December 2007 - AMSAT-BB - mailman.amsat.org

Re: Listening before Transmitting
by Clint Bradford 27 Dec '07

27 Dec '07

> >>...All sorts of weird ideas floating around now??? No, things haven't changed...(grin) I have been chastised for NOT telling folks that TRUE, FULL DUPLEX OPS IS MANDATORY - to monitor AO-51 and SO-50 downlinks while working them. Of course, it IS best to have a full-duplex setup for these birds. But these sats are so easily worked with low power, that I continue to turn folks on to AMSAT and this aspect of our hobby with my "How to Work Amateur Satellites with your HT" presentation. The "demo station" equipment I use for the presentation continues to consists of a single dual-band HT at 2.5W, and improved antenna. And so it goes.... Clint Bradford, K6LCS 909-241-7666

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AO-7 10 meter?
by Michael J. Wolthuis 27 Dec '07

27 Dec '07

I saw a video from Dayton on Youtube of AO-7 Mode A, does it still come up in this mode? Last notes I see on the Sat status page is November 26. I have an AR-10 and HTX-100, but I have NEVER used them for anything and was planning to Ebay, as I see no other satellite use for this equipment which is my primary radio operations. I don't do anything on 10m. It was for a project that got shelved. Could these be of any use for AO-7 or anything else sat related? Thanks, Mike Kb8zgl

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Listen before transmitting?
by Dave Guimont 27 Dec '07

27 Dec '07

The Weekly Satellite Report under AO7 says: Listen before transmitting! Is there some kind of "listening" one should be aware of??. We learned that 80 years ago in ham radio....That applies to any am/ssb/cw/fm modes, even if transmitting "in the blind" in an emergency.... All sorts of weird ideas floating around now??? 73, Dave, WB6LLO dguimon1(a)san.rr.com Disagree: I learn.... Pulling for P3E...

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Re: FT-847 Disaster - THE PAIN! - It could be worse !
by John W Lee 27 Dec '07

27 Dec '07

Don't feel too bad, we've all done things like that at one time or another. Here's one for ya: One of the locals sold a nice FT-301 (All solid state HF rig of the 1970's-1980's). at the swap meet one time. The fella that bought it called the seller in a couple of days and complained that the thing went up in smoke the first time he turned it on ! He was very mad at the seller until he found out what happend........... Turns out that he put an A.C. plug on the end of the red and black wires and plugged it in and turned it on! Faint ! 73, John, K6YK

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Re: How to calibrate the azimuth angle?
by Ronald Long 27 Dec '07

27 Dec '07

Here is an amsat-bb post from Tom Clark, K3IO, formerly W3IWI, on this subject. Wonderfully detailed. Thank you Tom. I have removed the From line since the original address from 12 years ago may not be accurate. ron w8gus ==== Date: Tue, 17 Jan 95 20:12:13 UTC From: Tom Clark To: amsat-bb(a)AMSAT.Org Subject: North/South vs East/West The recent thread of Magnetic vs. Geodetic north-south for the calibration of antenna azimuths has overlooked an even easier way to do the deed. The idea is not new -- I believe it is the way the ancient Egyptians had their Nubian slaves establish the orientation of the great pyramids to accuracies of about a half-degree. Instead of trying to establish a North/South line, determine East/West instead! Here is the recipe (with some footnotes): 1. Wait for the morning of a clear, sunny day. 2. Find a level, flat area. 3. Poke a 3-6 foot (1-2 meter) stick in the ground vertically (south of the flat area in the northern hemisphere or north in the southern hemisphere). 4. Several times during the day, mark the location of the tip of the shadow of the stick. 5. The points you just marked will be on a straight line which is nominally East/West. Drive stakes at the ends of the line (or if your shadow is on concrete, paint the line). Footnotes: a. The accuracy of the east/west line is best at the solstices (Dec.21/Jun.21) and worst at the equinoxes (Mar.21/Sep.21). The sun's declination is a cosine curve with extrema of +/- 22.5 degrees reached at he solstices. At the equinoxes, the declination changes about 1/2 degree/day so if you are observing at the equinoxes over an 8-hour period, the line will be in error by about 10 arc minutes. b. The diameter of the sun's disk is about 30 arc minutes, so the shadow is "fuzzy" at this level. You need to be consistent in picking the point corresponding to the tip's shadow to minimize the penumbral error. The diameter of the stick should be big enough to give a solid shadow -- i.e. the stick should subtend an angle > 30 arc minutes when viewed from the level, flat area. I recommend that the stick have a length/diameter ratio of 20-30. A typical tall antenna tower will not cast a sharp enough shadow to use. c. The level area need only be level in the east/west direction. A north/south slope will not affect the accuracy. If you don't have a level area, get a 4'x8' sheet of plywood and prop it with short stakes to make it level and cast the shadow onto the plywood. You should strive for east/west "levelness" of one degree or better if you want results good to about one degree. Hope this idea helps -- 73 de Tom.

