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CX2SA > SATDIG 19.11.10 22:09l 642 Lines 22259 Bytes #999 (0) @ WW
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Today's Topics:
1. Re: Verticals on FM sats (Robert Bruninga)
2. Na1iss (News Radio 6)
3. Live streaming of the new satellites (PA3GUO)
4. Re: ARISSat-1 and FOX fundraising (P.H.)
5. Re: ARISSat-1 and FOX fundraising (G0MRF@xxx.xxxx
6. Re: Verticals on FM sats (Edward R. Cole)
7. Re: Live streaming of the new satellites (G0MRF@xxx.xxxx
8. Re: Na1iss (wa4hfn@xxxxxxx.xxxx
9. Re: Verticals on FM sats (Bruce Robertson)
10. Re: Na1iss (Dale Hershberger)
----------------------------------------------------------------------
Message: 1
Date: Fri, 19 Nov 2010 13:10:43 -0500
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: Verticals on FM sats
To: "'Bruce Robertson'" <ve9qrp@xxxxx.xxx>, "'John Geiger'"
<aa5jg@xxxxxxx.xxx>
Cc: "'Amsat-Bb@xxxxx. Org'" <amsat-bb@xxxxx.xxx>
Message-ID: <BE1F2B45CC884AF7AC3E27283E89C1A0@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
> ... a typical 1/4 wave antenna... is super for
> terrestrial work, where we want to have as much
> power as possible going out to the horizon...
> but... from a station up 20 degrees or more, say,
> you'll find that you're working with much less ...
> And, say, 70 degrees... with an ideal 1/4 wave,
> you're putting out no power (and receiving none)
> (In reality, its not that bad, but its pretty darn bad.)
I think the essence of what is being said is relatively correct
individually, but on closer inspection I think this is mixing
apples and oranges. What is said is true for *gain* omni's, but
not really true for the 1/4 wave vertical. In fact, the 1/4
wave is about the best and simplest omni antenna for satellites.
Please see the detail explanation
http://aprs.org/rotator1.html
The argument being presented above *does* apply to a *gain*
verticla omni. Yes, that is NOT good for satellite work because
it does as stated, concentrates gain on the horizon and
drastically falls off at higher elevation. So that is why we
say "omnis" are not good for satellites. Because almost
everyone uses a *gain* omni.
But the 1/4 ground plane antenna does not concentrate all of its
energy on the horizon and is why most people will not use it for
terrestrial work because too much of it goes out at higher
elevations. And even though it does drop off by more than 10 dB
at high angles above 60 degrees, one has to remember that the
satellite is 10 dB closer at that high angle! So it still works
great. AND the amount of time that a LEO satelite is above even
50 degrees is only 2% of all the access time. Nothing at all to
worry about.
See the plot of gain on the above web page. It shows that a 1/4
vertical has nearly constant gain for a satellite from about 10
degrees up to over 70 degrees because of this range-gain. Of
course below 10 degrees the satellite is as much as 3 db further
away and hence weaker and most satellite link budgets were not
designed to operate with such 0 dB gain omnis AT the horizon.
So, the 1/4 vertical is very hard to beat for a simple omni
satellite antenna. And by the same rationale, the terrestrial
gain omni is NOT. SO watch out for apples and oranges
comparisons...
Bob, WB4APR
> What would be an ideal shape for our 'omnidirectional'
satellite
> antenna? Let's have a muffin instead of a bagel, lop its top
off and
> place that on the counter instead of the bagel. Now we have
increased
> power at the low elevations, but still some power at the
higher ones.
> Note, we don't want a situation where the power is all going
straight
> up, because satellites spend a good deal of time in the low
angles
> (depending on where you are). We just want to 'fill in' the
bits that
> we lose from our bagel pattern.
>
> There are many designs that aim to provide something like this
muffin
> pattern. You can make your vertical longer than 5/8 wavelength
(the
> 19" at 440, e.g.); you can tilt the 1/4 wave vertical at
around 20
> deg. from perpendicular to its ground plane; you can use
lindenblad
> arrangements to circularize and redistribute. I have a 2m
qadrifilar
> helix antenna that does its job nicely.
