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

Re: loop yagis
by George Henry 08 May '07

08 May '07

-----Original Message----- >From: "Greg D." <ko6th_greg(a)hotmail.com> >Sent: May 8, 2007 2:22 AM >To: kl7uw(a)acsalaska.net, amsat-bb(a)amsat.org >Subject: [amsat-bb] Re: loop yagis > >Hi Ed, > >I do have a hardline run from the shack, at least for most of the 60' path. >Need some flexible stuff at either end, so that will eat some signal. >You're right, I'm going to loose a lot before it gets there. AARRRRRRRRRRRRRGHHHHHHHHHHHHH!!!! It's "LOSE", not "loose" and "losing", not "loosing"!!!!!!!! Must.... switch.... to.... decaf............ ;-)

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Galileo politics
by Bob McGwier 08 May '07

08 May '07

http://news.bbc.co.uk/2/hi/science/nature/6634285.stm Bob N4HY -- Robert W. McGwier, Ph.D. Center for Communications Research 805 Bunn Drive Princeton, NJ 08540 (609)-924-4600

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Re: loop yagis
by Edward Cole 08 May '07

08 May '07

Greg, At 10:40 PM 5/7/2007, Edward Cole wrote: >Greg, > >My experience was with my 144/1268 15w DEMI Tx-converter mounted on >the elevation crossboom with 7-foot of 1/2-inch hardline to a single >45-element loop-yagi. I measured 9.5w at the feed with a Bird meter. After reading what I wrote, I realized this was not an accurate description of what I used on AO-40. This is what I built after my on-air experience to lessen losses. This setup resulted in about 14w to the antenna. I never got the chance to test this on AO-40 as it shutdown by then. What I ran on AO-40 was about 20-feet of LMR-400 from the antenna to the ground below my short roof-top tripod. That resulted in the 15w being attenuated to 9.5w at the antenna. This does show how little it takes in coax loss to reduce 1.2 GHz power delivered to the antenna and the uplink. I bought Ser. No. 102 of DEMI 144/1268 15w AO-40 transmitting converters. My order was placed a year in advance of launch so I got nearly the first production unit. Its a nice piece of equipment but DEMI discontinued it shortly after the demise of AO-40. The 18w PA chip used in it is no longer available. I have a DEMI 1296 15w PA that uses that same device. Hope they hold up as when they fail the equipment will not be reparable. 73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa(a)hotmail.com ======================================

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Re: loop yagis
by Edward Cole 08 May '07

08 May '07

Greg, My experience was with my 144/1268 15w DEMI Tx-converter mounted on the elevation crossboom with 7-foot of 1/2-inch hardline to a single 45-element loop-yagi. I measured 9.5w at the feed with a Bird meter. So I think anyone considering running mode-L uplink should consider the losses to the antenna. 10w in the shack will not do it unless you use a very big dish, since you may only get 1-2w to the dish (using hardline; don't even think 9913 or such for this frequency). Above 432 it is standard practise to locate the equipment close to the antenna so you do not suffer high losses. Directive systems makes a 6-foot loop-yagi with half the gain so one could stack two to get 20 dBi. The M2-23CM35EZ should work well, also. We do not know what the orbit and satellite 1268 antenna/receiver parameters are, so the only approach I have is to use AO-40 experience as a guide. If P3E is more like AO-13 then you get a bit more signal which will not hurt. Let's all remember that the S1 system failed after a very short period, and S2 used a lower gain helix antenna requiring better uplink capabilities. One should always design in a little "wiggle" room in your station. That way you can absorb some lowered performance on the satellite. This is just good engineering. At 08:34 PM 5/7/2007, you wrote: >Hi Ed, > >Yeah, I thought a loop in front of my grill might be too good to be true. >While probably fine for terrestrial work, I only have 10w in the >shack, so for satellite work there's no RF to waste on spillage and side lobes. > >The 12' Directive Systems antennas seem to be big and very well >built. Too much of both, probably. I only have a 4'-5' vertical >turning radius (cross-arm to sloped roof), so mid-span on a 12' boom >isn't going to work. >And it weighs 5 lbs. > >M2 has a 35 element beam (23CM35EZ) with similar specs, but its a >little shorter and weighs half as much. I might be able to squeeze >it in between the rotor and the tower cam. Anybody have any >comparative experience between the two? > >Thanks, > >Greg KO6TH 73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa(a)hotmail.com ======================================

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Re: FO-29 Operation Pause (Fwd from JARL)
by TOFFY 08 May '07

