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CX2SA > SATDIG 26.09.09 13:56l 1105 Lines 38340 Bytes #999 (0) @ WW
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Today's Topics:
1. Re: All Satellites (Alan P. Biddle) (Robert Bruninga)
2. Re: All Satellites (Robert Bruninga)
3. Re: Arrow antenna reconfiguration results - UPDATE (Art McBride)
4. Re: Arrow antenna reconfiguration results - UPDATE (Alan VE4YZ)
5. Re: All Satellites (Rocky Jones)
6. Re: All Satellites (Rocky Jones)
7. Re: All Satellites (Bruce Robertson)
8. Re: All Satellites (Bruce Robertson)
9. Re: All Satellites (Rocky Jones)
10. Re: All Satellites (Bruce Robertson)
11. Re: Arrow antenna reconfiguration results - UPDATE (Jeff Yanko)
12. Re: Arrow antenna reconfiguration results - UPDATE (Jeff Yanko)
13. Re: Arrow antenna reconfiguration results - UPDATE (Jeff Yanko)
----------------------------------------------------------------------
Message: 1
Date: Fri, 25 Sep 2009 22:19:09 -0400
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: All Satellites (Alan P. Biddle)
To: <amsat-bb@xxxxx.xxx>
Message-ID: <3B0B3A9C63004A17B2E9FBFDCFE69AE8@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
>> At a SmallSat conference... this summer,
>> I was amused at the casual assumption by
>> a researcher that 50, cubesats could be
>> launched as part of an upper atmosphere
>> project using ham frequencies for the
>> downlinks.
And wouldn?t it be a hoot if everyone of them could put their
RX/TX into a bent-pipe packet mode, and then we would have
amateur radio global hand-held text messaging satellite
system...
>> ?(They would have a lifetime of only 3-4 months.)
But it would be FUN for a while!
Using some of the 2-way very small micro APRS packet systems, a
2 to 5 Watt transponder will easily fit on a singl circuit card
in a small cubesat. See www.aprs.org/cubesat-comms.html
Bob, WB4APR
------------------------------
Message: 2
Date: Fri, 25 Sep 2009 22:22:57 -0400
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: "'Amsat BB'" <amsat-bb@xxxxx.xxx>
Message-ID: <1CFE63F86A8141AC85A093448902043E@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
> ... few of these sats are doing anything
> even remotely related to amateur radio or
> even communications in general.
Get a life. Maybe not your very narrowminded view of amateur
radio, but you outta open your mind and do a little
investigation as to the full depth and breadth of what people do
with their amateur radio hobby...
Bob
------------------------------
Message: 3
Date: Fri, 25 Sep 2009 19:21:50 -0700
From: "Art McBride" <kc6uqh@xxx.xxx>
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
To: "'Joe'" <nss@xxx.xxx>, "'Gary \"Joe\" Mayfield'"
<gary_mayfield@xxxxxxx.xxx>
Cc: 'AMSAT-BB' <amsat-bb@xxxxx.xxx>
Message-ID: <641AA3749CDC4F498D1F629738B460E4@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
To All,
The Diplexer also acts as a filter. All solid state transmitters have "White
Noise" contributions. If you receive while transmitting the White Noise from
the 2M side will desense the 70 cm receiver. The amount of noise typically
60 dB down from the carrier varies with the type of output filter used in
the transmitter. Of course this does not apply when working the satellite
simplex.
A bad diplexer can also be the problem. Soldering is poor in some of these
overseas units, also excessive power in a former life will cook the parts
inside. A good test with 50 loads and a power meter will tell the condition
of the diplexer.
Art,
KC6UQH
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Joe
Sent: Friday, September 25, 2009 6:43 PM
To: Gary "Joe" Mayfield
Cc: 'AMSAT-BB'
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
as in the texts below, there is something else going on here.
That Diplexor can not be all that bad. two reasons.
How many db down is the front to side of that antenna?
and I can not imaging someone would sell a diplexor that has greater
than 20 db of losses.
because of the statement that how criticalpolarity was with the
original, and now the antenna has to be nearly 90 degrees cross
polarized to make it drop out uhh
that close to 30 db,
at least 20,,
something else is going on here
Gary "Joe" Mayfield wrote:
>>
>>Another issue I came across was how wide the beamwidth is of the Arrow
>>Antenna between the Arrow diplexer and the new diplexer. I was wondering
>>
>>
>if
>
>
>>this was going to happen and it did. The reason that this happened was
>>
>>
>with
>
>
>>the old diplexer, the signal attenuated so much that you had to be pointed
>>right smack dab on the bird, a few degrees off and you lost the signal.