>
> One terribly important point on 70cm is that you have a low
noise
> preamp connected to the antenna on the mast, not in your
shack. I have
> a $5 70cm 1/4 wave groundplane that I made out of a female
> N-connector. I would much, much rather use it with my ARR
preamp than
> a 8 element yagi without the preamp. Way more fun. The reason
for this
> with omni antennas is that we are having to distribute all the
> 'receiving power' over all the elevation angles, as well as
the 360
> degrees of azimuth. In other words, your muffin has to be
smaller in
> diameter than your bagel half, because both have to have the
same
> total volume.
>
> Finally, your question suggests that simpler antennas, like
1/4 wave
> groundplanes, are not necessarily easy to use on SSB/CW birds.
I find
> the contrary, especially on CW. FM satellites are easier
because they
> don't require as frequent tuning due to doppler shift, and
because
> many hams already have the equipment needed to operate them.
But they
> aren't 'easier' in the sense that their signals are easier to
hear
> with simple equipment. Heck, with any sort of antenna and an
low-noise
> preamp you'll hear the CW beacon of HO-68 from horizon to
horizon.
>
> I hope you will forgive me if this reply was aimed at the
wrong level,
> and I wish you all the best in your satellite station
building.
>
> 73, Bruce
> VE9QRP
> --
> http://ve9qrp.blogspot.com
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. 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: 2
Date: Fri, 19 Nov 2010 13:19:16 -0500
From: News Radio 6 <newsradio6@xxxxx.xxx>
Subject: [amsat-bb] Na1iss
To: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Message-ID: <2981BF16-A645-4FD9-BE6E-1F48D4F02DE9@xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Anyone have any tips for working the iss? I've heard several passes this
week on 145.800 but cannot seem to get thru the pileup. Timing your
transmissions seems to be the hardest part. The Tx offset I'm using is
-1.31mhz. Any suggestions?
John
Va3bl
Mobile in fn03
Sent from my iPod
------------------------------
Message: 3
Date: Fri, 19 Nov 2010 19:29:45 +0100
From: PA3GUO <pa3guo@xxxxxxx.xx>
Subject: [amsat-bb] Live streaming of the new satellites
To: amsat-bb@xxxxx.xxx
Message-ID: <24074027.1290191385724.JavaMail.root@xxxxxxxx.xxxxxx.xx>
Content-Type: text/plain; charset=utf-8
We will try to stream as much as possible live the audio
of the new set of satellites in the upcoming launch today.
As a test, we will in the coming hours we will stream HO68
and other Cubesats.
http://www.dk3wn.info/p/?page_id=17689
--
Henk, PA3GUO
------------------------------
Message: 4
Date: Fri, 19 Nov 2010 18:41:56 +0000
From: "P.H." <bbjunkie@xxx.xxx>
Subject: [amsat-bb] Re: ARISSat-1 and FOX fundraising
To: amsat-bb@xxxxx.xxx
Message-ID:
<AANLkTi=zKP3E6uvtEpfqxgCYFd3zH-oactKnkrWhXuBE@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Forgive me if i'm asking a question which has been asked before, I don't
seem to see any reference to it on amsat-bb or anywhere else online.
ARISSat-1 is due to last *around *6 months, after which time the batteries
will become exhausted and it will deorbit. Does the time in space (and
research obviously, it's not just a repeater) really justify the money
spent?
As a percentage, how much cheaper was it to build and launch than Fox (which
I assume will have a longer lifespan) will be?
I'm sure there are lots of factors which make ARISSat-1 viable that I am
overlooking.
Just wondering
Pete
MI3EPN
On Fri, Nov 19, 2010 at 3:55 PM, Andrew Glasbrenner <
glasbrenner@xxxxxxxxxx.xxx> wrote:
> I'm proud to announce that the Facebook and PayPal widget campaign has
> raised $1,000 over the last 48 hours! This is a great first step towards
> replenishing the funds used in the construction of ARISSat-1, and
> beginning the design and construction of AMSAT-FOX. Thank you to those
> who posted the fundraiser to their own pages, and to those who donated.
>
> Did you know:
>
> ARISSat-1 will broadcast live slow scan pictures from space? All that
> will be needed to receive these pictures is a 2 meter FM receiver and a
> soundcard equipped computer.