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Automated ISS station
by Andrew Rich 27 Dec '07

27 Dec '07

I got fed up with noisy power supplies to here is my solution. 1. A linux computer runs Predict as a server 2. A perl script wakes up every minute, and asks predict if ISS is above the horizon. 3. If ISS is above the horizon, a command is sent to a parrallel port control card. 4. The control toggles a relay 5. The relay action turns off the battery charger and engages the radio 6. When the ISS is below the horizon once more, the script turns off the relay. 7. The radio turns off and the battery charger re-engages. 8. The radio has a 30 minute time out set as well to guard against problems. So far it works really well. The rack clicks and comes to life as ISS rises and goes back to sleep when it descends. Here is a photo. http://www.tech-software.net/rack_psu.jpg I am not having much luck with the helix's i have built the front to back seems bad. I have however had great success on 2m, with an 8 element quad. Cheers ---------------------------------------------------------------------------- Andrew Rich VK4TEC vk4tec(a)people.net.au http://www.tech-software.net

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Premap overload
by Andrew Rich 27 Dec '07

27 Dec '07

I think I went a little overboard. I replaced my coax with heliax and fitted a pre-amp to the base of my antenna. Now all I get is break through from commercial services. Oh well. I went from RG213 to LDF4-50. And I can now access a repeater 150 km's away I could not before. Have to bay antennas and back of the pre-amp I think. Cheers ---------------------------------------------------------------------------- Andrew Rich VK4TEC vk4tec(a)people.net.au http://www.tech-software.net

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Was Oregon fireball ANDE reentry?
by Ken Swaggart 27 Dec '07

27 Dec '07

The Associated Press is carrying a story from Bend, in central Oregon, concerning reports of a bright fireball the night (local) of 24 Dec. I haven't been able to obtain a time to check it against the orbital predictions and see if ANDE was supposed to be anywhere in this area. Here's a quote from the story: "Keith Clinton, who lives east of Bend says he saw a "large, bright green fireball descend out of the cloudless sky east of Bend. Clinton says the fireball turned yellow and exploded about 10 degrees above the horizon, breaking into several pieces as it did." 73, Ken, W7KKE

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Re: AMSAT-BB Digest, Vol 2, Issue 840
by Peleg Lapid 26 Dec '07

