May 2009 - AMSAT-BB - mailman.amsat.org

Re: FT-847 vs IC-910
by Wayne Estes 30 May '09

30 May '09

Not all FT-847's are alike. A stock FT-847 has wide, low-Q ceramic IF filters. My FT-847 has INRAD CW and SSB crystal filters that give narrower IF bandwidth, with MUCH higher Q. I haven't compared them, but I suspect that a FT-847 receiver with quality IF filters performs roughly on par with an IC-910. If shopping for a used FT-847, look for one with optional IF filters. Collins mechanical filters are an improvement over the stock ceramic filters, but crystal filters are even better. Wayne Estes W9AE Oakland, Oregon, USA

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Re: eggbeater rx performance MM
by MM 30 May '09

30 May '09

Let’s split your question into two parts Car and House: I have made literally hundreds of FM voice contacts with Mir and ISS from my car. I have also made hundreds of packet mail contacts with Mir. On Mir the default power setting was 5 watts, into a Larsen Dual band Mobile antenna, mounted outside on the hull of Mir. The transceiver was either a Kenwood TM-733 or TM-V7A. My car station was typically a 5/8 wave mono band 2-meter vertical, with a 45 watt class FM rig. I usually did not have the amps in the car since mobile amps are typically high maintenance. ISS is running a similar setup. The transceiver is a Kenwood TM-D700, modified for three power settings, 5,10,25 (special mods). The ISS D700 has been programmed to default to 10 watts for voice and packet, unless changed by the crew, however every time the crew pushes a PM/function button, it forces the radio back to 10 watts. The antenna is a Quad band system with 2, 440, patch for 1.2-2.4 Ghz. Gain is unknown, and must be assumed to be –3dBd for 2 meters. So for beginners, LEO satellites, Running simple verticals and a 45+ watt class system and 0 dBd gain antennas is a good way to start from your car (parked or driving). You will need to Pick your orbits in advance. I would usually only attempt orbits that were 45 degrees elevation or better from my Car. For the more advances mobile users, try this Mobile EME array. http://www.garysicecream.com/may909.htm Other Car Tips: Convert from RG-58 to LMR-240-UF or RG-213. The coax that usually comes with stock mobile antennas is too poor of quality to be used seriously. Run Mono-band antennas for 2 and 440, get the highest Gain mono band (whip) antennas that will fit your mobile and garage. You may need a signal splitter since most rigs only have one SO-239 for 2/440. Amps for your Car: Get best antennas and coax first before using amps. In some States, we are limited to 50 watts on 440. House Satellite Antennas: It’s ok to start with a few simpler verticals or small beams to see if you like the satellite hobby. If you do like Satellites and want to continue then you have two choices. #1 Gradually build your antenna gain over several years, 1 Element 0 dBd 2 Elements 3dBd 4 Elements 6dBd 8 Elements 9 dBd etc. or #2 you can jump in and buy a one of the 20+ element CP (circular polarized) 12-dBd class beams. In many cases it maybe cheaper to go from 0 dBd to 12 dBd than buying lots of little antennas in-between. A CP style antenna system can be used for both Satellite and terrestrial DX. Other Tips: Go with the most elements you can afford for a single boom. 20+ elements on 2-meters 40+ elements on 440 Coax: You can now get Flexible thick coax that will support an antenna Rotor. Most people used RG-8 style coax, which is approximately 10 mm in diameter. However you can now get flexible rotor grade coax which is approximately 15 mm in diameter, and has much lower loss than the best RG-8 style coax. Example: Belden RG-213 145 MHz 2.5 dB loss per 100 feet 438 MHz 4.5 dB loss per 100 feet LMR 600 UltraFlex Rotor cable 145 MHz 1.1 dB loss per 100 feet 438 MHz 2.0 dB loss per 100 feet As you can see, by switching from 10mm coax to 15mm coax you can reduce you loss by over 50%. The 15mm cables cost 2-3 times as much, however you will not have to worry about coax losses any more on Frequencies below 2 gig. 73 wf1f --- On Fri, 5/29/09, Eric Fort <eric.fort(a)gmail.com> wrote: > From: Eric Fort <eric.fort(a)gmail.com> > Subject: [amsat-bb] eggbeater rx performance > To: "Amsat BB" <amsat-bb(a)amsat.org> > Date: Friday, May 29, 2009, 9:17 PM > I/m interested in the possibility of > using oscars 27, 29, 50, 51, and 52 > without using rotors or directional antennas and maybe > while mobile. Uplink > seems not to be a problem as one can always QRO to a level > where the > satellite sees an apropriate signal level that is enough > but without robing > power from other transponder users. On recieve though > you still gotta be > able to hear 'em to work 'em. Is an eggbeater and a > preamp enough to hear > decently or is there another (better) way? Is working > mobile and/or without > directional antennas even practical? what's the best > way to do it? > > Thanks, > > Eric > AF6EP > _______________________________________________ > 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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Re: GO-32 status
by Mark L. Hammond 30 May '09