>>Now, with the new diplexer, you can point the beam in the general
>>
>>
>direction
>
>
>>and still copy the bird. In most cases I had to turn the beam 90 degrees
>>before I completely lost the downlink! Twisting the antenna to make
>>polarization changes makes absolutely no difference now. This also
>>attributes to the fact that now I'm copying the entire pass without
>>
>>
>dropouts
>
>
>>or fades. Makes sense. What I've regained over the lossy diplexer makes
>>
>>
>up
>
>
>>for any polarization differences, etc. for a better copiable signal.
>>
>>Next weekend I will have to try more passes and get a feel of how much
>>
>>
>this
>
>
>>system has changed.
>>
>>
>>73,
>>
>>Jeff WB3JFS
>>Las Vegas, NV
>>DM26
>>
>>
>>
>>
>>
>>
>>_______________________________________________
>>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
>>
>>
>>
>
>_______________________________________________
>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
>
>
>_______________________________________________
>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
>
>
>
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>
>
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_______________________________________________
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!
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------------------------------
Message: 4
Date: Fri, 25 Sep 2009 22:44:55 -0500
From: "Alan VE4YZ" <ve4yz@xxx.xxx>
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
To: "'AMSAT-BB'" <amsat-bb@xxxxx.xxx>
Message-ID: <70CA2C92B1B144BFAD4EFA499858539F@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
I rarely use my Arrow and 2 dual band HTs, but, dragged them out this week
because I'm scheduled to do a high school demo in 2 weeks and thought I
better start practicing my technique again, update the KEPS in my Palm
PocketSat+ and get the battery packs charged.
So this discussion in the last couple of days is very relevant to me and
here's my 2 cents...
The only compliant I have about the Arrow is that it looses it's speckles
and the plastic tips fad to white when used outdoor for long periods :-)
Several years ago I ran it for a full year on the roof with a hygain TV
rotator and fixed EL of about 30 degrees. The arrows are now plain
aluminium.
First I view all anecdotal comparisons of before and after results with some
caution. A diplexer change from the OEM to another cannot account for the
improvement in one pass with fades to the next pass with no fades IHMO. It
is so, please tell me the science behind this. If a defective diplexer was
acting as an attenuator then I sure can see there would be an improvement in
signal. In my location, 2 low passes with the same max elevation on the
same satellite can be quite different depending on which part of the horizon
is below the pass - open prairie vs the noise floor of city. Sometimes there
are fades and sometimes there aren't any. Satellites tumble. Sometimes to
your advantage and some times they work against you.
Now, as to the Arrow OEM diplexer; with the 2 HT's I don't use it except as
a mode J filter, see
http://www.amsat.org/amsat-new/articles/Mode-J/ to reduce desense, and, a
mini UHF preamp
http://www.hsmicrowave.com/html/amateur_lna.htm , and, anecdotally I can
tell you that I can see the increase in bars on S-PO Meter and these old
ears can hear the difference when the preamp is switched on and off.
For those of you who want to use an external diplexer such as a Comet, you
can still use the OEM diplexer at the same time as a filter.
BTW yesterday I just practiced listening and heard a monstrous booming
signal from ISS, got to hear 4 or 5 answers to questions during the Ottawa
ARISS with the Arrow and a max 10 degrees pass, no preamp needed, LOS just
under 5 degrees. Also AO-27 max 20 degrees over Eastern NOAM until it went
digital - ever notice it goes digital just as it hits the 49th parallel? Is
that an anti-Canadian thing?
73, Alan VE4YZ
EN19kv
AMSAT LM 2352
http://www.wincube.ca
------------------------------
Message: 5
Date: Fri, 25 Sep 2009 23:00:36 -0500
From: Rocky Jones <orbitjet@xxxxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: <kq6ea@xxxxxxx.xxx>, Amsat BB <amsat-bb@xxxxx.xxx>,
<kg4zlb@xxxxx.xxx>
Message-ID: <COL106-W50FB26274FCA3D2F66BF40D6D80@xxx.xxx>
Content-Type: text/plain; charset="Windows-1252"
Jim...very few of them have any potential for Amateur use at all...most
however also die quickly.
