July 2008 - AMSAT-BB - mailman.amsat.org

Re: Commercial Mode L Antenna sources
by Ronald Nutter 02 Jul '08

02 Jul '08

I understand the budget differences. I am looking for options since my antenna building skills arent that great. I will settle for LEO options at this point since there are no HEO's up at this point Ron KA4KYI AMSAT #1460 k0vty(a)juno.com wrote: > Ron > > I suggest there is a large difference between the two bird you quoted > ( LEO and HEO ) > A link budget study would provide the difference I speak of. > > Very best > > Joe K0VTY > Amsat # 860 > =============== > On Tue, 01 Jul 2008 20:41:45 -0500 Ronald Nutter <rnutter(a)networkref.com> > writes: >> I am thinking about putting in a 1.2 Ghz module in m IC910H. That >> has >> me looking at Mode L antennas. Until my browser blew up a few weeks >> >> ago, I had severa links to antenna candidates but have lost those >> now. >> Would appreciate any links to antennas that are usable with AO-51 >> and >> maybe the phase 3 birds when they launch. >> >> Thanks, >> Ron >> KA4KYI >> _______________________________________________ >> Sent via AMSAT-BB(a)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 >> >> > ____________________________________________________________ > Hotel pics, info and virtual tours. Click here to book a hotel online. > http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3nLmKwW3WK8At0FXUo7Z26P0m… >

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Re: Eliminating Desensing
by Andrew Glasbrenner 01 Jul '08

01 Jul '08

It's unusual to see desense on 2m receive from a 70cm uplink, but I think the same solution can be applied. Many use a common 2m/70cm diplexer as a high pass/low pass filter. In this case you would want to feed the 2m antenna to the common port of the diplexer, and the 2m port of the diplexer to the input of either your preamp or rig if you do not have a preamp. This blocks your transmitted signal from the receiver/preamp input very effectively. http://www.amsat.org/amsat-new/articles/Mode-J/ describes this for 70cm desense issues. Another option is to use a preamp with good filtering on the input. I had issues with Mode J desense with my Icom AG-35 preamp, but have none now that I have switched to SSB Electronics preamps. As always, Your Mileage May Vary (YMMV). 73, Drew KO4MA -----Original Message----- >From: "Reicher, James" <JReicher(a)hrblock.com> >Sent: Jun 30, 2008 12:50 PM >To: amsat-bb(a)amsat.org >Subject: [amsat-bb] Eliminating Desensing > >I got significant de-sensing of my 2 meter downlink from my 70cm uplink at Field Day. I know a good part of it was due to the short cross-boom (about 4 feet) I was using. I would like to decrease the de-sense on this set-up before I permanently install it at my home station. Any and all suggestions are welcome. > >73 de W0HV, Jim in Raymore, MO >Light travels faster than sound... This is why some people appear bright until you hear them speak. > >_______________________________________________ >Sent via AMSAT-BB(a)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

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SEEDS-II heared in FM packet !
by Henk, PA3GUO 01 Jul '08

01 Jul '08

Picked up the last part of a pass of SEEDS-II today. Satellite was in FM 1k2 packet mode. First time that I heared this mode over Europe. Freq: 437.485 MHz. Radio: TS2000, 2x8 elements antenna, no pre-amp. Here is how it sounds like (12 seconds / 50kb): http://home.vianetworks.nl/users/hamoen/pa3guo/seeds_01jul08_1115utc_pa3guo… JQ1YGU*>JQ1YGV F0 F9 61 05 28 00 00 40 D7 00 00 00 01 00 01 00 01 00 00 00 00 0B 43 0B 88 0A 10 0B 97 0B 27 0B 68 00 05 00 08 00 06 00 04 00 05 00 06 0C 7D 0F FD 08 3C 07 8F 0B 10 10 A7 08 B8 07 E4 09 2A 09 30 08 04 08 77 88 C1 09 58 08 D8 09 85 Henk, PA3GUO The Netherlands www.pa3guo.com

