| |
CX2SA > SATDIG 21.09.08 11:20l 958 Lines 32580 Bytes #999 (0) @ WW
BID : 35146_CX2SA
Read: GUEST
Subj: AMSAT-BB-digest V3 476
Path: IZ3LSV<IK2XDE<HB9TVW<DB0ANF<CX2SA
Sent: 080921/0906Z @:CX2SA.LAV.URY.SA #:35146 [Minas] FBB7.00e $:35146_CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: first impression (Mark Lunday, WD4ELG)
2. Re: first impression (Michael Tondee)
3. Re: Polarity questions (Luc Leblanc)
4. Re: Polarity questions (Edward Cole)
5. Opening up a U110 rotator motor?
(Doug Faunt N6TQS +1-510-655-8604)
6. Re: Polarity questions (Edward Cole)
7. Re: More: circular polarization (1/4wave physicaldistance) (i8cvs)
8. Re: Polarity questions (Edward Cole)
9. Re: Polarity questions (i8cvs)
10. Re: Polarity questions (Art McBride)
11. NASA Prepares... (Clint Bradford)
12. Re: first impression (Nate Duehr)
13. Re: Polarity questions (Angus)
14. Fw: Re: first impression (Doug Kuitula)
----------------------------------------------------------------------
Message: 1
Date: Sat, 20 Sep 2008 12:39:08 -0400
From: "Mark Lunday, WD4ELG" <mlunday(AT)nc.rr.com>
Subject: [amsat-bb] Re: first impression
To: "'Jim Danehy'" <jdanehy(AT)cinci.rr.com>, <amsat-bb(AT)amsat.org>
Message-ID: <000901c91b3f$67536ce0$35fa46a0$(AT)rr.com>
Content-Type: text/plain; charset="us-ascii"
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(AT)arrl.net
http://wd4elg.net
------------------------------
Message: 2
Date: Sat, 20 Sep 2008 13:09:59 -0400
From: "Michael Tondee" <mat_62(AT)netcommander.com>
Subject: [amsat-bb] Re: first impression
To: "Jim Danehy" <jdanehy(AT)cinci.rr.com>, <amsat-bb(AT)amsat.org>
Message-ID: <001801c91b43$b9e7ba20$6500a8c0(AT)w4hij1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi Jim,
I enjoyed this post. Lots of resources up there if we just use them. I too
am frustrated by the almost complete abscense of any thing related to
AMSAT
or the satellites coming out of QST. There used to be a regular column
that
rotated with other ones and appeared about every three months or so but it
has sadly disappeared. By looking in the mainstream amateur press, except
for the occasional brief mention of P3E, you would not even know that
satellite operations still exist.
I will be glad to be joining you guys on the linear SSB/CW birds if I can
jst get a couple of issues figured out here. I'm having a devil of a time
getting SatPC32 sorted out where I can hear my own downlink on them. I
had
thought I had a TX antenna issue on the 70cm uplink birds and still do but
recently I've been trying to get my downlink tuned in where it's
intelligible to me on FO-29 and haven't been able to do it. It used to
seem
so easy to set that up in the CAT screen of SatPC32 when I had a TS-2000X
but I had to sell that and now I'm using an Icom IC-820H and it's giving
me
fits. i guess it wouldn't be so much fun if it was easy though, would it?
73,
Michael, W4HIJ
AMSAT # 36017
----- Original Message -----
From: "Jim Danehy" <jdanehy(AT)cinci.rr.com>
To: <amsat-bb(AT)amsat.org>
Sent: Friday, September 19, 2008 10:45 PM
Subject: [amsat-bb] first impression
>I operated OSCAR satellites back in 1974-1976. It was simple with 2 meters
>up and 10 meters down. Not much doppler effect either. I got back on a
>month ago after a lapse of 32 years. I would like to give my impressions to
>date. I have had QSOs on 6 or 7 different birds using CW, SSB and of course
>FM. By far the most productive mode is FM. It is also the easy way to get
>on OSCAR. The transponders on AO7, VO52 and FO29 go aching for use. On 15
>minute passes you can find just one or two other users. Sadly nobody at
>times. Of course you need to be able to manage doppler and to track the
>bird with some degree of accuracy. I guess I have had over 400 QSOs during
>the past month. I have worked 42 states and 7 countries along with about
>110 grid squares. Being newly retired the XYL encourages me to stay in the
>shack. However of the 400 QSOs I have probably only worked 120 different
>stations. The biggest disappointment for me is the lack of information in
>QST and CQ magazines on OSCA!
