Dallas-FW, Ontario-CA, and maybe others. I have taken a FT-817, keypad mic, 45w linear, mag-mt whip, DC cord for cigarette lighter, coax cables in my carryon suitcase with my clothes. MY wife got the royal full open your suitcase turn your pockets insideout because she forgot about her small pen size jackknife on her key ring. I have not tried taking my Arrow since 9-11. I use to carry it on in a 2 x 25 inch pvc tube with caps. I suspect they figured it to be my fishing pole. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: No Hawaii stations on HO-68 pass
At 11:00 AM 2/14/2010, w6...@comcast.net wrote: No Hawaii stations were heard on the 1950 utc 2/14/10 pass of HO-68 FM ... VE4AMU, KL7XJ and myself were the only 3 trying to drag them away from the beach. John W6ZKH ___ Sent via amsat...@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 I heard VE4AMU and W6ZKH on that pass, but my efforts to uplink were unsuccessful. Running 50w ERP on 145.825 (67-Hz tone). I also heard a couple packet signals. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Good Night, Loran
I do not know the exact answer, but the Iridium satellites (constellation of 256?) each were supposed to cost $5M/each. But any of you who actually have used Loran-C, know that is a far cry from the accuracy or reliability (due to LF propagation) as GPS. Ed PS: I used to install them, but you could not repair them as mfr's would not release proprietary info. But then these days no one bothers to repair electronics (putting us component level tech's out to pasture - moo!). At 06:52 AM 2/9/2010, tosca...@umn.edu wrote: Does the US government NOT have any plans to launch any more GPS satellites? Does the existing array of satellites in orbit have any which are not in active use, i.e. reserved for future use as backups? As I recall, each satellite has two different atomic standards on board, one is on and the other is off (or is it 3 independent standards, one rubidium and two of something else?). So, how many spare atomic standards on functional satellites do we have to keep the aging fleet going? What is the cost of a GPS satellite launch vs. the cost savings of killing off Loran-C? Sorry if your comments triggered more questions than answers from me... 73 de W0JT On Feb 9 2010, w6...@comcast.net wrote: In our aging fleet of GPS Satellites, which are on the brink of dying, and no replacements in sight, wonder what will happen then?? ... John W6ZKH - Original Message - From: Clint BRADFORD clintbradf...@mac.com To: amsat-bb@amsat.org Sent: Tuesday, February 9, 2010 3:36:58 AM GMT -08:00 US/Canada Pacific Subject: [amsat-bb] Good Night, Loran In a series of small ceremonies, the U.S. Coast Guard on Monday shut down Loran-C, a navigation and timing system that has guided mariners and aviators since World War II. ... Clint Bradford, K6LCS ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: New Lindy's QRV
One more update: I tried pass #744, this morning and copied a big round-table of several west-coast stations, but was unable to break in. My downlink was as loud as them, so...? I had one call to my CQ right at LOS and could not complete, sorry! Bear with me as I am getting reaquainted with running my radio on satellites ;-) My sub-VFO tuning control is not working which complicates netting with another station. So I find my signal with the Rx and then engage tracking. That tracks for a little while. The interesting thing is that I copied signals to zero-elevation. I would say that I am pleased with the new antennas. Question: what ERP are most stations using on SSB on HO-68? I am running 50w ERP. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] HO68 Pass
I copied two stations on SSB at 435.733 for the second half of pass #732, 10:30-10:50 utc. They did not pass call signs while I listened. I hadn't reprogrammed he FT-847 for SSB so my uplink was on the wrong freq. but Rx signals were arm-chair until elevation 10 deg. Not too bad for omni-directional antennas. I looked up the freq. info after the pass and discovered why I didn't hear my self (uplinking at 145.825). I now have a separate satellite memory setup for the SSB freq. of HO68 (435.740Rx/145.950Tx). The next pass is for 0020-0105, Feb. 9. My window will be 0052-0109utc when HO-38 is mainly over arctic Canada and no footprint for lower-48. It is a ascending pass so I will have about ten min of coverage (0055-0105). Look for me on SSB. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: HO68 Pass
Too late to work anyone in lower-48 but heard my own signal, FB. 1850-1935 pass later on Feb. 9th (9am here) we will try again. Transponder shut down just as Northern Japan got AOS. 73, ED - KL7UW At 11:38 AM 2/8/2010, Edward Cole wrote: I copied two stations on SSB at 435.733 for the second half of pass #732, 10:30-10:50 utc. They did not pass call signs while I listened. I hadn't reprogrammed he FT-847 for SSB so my uplink was on the wrong freq. but Rx signals were arm-chair until elevation 10 deg. Not too bad for omni-directional antennas. I looked up the freq. info after the pass and discovered why I didn't hear my self (uplinking at 145.825). I now have a separate satellite memory setup for the SSB freq. of HO68 (435.740Rx/145.950Tx). The next pass is for 0020-0105, Feb. 9. My window will be 0052-0109utc when HO-38 is mainly over arctic Canada and no footprint for lower-48. It is a ascending pass so I will have about ten min of coverage (0055-0105). Look for me on SSB. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: New Lindy's QRV
At 05:13 PM 2/8/2010, Clint Bradford wrote: I read that article, and when I got to the last of it and he mentioned that he was using a pre-amp for working the FM birds, I wondered out loud: Why??? We're working '27, '50, and '51 with HTs and meager antenna improvements. Better yet, build a tape measure Yagi - you can realize great gain with about six bucks of parts. Note that I haven't mentioned, Buy a pre-amp anywhere. I was considering building one of those antennas mentioned in QST last month - until I read that he was using a pre-amp. I'll just stick with what works for me ... home-brew or commercial Yagis ... a log periodic every now and then ... and no pre-amp anywhere. Clint, K6LCS http://www.work-sat.com ___ Sent via amsat...@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 I am the original author of the referenced e-mail. I hope you noted that I am in Alaska, where it is not exactly nice wx in winter. I have a complete super tracking system of yagis that I used on AO-10/AO-40, but I thought ii would be nice to have a simple non-tracking antenna system for the easy sats. The preamp makes the UHF Lindy work nearly equal with the high-price stuff...and much simpler. The good news is that the Lindys work. They are not hard to make. They are as cheap as an Arrow. I believe it is equal or better than the M2 eggbeaters (and $400 cheaper). I paid $30 for my used DEMI preamp. It is equal to SSB or ARR preamps (new costs in between these two). ...and I do not have to stand outside at 10F to work the satellites ;-) And I would guess that you note in my signature line that I do some other stuff in ham radio. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: HO-68 Schedule - 07-21 Feb 2010
Listened to orbit #721 (per NOVA) (23:23-23:40 for my location) and did not hear any activity nor my 145.825 (67Hz) uplink. I heard the CW beacon on the previous pass, but not this time, though it was well pass TCA when I looked for it. Just wondering if it was my station or was the transponder off? According to the new sked by Alan Kung, 07 Feb. 2300-2345 it was to be on. I am just finding out what my capabilities are with the new antennas, so... 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: FT-847 - relating dbm to S units
At 07:36 PM 2/7/2010, Phil wrote: Thank you for reading this. I'm still trying to determine if the aerial I have is working correctly or not. If -120 dbm for a 12 db SINAD is considered the minimum usable signal, what is the likely signal level required to indicate an S1 reading (at 435 MHz) on an FT-847 with the internal pre-amplifier turned on? The Yaesu manual quotes 0.2 micro volts for a 12 db SINAD. How many S points is likely to be? -- Regards, Phil ___ Sent via amsat...@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 0.2 uV is directly convertable to dBm (assuming 50-ohms impedance). The answer is -121 dBm. I do not know where you found -120 dBm as MDS (min. detectable signal) but the 0.2 uV spec it for MDS on the FT-847 (for FM). For SSB it is 0.125 uV (-125 dBm). You will not read any s-meter reading at MDS because the signal is equal to noise (again by definition). S-1 is (by definition) +6 dB over MDS (i.e. -115 dBM for FM and -119 dBm for FM). The FT-847 s-meter is not linear so it reads a bit off from that. I calibrated my FT=-847 for FM some years ago, and can recall that S-1 was something like +8 dB over MDS (but each radio will differ a little so if you absolutely need to know then measure it with a calibrated signal generator and a SINAD meter which was designed for FM). (Note: by this reasoning S-9 = +54 dB over MDS, but most cite that S-9 is +50 dB; see that reality is a bit murky here). Do not be confused by the standard 12 dB SINAD. It is a standard amount of signal quieting for making comparable measurements (very over simplified definition). After 30-years experience making SINAD measurements on radios I can estimate within about 3 dB by ear when a signal is at 12 dB SINAD (obviously the meter makes more precise measurements possible). I hope this helps, 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Recommended TNC