30 May '09

Hello David, For what seems like an eternity GO-32 has been sending a telemetry packet at 9600 baud one per minute. So, NO, the BBS isn't open (and hasn't been for a long time). You can decode the telemetry GO-32 frames thanks to Mike DK3WN! Actually, he has decoders for just about every satellite ever launched ;) at http://www.dk3wn.info/software.shtml 73, -- Mark L. Hammond [N8MH] ______ Hello All, What is the status of GO-32? Is the BBS back up and running? 73 de David VK5DG

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Re: Mobile Coax?
by MM 30 May '09

30 May '09

Hi Bob, You comments are valid for 2-meters. You are not going to see much difference between 15 feet of cheap coax and good coax. Howver, as you go higher in frequency the losses increase. On the 440 band the Coax Loss difference between 15 feet of RG-58 and LMR-240 is approximately 1 dB. For Raw power, switching from 15 feet of RG-58 (~5 millimeter cable) and LMR-240 (-6 Millimeter cable) will give you 15-20% more RF at the antenna. So for people that are counting dB’s in mobile setup, this is just one more option to squeeze out a little more performance. And for those of you what want to run amplifiers on 440, you will find that RG-58 has approximately a 105-watt limit. The LMR-240 (-6 Millimeter cable) will support 380 watts. Here in Boston, Hams are starting to used 900 Mhz repeaters. The stock RG-58 coax just sucks up your TX and RX power on 900 mhz. Low Loss Coax for Home and Mobile usage Hi all: Most of the mobile antennas mounting systems that come with coax use the cheapest and highest loss coax available. If you read the fine print on these coaxes you will be surprised to find that your power loss may be as high as 40% and the coax will melt above 110 watts (on 440 mc). More and more of us are using 440 and higher frequencies. By selecting the correct coax you can save 1 or more DB of loss, even for a short length as 15 feet. Here are some number I put together on coax loss for the typical mobile installation. dB Loss (440 mc) dB Loss (900 mc) Length FT TX Freq/Length 15' 100' Pwr 15' 100' Pwr Size Center RG-58/U 1.5 9.9 105w 2.2 14.5 60w .195" .032 RG-58/A 1.5 9.9 105w 2.2 14.5 60w .195" Stranded RG-8X 1.2 8.1 250w 1.8 12.1 150w .240" Stranded LMR-240UF 0.5 3.2 380w 0.7 4.7 260w .240" .059 The coax RG-58 comes in many flavors, No letter, A, C and U. The letter "U" is sometimes a solid 20 AWG copper center. The letters "A" and "C" are stranded, the center size would be similar to solid, and will have a little more loss than Solid center. Most mobile installations will need 15 to 17 feet of coax. RG-8X and LMR-240 are the same size, however LMR has foil shield and lower published loss values. The UF version of 240 is the Ultra Flex flavor and can bend easier with a only a slight change in loss ratings. >From this list of small car style coax, the LMR beats them all; in lowest loss for the size and highest transmit power loads. I was planning on installing a 440 AMP in my car, but after looking at the coax, I realized that I would fry the stock RG-58 coax. I was looking for an NMO Mag mount that has LMR-240 installed. I was not able to find any, so I made my own. I took a Round style Larsen NMO mount and replaced the existing RG-58A coax with LMR-240. Use two screw drivers to pop the magnet off the metal mount. Remove the two Phillips screws hidden under the magnet. Remove the metal frame and now you will have access to the coax mounting point. Replace coax and glue on the magnet with epoxy cement. 145 meg 45 watts, in, 15 feet of LMR-240, = 40 watts out 45 watts, in, 15 feet of RG-58, = 37 watts out (~10% power loss difference) 440 meg 20 watts, in, 15 feet of LMR-240, = 17 watts out 20 watts, in, 15 feet of RG-58, = 14 watts out (15-20% power loss difference) 900 meg 10 watts, in, 15 feet of LMR-240, = 7.7 watts out 10 watts, in, 15 feet of RG-58, = 5.8 watts out Power reference http://www.ocarc.ca/coax.htm 73 Miles --- On Sat, 5/30/09, Bob Bruninga <bruninga(a)usna.edu> wrote: > From: Bob Bruninga <bruninga(a)usna.edu> > Subject: [amsat-bb] Mobile Coax? > To: "Amsat BB" <amsat-bb(a)amsat.org> > Date: Saturday, May 30, 2009, 10:48 AM > > 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 > _______________________________________________ > 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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eggbeater rx performance
by Eric Fort 30 May '09