> R. I had no idea that there were that many potential birds flying and
> providing the opportunity to make contacts. Having been a ham for 56 years
> and always active I don't miss a lot. Oh I see the AMSAT booth at Dayton.
> But there is little effective public relations going on to attract hams to
> use OSCAR satellites. There is some but not to the extent that is needed.
> I just rejoined AMSAT. It is obvious that there is plenty of transponder
> "spectrum" going unused. It is a very modest challenge to use satellites
> other than FM birds, in my opinion. I have some M Square yagis that I put
> together along with an elevation and azimuth rotators. I put them up about
> 15 feet off the ground. I learned a few things about switching polarity
> too. We did not have circular polarity being used in 1974 if my memory is
> working.
>
> The best part about being back on is the opportunity to meet a new group
> of hams. I have learned about SatPC32 and struggle to get it working with
> the Vista operating system. I also got the RHCP vs. LHCP wrong on my 2
> meter antenna. I owe thanks to K9QHO and K9CIS for helping me on that
> issue.
>
> Most use AO51 as the bird of choice. I wonder why there is so little use
> of SO50 ? It works great and is under used too. These are my first
> impressions. There really is a lack of public relations about how much is
> out there in the way of satellite opportunities. Of course that is just my
> opinion. One thing for sure you do not need to count the sun spots to see
> if you can make contacts. I would like to see folks give a little opening
> to some of the Central American stations who come on frequency but get
> stepped on. A QSO with a TI4 or a KP4 is still DX even for a guy like me
> who has been around long enough to have worked them all. One day HR1LW
> called me on VO52. What a thrill. There was no one else on. A few weeks
> later he called me again and called me by name. Same for a few European
> QSOs that I have had.
>
> My XYL wants to thank all of those that have kept me in the shack and out
> of her hair as she adjusts to my retirement. I do too.
>
> 73 Jim W9VNE
> Cincinnati, Ohio EM79tb
------------------------------
Message: 3
Date: Sat, 20 Sep 2008 05:53:22 -0400
From: Luc Leblanc <lucleblanc6(AT)videotron.ca>
Subject: [amsat-bb] Re: Polarity questions
To: amsat-bb(AT)AMSAT.Org
Message-ID: <48D48FD2.26027.480E76E(AT)lucleblanc6.videotron.ca>
Content-Type: text/plain; charset=US-ASCII
On 20 Sep 2008 at 0:56, Nate Duehr wrote:
>
> This is just the difference between the practice of radio
> communications, and the hard science of it all...
>
Or it is the difference between the engeneers and the real world...lets
say
they are right and the world have to adapt and when something
goes wrong it's not an error by a faulty application of their plans.
I will soon have 2 41 elements 2.4ghz beam installed one vertical the
other
horizontal and i will be able to switch between them. On 2.4 AO-
51 there is a strong QSB effect is it coming from polarity change? or from
the
satellite thumbling? Could be i will be able to eliminate
one variable.
Did any one try to feed 2 antennas through a splitter with one vertical
and
the other horizontal? Is this can solved this polatity
question?
"-"
Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE
------------------------------
Message: 4
Date: Sat, 20 Sep 2008 10:07:03 -0800
From: Edward Cole <kl7uw(AT)acsalaska.net>
Subject: [amsat-bb] Re: Polarity questions
To: "Michael Tondee" <mat_62(AT)netcommander.com>
Cc: amsat-bb(AT)amsat.org
Message-ID: <200809201807.m8KI73ni060735(AT)hermes.acsalaska.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
I am surprized no one caught the error! I even gave you a clue in
the sentence after the computations.
the formula for 1/4 WL = Vf * 248/Fmhz, not Vf * 492/Fmhz
So if you make your 144-MHz phasing line 27 inches of RG-11, it WILL
be too long!
It is true that manufacturing variations in Vf occur from roll to
roll of coax. If you can measure it, this is prefferable to assuming
the mfr's data. But, using the published numbers is fine if you do
not have special equipment.
73, Ed - KL7UW
At 09:59 PM 9/19/2008, Edward Cole wrote:
>You are making too much of a big deal out of this. Velocity factor
>is published by coax manufacturers so you do not need instruments to
>get close.