Having owned a FT-847 since 1998, I can. For 1200-baud packet it merely requires connecting a std TNC (I use a KPC-3+) to the 6-pin mini-Din packet connector (plug available from many Radio Shacks) on the back of the radio. Page-17 in the operators manual shows how. You can also connect 9600-baud audio-output from pin-6. Back in the AO-40 days I used Mix-W2 as a sw modem and connected to pin-6 for audio into the computer soundcard. 38k4 requires some radio modifications to tap wide bw ckts inside the FT-847. I never played with 38k4. Setting modulation for Packet without a deviation meter is harder (pin-1 on the radio). I use my FT-817 for packet, now. Nice thing is the connector on the radio is pin-compatible with the FT-847, so I could use the same TNC/radio cable. The FT-817 has packet mode available in menu so you can preset your mod levels by mode and by channel. Note: I may have my new Lindy's operational later today. Hooking up the preamp power and T/R relays wiring in the shack. Probably give AO-51 a try for my initial return to satellites. I also have my M2-436CP42, LY2345 (1.2-GHz Loop Yagi), 33-inch dish (2.4-GHz Rx), and a M2-2m7 yagi for hard-core satellite work (they also require wiring in the shack to be QRV). All those antennas have T/R relays, preamps and 432, 1268 have amps at the tower. So I am (about to be) ready for P3E! You can view these on my website: http://www.kl7uw.com/sat.htm 73, Ed - KL7UW At 10:06 AM 2/2/2010, you wrote: Hi Mike, You probably should specify which type of packet you are interested in working; an answer to your question depends on that. For 1200 baud packet, you can use just about anything, including some software solutions (MixW, for example). Or, one of many MFJ TNCs you find at hamsfest or on eBay. For 9600 baud packet, you'll need to be more careful in your search. For 38k4, you need to be even MORE selective, as there aren't many. If you want a TNC that does all three--1200, 9600, and 38k4-- you might consider a KPC-9612+ TNC. Never owned one myself, so I can't comment. For 9600 and 38k4, my personal choice is the Paccomm Spirit-2 satellite model. I've never owned or operated the FT-847, so I can't comment on that part of your question, either. But one thing's for sure--38k4 packet requires modification of any radio currently in (or out!) of production (well, except for the Icom PCR-1500/2500). 73, Mark N8MH On Tue, Feb 2, 2010 at 1:37 PM, Sean Cavanaugh se...@unixgeeks.ca wrote: On 02/02/2010 11:12 AM, Michael Wolthuis wrote: Can anyone point me to the recommended TNC for adding to an FT-847 for digital satellite work? Are there special modifications needed? What connector does it use on the FT-847? Thanks, Mike kb8zgl I can't speak to any specific recommended TNC, but I've been using my old PacComm Tiny-2 MK2 for years. It uses a 5-pin DIN (think ancient AT-style keyboard connector) and I connected it the packet port on my FT-847 (6-pin mini-din, like the slightly newer PS/2 keyboards) and have copied the ISS using this. The connections were fairly trivial to make following the manuals for the radio and TNC. Years ago I used the same TNC with my old radio shack HTX-242 to post messages to the BBS on the Mir. With a different TNC, I could also do 9600, but I don't have that capability at the moment. I'd think most any TNC should work. -- Sean - VA5LF ___ Sent via amsat...@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 -- Mark L. Hammond [N8MH] ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: Amateur Satellites Close Conjuctions
Sort of like walking 1000 paces, turning, and firing...not much danger of anyone perishing in such a duel? Better yet try to hit the other's bullet. The most amazing is that two orbiting satellites actually collided. 73, Ed - KL7UW afterall space is not like the San Diego Fwy in rush hour At 05:08 AM 1/26/2010, Joe Fitzgerald wrote: Hello, Given the recent close conjunction between Compass-1 and Sich 1, I was curious how common such encounters were. Using SOCRATES on the celestrak site, http://celestrak.com/SOCRATES/, it looks like they are fairly common. Take those forecasts with a grain of salt since they are based on TLE's with limited accuracy. On the day Iridium 33 and Cosmos 2251 collided, SOCRATES forecast a couple other conjunctions closer. SOCRATES predicted a miss of 584 m. Fortunately for us, there is a lot of space in space. -Joe KM1P ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Coaxial line question
At 01:04 AM 1/24/2010, Luc Leblanc wrote: Yes again a returning question preamp at the tower or near the shack I will have to do soon some maintenance work on my satellite antennas tower. I planned to use 2 heliax 1/78 45' individual line. Each line will be terminated by high quality 2psp coaxial microwave switch feeding UHF and VHF antennas. I don't know if i can move my VHF and UHF preamp at the other end near the shack where each line will enter the house on short LMR 400 run 10 feet max? I know the theory says the best place to put a preamp is at the antenna but with the very low loss on the Heliax coaxial line, is in the real world there will be any significant degradation in the noise figures who will be really noticeable? Note: If the relays are introducing too much loss i can feed the antenna directly from them on the 8' run on LMR-400 directly on the female N type heliax connector. P.S. One commercial microwave technician is telling me that i will be able to see difference only on labs spectrum/signal generator in short i will be unable to tell any difference due to the short length of my coaxial line. He told me he's playing with 300 to 600 feets of lines in his day to day work and 45 feet heliax run are nearly consider as jumper line in his world... - Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE ___ Sent via amsat...@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 OK, Luc. To make this decision you need to do the math. But you can just try comparing performance by installing the preamps at the antenna and at the shack and make your own evaluation. I'm guessing that is not convenient as antennas are on a tower. You mention running two coax lines 1/78. I do not know what that is but it sounds like ridiculously small stuff like RG-174. Or did you intend to say 7/8-inch? 7/8-inch Heliax is low loss (0.44 dB/100-ft and 0.83 dB/100-foot respectively) so that certainly helps when installing a preamp at the shack. But without numbers it is all hand waving and no decision is possible. How long is the Heliax? Also, not familiar with psp relays. What is their specification for insertion loss? If more than 0.2 dB they are not very good. I use relays rated at 0.05 dB loss. What is the NF and gain of the preamps? What is the NF of the radios that will be fed? Get all that and coax loss figures and input them into my spreadsheet program to find out what the overall NF will be. http://www.kl7uw.com/emelink.xls Add sky noise temp, Antenna noise temp, and radio bandwidth to determine minimum signal power that produces a zero SNR. Then you will have the figures to determine the effect. My overall experience is you will not have the best receiving system unless the preamps are at the antennas. You may be satisfied with preamps in the shack if you never compare with having them at the antenna. That is sort of saying driving a Ford Pinto is just as good as driving a Ferrari. Both will get you to a destination, but the ride is definitely different ;-) Regarding the opinion of the commercial mw engineer is not necessarily valid. Does he work with weak-signal detection? Probably not. My qualifications are ten years as mw engineer with NASA detecting spacecraft near the edge of the solar system. That is definitely weak-signal. The typical receiving system at Goldstone had a noise temp of 16K at 2115 MHz and a minimum detectable sensitivity of -185 dBm (the best system had -198 dBm). You can achieve -152 dBm with amateur equipment at 432-MHz. Typical 70cm ham station is -122 dBm without low noise preamps. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Life Members
Probably a method more personal to one's finances is compare your paycheck at the time getting the life membership with what one is paid, today. If I do that for 1985 vs 2009 I get 92K/15K = 6.13 Of course It will not do for me to use 2010 pay as that is only Unemployment ;-) I still pay my full annual Amsat dues as I was not smart enough to get a life membership in early years. In July I will apply for my soc. sec. and try to live on 1/3 of working years pay. I do appreciate organizations that have a retired dues level. Of course for ham radio memberships that would be the majority - oops! 73, Ed - KL7UW At 09:54 AM 1/17/2010, Glen Zook wrote: If you use the calculator that I referenced you will come out with the figures that I quoted. There are several ways of measuring the worth and those are shown on the calculator. Using the consumer price index as the basis the figures are correct. Using other things as the basis you will definitely come up with different figures. Glen, K9STH Website: http://k9sth.com --- On Sun, 1/17/10, Anthony Monteiro aa...@comcast.net wrote: From: Anthony Monteiro aa...@comcast.net Subject: Re: [amsat-bb] Re: Life Members To: Glen Zook gz...@yahoo.com, Amsat BB amsat-bb@amsat.org Cc: aa...@comcast.net Date: Sunday, January 17, 2010, 11:27 AM At 12:03 PM 1/17/2010, Glen Zook wrote: ... Based on the consumer price index, the $50 that I spent for my life membership back around 1970 is today the equivalent of right at $3300! That is 66 times in absolute dollars. Compare that to the present life membership fee of $880. That means that we who obtained our life memberships back in the early 1970s paid 3.75 times what new life members are paying. If you don't believe these figures then do the calculations on the following website: http://www.measuringworth.com/uscompare/ ... Hi Glen, I appreciate your sentiment about the fact that AMSAT needed the money back then but I don't think your math is correct. $1 in 1970 is equivalent to around $5.50 - $6.00 in todays dollars depending on how you compare it. Using the Measuring Worth web site, the CPI equivalent value of $50 in 1970 is $277.17 in 2009 dollars. 73, Tony AA2TX AMSAT VP Engineering ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: It's NOT Censorship
At 02:09 PM 1/15/2010, David - KG4ZLB wrote: It's not altogether surprising that this topic is being discussed but really folks, lets look at the facts! The whole issue revolves around just a few members/posters who continually try and push the boundaries on what is a large list with respected and influential members all over the World. We all know who they are; the ones that immediately post a facetious reply to a newbie question, the ones that post one line,or worse still, one word answers that are ambiguous at best and downright rude at worst; the ones that take childish delight in trying to elicit the maximum controversy with seemingly innocuous postings. We know who they are and they know who they are and the laws of defamation restrict me in naming them! There is a delete key on your keyboard; there are message filters built in to your e-mail client and if you really get offended then there is always the un-subscribe route. But if anyone on the list ever gets to having to be warned by AMSAT about their conduct on the BB or worse still, be faced with suspension/expulsion from the list then shame on you! For the most part we are all responsible adults involved in a fairly expensive hobby (note hobby) that is both highly technical and to most people, quite complicated. If anyone feels that they can do a better job than anyone on the current Board then by all means file a motion of no confidence and see how many fully paid up members back you. Put up or shut up. That we have even had to come to an Acceptable Use Policy for this board should make certain members/posters question whether they should even be members. Rant over David KG4ZLB ___ Sent via amsat...@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 My Delete key is overheating...tell you anything? Those that do not cause rules have nothing to worry about. Those that the rules were made for ...wellI have a delete key ;-) I am way too busy in my hobby to bother with lurkers or naysayers. For a clue look at my website. Genuine , respectful debate will not be censored. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Azimuth question
