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

Fw: Re: first impression
by Doug Kuitula 20 Sep '08

20 Sep '08

Mark Jim, Just wanted to say that I've gone through the same thrill as you with my first contact on the birds. I'm doing it the what you are with a handheld and an Arrow antenna. It took me a good month of just listening and getting used to the procedure, as well as the doppler shift, before I actually made a contact. Like you, my next step will be a basic rotor with a small antenna. As they say, "One step at a time". But the best time I've had is exposing my great niece and nephew (5 and 6 years old) to amateur radio satellites, as well as a small telescope. They probably think their uncle is a bit strange, but they had a lot of fun. Anything we can do to expose them to science will pay off in the future. 73 de Doug KA8QCU > ----- Original Message ----- > From: "Mark Lunday, WD4ELG" <mlunday(a)nc.rr.com> > To: "'Jim Danehy'" <jdanehy(a)cinci.rr.com>; <amsat-bb(a)amsat.org> > Sent: Saturday, September 20, 2008 12:39 > Subject: [amsat-bb] Re: first impression > > > > Jim > > > > I would like to add to your comments. I have been a ham for 31 years, and > a > > DXer almost from the start. CW has been my mode of choice, and I have > never > > run more than 100 watts (I get a lot of grief from the hard-core DXers for > > not using QRO, but that is another story). I have always wondered about > > AMSAT, but never wanted to invest in the heavy duty equipment and > antennas. > > With the sunspot lulls and a new FT817 from my XUL last Christmas and no > > progress in the sunspot department, I decided to see what all the > excitement > > was about. Starting in April with 5 watts and a hand-held Arrow dual-band > > yagi, I had a rejuvenated ham experience working satellites. My hands > shook > > with excitement when I made my first QSO through AO-51. The thrill was > just > > as great when I worked MODE A on AO-7 two weeks later. The Doppler on CW > > and SSB is an interesting challenge, but the satellite prediction programs > > (thanks, Simon for HRD!) make it much easier. Instead of firing up my rig > > on HF first thing, I now check the satellite passes first to see what is > > available! My Arrow is mounted on a radio shack rotor in the attic at a > > fixed elevation of 20 degrees, and I have heard every satellite that I am > > listening for so far. What a thrill! I agree with you Jim, this puts > even > > more excitement into the hobby for me. Although so far I have heard every > > bird active, I have already re-worked a couple of hams in just the 30 > QSO's > > made so far. I like how Patrick WD9EWK is actively evangelizing the > > satellites, and others are doing the same. I think it's time for a demo > at > > my local club meeting, and for groups beyond ham radio. This is another > > entry point for non-hams into our hobby. > > > > 73, look forward to hearing you on the "birds" > > > > Mark Lunday > > WD4ELG, FM06 > > wd4elg(a)arrl.net > > http://wd4elg.net > > > > > > > > _______________________________________________ > > 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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More: circular polarization (45deg physical distance)
by Henk, PA3GUO 20 Sep '08

20 Sep '08

So ! As the discussion is ongoing anyway: This is how I have done it for 2 meters: - 2 x 6 elements (phyically same position, no 1/4wave distance http://www.pa3guo.com/dk7zb.html - switch box for H/V/LHCP/RHCP in the shack (2 long cables needed) http://www.pa3guo.com/polarizer.html But now 70cm ! My 13 year old Cushcraft had always fixed circular polarization. - 435.300 (AO51) had never any fading and was strong - 435.150 (AO51) I could barely hear (proofs the >20 db separation) Now: as AO51 will be in an mode that I want to use in the coming days, with the 435.150 downlink, I needed to change the polarization. Initially I wanted to have a temporal situation (swapping the coax on the front dipol), but the screws needed replacement anyway, so I decided to take the whole antenna down. The 2x8 elements beam has the 2 antennas mounted 1/4 wave distance spaced on the boom (the physical method). Now, I want to be able to switch between LHCP and RHCP. Not fixed. A good website I found is: http://sv1bsx.50webs.com/antenna-pol/polarization.html At the bottom the physical method for CP is described. Almost what I needed, now I need to be able to switch on top of that. I would assume that this should still be possible :-) My preference would be only LHCP and RCHP, no need for Hor or Ver. Prefer to have eg the coaxes of the 2 beams to a small relay box on the back of the beam and then with a relais create the RHCP vs LCHP.... but I lack the schematic for that :-) ... can someone point me to a URL that has the solution described ? OR: would it be simply this: 1. take the front dipol 2. swap conductor/shielding to create LHCP or RCHP AT the solder points ? (is this how WIMO is able to get it all in their small boxes) Well, I have 2 days before AO51 is in the mode I requested, I really need to get the antenna in place :-) Thanks ! Henk, PA3GUO http://www.pa3guo.com