>1/4 WL = Vf * 492/Fmhz in feet
>1/4 WL (RG-213) = 0.66 * 492/144 = 2.25 feet or 27-inches
>
>If you are off 5% it will not destroy the circularity. Most hams get
>it "close enough". Of course if you are off by a quarter wavelength
>or more it will matter (20-inches at 144-MHz).
>GL
>
>*****************************************************
>73, Ed - KL7UW BP40iq, 6m - 3cm
>144-EME: FT-847, mgf-1801, 4x-xp20, 185w
>http://www.kl7uw.com AK VHF-Up Group
>NA Rep. for DUBUS: dubususa(AT)hotmail.com
>*****************************************************
>
>_______________________________________________
>Sent via AMSAT-BB(AT)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
------------------------------
Message: 5
Date: Sat, 20 Sep 2008 14:13:48 -0400 (EDT)
From: Doug Faunt N6TQS +1-510-655-8604 <faunt(AT)panix.com>
Subject: [amsat-bb] Opening up a U110 rotator motor?
To: amsat-bb(AT)amsat.org
Message-ID: <20080920181348.D3EDA1A404(AT)panix2.panix.com>
Does anyone have information on this? Has it been discussed on
AMSAT-BB or in the Journal at any time?
If you done it (and put it back together) any hints would be
appreciated.
73, doug
------------------------------
Message: 6
Date: Sat, 20 Sep 2008 10:18:18 -0800
From: Edward Cole <kl7uw(AT)acsalaska.net>
Subject: [amsat-bb] Re: Polarity questions
To: amsat-bb(AT)amsat.org
Message-ID: <200809201818.m8KIIICR063127(AT)iris.acsalaska.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 03:56 AM 9/20/2008, Anthony Monteiro wrote:
>At 07:29 PM 9/19/2008, Clint Bradford wrote:
> > >>...I have to disagree with Clint...
> >
> >I just must be the luckiest S.O.B.(*) working AO-51, then...During
> >demonstrations in front of folks, someone in the assemblage almost
> >always asks about polarization. I twist the Arrow, and we all "hear"
> >no difference in its strong, clean signal.
> >
> >Clint, K6LCS
> >909-241-7666
> >
>
>Dear Clint and friends,
>
>There is no luck involved. The UHF downlinks on AO-51 are
>circularly polarized. You can twist your Arrow all you want
>and you will not hear any difference, nor could you measure
>any because there isn't any difference!
>
>The cross-polarization loss from a circular TX antenna to a
>linear RX antenna is a constant 3 dB regardless of the
>actual linear polarization angle.
>
>If you want to demonstrate polarization mismatch loss, use AO-27
>(which is linear) with an Arrow.
>
>73,
>Tony AA2TX
>
>---
Well, theoretically the signal from AO-51 might be somewhat
elliptical if there is a significant squint angle. Apparently this
does not happen with enough change to be detectable. The human ear
cannot detect audio level differences under 3-dB. Other effects
probably mask any measurable variance.
73 Ed - KL7UW
------------------------------
Message: 7
Date: Sat, 20 Sep 2008 21:33:08 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: More: circular polarization (1/4wave
physicaldistance)
To: "Henk, PA3GUO" <hamoen(AT)iae.nl>, "AMSAT-BB" <amsat-bb(AT)amsat.org>,
<""(AT)iae.nl>
Cc: pa3guo(AT)amsat.org
Message-ID: <003301c91b57$b6d09f00$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
Hi Henk, PA3GUO
Since the physical distance between elements of your 70 cm crossed yagi
is 1/4 wave over the boom I suggest you to read my article:
"Switching four Polarizations on a 70 cm Crossed Yagi" published by the
AMSAT-Journal
Part-1 ( the theory ) issue of March/April 2007
Part-2 (construction) issue of May/June 2007
If you need the above articles I can send to you a pdf file of it.