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APRS FD
by Stu 01 Jul '08

01 Jul '08

Are there any success stories for APRS and FD? If so, can you share them? We (W4IY) worked a couple stations through VO-52 and I was surprised how many SSB ops were on. I used a couple of omnis, TS-2K and Ham Radio Deluxe for doppler correction. Nice to see all the activity! Stu W7IY

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2008 Field Day Submissions
by Bruce 01 Jul '08

01 Jul '08

Now that field day is over for 2008, there is one more thing that you have to take care of. Submitting your contacts for scoring under the AMSAT rules. You can download the rules from http://www.amsatnet.com/2008fd.pdf or http://www.amsatnet.com/2008fd.doc Below are the important dates and emailing/mailing information. 73...bruce The Satellite Summary Sheet should be used for submission of the AMSAT Field Day competition and be received by KK5DO (email or postal mail) by 11:59 P.M. CDT, Monday, July 14, 2008. The preferred method for submitting your log is via e-mail to kk5do(a)amsat.org or kk5do(a)arrl.net. You may also use the postal service but give plenty of time for your results to arrive by the submission date. Add photographs or other interesting information so that can be used an article for the Journal. *You will receive an email back (within one or two days) from me when I receive your email submission. If you do not receive a confirmation message, then I have not received your submission. Try sending it again or send it to my other email address. *** If mailing your submission, the address is: Bruce Paige, KK5DO Director of Awards and Contests PO Box 310 Alief, TX 77411-0310 -- Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0100z on SkyScanner Satellite Radio Network on Galaxy-25 @97° West, Transponder 23 (12115 Vert), Symbol Rate: 22425, APID: 1794 (DVB Free To Air) Also streaming MP3 at http://www.amsatnet.com Podcast at http://www.amsatnet.com/podcast.xml or iTunes Latest satellite news on the ARRL Audio News http://www.arrl.org

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Re: Eliminating Desensing
by David Donaldson 01 Jul '08

01 Jul '08

The quality of the devices and the design of the amp is significant. In the cellular world at 850 I have seen cheap poorly designed (talking thousands for these units) TTA's generate more crud from minimial colocated signals then the well designed cheap ones. All the units I now use have a high IP3 point with integrated filters or duplexers. The unit ADC Telecom used to make had the filter integrated in the housing (machined out of a solid aluminum block). I was able to use these in downtown settings without fear of intermod. Newer units work as well but now have a seperate filter from the housing. Moral of the story: It's design not price that is the key. Cheaper not always badder. Compare specs. Other suggestion would be to establish the power level where the interference begins. Though it is not linear it will give u a sense of the degree of interaction between the UL and DL antennas. Intermod and desense always has a bit of magic to it thanks to its none linear behaivor Hope this helps someone Dave D WB7DRU Sent with Wireless Sync from Verizon Wireless Another option is to use a preamp with good filtering on the input. I had issues with Mode J desense with my Icom AG-35 preamp, but have none now that I have switched to SSB Electronics preamps. As always, Your Mileage May Vary (YMMV). 73, Drew KO4MA --- Get FREE High Speed Internet from USFamily.Net! -- http://www.usfamily.net/mkt-freepromo.html ---

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Re: Eliminating Desensing
by Edward Cole 01 Jul '08