>
> ARISSat-1 has a Mode U/V (B) linear transponder using SDR technology as
> a testbed for future transponder missions.
>
> ARISSat-1 uses a new robust telemetry format including FEC to counteract
> signal losses during long fades.
>
> ARISSat-1 is set to deploy early in 2011, just months away.
>
> Our PayPal widget is now on the front page of amsat.org (thank you
> JoAnne!), where you can donate and download the widget for your own
> webpage or blog, and our Facebook application is available at
> http://bit.ly/c861N7 . With these two fundraising tools, it is as
> important to share and post the widgets on your own page as it is to
> actually donate. To succeed we must reach those amateurs and space
> enthusiasts not in the normal AMSAT circles. Please visit and share
> today, to help us fund these two projects. Thank you for all your support!
>
> 73, Drew KO4MA
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. 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: Fri, 19 Nov 2010 14:21:52 EST
From: G0MRF@xxx.xxx
Subject: [amsat-bb] Re: ARISSat-1 and FOX fundraising
To: bbjunkie@xxx.xxxx amsat-bb@xxxxx.xxx
Message-ID: <192d3.30acf1e.3a182850@xxx.xxx>
Content-Type: text/plain; charset="US-ASCII"
In a message dated 19/11/2010 18:55:28 GMT Standard Time, bbjunkie@xxx.xxx
writes:
I'm sure there are lots of factors which make ARISSat-1 viable that I am
overlooking.
Just wondering
Pete
MI3EPN
Yup.
Like
Developing a team of satellite engineers who are motivated to work on other
projects after ARISSat.
Demonstarting to NASA that AMSAT builds hardware. - Building reputation.
Providing an amateur / educational satellite with zero launch cost. (OK,
but a fair amount of other expenses)
Finding a platform to orbit and evaluate the first software defined
transponder.
etc etc. It's test and development as well as providing a valuable
service.
David G0MRF
------------------------------
Message: 6
Date: Fri, 19 Nov 2010 10:28:09 -0900
From: "Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Verticals on FM sats
To: <amsat-bb@xxxxx.xxx>
Message-ID: <201011191928.oAJJS9Q5081083@xxxxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 09:10 AM 11/19/2010, Robert Bruninga wrote:
> > ... a typical 1/4 wave antenna... is super for
> > terrestrial work, where we want to have as much
> > power as possible going out to the horizon...
> > but... from a station up 20 degrees or more, say,
> > you'll find that you're working with much less ...
> > And, say, 70 degrees... with an ideal 1/4 wave,
> > you're putting out no power (and receiving none)
> > (In reality, its not that bad, but its pretty darn bad.)
>
>I think the essence of what is being said is relatively correct
>individually, but on closer inspection I think this is mixing
>apples and oranges. What is said is true for *gain* omni's, but
>not really true for the 1/4 wave vertical. In fact, the 1/4
>wave is about the best and simplest omni antenna for satellites.
>Please see the detail explanation
>
>http://aprs.org/rotator1.html
>
>The argument being presented above *does* apply to a *gain*
>verticla omni. Yes, that is NOT good for satellite work because
>it does as stated, concentrates gain on the horizon and
>drastically falls off at higher elevation. So that is why we
>say "omnis" are not good for satellites. Because almost
>everyone uses a *gain* omni.
>
>But the 1/4 ground plane antenna does not concentrate all of its
>energy on the horizon and is why most people will not use it for
>terrestrial work because too much of it goes out at higher
>elevations. And even though it does drop off by more than 10 dB
>at high angles above 60 degrees, one has to remember that the
>satellite is 10 dB closer at that high angle! So it still works
>great. AND the amount of time that a LEO satelite is above even
>50 degrees is only 2% of all the access time. Nothing at all to
>worry about.
>
>See the plot of gain on the above web page. It shows that a 1/4
>vertical has nearly constant gain for a satellite from about 10
>degrees up to over 70 degrees because of this range-gain. Of
>course below 10 degrees the satellite is as much as 3 db further
>away and hence weaker and most satellite link budgets were not
>designed to operate with such 0 dB gain omnis AT the horizon.