At 04:11 PM 1/9/2010, Dave Guimont wrote: Dave, A fraction of a degree per year, and at least once in the history of the Earth the North and South magnetic poles reversed. Art Yes, I'm aware of that, it also rotates about 1° about true north, the earth wobbles a bit to change the AZ, but how many ham antennas in the world need that accuracy? And I doubt that the average ham can orient within more than 2° by eyeball! 73, Dave, WB6LLO dguim...@san.rr.com Disagree: I learn Pulling for P3E... ___ Sent via amsat...@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 For 144 432 that is probably adequate. On 2400 the beamwidth of my 33-inch dish is 10.6 deg. (24.9 dBi) so keeping a signal within 1dB, probably requires 3 deg beamwidth and knowing true north with an accuracy of 10% of that results in 0.3 deg accuracy. Of course if you are doing something like eme on 1296 with a 16-foot dish the beamwidth is 3.38 deg. (34.9 dBi). For eme it is desirable to track within 1db of maximum gain which may is something like 1-deg. and 10% accuracy is 0.1 deg. How would you set up a dish azimuth so that it is that accurate to true north? For eme it usually requires comparison with tracking sw for location of the Sun or Moon. At these freq. and dish sizes one can detect solar and lunar noise to peak onto, then adjust az and el calib. to match tracking sw az and el. As it turns out my dish digital az-el readout has 0.1 deg. resolution so that is best I can read. On the Yaesu B5400, one is lucky to determine direction within 7.5 deg. for azimuth and 3.75 deg. for elevation. Manually tracking AO-40 with the B5400 was very touchy, as fine adjustment is near impossible. But I did refine my azimuth positioning using solar noise on 2400. For 144 or 432 probably the most accurate method for calib of azimuth is using a repeater many miles away (knowing both its Lat-Lon and your Lat-Lon with bearing sw that produces a great-circle bearing). 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Compact Quadrifilar Helix antenna
At 09:14 AM 12/30/2009, Andrew Glasbrenner wrote: Jeff Kelly wrote: This antenna has been out for a while: http://www.antennas.us/store/p/229-UC-4364-328-Amateur-Satellite-antenna.html any feedback on it? Jeff KT2K ___ Sent via amsat...@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 Works OK with a good preamp. I have one mounted on my Explorer with some magnets from Harbor Freight, and an ARR preamp. Lots of guys here in deed-restricted communes, err, communities use them because of their stealth qualities. 73, Drew KO4MA ___ Sent via amsat...@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 If you like building antennas, you might look at the Lindenblad which performs similarly. I am finishing up my dual-band pair and may get them installed, today: http://www.kl7uw.com/LBant.htm I will fill in more info on this page in a day or two (just a few photos, now) 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Progress on Sat antennas
Sorry slight typo on my callsign http://www.kl7uw.com/LBant.htm 73, Ed At 05:15 PM 12/25/2009, you wrote: Ed, no soap with that website, as shows none exist. You sure on the website name? John W6ZKH - Original Message - From: Edward Cole kl...@acsalaska.net To: amsat-bb@amsat.org Sent: Friday, December 25, 2009 6:03:24 PM GMT -08:00 US/Canada Pacific Subject: [amsat-bb] Progress on Sat antennas Just a short note that I took the day off spending the day with my wife celebrating Christmas. I am finishing up construction of my Lindenblad antennas for 145 435 MHz and have a new webpage showing the results: http://www.kl7ujw.com/LBant.htm Just some photos at this point. If wind drops I may get it installed on the tower tomorrow. Merry Christmas Happy New Year! 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Satellite array tower Up
Thursday, Dec. 3rd we got the satellite tower tilted back up with antennas for 145, 435, 1268, and 2401. Cables and the electronics enclosure remain to be installed. I do have the 15w 1268 Tx up and tested. I have a 150-foot piece of LMR-400 to run to the 435 x-yagi. I have LMR-400 and N-connectors to make more cables. photos of the array on: http://www.kl7uw.com/sat.htm The dual Lindenblad antennas are still partially done on the workbench. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Frustration Solved!
At 05:47 AM 12/1/2009, Bob McGwier wrote: I wish I had a buck for every time I have done this. I could drink coffee for a year at Starbuck's. Why does the technical mind (more male than female but both nevertheless) tend to run to the worst possibility rather than look for the simplest. I am about the worst offender I know. Bob Just yesterday I spent a half hour wondering why my printer didn't print. When you remove the wrong ethernet cable earlier in the day and assumed it was the correct one for another device...well, you know the rest of the story. 73 Greg N3MVF ___ Sent via amsat...@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 I smile (in self recognition). An old mentor, when I was starting in a career of electronic repair, said its usually something simple! Do not automatically look for the worst cause. The first step in troubleshooting is to verify all the inputs are present, then check the outputs, then back up an look and smell. And by all means do not assume. My eme station was not receiving last night when I started it up after a month's idleness. So I check the dc voltages (all there), then noticing the coax is connected differently, I check the outside connection (was to a different feedthru connector...hmm). Only took about 20-min to discover (apparently changed my mind on which connector to use and didn't complete the changeover). Years ago when a satellite-TV dealer, a customer called to say his set quit. I drove 100-miles to work on it to find the ac cord disconnected in back of his large entertainment cabinet. I could only justify taking some gas money from the very apologetic customer (I blew off 5-hours of my time). 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Icom 910H vs Kenwood TS2000
Tom, That is the old standard for satellite operation when we had MEO and HEO sats to work. Since I have my old antennas that is what I am putting up: 145: 7-element M2 yagi, mgf-1302 preamp, TR relay at tower, 50w FT-847 (about 20w max at antenna). The KLM-22C will replace this antenna once I have re-assembled. 435: M2-436CP42, 50w PA at tower, mgf-1302 preamp, with TR relay to support either mode-B or J 1268: 45-element loop-yagi, 15w Tx converter (DEMI 1268/144) (drives with 2w on 144) 2400: 33-inch dish, helix feed, MK232 LNA, two Drake converters (123 435 IF's) Since these are all narrow beamwidth antennas auto-tracking is desirable. I am using the B5400 az-el rotator with Unitrac-2000, SATPC32 I have all the antennasand the 1268 unit mounted . Dish is next then we swing it all up into place and install the outdoor box with 12v PS and electronics: http://www.kl7uw.com/sat.htm 73, Ed - KL7UW At 10:38 AM 11/30/2009, Tom wrote: Thanks for all of the great information. Since both the TS2000 and IC910H have been around a while I believe that most of their 'problems' have been at least discovered. So, in that respect, I'm leaning away from the still to be debugged IC-9100. Also new rigs always are priced high in the beginning of their life, as we all know. I know that some of the ham dealers are offering Closeout prices on the 910H but I didn't see much difference from previous pricing. Not to prolong this thread but Jerry's append (below) brings up another question. How much antenna is too much for satellite operation. Someone earlier mentioned that an 11 element yagi might have a beam width too narrow to closely follow an LEO bird. I had planned on using yagis with 13 elements on 2M and 18 els on 70cm. Is that a bad plan? Thanks again. Tom, KØTW Hi; I have owned the Ft-736 R and the Ft-847, which I am using now. No matter which rig you decide to buy the most important thing is the antenna system. I use KLM,s with switchers and pre amps. I switch my pre amps off and on from the shack. My 847 has a pre amp built in too. Nothing is better than MAST MOUNTED PRE AMPS THOUGH. If my 847 goes bad I will replace it with another used 847. I also work a lot of HF too. I run barefoot on HF all the time. I also get through all the pile ups because I have a good antenna with gain. Through the years I have made over 15,000 satellite contacts alone. 73,s Jerry w0sat ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: adding UX-910 to radio
Another consideration for installing 1296 into a radio that will be desk located is the feedline loss at 1296. If your antenna is a long coax run from the radio, you may lose too much RF power and suffer too much deterioration of noise figure using an inside unit. The advantage of separate 1296 units is that one can run the IF over the coax to the tower-mounted 1296 converter/amplifier and only a short run to the antenna for 1296. I have one of the very rare DEMI 144/1268 Tx converters (15w out) and will be mounting it on the crossboom of my satellite array. This means I can run cheap RG-213 on 144 from my radio and about 10-foot of 1/2-inch hardline from the DEMI to the antenna (losing only 1-2w of output). For AO-51 this is way more than needed power, but for a MEO or HEO one needs much more power than 1-2w. I should have about 1300w ERP. My satellite tower is 150-feet from the shack. You would need 1-5/8 inch hardline to get any useful RF on 1296 over that long a run. In fact I have just installed a 120-foot run of 1-5/8 inch hardline for my eme tower and I have a 1296 loop-yagi (for terrestrial use) that I feed with 60w. I will be lucky to get 30w to the 1296 antenna with this hardline (coupled to 45-foot of 7/8 hardline running up the 50-foot tower). I have a GasFet preamp at the antenna so that coax losses don't affect receiver NF. The trick that many mw hams use is to locate the mw equipment close to the antenna and avoid coax line losses. 73, Ed At 08:07 AM 11/22/2009, Stan, W1LE wrote: In addition: A transverter is always possible to get on the 1.2 GHz band. Use a IC-706 MK2/G or similar radio as a 28 MHz IF. Transverters are available from DEMI and DB6NT and others, or homebrew ala W1GHZ.ORG Use the building block approach instead of the one box doing all. Of course, integrating your system with different building blocks is more complex than a one box does all approach. Stan, W1LE Jack Barbera wrote: I've been thinking about adding the 1200 MHz band unit to my 910 radio. My dilemma is foremost that will this band be used on any of the new satellites? The rumor is that the 910 radio may be discontinued. The question I have is whether to quickly obtain the module in the event that this is also discontinued. I would really appreciate any thoughts on what action I should take. I do like ICOM products but find it difficult to get information about this type of situation. Thanks for any input. Jack WA1ZDV ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: Satellite Thermal Lesson