01 Jul '08

Andrew is onto something when he suggests different preamp sensitivities to out of band interference. One can also just have front-end oveload of energy on frequency. I have not had any issues with either Mode-UV or Mode-VU with my system where the antennas are separated 5-feet on a metal boom. My preamps both sue mgf-1302 GasFets. Both were special designs and not commercial mfrs. But I will say that ARR preamps seem to work well as do Kuhne Engineering (DB6NT) designs. The diplexer solution works for out of band interference when used in front of the preamp. In band front-end blockage can be handled by filtering the transmit coax line either with a bandpass filter or 1/4 wave coax stub tuned for the receive frequency. Often it takes a bit of trial and error to find the solution for your particular situation. 73 Ed - KL7UW At 09:22 AM 6/30/2008, Andrew Glasbrenner wrote: >It's unusual to see desense on 2m receive from a >70cm uplink, but I think the same solution can >be applied. Many use a common 2m/70cm diplexer >as a high pass/low pass filter. In this case you >would want to feed the 2m antenna to the common >port of the diplexer, and the 2m port of the >diplexer to the input of either your preamp or >rig if you do not have a preamp. This blocks >your transmitted signal from the receiver/preamp >input very effectively. >http://www.amsat.org/amsat-new/articles/Mode-J/ >describes this for 70cm desense issues. Another >option is to use a preamp with good filtering on >the input. I had issues with Mode J desense with >my Icom AG-35 preamp, but have none now that I >have switched to SSB Electronics preamps. As >always, Your Mileage May Vary (YMMV). 73, Drew >KO4MA -----Original Message----- >From: >"Reicher, James" <JReicher(a)hrblock.com> >Sent: >Jun 30, 2008 12:50 PM >To: >amsat-bb(a)amsat.org >Subject: >[amsat-bb] Eliminating Desensing > >I got >significant de-sensing of my 2 meter downlink >from my 70cm uplink at Field Day. I know a good >part of it was due to the short cross-boom >(about 4 feet) I was using. I would like to >decrease the de-sense on this set-up before I >permanently install it at my home station. Any >and all suggestions are welcome. > >73 de W0HV, >Jim in Raymore, MOÂ >Light travels faster than >sound... This is why some people appear bright >until you hear them >speak. > >_______________________________________ >________ >Sent via AMSAT-BB(a)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-BB(a)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

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Eliminating Desensing
by Reicher, James 01 Jul '08

01 Jul '08

I got significant de-sensing of my 2 meter downlink from my 70cm uplink at Field Day. I know a good part of it was due to the short cross-boom (about 4 feet) I was using. I would like to decrease the de-sense on this set-up before I permanently install it at my home station. Any and all suggestions are welcome. 73 de W0HV, Jim in Raymore, MO Light travels faster than sound... This is why some people appear bright until you hear them speak.

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Fwd: Carl Eilers, SK
by Arthur Feller 01 Jul '08

01 Jul '08

Begin forwarded message: > THIS WEEK'S HONORARY UNSUBSCRIBE goes to Carl G. Eilers. When he > went to > work for Zenith Electronics in 1948, Eilers' assignment was to > work on > "Phonevision", or pay television. "Even then he developed the core > concepts that are used today, such as scrambling a signal and you > only > get an unscrambled signal if you pay for it," a Zenith spokesman > said. > But Eilers is better known for a couple of other Zenith > innovations: he > led the team that created the standard for FM stereo, which was > adopted > by the FCC in 1961 and is still in use today, and Eilers later > expanded > that work for another medium: TV. Zenith's multichannel television > sound, or stereo TV with a "separate audio program" that for > instance > could carry the soundtrack in other languages, was adopted > industry- > wide in 1984. Eilers stayed at the company for 50 years before > retiring. He died June 20 from an apparent heart attack at 83. Life is short. Be swift to love! Make haste to be kind! - Henri Frederic Amiel, philosopher and writer (1821-1881)

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Re: RS-15 heard again
by w7lrd＠comcast.net 01 Jul '08

01 Jul '08

I have tried at times to give it a shot of RF uplink, "just in case". I mean after all AO-7 came back to us! Maybe it just needs enough up RF to jump start it. Does anyone know what it's final demise was from? 73 Bob W7LRD -- "if this were easy, everyone would be doing it" -------------- Original message -------------- From: "Auke de Jong, VE6PWN" <sparkycivic(a)shaw.ca> > I just copied the beacon on 29.351, after not hearing anything for a long tmie. > It's sending relatively short duration pulses today... 1 second on, 2 seconds > off, give or take... later in the ascending pass(as I write this) , times are up > to greater-than 4 seconds off /.75 seconds on Does that mean the spacecraft is > warm? > > Strange, that this is the ONLY mode-A signal around these days-besides AO-7 if > she feels like it ;) > > > > Auke de Jong > VE6PWN > DO33go > Edmonton, AB > > _______________________________________________ > Sent via AMSAT-BB(a)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

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