>
>So, the 1/4 vertical is very hard to beat for a simple omni
>satellite antenna. And by the same rationale, the terrestrial
>gain omni is NOT. SO watch out for apples and oranges
>comparisons...
>
>Bob, WB4APR
Just a note that I used a 19-inch mag-mount whip on a square sheet of
steel sheetmetal on my roof to copy telemetry on AO-51 when it was
first launched. This was UHF so the whip was working as a 3/4 wave
vertical. The important part of that is that the 432-MHz preamp MUST
be installed very near the antenna (I had about 10-foot of RG-58 as
the standard cable for the magnetic base).
If you are planning to use it for up and down link then you need a
diplexer to separate the two frequencies and isolate the preamp from
the 2m transmit signal. Since typically all you need is about 5w
that is not difficult.
73, Ed - KL7UWRe: Live streaming of the new satellites
To: pa3guo@xxxxx.xxxx amsat-bb@xxxxx.xxx
Message-ID: <19eef.5f53447b.3a182b67@xxx.xxx>
Content-Type: text/plain; charset="US-ASCII"
Excellent Henk.
I took a quick look at Kodiak.
I estimate AOS on orbit 3 around at 5.54 UTC with LOS at 06.06 (That's 4
hr 30mins after launch)
With orbit 4 at 6hrs 9min after launch.
Reasonable??
David G0MRF
In a message dated 19/11/2010 18:36:35 GMT Standard Time, pa3guo@xxxxxxx.xx
writes:
We will try to stream as much as possible live the audio
of the new set of satellites in the upcoming launch today.
As a test, we will in the coming hours we will stream HO68
and other Cubesats.
http://www.dk3wn.info/p/?page_id=17689
--
Henk, PA3GUO
------------------------------
Message: 8
Date: Fri, 19 Nov 2010 19:45:53 +0000 (UTC)
From: wa4hfn@xxxxxxx.xxx
Subject: [amsat-bb] Re: Na1iss
To: News Radio 6 <newsradio6@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID:
<1765928683.1502489.1290195953859.JavaMail.root@xxxxxxx.xxxxxxxxxxx.xx.xxxx.xx
xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Try 145.800 rec and 144-490 transmitt that works for me and best chance is
when they are the closest to your location
WA4HFN
----- Original Message -----
From: "News Radio 6" <newsradio6@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Sent: Friday, November 19, 2010 12:19:16 PM
Subject: [amsat-bb] ?Na1iss
Anyone have any tips for working the iss? I've heard several passes this
week on 145.800 but cannot seem to get thru the pileup. Timing your
transmissions seems to be the hardest part. The Tx offset I'm using is
-1.31mhz. Any suggestions?
John
Va3bl
Mobile in fn03
Sent from my iPod
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: 9
Date: Fri, 19 Nov 2010 15:57:07 -0400
From: Bruce Robertson <ve9qrp@xxxxx.xxx>
Subject: [amsat-bb] Re: Verticals on FM sats
To: bruninga@xxxx.xxxx AMSAT-BB <amsat-bb@xxxxx.xxx>
Message-ID:
<AANLkTikSOW3=KkY5uMzOXGXrAbj01spfWhn7s5o5009G@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Thank you, Bob, for clarifying this. The original letter made mention
of several types of antennas, including 1/4wave dualband and jpole,
both of which are, in your terms below, gain omnis at 440. (Jpole
being a 1/2wave antenna, e.g.) I first wrote the letter with these
distinctions kept intact, but then, in an attempt to keep things
simple, used 1/4 throughout, which meant that the claims about 1/4
elevation patterns were not accurate. However they would be accurate
for the "1/4 wave vertical" that John originally mentioned, at least
on 70cm.
So for the purpose of practical advice, I hope we can agree that:
a) a *true* 1/4 wave gp vertical makes a fine and inexpensive vertical
omni for satellite work. But this means that the 70cm's vertical
element should be around 18cm long. If it's longer, you're likely
getting gain, and that ain't good in this circumstance.
b) using a gain omni such as a jpole (or, likely, a multiband vertical
on 70cm) will produce the effects described in my letter below
c) with such an vertical you will occasionally suffer drop-outs at
very high elevation
d) I could have been clearer :-)
73, Bruce
VE9QRP
On Fri, Nov 19, 2010 at 2:10 PM, Robert Bruninga <bruninga@xxxx.xxx> wrote:
>> ... a typical 1/4 wave antenna... is super for
>> terrestrial work, where we want to have as much
>> power as possible going out to the horizon...