Robert WB5MZO
> Date: Fri, 25 Sep 2009 13:38:45 -0700
> From: kq6ea@xxxxxxx.xxx
> To: amsat-bb@xxxxx.xxxx kg4zlb@xxxxx.xxx
> Subject: [amsat-bb] Re: All Satellites
>
> Do any of these have potential for Amateur use after their "primary
mission" is completed? If they can be repurposed like AO-27, then I don't
have any complaints. If, OTOH, all they're good for is sending telemetry for
somebody's experiment, then I feel this is an inappropriate use of Amateur
frequencies.
> 73, Jim KQ6EA
>
> --- On Fri, 9/25/09, David - KG4ZLB <kg4zlb@xxxxxxxxxx.xxx> wrote:
>
> > From: David - KG4ZLB <kg4zlb@xxxxxxxxxx.xxx>
> > Subject: [amsat-bb] Re: All Satellites
> > To: amsat-bb@xxxxx.xxx
> > Date: Friday, September 25, 2009, 1:10 PM
> > I hate to say it but you may be right
> > - the sky is now full of
> > "beep-beep" sats!
> >
> > David KG4ZLB
> >
> >
> >
> > Rocky Jones wrote:
> > > The hamsat bands are slowly being converted into
> > "cheap" telemetry bands...
> > >
> > > Robert WB5MZO
> > >
> > >
> > >
> >
> >
> >
> > >
> > _________________________________________________________________
> > > Bing? brings you maps, menus, and reviews
> > organized in one place. Try it now.
> > >
http://www.bing.com/search?q=restaurants&form=MLOGEN&publ=WLHMTAG&crea=TEXT_ML
OGEN_Core_tagline_local_1x1
> > > _______________________________________________
> > > 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
> > >
> > >
> >
> > _______________________________________________
> > 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
> >
>
> _______________________________________________
> 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
_________________________________________________________________
Insert movie times and more without leaving Hotmail?.
http://windowslive.com/Tutorial/Hotmail/QuickAdd?ocid=TXT_TAGLM_WL_HM_Tutorial
_QuickAdd_062009
------------------------------
Message: 6
Date: Fri, 25 Sep 2009 23:04:11 -0500
From: Rocky Jones <orbitjet@xxxxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: <k6hx@xxxx.xxx>, Amsat BB <amsat-bb@xxxxx.xxx>
Message-ID: <COL106-W4B78F6399F8F0029D9CEDD6D80@xxx.xxx>
Content-Type: text/plain; charset="Windows-1252"
> Perhaps when commercial vehicles like the Falcon 9 begin launching,
> we'll see a sufficient reduction in payload boosting costs to make
> raising the money for a HEO satellite with significant mass reasonable.
> We shall have to see.
>
> Mark K6HX
> _______________________________________________
> 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
Mark if there is a future for amateur HEO's the birds are going to be more
Arsene and Oscar IV size.
Robert WB5MZO
_________________________________________________________________
Lauren found her dream laptop. Find the PC that?s right for you.
http://www.microsoft.com/windows/choosepc/?ocid=ftp_val_wl_290
------------------------------
Message: 7
Date: Sat, 26 Sep 2009 01:26:36 -0300
From: Bruce Robertson <ve9qrp@xxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: Tony Langdon <vk3jed@xxxxx.xxx>
Cc: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Message-ID:
<49657a760909252126j27cb1a0fi987b1552f989c8e4@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
I will attempt a reply to both of these responses.
On Fri, Sep 25, 2009 at 9:27 PM, Tony Langdon <vk3jed@xxxxx.xxx> wrote:
> At 09:34 AM 9/26/2009, James Craig wrote:
>>Good point. Not everybody is interested in monitoring the one way
>>downlinks on the majority of these more recent birds. Why is it that
>>there is no problem getting large numbers of these types of satellites
>>into orbit, yet good old fashioned two way linear and FM transponder
>>birds are relatively far and few between?
The reason cubesats are being built is because they are seen as an
excellent platform for educating space science students at the
undergraduate level. The amount of money being spent per launch is
pretty doable for many institutions or local granting agencies. These
agencies and universities are likely simply not interested in
providing you or me with a platform for two-way terrestrial
communication if it is going to slow down their project or lower its
probability of success.