73" de
i8CVS Domenico
----- Original Message -----
From: "Henk, PA3GUO" <hamoen(AT)iae.nl>
To: <amsat-bb(AT)amsat.org>; <""(AT)iae.nl>
Cc: <pa3guo(AT)amsat.org>
Sent: Saturday, September 20, 2008 5:03 PM
Subject: [amsat-bb] Re: More: circular polarization (1/4wave
physicaldistance)
> Maybe my question becomes clearer with thse pictures (taken today)
>
> 1. this morning, the original set-up, on the roof
> http://www.pa3guo.com/416_original.jpg
>
> 2. this afternoon, stripped, waiting for advice from the amsat-bb :-)
> http://www.pa3guo.com/416_stripped.jpg
>
> Henk
>
> > 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
>
>
>
> _______________________________________________
> Sent via AMSAT-BB(AT)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
------------------------------
Message: 8
Date: Sat, 20 Sep 2008 12:07:55 -0800
From: Edward Cole <kl7uw(AT)acsalaska.net>
Subject: [amsat-bb] Re: Polarity questions
To: Luc Leblanc <lucleblanc6(AT)videotron.ca>, amsat-bb(AT)amsat.org
Message-ID: <200809202007.m8KK7tJq069526(AT)iris.acsalaska.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 01:53 AM 9/20/2008, Luc Leblanc wrote:
>On 20 Sep 2008 at 0:56, Nate Duehr wrote:
>======snip
>
>Did any one try to feed 2 antennas through a splitter with one
>vertical and the other horizontal? Is this can solved this polatity
>question?
>
>"-"
>
>
>Luc Leblanc VE2DWE
>Skype VE2DWE
>www.qsl.net/ve2dwe
>WAC BASIC CW PHONE SATELLITE
>
>
>
>_______________________________________________
>Sent via AMSAT-BB(AT)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
Luc if both antennas are identical and have equal length feedlines to
the splitter, the result is slant polarization (linear pol slanted at
45-degrees if one antenna is vertical and the other horizontal). You
are better running each antenna to a coaxial switch and chosing
either one (not both).
73, Ed
------------------------------
Message: 9
Date: Sun, 21 Sep 2008 01:53:40 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: Polarity questions
To: "Luc Leblanc" <lucleblanc6(AT)videotron.ca>, "AMSAT-BB"
<amsat-bb(AT)amsat.org>
Message-ID: <007b01c91b7c$1bf670c0$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Luc Leblanc" <lucleblanc6(AT)videotron.ca>
To: <amsat-bb(AT)amsat.org>
Sent: Saturday, September 20, 2008 11:53 AM
Subject: [amsat-bb] Re: Polarity questions
>
> I will soon have 2 41 elements 2.4ghz beam installed one vertical the
> other horizontal and i will be able to switch between them. On 2.4 AO-
> 51 there is a strong QSB effect is it coming from polarity change? or from
> the satellite thumbling? Could be i will be able to eliminate
> one variable.
>
> Did any one try to feed 2 antennas through a splitter with one vertical
> and the other horizontal? Is this can solved this polatity
> question?
>
> "-"
> Luc Leblanc VE2DWE
> Skype VE2DWE
> www.qsl.net/ve2dwe
> WAC BASIC CW PHONE SATELLITE
>
Hi Luc, VE2DWE
A two port power splitter 1/4 wavelenght electrically long at 2400 MHz
with
characteristic impedance of 36 ohm is only 31 mm long and probably due to
the intrusion for the lenght of three N connectors will not make the
impedance transformation between 25 ohm of both antennas in parallel to
50 ohm of your transmission line.
If you have available a 1/4 wavelenght two port power divider for 435 MHz
you can readily use it as a quik test because 2400 / 5 = 480 MHz wich is
not
too much far away from 435 MHz
Since the ratio by 5 is an odd numbar then the impedance transformation
between 25 ohm to 50 ohm can be accomplished with a small increase in
VSWR
If the above test is encouraging then you can cut the above 435 MHz power
divider to resonate exactly at 480 MHz.
To get CP don't forget to make one coax line 1/4 electrical wave longer
than
the other one or to shift one antenna 1/4 wave free space behind the other
one with respect to the satellite...........a very difficult affair at
these
frequencies.
In my opinion it would be better to use two helix antennas one RHCP and
the other one LHCP switching polarity with only one coax relay.