>> but... from a station up 20 degrees or more, say,
>> you'll find that you're working with much less ...
>> And, say, 70 degrees... with an ideal 1/4 wave,
>> you're putting out no power (and receiving none)
>> (In reality, its not that bad, but its pretty darn bad.)
>
> I think the essence of what is being said is relatively correct
> individually, but on closer inspection I think this is mixing
> apples and oranges. ?What is said is true for *gain* omni's, but
> not really true for the 1/4 wave vertical. ?In fact, the 1/4
> wave is about the best and simplest omni antenna for satellites.
> Please see the detail explanation
>
> http://aprs.org/rotator1.html
>
> The argument being presented above *does* apply to a *gain*
> verticla omni. ?Yes, that is NOT good for satellite work because
> it does as stated, concentrates gain on the horizon and
> drastically falls off at higher elevation. ?So that is why we
> say "omnis" are not good for satellites. ?Because almost
> everyone uses a *gain* omni.
>
> But the 1/4 ground plane antenna does not concentrate all of its
> energy on the horizon and is why most people will not use it for
> terrestrial work because too much of it goes out at higher
> elevations. ?And even though it does drop off by more than 10 dB
> at high angles above 60 degrees, one has to remember that the
> satellite is 10 dB closer at that high angle! ?So it still works
> great. ?AND the amount of time that a LEO satelite is above even
> 50 degrees is only 2% of all the access time. ?Nothing at all to
> worry about.
>
> See the plot of gain on the above web page. ?It shows that a 1/4
> vertical has nearly constant gain for a satellite from about 10
> degrees up to over 70 degrees because of this range-gain. ?Of
> course below 10 degrees the satellite is as much as 3 db further
> away and hence weaker and most satellite link budgets were not
> designed to operate with such 0 dB gain omnis AT the horizon.
>
> So, the 1/4 vertical is very hard to fun. The reason
> for this
>> with omni antennas is that we are having to distribute all the
>> 'receiving power' over all the elevation angles, as well as
> the 360
>> degrees of azimuth. In other words, your muffin has to be
> smaller in
>> diameter than your bagel half, because both have to have the
> same
>> total volume.
>>
>> Finally, your question suggests that simpler antennas, like
> 1/4 wave
>> groundplanes, are not necessarily easy to use on SSB/CW birds.
> I find
>> the contrary, especially on CW. FM satellites are easier
> because they
>> don't require as frequent tuning due to doppler shift, and
> because
>> many hams already have the equipment needed to operate them.
> But they
>> aren't 'easier' in the sense that their signals are easier to
> hear
>> with simple equipment. Heck, with any sort of antenna and an
> low-noise
>> preamp you'll hear the CW beacon of HO-68 from horizon to
> horizon.
>>
>> I hope you will forgive me if this reply was aimed at the
> wrong level,
>> and I wish you all the best in your satellite station
> building.
>>
>> 73, Bruce
>> VE9QRP
>> --
>> http://ve9qrp.blogspot.com
>>
>> _______________________________________________
>> Sent via AMSAT-BB@xxxxx.xxx. 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/listinfoa1iss
To: amsat-bb@xxxxx.xxx
Message-ID: <4CE6D737.4000605@xxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 11/19/2010 9:19 AM, News Radio 6 wrote:
> Anyone have any tips for working the iss? I've heard several passes this
week on 145.800 but cannot seem to get thru the pileup. Timing your
transmissions seems to be the hardest part. The Tx offset I'm using is
-1.31mhz. Any suggestions?
>
> John
> Va3bl
> Mobile in fn03
>
> Sent from my iPod
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. 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
>
I use 1448.00 rx and 144.900 tx in split. When the footprint covers my
area it works great.
I use IC910H for transceiver.
Dale
KL7XJ
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. 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 5, Issue 457
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