At 05:46 AM 11/18/2009, Bruce wrote: On 11/18/2009 8:34 AM, Robert Bruninga wrote: Lesson learned on Satellite Thermal. For years, we have been trying to demonstrate to students the extreme differences in Temperature of a satellite based simply on its color. In space, far from earth, here is what you should get for three identical satellites: Black will be about +55 deg F White will be about -60 deg F Aluminum will be about +225 deg F snip... This was sent by Bob on April 26, 1996. I found it interesting and kept it. KEEPING ELECTRONICS COOL IN THE SUN. WHile building a GPS unit for mounting on my dashboard and noting the comming summer months, I looked up the difference in absorption and emissivity for Aluminum, Black paint, and white paint. Satellite builders are well aware of these facts, but many of us landlubbers are not. ALUMINUM will get 30 TIMES hotter than WHITE paint! (in a vacuum) The following table is for a vacuum and accounts for RADIATIVE effects. It does not account for convective or conductive cooling (air).. Absorbtion Emissivity RatioTemp C ALUMINUM .4 .03 11:1 400 STEEL .6 .4 3:2 150 BLACK PAINT.9 .9 1:1 110 WHITE PAINT.25.851:3 72 Most people are aware that Black gets hotter than white, but the fact that bright, reflective, shinny Aluminum gets 10 times hotter than BLACK is a surprise to most people... So, if it sits in the sun, paint it white! If you dont believe this, put an aluminum baking sheet in the sun. I baked my first roof mount GPS stand alone tracker thinking that the upside down baking pan would reflect the sun... WRONG! Painted it white and it is now as cool as a cucumber. The difference in Aluminum is the POOR EMISSIVITY at infrared. It can't radiate the heat away... ___ Sent via amsat...@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 Yep, a hard lesson for the uninitiated working in the desert in summer: lay those shiny metal tools in the sun for ten minutes and you better wear gloves to pick em up. They get extremely hot and will burn skin. We always took care to lay the tools in shade or cover them with a cloth. Regarding painting dishes white, all the dishes at Goldstone were painted white. What you may find interesting was that receive waveguide was painted white while transmit waveguide was flat-black. The heat buildup in the transmit waveguide required water-cooling by silver soldering cooling tubes to the surface of the waveguide. I suppose the black color aided black-body radiation. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Satellite Thermal Lesson
At 05:46 AM 11/18/2009, Bruce wrote: On 11/18/2009 8:34 AM, Robert Bruninga wrote: Lesson learned on Satellite Thermal. For years, we have been trying to demonstrate to students the extreme differences in Temperature of a satellite based simply on its color. In space, far from earth, here is what you should get for three identical satellites: Black will be about +55 deg F White will be about -60 deg F Aluminum will be about +225 deg F snip... This was sent by Bob on April 26, 1996. I found it interesting and kept it. KEEPING ELECTRONICS COOL IN THE SUN. WHile building a GPS unit for mounting on my dashboard and noting the comming summer months, I looked up the difference in absorption and emissivity for Aluminum, Black paint, and white paint. Satellite builders are well aware of these facts, but many of us landlubbers are not. ALUMINUM will get 30 TIMES hotter than WHITE paint! (in a vacuum) The following table is for a vacuum and accounts for RADIATIVE effects. It does not account for convective or conductive cooling (air).. Absorbtion Emissivity RatioTemp C ALUMINUM .4 .03 11:1 400 STEEL .6 .4 3:2 150 BLACK PAINT.9 .9 1:1 110 WHITE PAINT.25.851:3 72 Most people are aware that Black gets hotter than white, but the fact that bright, reflective, shinny Aluminum gets 10 times hotter than BLACK is a surprise to most people... So, if it sits in the sun, paint it white! If you dont believe this, put an aluminum baking sheet in the sun. I baked my first roof mount GPS stand alone tracker thinking that the upside down baking pan would reflect the sun... WRONG! Painted it white and it is now as cool as a cucumber. The difference in Aluminum is the POOR EMISSIVITY at infrared. It can't radiate the heat away... ___ Sent via amsat...@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 Second thought on this: I painted my eme dish flat-gray for visual environmental reasons, but the color aids melting ice/snow from the surface. It was previously white. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Simple 2.4Ghz helix plans?
Actually: A comprehensive FAQ with a good search engine linked from the Amsat webpage would serve well. I know you want me to do it. Sorry, I don' t have the computer skills. But if such were to exist, when someone new asks one of the standard questions then all you need is to refer them to the FAQ (and anyone else reading the mail can also look for themselves). If the FAQ does not completely cover the question that a reader has - - then come back and ask on the -bb. Many good new questions come up and can be handled, here, so I do not think a separate forum list is needed. I already read about 8 lists as it is. Those that often answer certain questions could submit the item to be included in the FAQ. (i.e. I would offer noise figure and preamp answers). Others, might offer answers on fixing the Yaesu az-el rotor or software questions, Doppler tracking, Transponder on the Moon, what happened to AO-40, etc. my two cents. Ed, KL7UW At 11:47 PM 10/30/2009, Andrew Rich wrote: You know this amsat-bb needs to collect up all the info and make a forum web page Same old info over and over - Original Message - From: Greg D. ko6th_g...@hotmail.com To: mat...@netcommander.com; amsat-bb@amsat.org Sent: Saturday, October 31, 2009 5:15 PM Subject: [amsat-bb] Re: Simple 2.4Ghz helix plans? Hi Michael, I followed instructions from Howard Long, G6LVB, posted here a few years ago. (If the archives go back far enough, it was in November of 2001). I don't have it electronically, but the instructions went something like this: Get a long piece of thick bare copper wire (#10 is what I think I used), and put a small mark on it every 5 3/4 inches (146mm). Sharpie marker works well. Wrap it around a cardboard tube that's about 1 3/4 inches in diameter. The tube from a roll of paper towels works fine; the dimension is not critical. Space the turns about 1 1/4 inches (32mm) apart. Now, here's the magic part: once you get the helix about right, sight down one edge, and you'll see those 146mm marks you made in the first step. Twist and stretch the coils so that they all line up, AND at the same time, keep the turns spaced (center to center) 32mm apart. Take your time. The diameter of the turns will take care of itself. For the first 1/4 turn (the matching section), decrease the pitch so that it gently slopes away from the reflector, which needs to be something around 4 or so inches in diameter. The rest of the mechanical stuff you can pretty much make up yourself. There are a lot of examples if you browse around the web a bit. Helix antennas are pretty forgiving in construction, and really cheap to make. Greg KO6TH p.s. If you already have a Wi-Fi antenna, it should work too. Conversely, I've found that a Helix easily outperforms those Pringles can Wi-Fi antennas that were popular a few years ago, in a Wi-Fi application. Date: Sat, 31 Oct 2009 00:03:02 -0400 From: mat...@netcommander.com To: amsat-bb@amsat.org Subject: [amsat-bb] Simple 2.4Ghz helix plans? I threw this out there on the eham satellite forum looking for answers but I'll try here too. I'm looking for some fairly simple plans for this antenna. Everything I find either seems to be intended for WiFi or if it is ham related is full of mathematical formulas to figure length, diameter, spacing etc. Math was never my strong suit so I'd prefer to find something with the actual already computed dimensions clearly stated. Preferably in English rather than metric measurements. I found an article in the May/June 2008 AMSAT Journal that looked promising but there are no hard numbers, just the formulas and I don't have a calculator capable of some of the computations, much less being able to work them out in my head. Been a long time since I was in school!.. hi hi... I have a downconverter I'm not sure even works and I don't want to spend a huge amount of time and trouble to be able to test it. Tnx and 73, Michael, W4HIJ ___ Sent via amsat...@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 _ Windows 7: Simplify your PC. Learn more. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen1:102009 ___ Sent via amsat...@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 No virus found in this incoming message.
[amsat-bb] Re: Can we get them to fix AO-40 first then?
So, IF the battery un-shorts, IF the IHU boots and resets the beacon (S-band, I assume). Therefore, for the rest of us, occasional monitoring the beacon frequency would be good (using the current keps to estimate Doppler offset). IF detected, then commands could be attempted. Sounds like a lot of IF's. Is this a good reason to keep your S-band downlink equipment working? Think about it. Integrity of S/C is unknown, so its all a big guessing game. I remain available (when QRV on L-band with 865 kW EIRP) for command attempts (lat=60.675N, Lon=151.316W). 73, Ed - KL7UW At 07:20 PM 10/15/2009, Rocky Jones wrote: Hello Peter and thanks for the reply...sorry mine was so late, busy afternoon. you answered my question. I had heard that with the arrays folded or based on some failures...that AO-40 did not have 360 degree coverage in solar cells around its spin access. If that was the case then the battery was going to be essential for any type of recovery...but since it is not accurate then I agree if the battery will open (do a seven) then the only question would be the Solar angle. Thank you for a very good and straight forward answer 73 Robert WB5MZO Date: Thu, 15 Oct 2009 23:30:03 +0200 From: peter.guel...@kourou.de To: orbit...@hotmail.com CC: samudra.ha...@gmail.com; amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: Can we get them to fix AO-40 first then? Hi Robert, that's indeed the big question... We do not know in which attitude the spacecraft is.. is it still spinning very slowly or tumbling? What is the Solar-ß-Angel? If the S/C has a good orientation to the sun and the battery opens, than there should be enough power to operate the IHU and Beacon etc... do some magnetorquing to improve attitude. Something like this was done when AO-10 was hit by the last rocket stage, spinning the wrong direction with sun directly on top and almost no power... Unfolding the solar panels would give very high power only when they are oriented towards the sun. With folded solar arrays, all panels around the satellite can still see the sun around it's spin axis. Only when it shines on top or bottom, we will have problems... 73s Peter Rocky Jones wrote: Peter. In the current configuration (or the last known config) of the vehicle does the vehicle have sufficient solar illumination to spin and maintain the DC busses without a battery? Robert WB5MZO Hotmail: Powerful Free email with security by Microsoft. Get it now. http://clk.atdmt.com/GBL/go/171222986/direct/01/ _ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/171222985/direct/01/ ___ Sent via amsat...@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 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Can we get them to fix AO-40 first then?