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Re: Polarity questions
by Edward Cole 20 Sep '08

20 Sep '08

If I may try to interpret what Clint wrote: If a yagi has 15 or 20 dB more gain than needed to receive a decent signal, then one can "throw away" some of that gain to cross polarization loss and still have enough gain to adequately receive a signal. Sort like saying if you have a 150-foot dish for receiving AO-51 it don't matter! But it "does matter" about polarization as far as maximizing signal. A yagi is not different than any other linear antenna in this respect. Now I will have a 22-element CP 2m yagi and 42-element CP 70cm yagi for satellites. This is obvious overkill for working the Leo sats. It is the old standard for mode-B sats like AO-10/13. With this pair you had really good signals with those old satellites. If and when we get another Heo, they will be appropriate for mode-UV, LU, US, etc. (of course this will require 1268 and 2400 antennas for half the link). On the HF bands polarization is generally less important because the ionosphere messes with polarity when the signal is refracted. Perhaps this is where that saying originates. If so, be cautious about generalizing and applying to VHF/UHF/and above! Get a copy of the ARRL Handbook or Antenna Book and read it. The information is in them. There are even better antenna texts like Jasik and Kraus if you like calculus. 73 Ed - KL7UW At 03:23 PM 9/19/2008, n3tl(a)bellsouth.net wrote: >" ... and the polarization of the Yagi makes no difference in >quality of TX/RX signal." > >I know I haven't been working the satellites nearly as long as Clint >and many others - and with all due respect, my friend - I have to >disagree with the above statement. I routinely work passes during >which I swing my Arrow through, and sometimes beyond, 90 degrees to >maintain signal quality. There also have been times when a quick >twist of the wrist has made the difference between making a contact >and getting a new grid square ... and not. > >I don't-at-all disagree with the concept that working AO-27, AO-51 >and SO-50 isn't terribly difficult with a handheld station. Frankly, >that has really (and pleasantly) surprised me. However, I do believe >that adjusting polarity when hand-holding the Arrow provides >improved performance during many passes. > >73 to all, > >Tim > >-------------- Original message from Clint Bradford ><clintbrad4d(a)earthlink.net>: -------------- > > > > >>...20-dB, assuming the signal is pure circular > > polarization...linear, then -3 dB...difference between RHCP and LHCP > > is 20 dB...difference between Horizontal and Vertical Linear is 20 > > dB...difference between (RHCP or LHCP) and (Horizontal or Vertical) is > > 3 dB...the VHF/UHF Manual handbook says 20 -30dB...in the real world, > > expect around 20~25dB loss from being completely cross- > > polarized...Between linear and circular, expect about 3dB loss... > > > > Ahh, thank goodness for the engineers... > > > > Just know that to get started working the FM satellites, you do not > > need to spend much to make successful contacts...Working AO-51 from > > Southern California (which some claim is not a "real world") at a Watt > > or so with an HT and Arrow Antenna is a breeze, and the polarization > > of the Yagi makes no difference in quality of TX/RX signal. > > > > And as you refine your satellite comms requirements, you can spend > > more money! > > > > Clint Bradford, K6LCS > > 909-241-7666 > > _______________________________________________ > > 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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Re: Polarity questions
by Clint Bradford 20 Sep '08

20 Sep '08

>>...20-dB, assuming the signal is pure circular polarization. >>...linear, then -3 dB. >>...difference between RHCP and LHCP is 20 dB >>...difference between Horizontal and Vertical Linear is 20 dB >>...difference between (RHCP or LHCP) and (Horizontal or Vertical) is 3 dB >>...the VHF/UHF Manual handbook says 20 -30dB >>...in the real world, expect around 20~25dB loss from being completely cross-polarized >>...Between linear and circular, expect about 3dB loss. Ahh, thank goodness for the engineers... Just know that to get started working the FM satellites, you do not need to spend much to make successful contacts...Working AO-51 from Southern California (which some claim is not a "real world") at a Watt or so with an HT and Arrow Antenna is a breeze, and the polarization of the Yagi makes no difference in quality of TX/RX signal. And as you refine your satellite comms requirements, you can spend more money! Clint Bradford, K6LCS 909-241-7666

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FS: Wiltron Scalar Network Analyzrer
by Chris Hackworth 20 Sep '08