26 Dec '07

Try to reduce the comunication bit rate to minimum, it helped for me with the 857 73 Peleg 4x1gp -----Original Message----- From: amsat-bb-bounces(a)amsat.org [mailto:[email protected]] On Behalf Of amsat-bb-request(a)amsat.org Sent: Wednesday, December 26, 2007 10:00 PM To: amsat-bb(a)amsat.org Subject: AMSAT-BB Digest, Vol 2, Issue 840 Send AMSAT-BB mailing list submissions to amsat-bb(a)amsat.org To subscribe or unsubscribe via the World Wide Web, visit http://amsat.org/mailman/listinfo/amsat-bb or, via email, send a message with subject or body 'help' to amsat-bb-request(a)amsat.org You can reach the person managing the list at amsat-bb-owner(a)amsat.org When replying, please edit your Subject line so it is more specific than "Re: Contents of AMSAT-BB digest..." Today's Topics: 1. Re: RigExpert Tiny to Yaesu FT-847 (Alan P. Biddle) 2. Re: Questions on physically offset CP yagi feeding (i8cvs) 3. Yaesu FT-897 and HRD satellite tracking problem (Dave Matthews) 4. Ande. (John Ronan) 5. Re: Yaesu FT-897 and HRD satellite tracking problem (Simon Brown (HB9DRV)) ---------------------------------------------------------------------- Message: 1 Date: Tue, 25 Dec 2007 15:19:41 -0600 From: "Alan P. Biddle" <APBIDDLE(a)UNITED.NET> Subject: [amsat-bb] Re: RigExpert Tiny to Yaesu FT-847 To: "'Amsat-Bb'" <amsat-bb(a)amsat.org> Message-ID: <000001c8473b$dd3f60e0$6401a8c0@WA4SCA> Content-Type: text/plain; charset="us-ascii" Rod, Take a look at http://www.usinterface.com/naviusa_007.htm for a wide variety of cables for the full RigExpert. (The Navigator uses the same pin out.) They should give you some good ideas for the Tiny. Note that the FT-847 has the cables for the PKT and DATA ports wired in parallel, so you will need swap the plugs depending on what mode you are operating. Or, as I did, wire up a simple AB switch. Note that for the PKT connection to use the 1200 baud RX. Several of the RE sites have the wiring incorrectly using the 9600 baud output. It will work, somewhat, but with a very poor S/N. The interface will not handle 9600 baud. 73s, Alan WA4SCA ------------------------------ Message: 2 Date: Wed, 26 Dec 2007 00:04:29 +0100 From: "i8cvs" <domenico.i8cvs(a)tin.it> Subject: [amsat-bb] Re: Questions on physically offset CP yagi feeding To: "jonny 290" <jonny290(a)gmail.com>, "AMSAT-BB" <amsat-bb(a)amsat.org> Message-ID: <001d01c8474a$815a7440$0201a8c0(a)tin.it> Content-Type: text/plain; charset="iso-8859-1" ----- Original Message ----- From: "jonny 290" <jonny290(a)gmail.com> To: <amsat-bb(a)amsat.org> Sent: Monday, December 24, 2007 10:59 PM Subject: [amsat-bb] Questions on physically offset CP yagi feeding > I've decided to rebuild my 2m antenna and have a couple of questions. > > My thinking is to build a six element wide-band 50 ohm match yagi and > mount the vertically polarized elements 1/4 wavelength ahead of the > horizontal ones, and feed the elements in phase. Hi Matt, KC4YLV Mounting the vertical and horizontal elements with an offset of 1/4 wavelength over the boom is good because feeding the driven elements in phase you get almost a one sense CP without adding delay lines. . > I have > examined the possibility of masthead CP phasing, but am concerned > about mismatching and like the arguments given for the physically > offset, in-phase fed elements. There are masthead CP phasing and switching circuits with a minimum of mismatching and in addition the lenght of coax relays is not to be taken into account because the length of relays is compensated for provided all relays are of the same type and the same lenght. As an example using 4 coax relays of the same type antenna mounted you can switch from the shack V-H-RHCP and LHCP as described into the AMSAT-Journal march/april 2007 and may/june 2007 > > My antenna to radio coax run is right around 30 feet. I am thinking of > running two lengths of LMR-240, speced at 3 dB loss/100ft, so loss > should be about 1 dB. If I cut the two feedlines to identical lengths, > I should be able to connect them with a coax tee in the shack and use > a > 1/4 wave 37 ohm line to bring the system impedance back up from 25 (at > the tee) to 50 ohms. This is correct but you must be able to exactly cut two runs of coax cable 30 feet long and having the same electrical lenght and first of all it is good to use both coax lines coming from the same coil and if you have access to a network analyser you can check if the phase difference between both feed lines is 0? degrees or not. > I'd then have an RHCP signal for the birds. If the vertical driven element is ahead of the horizontal one to get RHCP the center conductor of the coax cable feeding the vertical driven element must be connected UP and the braid DOWN while looking the elements standing behind the reflector the inner conductor of the coax cable feeding the horizontal driven element must be connected to the RIGHT side and the braid to LEFT side. Since you plan to run two identical coax lines from the shack if you add in the shack a 1/2 electrical wavelenght of coax into the line feeding the vertical driving element then you get LHCP without changing any coax connections on top of the dipoles. The use of folded dipoles with the classic 1/2 wavelength coax balun is recommended. > Do I > _need_ to cut the feedlines to half-wave multiples, or is it just a > good idea? I plan on tuning the antennas as dead on to 145.8 as I can, > so mismatch will be a minimum at that frequency. In theory if you cut the feedlines to half-wave multiples you only have the advantage to exacly measure the impedance of the antenna with an impedance bridge from