At 07:52 AM 10/12/2009, John P. Toscano wrote: Indeed, it would be wonderful if the patient woke up from her long sleep like AO-7 did. There's no harm in wishing, even when the odds of success are so slim... 73 de WØJT ___ Sent via amsat...@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 John, I have had discussion on this topic with Drew and I believe that periodically commands are transmitted in the off chance that they might be received. I do not recall what band the command is on but I will soon have a very large L-band station (16-foot dish (34.5 dBi gain) and 300w at the feed) that could make some attempts with commanding. This is an eme station, of course. I hope to be QRV by December. I also wonder how good the Keps are for AO-40. My L-band beamwidth is only 2.5 deg. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com 500-KHz/CW, 144-MHz EME, 1296-MHz EME DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via amsat...@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
[amsat-bb] Re: Solar Power (I was wrong)
At 04:37 PM 10/1/2009, Robert Bruninga wrote: Since Satellite design is heavy into Solar power, and I talk about that a lot, you may have heard me compare my Solar car to Solar panels on the roof of your house as not economical, I WAS WRONG. I was overlooking many recent changes in the environment: 1) Solar panels (PV) are 1% of what they cost in 1970 2) PV dropped 40% this year due to 2007 Energy Boom and 2009 economic bust 4) $5,000 to $20,000 tax and cash back incentives for YOU 5) Grid-tie systems operate at 95% efficiency compared to 70% of battery systems 6) Local electric rates DOUBLED in the last 2 years 7) Laws require utilities to pay you the same peak rates they charge you. 8) Solar Energy credits can gain an additional $275 per 1Kw system per year 9) Payback is at least 10% per year or better 10) The same money in the bank gets 1% interest So I was wrong in not keeping current with all the changing environment, and now I am full speed to get my system approved and built and correct any miss-guidance I may have helped propagate. Sorry. I am claiming this particular email is on-topic because of public statements to the contrary I have made at satellite forums. But this hot topic should probably spin off elsewhere. We need a HAM Solar Power group somewhere...? Summary: Do NOT make the mistake (as most of us do) of thinking in terms of stand-alone Battery back-up solar power systems . They cost more and you don't need it in most places where you have access to the grid. They cost $5 to $10,000 more, are only 70% efficient (compared to 95% for grid-tie) and are a never ending maintenance headache. Instead, most any enterprising ham should be able to provide his own backup power using a cheap 1 kW inverter for about $150 from any auto store or radio shack running off his car's 12V system for any power outages. That, a few deep cycle batteries, (and using CFL lightbulbs in your house) will give you enough emergency power to operate your full Ham station, all the lights in the house you want plus your refrigerator for as long as you can buy gas. But the other 99.99% of the time, sell your solar power to the power company (at peak rates during the day) and buy it back cheap at night (you win and you don't even have to worrry about batteries)... And even if your grid-tie solar array produces nothing (in the way of AC power) when the grid goes out, you still have many Killowatts of DC power on your roof, that you can surely find lots of things to do with until the grid comes back. For example, have the electrician wire a 250 volt string of the 200 Watt solar panels in the array to a DPDT switch so they can be disconnected from the Grid Tie system and the 250 VDC can be available to you. THen you can plug in as many modern DC/DC pwer supplies into that 250 VDC to give you LOTS of amps at 12 volts, or ... almost any modern gizmo has a universal power supply input that will run on anything from 110V to 330V DC as is. Anyway, for similar hints www.aprs.org/FD-Prius-Power.html Sorry for the off-topic. But I was wrong. PV works! (even in Maryland). If you live in the SW, you are lucky, and it works TWICE as much or at HALF the price! A Born-again Home PV junkie Bob, WB4APR ___ Sent via amsat...@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 Couple comments: A 12-vdc battery back-up for your stations requires no conversion to AC, since most ham gear runs on 12v. A PV to battery system will keep one going when the lights go out! may not happen much down there in civilization but here in Alaska, several outages a year happen, some go for days. We have a 2500w standby gen that outputs 240vac to feed the main ckt breaker (with mains isolated). We have to load shed some areas of the house in that scenario. The same ckt can be connected to my shack to feed a small breaker box that supplies 240vc to the HV Power Supplies. (obviously we do not run the big amps when the power is out). I have installed many PV panels in remote sites over the years. They are much more efficient these days. It gets more challenging to depend on solar year-round since winter sunlight is only 5.5 hours/day. At my company's sites we opted to use supplemental solar during the warmer months when there is long sunlight and have an auto switch that detects low voltage to switch to the primary oxygen-activated alkaline battery plant (15vdc @ 10,800 AH). The primary batteries have a life of 3-years+ so we schedule their replacement (involves helicopter delivery= $2500) on the third year ($5500). Cheaper power exists but due to extreme weather on the mountain (-30F and 200mph winds), it is not feasible to visit the mountain 8-months/year! If one is still planning to utilize a stand-alone PV electric
[amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
Folks, I think you are focusing only on transmitting loss and have overlooked the impact that loss has on noise figure. If your HT has a low NF (doubtful) adding 3-dB loss in Rx will raise the NF 3-dB higher. The actual loss of sensitivity could be more than that. Filter's size determines efficiency and insertion loss. The tiny diplexer in the Arrow is a compromise between performance and size. I have a Comet 416B and even it has some loss about 47w out for 50w in. But that is not anywhere near 3-dB. I use mine to connect my dual-band vertical to my FT-847 which has separate connectors for 2m and 70cm. I used this antenna to contact the ISS a few years ago (worked well because the ISS never rises above 11-deg. elevation, here). But I do not use if for SSB or other weak-signal use. Ed - KL7UW At 02:26 AM 9/26/2009, Jeff Yanko wrote: Hi Joe and all, I doubt if the Arrow diplexer has 20dB of loss. If it did, we'd never receive a signal! :) I believe somebody here on the -bb will be performing a test on the Arrow diplexer using a vector/network analyzer. It will be interesting to say the least. There were preliminary reports saying the device had a loss anywhere from 2.65 to 2.80dB. That's close enough to 3dB which is technically half power loss. Add the loss of a short piece of coax and it will certainly be pushed over the 3dB line. If I recall correctly, cross polarity is also a 3dB loss. I have noticed that when I rotate the antenna I might get a stronger downlink but I never lose it when I rotate it back. Before, when I would do that it would drop once I rotated in either direction from the peak signal. Basically what is going on is the lossy device is removed and replaced with a more efficient one, that extra net gain you just boosted now shows how the system on the antenna side of the diplexer is truly performing. I don't have an antenna analysis program to perform a test, but what does a 7 element 440 yagi pattern look like and what is its overall gain? What we need to do is break down the antenna configuration into 3 segments, see what their losses and gains are then combine them for the overall figure. The 3 segment would be the antenna, the diplexer and the coax. Each one will be tested individually to give an accurate number for each. 73, Jeff WB3JFS - Original Message - From: Joe n...@mwt.net To: Gary Joe Mayfield gary_mayfi...@hotmail.com Cc: 'AMSAT-BB' amsat-bb@amsat.org Sent: Friday, September 25, 2009 6:42 PM Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE as in the texts below, there is something else going on here. That Diplexor can not be all that bad. two reasons. How many db down is the front to side of that antenna? and I can not imaging someone would sell a diplexor that has greater than 20 db of losses. because of the statement that how criticalpolarity was with the original, and now the antenna has to be nearly 90 degrees cross polarized to make it drop out uhh that close to 30 db, at least 20,, something else is going on here Gary Joe Mayfield wrote: Another issue I came across was how wide the beamwidth is of the Arrow Antenna between the Arrow diplexer and the new diplexer. I was wondering if this was going to happen and it did. The reason that this happened was with the old diplexer, the signal attenuated so much that you had to be pointed right smack dab on the bird, a few degrees off and you lost the signal. Now, with the new diplexer, you can point the beam in the general direction and still copy the bird. In most cases I had to turn the beam 90 degrees before I completely lost the downlink! Twisting the antenna to make polarization changes makes absolutely no difference now. This also attributes to the fact that now I'm copying the entire pass without dropouts or fades. Makes sense. What I've regained over the lossy diplexer makes up for any polarization differences, etc. for a better copiable signal. Next weekend I will have to try more passes and get a feel of how much this system has changed. 73, Jeff WB3JFS Las Vegas, NV DM26 ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program!
[amsat-bb] Re: 1.2 GHz Loop Yagis
At 06:06 AM 9/1/2009, nac...@terra.com.br wrote:
BODY { font-family:Arial, Helvetica, sans-serif;font-size:12px; }
Has anyone used 1.2 GHz loop yagis on AO-51 or any other satellites
before?
Was it worth? Would you recommend?
Any comment?
73,
Luciano PT9KK
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I have the 45 element loop-yagi from Directive Systems that I worked
AO-40 with 9.5w (at the antenna). It has 20-dBi of gain and is
12-foot long. For satellite use you want the 1268 model not the 1296
model. I tried stacking one of each and had bad SWR as a result. I
removed the 1268 model last weekend to install on my short tower for
satellite (with B5400 az-el rotor). I have a 15w 1268/144 Tx
convertor which will be mounted on the elevation crossboom with a
short run of 1/2-inch hardline. The 1296 model will remain on my
50-foot tower mounted inside my four 2m-eme yagis for tropo operation
with 60w in the shack. I also have a loop-yagi for 927.5 MHz use.
For AO-40, my experience indicated that 15-25w would have worked
better, but then AO-40 ranged out to 65,000 km range. For Leos, one
of these loop-yagi should suffice with 10w. KL7XJ has a Helix that
he uses with 10w in the shack on AO-51.
