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

EU Commission Decision on UWB below 6 GHz
by Trevor 13 Mar '07

13 Mar '07

European Commission Decision on UWB below 6 GHz http://www.uk.amsat.org/ 73 Trevor M5AKA ___________________________________________________________ What kind of emailer are you? Find out today - get a free analysis of your email personality. Take the quiz at the Yahoo! Mail Championship. http://uk.rd.yahoo.com/evt=44106/*http://mail.yahoo.net/uk

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Re: F9FT Tonna 432 skeleton antenna?
by richard＠g3rwl.demon.co.uk 13 Mar '07

13 Mar '07

Dave hartzell wrote: > Just wondering if anyone knows anything about this antenna. A couple surfaced and the price was right, but no one knew anything about the antennas at the time. As you noted, its a 432 antenna not 435, and it is NOT optimum at 435. I had one of these several years ago; I wrote to the company for modification info (to 435) but they never replied. Nevertheless, it WILL work; just not quite as well as one optimised at the higher frequency. 73 Richard G3RWL

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Re: fixed elevation.
by KA2AEV＠aol.com 13 Mar '07

13 Mar '07

Just to let everyone know that the majority of the answers came back within the 20-25 degree range 73 de Mike KA2AEV <BR><BR><BR>**************************************<BR> AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com.

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sat tracking
by Patrick McGrane 13 Mar '07

13 Mar '07

hello tim- look for SATSCAPE tracking software links on the amsat homepage from tools to software. I downloaded it recently and it seems to work fine with windows XP. You can make custom pass predictions for whenever or however long you like. Very nice little program. 73, pat n2oeq

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Sequencer
by Stargate 12 Mar '07

12 Mar '07

Is a sequencer needed when using a 160w switchable preamp from ARR? (Advanced Receiver Research) Thanks, RoD KD0XX A good friend will come and bail you out of jail, A TRUE friend will be sitting next to you saying..... "DAMN THAT WAS FUN"

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Orbit prediction
by Tim Tapio 12 Mar '07

12 Mar '07

All, What's the easiest method by which I can print out a week's worth of visible passes with pertinent information (I'm using WinXP) 73 de Tim, K4SHF FM04

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F9FT Tonna 432 skeleton antenna?
by Dave hartzell 12 Mar '07

12 Mar '07

Hi all, Just wondering if anyone knows anything about this antenna. A couple surfaced and the price was right, but no one knew anything about the antennas at the time. 73, Dave N0TGD

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AEA ST-1
by David 12 Mar '07

12 Mar '07

Greetings. I have an AEA ST-1 tracker unit that I would like to find drivers for DOS and Windows. I am using a 233MMX with windows 98 and running Nova for DOS which controls my 736R ok, but will not load the DOS driver that I have. Can anyone point me in the right direction or tell me what I am doing wrong besides running old programs. Thanks. Dave VA7DG

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Re: Sequencer
by joseph Murray 12 Mar '07

12 Mar '07

This issue might best include VOX and full duplex in a round table on HEO. Just in case Joe K0VTY ==================== On 12 Mar 2007 14:18:32 -0500 tosca005(a)umn.edu writes: > On Mar 12 2007, Edward Cole wrote: > > >At 05:15 AM 3/12/2007, Stargate wrote: > >>Is a sequencer needed when using a 160w switchable preamp from > ARR? > > > >Let's analyze this: > > > >You send a voltage to run the preamp. It needs voltage to switch > to > >Tx mode. When RF from your transmitter arrives it switches over to > > >bypass the preamp. I would guess if you turn off the power to the > > >unit, it can't operate correctly, so how is a sequencer going to > >help? I have not owned one of these units so not familiar with > their > >power wiring. If you have two 12 volt power contacts then you > might > >run the preamp separately from a sequencer. > > Sequencers don't have to only apply/remove DC power in a set > sequence. In > fact, in the general case, a sequencer has a series of switch > contacts that > are enabled in the proper order and disabled in the opposite order. > The > switch contacts could be configured as NO (normally open) or NC > (normally > closed). These can either provide and remove DC power, or short the > > pre-amp's own PTT circuit to ground to take it out of receive mode > (or, > depending on the model of preamp, maybe +12 is PTT instead of GND). > The > Down East Microwave sequencer has a DPDT relay for each of the > sequence > stages, so you get two independent NO and NC contact sets to play > with as > you wish. > > If (like the ARR models) the preamp has built-in bypass switching, > one > issue that remains is how quickly and completely the preamp gets > switched > out of the transmit path. If slow to switch, and/or if the isolation > is > insufficient, a spike of RF may still enter the very sensitive > preamp and > fry it. With a sequencer, you can (usually) select whatever > switching delay > is needed for the isolation relays to reach a fully switched > position, and > you also get to pick the isolation relays themselves, with attention > to > power dissipation and degree of isolation needed. I believe that ARR > says > that the built-in RF-sensing relay is good for up to 160 watts, but > a > sequencer with a separate isolation relay could basically allow you > to use > 1.5 kW, if you had an awfully darn good reason to use so much power, > ;) > that is. > > On my 144, 222, and 432 bands, I have an RF Concepts "brick" > amplifier with > an internal preamp and RF-sensed automatic switching. On 144 and > 432, these > are "soft keyed" (i.e. keyed by sensing RF). On 222, which is done > with a > transverter instead of directly out the back of my FT-847, I went to > the > effort to "hard key" the amp/preamp by using its PTT input (which I > had to > re-configure as PTT to GND instead of PTT to HI). Both "soft" and > "hard" > switching methods work OK, but on 144 and 432 it is best to briefly > pause > after keying the mic before you start talking, to insure that the PA > is > switched in, and when you unkey, you have to hope that the person on > the > other end pauses briefly before responding because it takes a > noticeable > amount of time for the amp/preamp relay to switch back to receive > mode. > (The delay is intentional, to prevent relay chattering.) On 222, > since the > radio, transverter, and external PA/preamp are all hard-switched by > their > own PTT signal, the send/receive cycle is much smoother, no excess > delays, > no chance of relay chattering if the loudness of your voice drops > low for a > moment, etc. So I definitely prefer the "hard keyed" method of > operation. > One of these days, I will get around to modifying the 144 and 432 > amps for > hard keying also... > > On 902, 1296, 2305, and 3456 MHz, my transverters were built with > split > Tx/Rx, which makes it simpler to connect a preamp (if needed) to the > Rx and > a power amp to the Tx, and of course you need a T/R coax relay > external to > the transverter. So far, because my PA's on these bands are low > power, I > hard-key the T/R relay but it is not sequenced -- radio PTT = > transverter > PTT = T/R relay PTT, all at the "same" time. When I move up to the > high-power class of operation, I will install a sequencer on each. > We have > local folks here who have had the experience I am trying to avoid, > namely > simultaneous switching works ok at low power, but add in some REAL > output > power and things fry if not sequenced. These bands have PA's of > 40-120 > watts waiting to be integrated. (This is for terrestrial work, not > satellites, by the way, as you can probably figure from the high > powers and > non-satellite bands/sub-bands mentioned...) > > 73 de W0JT > AMSAT-NA LM#2292 > _______________________________________________ > 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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Timonium
by MARTHA SARAGOVITZ 12 Mar '07

12 Mar '07

It now appears we have NO ONE to handle Timonium on March 31st and April 1st. Would someone PLEASE volunteer to "man" the booth on Saturday? 73- Martha

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