Have fun
73" de
i8CVS Domenico
------------------------------
Message: 10
Date: Sat, 20 Sep 2008 22:31:28 -0700
From: "Art McBride" <kc6uqh(AT)cox.net>
Subject: [amsat-bb] Re: Polarity questions
To: "'i8cvs'" <domenico.i8cvs(AT)tin.it>, "'Luc Leblanc'"
<lucleblanc6(AT)videotron.ca>, "'AMSAT-BB'" <amsat-bb(AT)amsat.org>
Message-ID: <57CFE8851993498E926E177B1A886608(AT)kc6uqh>
Content-Type: text/plain; charset="us-ascii"
Luc,
You loose 3 dB if you are not circular. Phasing YAGI antennas at 2.4 GHz
is
very difficult, YAGI antennas must be identical and have the exact same
phase center. You would be better off to use a 18" dish and a patch feed,
or
a helix. I am not sure that AO-51 is circular polarized on 2.4 GHz.
Art,
KC6UQH
-Original Message-----
From: amsat-bb-bounces(AT)amsat.org [mailto:amsat-bb-bounces(AT)amsat.org]
On
Behalf Of i8cvs
Sent: Saturday, September 20, 2008 4:54 PM
To: Luc Leblanc; AMSAT-BB
Subject: [amsat-bb] Re: Polarity questions
----- Original Message -----
From: "Luc Leblanc" <lucleblanc6(AT)videotron.ca>
To: <amsat-bb(AT)amsat.org>
Sent: Saturday, September 20, 2008 11:53 AM
Subject: [amsat-bb] Re: Polarity questions
>
> I will soon have 2 41 elements 2.4ghz beam installed one vertical the
> other horizontal and i will be able to switch between them. On 2.4 AO-
> 51 there is a strong QSB effect is it coming from polarity change? or from
> the satellite thumbling? Could be i will be able to eliminate
> one variable.
>
> Did any one try to feed 2 antennas through a splitter with one vertical
> and the other horizontal? Is this can solved this polatity
> question?
>
> "-"
> Luc Leblanc VE2DWE
> Skype VE2DWE
> www.qsl.net/ve2dwe
> WAC BASIC CW PHONE SATELLITE
>
Hi Luc, VE2DWE
A two port power splitter 1/4 wavelenght electrically long at 2400 MHz
with
characteristic impedance of 36 ohm is only 31 mm long and probably due to
the intrusion for the lenght of three N connectors will not make the
impedance transformation between 25 ohm of both antennas in parallel to
50 ohm of your transmission line.
If you have available a 1/4 wavelenght two port power divider for 435 MHz
you can readily use it as a quik test because 2400 / 5 = 480 MHz wich is
not
too much far away from 435 MHz
Since the ratio by 5 is an odd numbar then the impedance transformation
between 25 ohm to 50 ohm can be accomplished with a small increase in
VSWR
If the above test is encouraging then you can cut the above 435 MHz power
divider to resonate exactly at 480 MHz.
To get CP don't forget to make one coax line 1/4 electrical wave longer
than
the other one or to shift one antenna 1/4 wave free space behind the other
one with respect to the satellite...........a very difficult affair at
these
frequencies.
In my opinion it would be better to use two helix antennas one RHCP and
the other one LHCP switching polarity with only one coax relay.
Have fun
73" de
i8CVS Domenico
_______________________________________________
Sent via AMSAT-BB(AT)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
__________ Information from ESET NOD32 Antivirus, version of virus
signature
database 3458 (20080921) __________
The message was checked by ESET NOD32 Antivirus.
http://www.eset.com
__________ Information from ESET NOD32 Antivirus, version of virus
signature
database 3458 (20080921) __________
The message was checked by ESET NOD32 Antivirus.
http://www.eset.com
------------------------------
Message: 11
Date: Sat, 20 Sep 2008 22:31:05 -0700
From: Clint Bradford <clintbrad4d(AT)earthlink.net>
Subject: [amsat-bb] NASA Prepares...
To: amsat-bb(AT)amsat.org
Message-ID: <8F783EA0-A901-4450-91C0-ED025AF1A3DA(AT)earthlink.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
This spectacular NASA photo from the Kennedy Space Center shows how,
for the first time since July 2001, two shuttles are on launch pads at
the same time. Atlantis is in the foreground on Launch Pad A, and
Endeavour is behind it on Launch Pad B.
http://www.nasa.gov/images/content/271560main_08pd2730.jpg
Endeavour was moved into position Friday so it could be on standby in
the unlikely event that a rescue mission is necessary for the
Atlantis' planned October 10 mission to repair NASA's Hubble Space
Telescope, the agency said.
Once Endeavour is cleared from its rescue spacecraft duty, it's
scheduled to move to Launch Pad A for planned November 12 mission to
the International Space Station.