73, Ed - KL7UW
http://www.kl7uw.com/sat.htm
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[amsat-bb] Re: rotator questions
Using my 85cm offset feed dish on 2400-MHz with a 0.6 dBNF preamp (MK232A2), I could see about 1/2 s-unit of sun noise and a similar amount of ground noise when looking at nearby forest on the horizon. Comparing the sun shaddow on the dish vs. noise peak az-el readings would indicate how close the feed was to perfect boresight and alignment. 73, Ed - KL7UW At 06:53 AM 8/13/2009, i8cvs wrote: Hi Nigel, G8IFF/W8IFF You are right Aiming the antenna for maximum receiver Sun noise is the best method because the antenna pattern can be affected by some squint angle and not be perfectly aligned with the boom but receiving Noise from the Sun in 2 meters and 70 cm implies a very high antenna gain and a very low overall receiving Noise Figure with a very low Antenna temperature. By the way at microwave such as 2400 MHz it is possible to receive the Sun Noise using a modest dish diameter even when the Sun activity is low as actually with around 67 sfu at 2800 MHz (10.7 cm) See here: http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt I use this method with my 1.2 meter dish 27 dBi at 2400 MHz and an overall receiving Noise Figure of 1 dB equivalent to a Noise Temperature of 75 kelvin With the above dish and receiver I actually get a Sun Noise of about 3.5 dB of (S+N)/N wich is easily readible on the S meter or better using an AC Voltmeter connected to the audio output of receiver. Using a tracking program and aiming the dish for maximum Sun Noise it is possible to calibrate the AZ and EL angle of the control box for the through reference Sun position in the sky. In addition repeating time to time the above procedure and knowing the actual Sun's sfu it is possible to monitor the state of healt of our receiving system. By the way without an HEO satellite using 2400 MHz the above procedure is as well a little and interesting Radioastronomy exercise. Best 73 de i8CVS Domenico - Original Message - From: Nigel Gunn G8IFF/W8IFF ni...@ngunn.net To: Greg D. ko6th_g...@hotmail.com Cc: amsat-bb@amsat.org; n...@lavabit.com Sent: Thursday, August 13, 2009 2:17 PM Subject: [amsat-bb] Re: rotator questions How about aiming for maximum receiver noise? That should be even more accurate. Greg Wrote: and then adjust the antenna so the shadow falls directly down the antenna boom. ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: Cross boom question
That may be OK in country that does not experience snow. I built a 437-MHz Helix using a wooden closet pole (painted) and it only lasted two seasons before the pole split from the wieight of the snow. Wood makes a good stiffener but really does not have the strength that fiberglass has. But one need not worry mounting CP satellite x-yagis on a metal crossboom. WA5VJB analyzed and tested the concept proving that mounted in the X confiuration with cables dressed tight to the antenna and crossbooms negilible effects are seen (at least for satellite class operations). 73, Ed - KL7UW I have used a metal crossboom for years. At 02:24 PM 7/25/2009, Greg D. wrote: Wooden pole for me. Just a regular closet pole from the lumber yard. I've never been impressed by the structural qualities of plastic pipe, and putting a wooden dowel up the middle of one still leaves much of the structural responsibility with the plastic on the outside. So, why not make it all wood? Heck, if it can support my wife's wardrobe, it should be able to handle a couple of antennas :-). How long of a span do you need? Greg KO6TH From: w0...@msn.com To: kq...@pacbell.net; amsat-bb@amsat.org; hisl...@gmail.com Date: Sat, 25 Jul 2009 17:14:20 -0500 Subject: [amsat-bb] Re: Cross boom question Amen: I have been aluminum cross booms for several years now. Jerry w0sat -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Jim Jerzycke Sent: Saturday, July 25, 2009 4:36 PM To: amsat-bb@amsat.org; Kevin Groth Subject: [amsat-bb] Re: Cross boom question This has been gone over a zillion times. Short answer; Mount them in an X configuration and don't worry about it. http://www.g6lvb.com/fibermetalboom.htm --- On Sat, 7/25/09, Kevin Groth hisl...@gmail.com wrote: From: Kevin Groth hisl...@gmail.com Subject: [amsat-bb] Cross boom question To: amsat-bb@amsat.org Date: Saturday, July 25, 2009, 1:47 PM I have just finished building a set of 2m and 440mhz circular polarized beams to work the birds. (tired of standing in the heat and cold outside!) I tried to save a little bit of money by building a wood dowel inserted into a sched 40 uv resistant pipe. I hung the beams on either side of the cross boom and it sags way too much and is ugly. I thought about using some eyebolts and some nylon cording for support to the vertical mast, but I'm trying to keep everything as clean as possible for the neighbors. I would really rather not have to purchase a fiberglass satellite boom commercially, but if I have to, I will. I have a bunch of 1.75 aluminum pipe that would be more than able to support most anything I plan to add to the antenna collection in the future (1.2 and 2.4 ghz). My question is how much of a difference would it make if I mounted the 2m and 440 beams in an X position to the aluminum beam? I have read some short answers that it would minimize the swr issue, but haven't really found an answer that I am comfortable with. Also, how would that effect a later addition like a 1.2 or 2.4 ghz antenna.? My current antennas are a KLM 2m-14c and a 435-40cx, both circular polarized and switchable RH and LH polarization. Does anyone have any experience with a metal crossboom? Thanks! Kevin N9EME Fort Worth, TX ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@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 _ Bing brings you maps, menus, and reviews organized in one place. Try it now. http://www.bing.com/search?q=restaurantsform=MLOGENpubl=WLHMTAGcrea=TXT_MLOGEN_Local_Local_Restaurants_1x1 ___ Sent via amsat...@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 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings:
[amsat-bb] Re: AO-51 message + SSTV
I have the recording on my website: http://www.kl7uw.com/40th_apollo_message.wav 2.2 MB 73, Ed - KL7UW At 07:30 AM 7/21/2009, Nitin Muttin [VU3TYG] wrote: Drew, Thanks for the update. Please upload so we can hear the message. 73's Nitin VU3TYG - Original Message From: Andrew Glasbrenner glasbren...@mindspring.com To: Nitin Muttin [VU3TYG] vu3...@amsatindia.org, amsat-bb@amsat.org amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: AO-51 message + SSTV Date: 07/20/09 07:50 PM The event is over. If you'd like to hear the audio I'll try to get it posted online somewhere. 73, Drew ___ Sent via amsat...@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
[amsat-bb] Re: Evidence of moon landings....!
LeRoy, I'm not sure how you can have a source other than NASA, other than two hams who made independant recordings of Apollo transmissions. In 1971 (summer issue) a QST article talks of Dick Knadle(sp?) KRIW who got some, and another ham, I believe W4HHK received signals as well. I'd also bet the Russian space agency has stuff. Please don't take this the wrong way, but if you have questions about any fakery of moon landings, find the Myth Busters TV show. They did a *really* good job of debunking several myths about how things were faked. I do not find this discussion OT for Amsat-bb, because this affects us. It erodes the effort of tens of thousands of technical people, and has ripple effects for the USA, far beyond the original topic. --STeve Andre' wb8wsf en82 ___ Sent via amsat...@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 Steve you can add my witness of the Lunar orbiter signal on S-band received on a ten foot comm dish that my supervisor with JPL set up in his yard using a diode mixer and a microwave signal generator for LO. The signal exhibited expected Doppler shift and every 20-minutes or so it dropped out (occulted by the Moon as the orbiter orbited behind). This was not Apollo-11 but one of the other missions afterward, to memory (long time ago - 1971). We both worked at Goldstone tracking facility back then. We only detected the carrier since the dish was insufficient size for recovering the modulated signal. 73, Ed - KL7UW (then K8MWA/K6) ___ Sent via amsat...@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
[amsat-bb] Re: Moon can cost less than HEO/GEO
Sometimes it pays to go on vacation (600+ back e-mail). The lunar link analysis has been done on Amsat-bb at least 4 or 5 times in the last ten years. I have a spreadsheet program that can be used for any point to point communication in space (plug in your own numbers) http://www.kl7uw.com/MROCalc.xls Since we assume to ride to the Moon with NASA (manned flight) it could be buried on the Moon with only antenna exposed (solves some of the temperature and radiation issues). Make it the emergency comm system for the astronauts like ARISS provides on the ISS (selling point to NASA). Make it a digital passband or multi-channel system. NOT a single-channel FM repeater like AO-51 (consider have the world's hams trying to use that channel at the same time!). Microwave only make sense. Maybe use the CC-rider concept from Eagle. Now it has Emcomm potential. as well. With the 2.5 second RTLT time delay text modes make more sense. Digital voice at minimum. 30 to 50w uplink transmitter would do it (play with the calculator, above). Try for 2-foot dish on the earth station. Moon gravity is 1/6 earth and no wind (light weight dish will work). Or perhaps a electronically steared panel array. Auto-tracking by carrier from NASA DSN tracking network (let them have 3-4 channels exclusive use). 73, Ed - KL7UW At 08:43 PM 7/2/2009, Greg D. wrote: Hi Kenneth, et al, Would this be a good opportunity to dust off the low data rate digital package that was planned for Eagle? If I recall, it was to be multi-service and operate at relatively low s/n levels. Replace the antennas, of course, and the radio power amps. The resulting Earth station should still be quite affordable. Just a thought, Greg KO6TH From: kenneth.g.ran...@nasa.gov To: ka1...@yahoo.com; amsat-bb@amsat.org Date: Thu, 2 Jul 2009 21:29:47 -0500 Subject: [amsat-bb] Re: Moon can cost less than HEO/GEO I realize this is still very early in the dreaming stage but it would be nice to start seeing some realistic proposals soon. How about starting with a blank worksheet that outlines the desirements and requirements. This would give folks some specifics to address. *LUNAR System* Modulation type: Mode: Power source: Lunar transmitter (type, output power and band): Lunar TX antenna (type and gain): Lunar receiver (type and band): Lunar RX antenna (type and gain): Lunar controller (type and capability): Delivery deadline for flight certified hardware to be launched: Length of time the system is expected to operate: Periods that the system is expected to be available for use: Once you have some general ideas as to what the items are then you will have a good idea of the total weight, size and what it will cost to buy, build and certify for spaceflight. It would also be nice to know what sort of station equipment would be needed to use this lunar system. *EARTH Station* Description of minimal Earth station capable of operation through above mentioned lunar system: Transmitter (type, output power and band): TX antenna (type and gain): Receiver (type and band): RX antenna (type and gain): Antenna tracking system: The above should allow for a realistic guess at the number of users willing to and capable of operating through the system. Kenneth From: amsat-bb-boun...@amsat.org [amsat-bb-boun...@amsat.org] On Behalf Of MM [ka1...@yahoo.com] Sent: Thursday, July 02, 2009 8:14 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Moon can cost less than HEO/GEO High orbit launch prices It is hard to find exact values for the price per kilo to a geo-stationery orbit. I did find a few old numbers on the web suggesting that around the year 2000 prices were approximately 25,000 to 35,000 USD per kilo. I can only assume it will cost more todays 2009 dollars. If we were to build our own Geo-stationary satellite and were able to keep the weight down to the same weight of AO-40 (244 kilos), that would only cost us $8.5 USD million in launching fees (plus inflation). That is not including the cost of the satellite. A ballpark Geo-stationary amateur radio satellite and launching fees would be in the 20-40 million-dollar range per satellite (SWAG). If you have an extra 40 million kicking around then go ahead and build us a Geo satellite. Or if you work at Huges and can talk them into attaching a Micro Satellite to the next geo satellite for Free great, go for it. I cant afford that and I do not know anyone at Huges, so I am looking into the piggyback options. Let some other company pay the big bucks for the flight and navigation and just tag along for the ride. In this case NASA wants to send Un-manned Landers to the Moon. All we need to do is convince them to let us attached a 1-2 kilo micro-satellite to the moon lander and use