08 May '07

Thank very much. 73s de Toff HS0NNU ----- Original Message ---- From: Mineo Wakita <ei7m-wkt(a)asahi-net.or.jp> To: amsat-bb(a)amsat.org Sent: Saturday, May 5, 2007 4:19:04 PM Subject: [amsat-bb] FO-29 Operation Pause (Fwd from JARL) About "Fuji-3" Present Condition and Operation: (Although the normal operation is checked, the operation is stopped for a while.) It is as a previous report an amateur satellite "Fuji-3" (JAS-2, FO-29, 8J1JCS) of JARL. From 21 April, 2007, although the analog system transponder had stopped, we announce you the subsequent present condition. On 3 May, Thu. 16:00 (UTC), We could check an analog system transponder (JTA) of "Fuji-3" was worked to ON and OFF by command from a GS control office and there was no fault in a command system. On 4 May, Fri., we made turn ON the analog system transponder, and the electric power income and outgo were checked. The rate of the shade was 25%, so the electric power income and outgo turned out that it is in a quite severe state. Since the check of the electric power income and outgo, the battery reconditioning, etc. are worked, we do as stopping the operation of "Fuji-3" for a while. Although we cause users much anxiety, we consent-wish-do. In addition, although it may turn ON temporarily an analog system transponder over Japan during an operation dormant period, please refrain from use of transponder such as a loop test and a communication. Translated by JE9PEL, Mineo Wakita. _______________________________________________ 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 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Cape-1 decoded thanks
by john heath 08 May '07

08 May '07

Hi, got my first CW telemetry from Cape-1 last night (Sunday) on the 21:50 utc pass over the UK. Strong signal on 435.247+/- Doppler. Object number 31130. K5ULS 1 9d 00 ff ff 00 00 85 ?? Thanks to everyone on the list who has contributed hints and tips. Hope to get data from beacon 2 and 3 on the next few passes. 73 John g7hia

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Helix vs. loopers
by Steve Raas 08 May '07

08 May '07

In reading much of the discussion that has hit the BB lately in regards to antennas I figured Ide toss in my questions to the group. In trying to figure out which style antenna is going to suit my needs best I have a few questions. #1 Is a linear polarized antenna less efficient than a RHCP antenna when trying to receive or transmit to a rhcp signal / receiver? #2 If yes.. in theory how much? #3 In looking @ pre-built helix options for 1.2g I have found the DSH23-12 which is a 23 cm RHCP 12 turn helix 14.5 dBic gain in a machined radome for best weather protection. 1.2-1.3 GHz bandwidth. 50 ohm feed with N (f) connector on 8" backplane. All stainless hardware; Designed for PHASE 3D uplink operation. Wide bandwidth actually covers from 900 - 1600 MHz ( copied verbatium from the www.directivesystems.com website. In looking at the specs of this helix, it seems it may not have the desired gain for P3E or others. In 'theroy' is it possible to make a 24 turn helix , and if so would I be correct in thinking that double the turns would provide at or near 3.0 db of additional gain? #4 If yes to question 3 would this antenna be @ or near double the physical length? In a email I sent to Dave @ Directive he told me that the loopers he has can be arranged for vert/linear or horizontal polarization, so I do think that a looper although a great antenna may not be the best single antenna solution for 1.2 Uplink. Thoughts, Ideas & comments please. -Steve Raas N2JDQ FN20vg

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WTB: Icom IC-1275 1.2ghz transceiver
by Jan Robbins 08 May '07

08 May '07

For a friend, I am seeking a new or mint Icom IC-1275H 1.2ghz transceiver. Pse email info and photos. Many tks to all es vy 73! Jan N0JR

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CAPE-1 CW ,Heard ¡
by EB3SA - Carles 07 May '07

07 May '07

22:35 utc Orbit 275 59 CW Heard Max. elev. 59º 73´s -- Carles Roy eb3sa(a)eb3sa.com www.eb3sa.com

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L band antenna
by w7lrd＠comcast.net 07 May '07

07 May '07

Hello (again) Not wanting to reinvent the wheel and with multiple options it's not as easy as I thought. I built a dual L/S helix feed (untested) for my four foot primestar. I'm considering long loop yagis, Homebrew a couple of long L band helix antennas (VE3NPC). Then if I can figure out how to aim it there's my 12 TVRO. I'm trying to generate more discussion on this issue. See you at Seapac -- 73 Bob W7LRD AMSAT member 28498 Seattle

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