The cubesat design is quite constrained moreover, typically 10cm^3 and
under one kg, even the milk-carton sized 3U format is pretty small for
the power needs of a linear or FM transponder of the sort we are
typically using. We owe a debt of gratitude to Delfi, which showed
that a linear can be put up as a secondary mission, and to William for
his 10cm^2 transponder implementation.
Those are very recent developments, and I'd agree that we should jump
on them as golden opportunities, noting however, that the result will
still be very low altitude orbits and therefore small footprints.
Similarly, SDX technology might be able to miniaturize the transponder
further and reduce its power needs (while making one circuit a
do-everything transponder!), so we're lucky that we're testing that
technology in the near future.
Please note that there is no contention for resources here: the
opportunities the universities made use of are not available to us. If
we want this phenomenon to work to the advantage of those of us who
enjoy two-way voice communications, we need to either launch a cubesat
ourselves or offer the university projects a reason that adding this
capability will *improve* the time-to-launch or probability of
success. This might be in the form of a free, tested, reliable
communications board that happens to have two-way voice capability
integrated into it. It also could be in the form of increased amateur
enthusiasm for the transponder-bearing cubesat and the resulting
increase in telemetry collection, a bargain which we proved to be good
for in Delfi C3.
> I for one was never a SWL, so I tend not to follow the one way
> satellites, unless there's a compelling reason (e.g. for test
> signals, or telemetry decoding - had fun decoding telemetry on AO-40
> when it was first launched).
Nor was I, yet I very much enjoy listening to telemetry from cubesats,
along with other activities in this corner of the hobby. I can offer
you this reason: when I listen to telemetry, I'm listening to
something which is in space and in orbit around the earth, one of the
most exotic locales from which you could receive a message. If I talk
to you on AO-51, I'm talking to you on earth by means of a space-borne
vehicle. It turns out that what's fun about that for me is not
necessarily your voice, but the vehicle. Telemetry tells me about
those vehicles: how fast they are moving, how they are tumbling and
the contents of the telemetry stream: how much power they're
collecting and using. Moreover, with some of the cubesats, the
decoding of this is very easy if one knows CW.
Two more points in my brief "apologia pro cubesatibus"
1. So-called 'telemetry only' birds are not necessarily that. We had
the opportunity to control COMPASS during its crisis last year. The
low cost of the mission meant that any one of us was solicited to
enter the appropriate codes. I'll never be a control station for a
major bird, but I thrilled to do this for COMPASS.
2. Given that you admit above that telemetry collection is necessary
for the maintenance of communication satellites, shouldn't you be glad
that this steady stream of cubesats has allowed some enthusiasts to
continue to hone their skills in this field?
Finally, a truism that probably bears repeating, though not addressing
the two comments quoted above: if we call cubesats 'not amateur
radio', then we should tar OSCAR 1 with that same brush.
73, Bruce
VE9QRP
------------------------------
Message: 8
Date: Sat, 26 Sep 2009 01:34:14 -0300
From: Bruce Robertson <ve9qrp@xxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: G0MRF@xxx.xxx
Cc: amsat-bb@xxxxx.xxx
Message-ID:
<49657a760909252134p7ccc0a93m29d054566f9a2119@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
On Fri, Sep 25, 2009 at 7:34 PM, <G0MRF@xxx.xxx> wrote:
>
> In a message dated 25/09/2009 22:10:17 GMT Standard Time, m5aka@xxxxx.xx.xx
> ?writes:
>
> Hi Bill,
>
> You're right, the potential is there for a 3U CubeSat that can achieve ?an
> apogee > 1400 km.
>
> We'd need 1U of that to house the linear ?transponder but as you say the
> rest could be used for the propulsion system.
>
> As yet, as far as I'm aware, no-one has actually demonstrated a ?working
> propulsion mechanism that can fit in 2U but I'm convinced this is ?possible.
>
> The launch costs for a 3U CubeSat into 700 km LEO are well ?within the
> reach of the Amateur community, our challenge is to develop a means ?of
raising
> the apogee.
>
> 73 Trevor M5AKA
>
>
>
>
>
> Hi Trevor.