the shack without to go on the roof and disconnect cables from the dipoles. By the way the VSWR into the line do not change cutting feed lines to half-wave multiples or any other lenght if the impedance of the antenna do not match with the impedance of the coax line. > > When I don't need RHCP, I can simply use the horizontal feedline for > SSB work and the vertical feedline for FM work, setting the coax tee > nonsense aside. It is correct > (as a note, the two sets of elements would be tuned identically, > centered for minimum swr on 145.8, It is good > but in my experience > operation across the band is no problem). > Agree > A good coax relay costs about 60-80 dollars and requires associated > mounting hardware and weatherproofing, this only adds another $15 for > 30 more feet of LMR240. Since your need is satellite and tropo your project sound to be good and simple. > > Anybody care to share thoughts on this? > > 73 and merry christmas > matt kc4ylv > 73" and merry cristmas from i8CVS Domenico ------------------------------ Message: 3 Date: Tue, 25 Dec 2007 18:09:39 -0600 From: Dave Matthews <dave(a)lostfrogs.com> Subject: [amsat-bb] Yaesu FT-897 and HRD satellite tracking problem To: amsat-bb(a)amsat.org Message-ID: <47719BC3.80609(a)lostfrogs.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Merry Christmas everyone. And apologies since I expect the question I ask here is old hat, but I've researched everywhere and still can't find a solution that works: When using the Ham Radio Deluxe satellite tool for satellite tracking with automatic Doppler shift adjustment, I have a periodic 'polling?' noise issue with my Yaesu FT-897, the same as I had last field day with HRD and a FT-857. There is a periodic noise burst that coincides with the black square animation on the upper left of the satellite tracking tool screen. This noise burst makes it impossible to listen to very faint signals, and is annoying as all get out when waiting for a satellite to come into range. FM and SSB modes. I want to use the HRD program with its built in Doppler shift tracking, but it is unusable -for me- as a result of this problem. During Field Day the FT-857 rig was controlled by a laptop, and yagis were about 20' away pointing at the sky. This current FT-897 setup is on a desktop style office computer into eggbeaters warming the clouds. My CT-62 interface cable is shielded, but the shield was not connected! I tied the shield to ground, no difference. The RS-232 extension cable used is also shielded. Grounds are good in this upstairs office shack but I am about 12' above the ground rod. Trying different grounding makes no difference. Ferrite Beads on the comm cable, looped multiple times through the beads, etc. makes absolutely no difference. And I just tried a USB to serial interface replacing the RS-232 from the computer, no difference. So I've shielded and beaded and grounded and experimented to no avail. This is a really annoying problem, and I feel there must be something elementary that I am missing either in the FT-897 setup or in HRD. I expect it is a Yaesu FT-897/857 problem, but again it may just be a setup issue. Any response is appreciated, Dave KI4PSR ------------------------------ Message: 4 Date: Wed, 26 Dec 2007 15:44:28 +0000 From: John Ronan <jronan(a)irishsystems.com> Subject: [amsat-bb] Ande. To: AMSAT-BB BB <amsat-bb(a)amsat.org> Message-ID: <54CED6C4-364E-44C6-8876-B92B145DF982(a)irishsystems.com> Content-Type: text/plain; charset=US-ASCII; format=flowed Has it's fate been ascertained? Regards de John EI7IG ------------------------------ Message: 5 Date: Wed, 26 Dec 2007 19:14:55 +0100 From: "Simon Brown $HB9DRV$" <simon(a)hb9drv.ch> Subject: [amsat-bb] Re: Yaesu FT-897 and HRD satellite tracking problem To: "Dave Matthews" <dave(a)lostfrogs.com>, <amsat-bb(a)amsat.org> Message-ID: <002001c847eb$37d34b20$a400a8c0@hairycreatures> Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Sounds like radiation from the CT-62 cable - try putting a ferrite or two on the cable. Simon Brown, HB9DRV ----- Original Message ----- From: "Dave Matthews" <dave(a)lostfrogs.com> > I have a periodic 'polling?' noise issue with my Yaesu FT-897 ------------------------------ _______________________________________________ Sent via amsat-bb(a)amsat.org. Opinions expressed are those of the author. Not an AMSAT member? Join now to support the amateur satellite program! http://amsat.org/mailman/listinfo/amsat-bb End of AMSAT-BB Digest, Vol 2, Issue 840 ****************************************

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AMSAT Awards
by Bruce 26 Dec '07

26 Dec '07

Here are the last awards that I will be processing for 2007: We would like to welcome the following to the satellite community. They have made their first satellite contact and are now members of the AMSAT Satellite Communicators Club. Jeremy Ramirez, KB9QIC Charles Doolittle, N1SPX Jose Vitor Toste, CU3EQ AMSAT Communication Achievement Award John Henderson, N4NAB, #456 Charles Doolittle, N1SPX, #457 South Africa AMSAT Communication Achievement Award John Henderson, N4NAB, US115 Charles Doolittle, N1SPX, US116 To see all the awards visit http://www.amsat.org or http://www.amsatnet.com Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0100z on W0KIE Intelsat Americas, T1, 6.8Mhz Also streaming MP3 at http://www.amsatnet.com -- Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0200z on W0KIE new satellite soon. Also streaming MP3 at http://www.amsatnet.com Latest satellite news on the ARRL Audio News http://www.arrl.org

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