30 May '09

I/m interested in the possibility of using oscars 27, 29, 50, 51, and 52 without using rotors or directional antennas and maybe while mobile. Uplink seems not to be a problem as one can always QRO to a level where the satellite sees an apropriate signal level that is enough but without robing power from other transponder users. On recieve though you still gotta be able to hear 'em to work 'em. Is an eggbeater and a preamp enough to hear decently or is there another (better) way? Is working mobile and/or without directional antennas even practical? what's the best way to do it? Thanks, Eric AF6EP

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Gulf Alpha antenna
by Norman W Osborne 30 May '09

30 May '09

Is there anyone using Gulf Alpha antenna's? I am looking for feedback as I am considering buying the 70cm X yagi. 73, Norman.

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Fw: eggbeater rx performance
by john heath 30 May '09

30 May '09

----- Original Message ----- From: "john heath" <g7hia(a)btinternet.com> To: <eric.fort(a)gmail.com> Sent: Saturday, May 30, 2009 8:48 AM Subject: Re: [amsat-bb] eggbeater rx performance > Hi Eric, > > For the downlink on 70cm why not have a look at the paraistic Lindenblad > design by Anthony Monteiro AA2TX. Its small and neat, excellent omni > performance and has been "on air tested" with good results on all sats. > > Much easier to construct than a true Lindenblad, I have built both types. > > Good luck. > > 73 John G7HIA >

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Eggbeater-AF6EP
by Amateur Radio Station WA2S 30 May '09

30 May '09

Hi Eric If your goal is to work mobile while driving, your windows of opportunity are going to be slim. I've done it, but effective air time will be pretty short. On the portable side, I've been able to achieve VUCC Satellite using 5 Watts FT-60R handheld and an Arrow antenna mounted on a photo tripod standing on the back deck. I also have the Elk but school's out on which I prefer (for me- but most guys prefer the Elk). I've also built K5OE's Eggbeater II for 2 meters which I have mounted in the attic along with an antennas.us quadrifilar for 70 cm. Preamplifiers on both. Results are OK but not as effective as even a simple directional antenna. I suspect that the weak link is the quadrifilar and if I mounted a homebrew Eggbeater for the downlink, it might improve results. Have also built EA4CYQ's "IOio" handheld combo which works very well also. Go to http://www.eb4dka.tk to see some great videos on how they work. Simple to build and effective for portable work. Good luck. 73 Marc W4MPS (formerly WA2S)

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Re: help with satpc32
by Lowell White 30 May '09

30 May '09

See if you can set explicit permission for satpce32 to be run as administrator. I am presuming that the error is that the user doesn't have adequate permission to run said program (or at least to make the change to the 'rotator north' parm). Right click on the program icon, select Properties, Shortcut tab, Advanced, check the box to run as another user... 73, Lowell K9LDW ------ Original Message ------ Received: Thu, 28 May 2009 07:36:09 AM CDT From: "Nick" <quadpugh(a)bellsouth.net> To: <amsat-bb(a)amsat.org> Subject: [amsat-bb] help with satpc32 > The UL is running xp and satpce32 the xp is set with administrator and a > user profile and will not store the rotator North point parameter . > > > > Help ???? > > > > Thanks > > nick > > _______________________________________________ > 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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Re eggbeater performance - mobile
by mikehooles 30 May '09

30 May '09

For mobile work on AO27, SO50, AO51 a 2 metre quarter wave whip is all you need with an IC-706 to work the LEO's when mobile and the satellite is 15 degrees or more above the horizon, Regards Mike G3LGR

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