[amsat-bb] Re: Way-OT: Re: Full Duplex HT's (Ben Jackson)
At 11:50 AM 6/11/2009, Ben Jackson wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Clint Bradford wrote: ... Also check out the Motorola JT1000 ... Sure ... Let's discuss a fifteen-year-old HT that has long been discontinued by Motorola So, that proves that front-panel programmable commercial radios have been approved by the FCC for at least 15 years. - -- Ben Jackson - N1WBV - New Bedford, MA bbj at innismir.net - http://www.innismir.net/ A point missed about programable commercial radio equipment is that this was allowed as an experiment by the FCC and approval for their manufacture was recinded after a short trial use period. Non-technically trained operators could and did program their radios to operate on top of licensed services such as public safety with severe results. Lets define programable while were at this. It does not mean a radio that can be changed in frequency to predetermined frequencies. Marine (part-80) radios are pre-programmed with a standard set of channels established for the marine community. Aviation radios can dial in any frequency in 5-KHz steps within the aviation band. But both of these services have been set up by the authorities governing them to use certain frequencies within a reserved sub-band. A programable radio can be set to any frequency that the radio can operate. Commercial Hi-band VHF: 150-174 MHz. ___ Sent via amsat...@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
[amsat-bb] Re: Way-OT: Re: Full Duplex HT's (Howard Kowall) (Ben Jackson)
At 10:20 AM 6/10/2009, Nigel Gunn G8IFF/W8IFF wrote: True. If equipment needed an FCC number then you wouldn't be allowed to use home brew gear without it being tested by the FCC. Ben Jackson wrote: Devices used in the Amateur Radio Service do not require authorization prior to being imported into the United States, but devices for other services, including the CB service, require Commission approval. Thus, provided the importer only uses it under Part 97, it's kosher. I just can't, say, use it under a GMRS license or something. ___ Sent via amsat...@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 I think you will find that manufactured ham transmitters and receivers are submitted for FGCC approval. Home built is not per regulations. How often you see a new piece fo equipment advertised not that waiting for FCC approval to be marketed. What regulations are for imported equipment to the US? 73, Ed - KL7UW ___ Sent via amsat...@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
[amsat-bb] Re: true duplex radios
Thanks also. Saving this for reference when replacing my mobile rig and handheld (TH-D7). Now has anyone documented 1.2 GHz mobile/handhelds? 73, Ed - KL7UW At 03:40 PM 6/1/2009, D. Craig Fox wrote: Thanks Andrew! As the one who started this thread I am pleased it has generated so much interest and willingness to participate. For those of us who like to shop EHAM, QRZ and QTH, and the 'fests, for potential satellite radios, this list has great utility. Perhaps it would be something worth having access to on the AMSAT website. 73s Craig N6RSX -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org]on Behalf Of Andrew Koenig Sent: Monday, June 01, 2009 4:21 PM Cc: amsat-bb@amsat.org Subject: [amsat-bb] Re: true duplex radios Here's my attempt of to update the list of full duplex capable radios. Did I miss anything? HTs - Icom IC-W2A Icom IC-W31A Icom IC-W32 Icom IC-Z1A Icom IC-X2A (440MHz/1.2GHz) Yaesu FT-470 Yaesu FT-530 Yaesu FR-51R Kenwood TH-D7 Kenwood TH-75A Kenwood TH-77 Kenwood TH-78 Alinco DJ-G5T Alinco DJ-580T Alinco DJ-G7 Mobile rigs - Kenwood TM732 Kenwood TM733 Kenwood TM741 Kenwood TM742 Kenwood TM941 Kenwood TM942 Kenwood TM-D700/710 Yaesu FT-4700 Yaesu FT-5100 Yaesu FT-5200 Yaesu FT-8800 Yaesu FT-8900 Icom 2728H Icom IC2800 Icom IC-2340 Icom IC-2720 Icom IC-2820 Icom IC-Delta-100 Heathkit HW-24/HW-24A Base rigs - Yaesu FT-726 (with OSCAR Module) Yaesu FT-736 Yaesu FT-847 Kenwood TS-2000 Icom 820 Icom 821 Icom IC-910H Icom IC-970 -- Andrew Koenig KE5GDB ___ Sent via amsat...@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 NOTICE: This communication may contain privileged or other confidential information. If you are not the intended recipient of this communication, or an employee or agent responsible for delivering this communication to the intended recipient, please advise the sender by reply email and immediately delete the message and any attachments without copying or disclosing the contents. Thank you. ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: Re eggbeater performance - mobile
At 04:19 AM 5/30/2009, Bob Bruninga wrote: For mobile work on AO27, SO50, AO51 a 2 metre quarter wave whip is all you need... to work the LEO's mobile and the satellite is 15 degrees or more above the horizon, Absolutely, For a 19.5 whip in center of roof: 1) Has 5 dBi gain above 20 deg on 2m 2) Has 7+ dBi gain above 30 deg on 70cm 3) Is an omni 4) does not sacrifice 3 dB for circular 5) Above 25 deg, satellite is 6 to 10 dB closer! 6) works the birds solid for the center of high passes 7) Simplicity at its best! Read about it: www.aprs.org/rotator1.html Disadvantage: The only disadvantage is TIME. On the above web page you can also see that satellites spend 70% of their daily pass times below 25 degrees. BUT! For those best passes in the morning and the evening (or whenever) you can make solid contacts while mobile for about 5 minutes. Also note, that you do NOT need any tracking program to predict passes. AO51 schdule repeats evry 5 days for example. Just write down the CENTER pass of the morning and evening for each day for 5 days. Update those 10 times on a small 3/5 card on the dash about once a month or so will predict all passes whenever you are mobile. There will be a pass 100 minutes earlier and 100 minutes later each day too. So you can predict all 6 passes a day from those same 10 times. See how: www.aprs.org/MobileLEOtracking.html Bob, WB4APR I've posted this before, but maybe it helps to repeat. When AO-51 launched, I used a 19-inch mag-mount mobile whip on a steel ground plane to copy telemetry on 435-MHz using a preamp. Signals were quite adequate. Probably low horizon AOS/LOS was limited (too long ago to remember). But very simple to implement and use as Bob states. I have two Lindenblad antennas under construction so will play with them (using my 435 preamp) when I get them up. I am preoccupied with finishing my 1296-eme station with 16-foot dish. In July, I should be able to re-assemble the old AO-40 tracking super-array of antenna as can be seen on my website. *** 73, Ed - KL7UW BP40iq, 6m - 3cm 144-EME: FT-847, mgf-1801, 4x-xp20, 8877-600w 1296-EME: DEMI-Xvtr, 0.30 dBNF, 4.9m dish, 60/300W (not QRV) http://www.kl7uw.com AK VHF-Up Group NA Rep. for DUBUS: dubus...@hotmail.com *** ___ Sent via amsat...@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
[amsat-bb] Re: Mobile Coax?
At 06:48 AM 5/30/2009, Bob Bruninga wrote: Other Car Tips: Convert from RG-58 to LMR-240-UF or RG-213. I'd take that with a grain of salt. The length of coax in a car is about say 10 feet. The loss of 100 feet of RG-58 is say 5 dB? and the loss of fancy stuff might be 3 db? But the diffrence for only a 10 foot run is only .5 dB versus .3 dB or only 0.2 dB. Nothing at all to even consider compared to all the work it will take, and the lack of flexibility and trying to run something almost like pipe through places where a simple wire (RG-58) fits. My lesson was learned 40 years ago when I go my first 100 lb UHF mobile rig (tubes) just after highschool. The boat anchor filled the entire trunk of my MGB. But the first thing I did when we go the lot of them in my club was spend a day replacing the 8 internal piece of RG-58 in mine from the Transmitter output over to the chassis connector with a 8 run of RG-8. It was hard work getting that 8 piece of RG-8 coax inside the radio and routed all around the internal chassis. The elmer at the time laughed. He said you just wasted a day and all that work to save 0.01% of loss. So now your radio works at 100% where as before it worked at 99.99%. Losing 3 dB of course is one thing (50%), but trying to worry about that last 1% when the effort is tremendous is just not effective. Anyway, just my 2 cents... Bob, Wb4APR Yep. Commercial NMO mount mobile VHF/UHF antennas typically come with 17-feet of RG-58 and a connector to install when coax is trimmed for the particular installation. I have way too many 100w mobile installs in my past ;-) Of course, FM repeater design is for overkill on signal margins so no one sweats coax loss for mobiles. The repeater sites may see 100-150 foot hardline runs, though. I have one 120-ffot tower with 17 antennas and the coax are 1/2 or 7/8 inch Heliax with the longest run 180-feet. 73, Ed - KL7UW ___ Sent via amsat...@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
[amsat-bb] Re: Re eggbeater performance - mobile
One more comment (and not contrary to what Bob is saying): For us at far north latitudes, ISS never rises very high (about 11-deg. max), so using a high gain vertical works well with ISS which is always near the horizon. I worked Bill MacArthur in 2005 using my 9-dB cushcraft 17-foot base whip running only 50w. But for polar orbiting Leos this is not good. 73, Ed - KL7UW At 10:20 AM 5/30/2009, Bob Bruninga wrote: It also has a null on an overhead pass. But that is quite insignificant. Looking at the gain plot of a 3/4 wave vertical (the 19.5 whip on 70cm) it is only down say 6 to 10 dB above 85 degrees. BUT the satellie is 10 dB or more closer when it is above 50 degrees which more than makes up for any loss of gain straight up. see plots on www.aprs.org/rotator1.html But yes, there can be a complete fade when it is perfectly directly overhead (extremely rare). But since the satellite is only above 50 degrees only 5% of the time, it is only above 85 degrees only 1/8th of that 5%, or much less than 1% of all access times. Again, losing less than 1% of access time due to a possible less than 1% chance of a fade is nothing to be concerned about. Just 2 cents worth... Bob, Wb4APR For mobile work on AO27, SO50, AO51 a 2 meter quarter wave whip is all you need... Absolutely, For a 19.5 whip in center of roof: 1) Has 5 dBi gain above 20 deg on 2m 2) Has 7+ dBi gain above 30 deg on 70cm 3) Is an omni 4) does not sacrifice 3 dB for circular 5) Above 25 deg, satellite is 6 to 10 dB closer! 6) works the birds solid for the center of high passes 7) Simplicity at its best! Read about it: www.aprs.org/rotator1.html Disadvantage: The only disadvantage is TIME. On the above web page you can also see that satellites spend 70% of their daily pass times below 25 degrees. BUT! For those best passes in the morning and the evening (or whenever) you can make solid contacts while mobile for about 5 minutes. Also note, that you do NOT need any tracking program to predict passes. AO51 schdule repeats evry 5 days for example. Just write down the CENTER pass of the morning and evening for each day for 5 days. Update those 10 times on a small 3/5 card on the dash about once a month or so will predict all passes whenever you are mobile. There will be a pass 100 minutes earlier and 100 minutes later each day too. So you can predict all 6 passes a day from those same 10 times. See how: www.aprs.org/MobileLEOtracking.html Bob, WB4APR ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ
At 10:33 AM 5/16/2009, Greg D. wrote: --snip- Pretty much every Wi-Fi antenna I've ever seen is linearly polarized. The diversity antennas are two separate antennas, usually one vertical and one horizontal, with separate cables going to two radios. Going circular would seem to be a no-brain improvement for the Wi-Fi crowd, but I think I've only seen one vendor do it. Enjoy the new toy, Greg KO6TH I have toyed with using a comercial medium gain patch array for 2.4 GHz Leos. I would guess that there is no incentive to use circular pol for terrestrial data links. Even reflections and multi-path signals would remain linear. Space com is a totally different deal and circular makes sense if there is room for the CP antenna on the sat. I still have my 85cm offset dish fed with short helix for AO-40 2.4 GHz, but I expect the narrow beamwidth would be lots of trouble for manual tracking 2.4 Leos. That is why I thought to use a 10-dB commercial antenna (also cheap and easy). Is CP a better idea? ...and would one need to reverse the sense on 2.4 GHz very often? 73, Ed - KL7UW ___ Sent via amsat...@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
[amsat-bb] Re: Hygain Sat Antenna's and SSB UEK3000 Sat.