What makes the Hubble repair mission particularly dangerous is that if
Atlantis gets seriously damaged during flight, the seven astronauts
would be stranded--they couldn't just hang out at the International
Space Station waiting for a ride.
Plus, as the Associated Press points out, Atlantis "faces an estimated
1-in-185 chance that a piece of space junk or a micrometeoroid will
cause catastrophic damage to their ship." Those odds are greater than
for a typical shuttle flight because of Hubble's unusually high and
debris-filled orbit.
Clint Bradford, K6LCS / KAF3359
909-241-7666
------------------------------
Message: 12
Date: Sun, 21 Sep 2008 00:12:46 -0600
From: Nate Duehr <nate(AT)natetech.com>
Subject: [amsat-bb] Re: first impression
To: "Mark Lunday, WD4ELG" <mlunday(AT)nc.rr.com>
Cc: AMSAT BB <amsat-bb(AT)amsat.org>
Message-ID: <50F9E3D3-8B37-4696-BB1F-69C016309298(AT)natetech.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
On Sep 20, 2008, at 10:39 AM, Mark Lunday, WD4ELG wrote:
> 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.
Radio is just wicked fun, isn't it? :-)
--
Nate Duehr, WY0X
nate(AT)natetech.com
------------------------------
Message: 13
Date: Sun, 21 Sep 2008 06:57:46 +0100
From: "Angus" <angus(AT)young5769.freeserve.co.uk>
Subject: [amsat-bb] Re: Polarity questions
To: <AMSAT-BB(AT)amsat.org>
Message-ID: <59C3FE6F23374234A54B702BB5659255(AT)GusPC>
Content-Type: text/plain; format="flowed"; charset="iso-8859-1";
reply-type="original"
Hmmmmm might get shot down in flames for this but.
If you want to know the velocity factor of a coax (known or un-known) try
getting two eaqual lengths of coax which are physically 1/4wavelength long
i.e. 50cms for 2mtrs.
Short out ONE end (join the inner and outers together with a short a link
as
possible) and do this for both pieces of coax.
We are going to make a coaxial dipole so these two shortened ends go on to
a
piece of feeder (try and keep this feeder as short as possible also but
the
dipole needs to be somewhere clear but does not to be 100 feet up either).
Yes you will need to support the dipole elements as they will just hang
down
so perhaps a piece of garden cane or some other RF invisible material.
Trim back both OPEN ends of the dipole until you get the lowest possible
VSWR (on the centre frequency you want to use) and you should have very
close to an electrically 1/2wave dipole for the coax you used (each side
of
the dipole will be a 1/4 wave long). You can use these figures for making
a
1/4wave delay line or if your making a polarity control box you will need
to
know the lengths of both 1/2 and 1/4 of the coax you are going to use, the
dipole will be considerably shorter than a normal wire dipole for the same
frequency because we have used the velocity factor to help reduce its
length.
If you think that the feeder you have used is radiating either do perhaps
6
turns around a small 1" tube to make a balun at the feedpoint or alter the
length of the feeder slightly, if theVSWR alters when you change the
length
of the feeder then the feeder is radiating.
My two pennys worth, should help you get very close to the figures you
need
without the use of a GDO or an antenna analyser.
regards
Gus
--
I am using the free version of SPAMfighter for home users.
SPAMfighter has removed 3111 spam emails to date.
Paying users do not have this message in their emails.
Get the free SPAMfighter here: http://www.spamfighter.com/len
------------------------------
Message: 14
Date: Sat, 20 Sep 2008 20:14:33 -0400
From: "Doug Kuitula" <ka8qcu(AT)pasty.net>
Subject: [amsat-bb] Fw: Re: first impression
To: <amsat-bb(AT)AMSAT.Org>
Message-ID: <002d01c91b7f$0f645540$8ecf64d0(AT)net>
Content-Type: text/plain; charset="iso-8859-1"
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(AT)nc.rr.com>
> To: "'Jim Danehy'" <jdanehy(AT)cinci.rr.com>; <amsat-bb(AT)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(AT)arrl.net
> > http://wd4elg.net
> >
> >
> >
> > _______________________________________________
> > Sent via AMSAT-BB(AT)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(AT)amsat.org. Opinions expressed are those of the
author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 3, Issue 476
****************************************
Read previous mail | Read next mail
| |