20 Sep '08

Functional Wiltron Scalar Network Analyzer. From My personal test bench. Analyzer, sweeper, detector, manuals ,cables. Its all there. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MESELX:IT&ite… -- Chris N8PHU ET1(SW) USN (Ret) Chief transmitter Heavy SES-Americom

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Polarity questions
by Tim Tapio 19 Sep '08

19 Sep '08

Hi, How much signal reduction is there as the result of having the wrong circular polarization? I'm looking at M2 circular antennas for the 70cm downlink, it's another $200 for the switching to change polarity (woo hoo). 73 de Tim, K4SHF

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Re: OLPC-HYPERTERM-PICOCOM
by nigel＠ngunn.net 19 Sep '08

19 Sep '08

Nobody else has a OLPC. From where does one buy them? Original Message: ----------------- From: Mr Jeffrey L Ross radiooperator(a)comcast.net Date: Tue, 16 Sep 2008 12:33:42 -0400 To: amsat-bb(a)amsat.org Subject: [amsat-bb] OLPC-HYPERTERM-PICOCOM Hi folks, I am real close to getting the OLPC To run a tnc and rig. I found A software called PICOCOM/MINICOM Thats similar to hyperterm in windows. Just type yum install picocom or yum install minicom at the terminal acitivity root. Then type the name to start it. anyone want to work with me on it contact me off list. Now we can use them for sat work,packet, aprs. emcom,, etc. kc8gkf p.s. how come no one else is working on this? must be busy. KC8GKF _______________________________________________ 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 -------------------------------------------------------------------- mail2web.com - Microsoft® Exchange solutions from a leading provider - http://link.mail2web.com/Business/Exchange

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Re: OLPC ONE LAPTOP PER CHILD
by GW1FKY＠aol.com 19 Sep '08

19 Sep '08

Hi , If they are the same Laptops that you are referring to they are now on sale over in the UK. They are notebook computers are produced by a company "HCL" and the operating system Windows XP. The UK distributor is a company that can be found at www,stirling house .co.uk 1520 London Road, Leigh on Sea, Essex SS9 2UR. They selling at a price of £179.99 ( UK) but of course carriage to the USA might put the price out of range. The package includes a Window XP CD and another with additional drivers, it does not have a CD or DVD built in so one would have to use an external device using the USB port. Cheers Ken Eaton GW1FKY Amsat -UK Amsat NA

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OLPC ONE LAPTOP PER CHILD
by Mr Jeffrey L Ross 18 Sep '08

18 Sep '08

Hi folks, thought I would drop in here that I just seen where they are going to place windows xp in the next OLPC"S.. Wonder if we can get the update/OS Installed on ours that we have. Anyway good luck on using your OLPC for packet, telnet, tnc,s. glad to get them working for us.Now if my son will just let me use it more. hi hi kc8gkf

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GO32 APRS ?
by Henk, PA3GUO 18 Sep '08

18 Sep '08

Grrrr I seem to fail to understand the APRS mode of GO32: Kenwood TS2000X HamRadioDeluxe for auto doppler correction External TNC (PK96) hbaud 8600 u aprs via 4xtech uplink 145.850 in CONV mode: ":AP hello" ... some days ago this worked twice, then nothing got digipeated uplink 145.930 in CONV mode: ":2 hello" ... never any success Then: I see JA stations getting stuff like this over it: JA0CAW]APRS,4XTECH*,qAS,JH4BTI::JA5BLZ :GE ur599 TNXp whereas I would have expected somethin like "AP JA5BLZ ...." (AP in front) This is the only source of documentation I have: http://web.usna.navy.mil/~bruninga/GO32-ops.html Which states: 145.85 MHz All APRS messaging (or fixed station non-Mic-E positions). . Only TOCALLs that begin with "APxxxx". 145.93 MHz All APRS Mic-E positions and status(D7, D700 and D710s with comment set to "Committed, Special or PRIORITY"... The reason for these uplink distinctions is due to GO-32 hardware that will only digipeat a packet on 145.85 that has a TOCALL beginning with "A". (All APRS fixed station packets and all APRS messages including D7 and D700's) . The 145.93 channel will only accept packets that begin with a digit between 1,2,3,4,5,6,7. . But fortunately the D7 and D700's do this naturally as long as the position comment is set to "committed, SPecial or PRIORITY"... Q1: do the TOCALLs need APxxx or Axxx on 850 ? (in CONV mode type :APxxx ?) Q2: should here ":2xxx" work ? Thanks ! Henk, PA3GUO .... so lost :-)

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