Norman, By your questions I guess you have heard that coax loss between antenna and input of preamps degrades noise figure (which is why we put preamps at the antenna in the first place). You do not mention frequencies for the RG-213 but I am guessing you mean 145 and 435 for satellite. Ten foot probably will not matter too much on those frequencies though the higher the frequency the more coax loss gets (and coax loss adds to the noise figure directly; e.g. 1-dB loss add 1 dB noise figure to the noise figure of the preamp - not good if the preamp is 0.5 dB NF). MY best advice then, is to use the lease length of coax in front of the preamp. Compare how it hears with the coax and without the coax and decide for yourself. For 2401 MHz the situation is totally different. 80-feet of RG-6 will kill the low-noise performance of the UEK3000. Install the UEK at the antenna with no coax or as short as possible a jumper cable. If you meant to use RG-6 from the output of the UEK that is quite OK. I use a MKU-232A2 + Drake downconverter on 2401 and run over 100-foot of RG-6 from the Drake to my FT-847. But the MKU preamp is directly connected to my 6-turn helix feed for my 85cm dish. I am considering the purchase of a 10-dBi patch antenna to use on 2401 Leo-sats as it will be easier to point and should not need as much antenna gain. This will be coupled with a 2400 DEMI preamp and my second Drake converter. 73, Ed - KL7UW At 07:44 AM 5/9/2009, Norman W Osborne wrote: Hello to All, Looking for suggestions for feed lines to my preamps, could I use RG213-U ? I am thinking this should be ok as both lines will be only about 10ft in length. From the preamps, I am using hard line. I also have a UEK3000 receive converter for 2.4 , for feedline, could I get away with RG6, same cable used for sat TV. the run will about 80 ft Getting setup for future HEO.s Any suggestion greatly appreciated and many thanks in advance. Norman ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: A Fully Rechargeable Satellite Station
I have an old IBM thinkpad whose battery charger outputs 16vdc at 2.2amp. I cut the dc cord and installed some crimp-on eyelets so that it could attach to a small two terminal strip for which I made a cigarette lighter cord. I was able to run that computer charging off my wife's Ford minivan for the 6000 mile trip from MS to AK in spring of 2004. The vehicle voltage is damped by the car's battery and runs about 14.2 volts when the engine is running and sags to 13.2v when off. I never had the computer running when starting the engine. The computer battery will also act as a huge capacitor for smoothing out any voltage spikes. I also ran my FT-817, 45w amp, KPC-3, and Garmin GPS from the car's battery. The Garmin requires 3.2 volts which was easily provided using a voltage-regulator. Most cigarette lighters circuits have a 15 to 20 amp fuse on them. That ought to work fine for charging/using with your computer. 73, Ed - KL7UW At 06:34 AM 4/29/2009, Roger Kolakowski wrote: A quick inquiry about running a laptop directly off of a cigarette outlet in the car... for example...let's consider the HP/Compaq series of laptops that take 16-19V from their chargers/power supplies... Can they be run directly from the auto's 13.6v supply...the available amperage always made me nervous...as does the voltage swings when starting and out of the regulator. Roger WA1KAT - Original Message - From: n...@bellsouth.net To: Greg D. ko6th_g...@hotmail.com; amsat-bb@amsat.org Sent: Wednesday, April 29, 2009 8:52 AM Subject: [amsat-bb] Re: A Fully Rechargeable Satellite Station Hey Greg, In addition to the internal rechargeable pack, Yaesu provides a battery tray for a DIY battery pack, and I have been assembling rechargeable individual batteries for these trays. In the case of a longterm power outage, it occurs to me that, as you suggest, a larger 12v battery could come into play. The regular power supply I use in the shack includes the provision to connect a gel cell battery for charging and backup, so that's one option. An auto battery certainly is another although, I suspect I'd opt for a deep-cycle marine battery (or batteries) if I was going to buy them for this use. My intial plan would be to have enough internal-battery power to get through at least two cycles (i.e., at least two battery packs ready to go for each radio). The hope is that accesss to power from a generator or the larger batteries would be available for recharging the batteries and powering the radios. As for the computer, the 6-cell pack that is available for the Acer is a lithion ion pack that, when fully charged, provides up to six hours of continuous use. Given the nature of our satellite passes - in chunks of 10-15 minutes - I have been able to make days worth of passes without a recharge. I hope to pick up another 6-cell battery because I believe two of them would provide the power necessary to handle things until power was available for recharging. Reading yours and some other comments have me thinking about a few more elements I need to look into ... things I hadn't given much thought to, but elements that would be helpful to know. Both on and off the reflector, I've received multiple requests to write this up for the Journal, and that's very gratifying. I'll definitely do that, and thank everyone for their positive feedback. 73 to all, Tim ___ Sent via amsat...@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 ___ Sent via amsat...@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
[amsat-bb] Re: Cross Boom
The coax shield coming off the antenna boom at a right angle looks like another parasitic element being added to the antenna causing severe distortion of the antenna pattern. But if one installs the antenna in the X configuration and attach the cross boom in a location away from any of the elements one can tightly run the coax across the metallic cross boom with little effect. This was tested by WA5VJB and is a published article. I have my M2 436CP42UG mounted in this fashion and it preforms well. 73, Ed - KL7UW maybe someone else can point to the link to that article. At 11:41 AM 4/22/2009, Jeff Yanko wrote: OK, I see where this is coming into play. So it's possible that the coax shield could react to the feedpoint system and pattern. Now this raises a question. If this is the case, has anybody tried a broadband choke balun to limit this potential problem? If you think about it, the bigger issue with coax effecting the radiation pattern is improper decoupling of the fed point. If the outside shield is hot with RF it will radiated and effect the pattern big time. If the coax is properly decoupled at the fed point the outside shield will ideally have zero rf current on it and ideally have no impact on the pattern. Thoughts? 73, Jeff WB3JFS - Original Message - From: Jim Jerzycke kq...@pacbell.net To: Joe n...@mwt.net; Billy Simpkins bsimpkin...@dishmail.net; Jeff Yanko wb3...@cox.net Cc: amsat-bb@amsat.org Sent: Wednesday, April 22, 2009 11:09 AM Subject: Re: [amsat-bb] Re: Cross Boom Because the shield of the coax looks like a piece of pipe, and has the same effect on the antenna pattern that you're trying to eliminate by going to a non-metallic cross-boom. Jim KQ6EA --- On Wed, 4/22/09, Jeff Yanko wb3...@cox.net wrote: From: Jeff Yanko wb3...@cox.net Subject: [amsat-bb] Re: Cross Boom To: Joe n...@mwt.net, Billy Simpkins bsimpkin...@dishmail.net Cc: amsat-bb@amsat.org Date: Wednesday, April 22, 2009, 10:55 AM Hi all, I found this line confusing But then if you go insulated then do not run the feedline along it either or you just defeated the purpose of the insulated boom. My question is if you run the coax along an insulated crossboom, ie. fiberglass, how could that affect the coupling of the transmission line when the object it is being attached to is insulated? 73, Jeff WB3JFS - Original Message - From: Joe n...@mwt.net To: Billy Simpkins bsimpkin...@dishmail.net Cc: amsat-bb@amsat.org Sent: Wednesday, April 22, 2009 7:06 AM Subject: [amsat-bb] Re: Cross Boom It all depends on how the elements are mounted. If at 45 to 90 degrees from the crossarm, no propblem and use anything, But if in the same plane then need insulated crossboom, But then if you go insulated then do not run the feedline along it either or you just defeated the purpose of the insulated boom. Billy Simpkins wrote: Is a fiber glass or some other non-conductive material necessary for a cross boom? What or the advantages and disadvantages versus a metal one? Thanks, Billy KF0CK ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@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 ___ Sent via amsat...@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