>
> There is a propulsion system being developed for cubesats using a hydrazine
> ?mono propellant that uses catalytic decomposition to produce a large
> volume of ?hot gaseous products.
>
> If initial claimed results can be repeated in production, then that unit
> can be propelled from typical LEO up to 1400km circular or 2000km
?eliptical.
> ?It's based on a 3U structure. It's not MEO, but its a lot more ?fun than
> 500km
>
> David ?G0MRF
Oh, I love this idea, and I put my vote in for the elliptical. (Not
that I have a vote :-) The occasional massive footprint would be
really neat to play with, and justify all our overkill antenna arrays.
I'm guessing we'd need the 3U format for linear transponder anyway,
since the requisite solar panel area is not available in 1U.
73, Bruce
VE9QRP
------------------------------
Message: 9
Date: Sat, 26 Sep 2009 00:03:14 -0500
From: Rocky Jones <orbitjet@xxxxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: <ve9qrp@xxxxx.xxx>, <vk3jed@xxxxx.xxx>
Cc: Amsat BB <amsat-bb@xxxxx.xxx>
Message-ID: <COL106-W65C6CE002211A77AFF47DAD6D80@xxx.xxx>
Content-Type: text/plain; charset="Windows-1252"
>
> Finally, a truism that probably bears repeating, though not addressing
> the two comments quoted above: if we call cubesats 'not amateur
> radio', then we should tar OSCAR 1 with that same brush.
>
> 73, Bruce
> VE9QRP
> _______________________________________________
> 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
Bruce...that is really not fair.
Oscar 1 (and 2) were "first time" for a lot of things and had at their heart
the goal of building amateur radio communications platforms...that is why
Oscar "X" (I think that is what they call it...a repeat of Oscar 1 and 2)
was shelved in favor of Oscar III a communications platform.
Both Oscar 1 and II lasted until their batteries ran out...indeed I think
Number 1 lasted until it decayed..Oscar V tested communications technology
from spacecraft stabilization to command systems etc. and it lasted until
its batteries ran out
.that is far longer sat life then most of the cubesats have. which mostly
have nothing to do with amateur radio
Robert WB5MZO
_________________________________________________________________
Lauren found her dream laptop. Find the PC that?s right for you.
http://www.microsoft.com/windows/choosepc/?ocid=ftp_val_wl_290
------------------------------
Message: 10
Date: Sat, 26 Sep 2009 02:46:55 -0300
From: Bruce Robertson <ve9qrp@xxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites
To: Rocky Jones <orbitjet@xxxxxxx.xxx>
Cc: Amsat BB <amsat-bb@xxxxx.xxx>
Message-ID:
<49657a760909252246j12b1474w24cf5eca3a3cec3a@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
On Sat, Sep 26, 2009 at 2:03 AM, Rocky Jones <orbitjet@xxxxxxx.xxx> wrote:
>
>>
>> Finally, a truism that probably bears repeating, though not addressing
>> the two comments quoted above: if we call cubesats 'not amateur
>> radio', then we should tar OSCAR 1 with that same brush.
>>
>> 73, Bruce
>> VE9QRP
>> _______________________________________________
>> 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
>
> Bruce...that is really not fair.
I'm sorry if I'm not being fair. I rather think, though, that there is
an important difference of opinion here on what constitutes amateur
activity. I'd like to explore it further with your permission.
> Oscar 1 (and 2) were "first time" for a lot of things and had at their heart
> the goal of building amateur radio communications platforms...that is why
> Oscar "X" (I think that is what they call it...a repeat of Oscar 1 and 2)
> was shelved in favor of Oscar III a communications platform.
If you are advocating a litmus test for amateur activity, especially
in the satellite field, that is based on novelty, then I cannot see
how you are not equally opposed to those aspects of P3E that are
self-consciously emulating previous satellites (everything other than
SDX and CAN-DO?)
In fact, in common practice innovation is too high a bar to set for
amateur activity: we don't expect each ham to invent a new modulation
scheme before getting on a local repeater for the first time; and I
know that when and if a HEO satellite is in orbit again, you will not
deprecate my enjoyment of following in the footsteps of many before me
who have undertaken linear transponder communications on that
platform.
I will meet you half way and say that innovation is a hallmark of
amateur satellite operations, though not a requirement. This is why I
am very excited by upcoming tests of SDX. It is also, incidentally,
why I applaud the achievements of the cubesat groups, whose very
form-factor is innovative, and who undertake innovative applications,
such as spacecraft stabilization for potential experiments in
formation flying, high-quality image capture, new communication modes,
physics experiments, etc., a list that reads much like the one you
apply to Oscar V below:
> Both Oscar 1 and II lasted until their batteries ran out...indeed I think
> Number 1 lasted until it decayed..Oscar V tested communications technology
> from spacecraft stabilization to command systems etc. and it lasted until
> its batteries ran out
I can't tell here: are you suggesting that battery-operated satellites
are more in the amateur spirit? Doesn't this contravene your
innovation criterion? Were not batteries in Oscar 1-5 faute de mieux?
You seem to be implying that the Oscar 1 designers eschewed the solar
panels available to them and wisely chose the limited lifetime option.
My understanding of the history of technology is somewhat hazy, but as
it is, it doesn't fit this picture.
> .that is far longer sat life then most of the cubesats have.? which mostly
> have nothing to do with amateur radio
In your opinion, is short life a knock against cubesats? Maybe it's a
good idea to have shorter missions in some cases. Short life is not
always true, of course: CO-57, e.g., has been in operation for over
six years.
73, Bruce
VE9QRP
------------------------------
Message: 11
Date: Sat, 26 Sep 2009 03:08:29 -0700
From: "Jeff Yanko" <wb3jfs@xxx.xxx>
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
To: "James Duffey" <jamesduffey@xxxxxxx.xxx>, "Bruce Robertson"
<ve9qrp@xxxxx.xxx>
Cc: James Duffey <jamesduffey@xxxxxxx.xxx>, AMSAT-BB
<amsat-bb@xxxxx.xxx>
Message-ID: <E704C0AE8F924F6499341B2284848C9B@xxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
Yes, it is larger than the OEM supplied by Arrow, however, the loss is
considerably less. I'll trade that any day! :) I connected it directly to
the radio's input using a double male adaptor, male N connector to male
PL-259. No coax between the radio and diplexer.
73,
Jeff WB3JFS
----- Original Message -----
From: "James Duffey" <jamesduffey@xxxxxxx.xxx>
To: "Bruce Robertson" <ve9qrp@xxxxx.xxx>
Cc: "James Duffey" <jamesduffey@xxxxxxx.xxx>; "Jeff Yanko" <wb3jfs@xxx.xxx>;
"AMSAT-BB" <amsat-bb@xxxxx.xxx>
Sent: Friday, September 25, 2009 8:20 AM
Subject: Re: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
>
> On Sep 25, 2009, at 7:53 AM, Bruce Robertson wrote:
>
>>
>> 2. If I'm correct, your replacement duplexer is rather larger than the
>> one it is replacing. It would be a great topic for a Journal article
>> if someone with the necessary equipment and expertise were to design a
>> replacement with less loss.
>
> There is a diplexer that is easy to make and has good performance in this
> article:
>
> < http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf >
>
> As a bonus you get details on how to build your own handheld antenna for
> LEO Satellites. - Duffey
>
------------------------------
Message: 12
Date: Sat, 26 Sep 2009 03:26:07 -0700
From: "Jeff Yanko" <wb3jfs@xxx.xxx>
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
To: "Joe" <nss@xxx.xxx>, "Gary \"Joe\" Mayfield"
<gary_mayfield@xxxxxxx.xxx>
Cc: 'AMSAT-BB' <amsat-bb@xxxxx.xxx>
Message-ID: <8010C8720E884613A8421640657D1A8A@xxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi Joe and all,
I doubt if the Arrow diplexer has 20dB of loss. If it did, we'd never
receive a signal! :)
I believe somebody here on the -bb will be performing a test on the Arrow
diplexer using a vector/network analyzer. It will be interesting to say the
least. There were preliminary reports saying the device had a loss anywhere
from 2.65 to 2.80dB. That's close enough to 3dB which is technically half
power loss. Add the loss of a short piece of coax and it will certainly be
pushed over the 3dB line.
If I recall correctly, cross polarity is also a 3dB loss. I have noticed
that when I rotate the antenna I might get a stronger downlink but I never
lose it when I rotate it back. Before, when I would do that it would drop
once I rotated in either direction from the peak signal. Basically what is
going on is the lossy device is removed and replaced with a more efficient
one, that extra net gain you just boosted now shows how the system on the
antenna side of the diplexer is truly performing.
I don't have an antenna analysis program to perform a test, but what does a
7 element 440 yagi pattern look like and what is its overall gain?
What we need to do is break down the antenna configuration into 3 segments,
see what their losses and gains are then combine them for the overall
figure. The 3 segment would be the antenna, the diplexer and the coax.
Each one will be tested individually to give an accurate number for each.
73,
Jeff WB3JFS
----- Original Message -----
From: "Joe" <nss@xxx.xxx>
To: "Gary "Joe" Mayfield" <gary_mayfield@xxxxxxx.xxx>
Cc: "'AMSAT-BB'" <amsat-bb@xxxxx.xxx>
Sent: Friday, September 25, 2009 6:42 PM
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
> as in the texts below, there is something else going on here.
>
> That Diplexor can not be all that bad. two reasons.
>
> How many db down is the front to side of that antenna?
>
> and I can not imaging someone would sell a diplexor that has greater
> than 20 db of losses.
>
> because of the statement that how criticalpolarity was with the
> original, and now the antenna has to be nearly 90 degrees cross
> polarized to make it drop out uhh
>
> that close to 30 db,
>
> at least 20,,
>
> something else is going on here
>
> Gary "Joe" Mayfield wrote:
>
>>>
>>>Another issue I came across was how wide the beamwidth is of the Arrow
>>>Antenna between the Arrow diplexer and the new diplexer. I was wondering
>>>
>>>
>>if
>>
>>
>>>this was going to happen and it did. The reason that this happened was
>>>
>>>
>>with
>>
>>
>>>the old diplexer, the signal attenuated so much that you had to be
>>>pointed
>>>right smack dab on the bird, a few degrees off and you lost the signal.
>>>Now, with the new diplexer, you can point the beam in the general
>>>
>>>
>>direction
>>
>>
>>>and still copy the bird. In most cases I had to turn the beam 90 degrees
>>>before I completely lost the downlink! Twisting the antenna to make
>>>polarization changes makes absolutely no difference now. This also
>>>attributes to the fact that now I'm copying the entire pass without
>>>
>>>
>>dropouts
>>
>>
>>>or fades. Makes sense. What I've regained over the lossy diplexer makes
>>>
>>>
>>up
>>
>>
>>>for any polarization differences, etc. for a better copiable signal.
>>>
>>>Next weekend I will have to try more passes and get a feel of how much
>>>
>>>
>>this
>>
>>
>>>system has changed.
>>>
>>>
>>>73,
>>>
>>>Jeff WB3JFS
>>>Las Vegas, NV
>>>DM26
>>>
>>>
>>>
>>>
>>>
>>>
>>>_______________________________________________
>>>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
>>>
>>>
>>>
>>
>>_______________________________________________
>>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
>>
>>
>>_______________________________________________
>>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
>>
>>
>>
>>------------------------------------------------------------------------
>>
>>
>>No virus found in this incoming message.
>>Checked by AVG - www.avg.com
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>>
>>
> _______________________________________________
> 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: 13
Date: Sat, 26 Sep 2009 04:48:23 -0700
From: "Jeff Yanko" <wb3jfs@xxx.xxx>
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE
To: "Bruce Robertson" <ve9qrp@xxxxx.xxx>
Cc: AMSAT-BB <amsat-bb@xxxxx.xxx>
Message-ID: <F41260F895414DC5988B128255DDA927@xxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi Bruce and all,
No problem. Actually, I wouldn't call it research as much as curiosity.
Maybe the research will come later when developing something better. :) I
know the antenna "works" but can it be made to perform better? The antenna
itself is of great quality and workmanship, it's the diplexer that has been
making me wonder if that is the weak spot. The Achilles heel of the system.
OK on setting up the FT-817 using two coaxes. I've heard a number of others
doing the same thing with great results. I would suggest doing what best
suits the individuals needs and affordability. You be surprised what one
can dream up when you plan it out and follow through with the design.
73,
Jeff WB3JFS
----- Original Message -----
From: "Bruce Robertson" <ve9qrp@xxxxx.xxx>
To: "Jeff Yanko" <wb3jfs@xxx.xxx>
Cc: "AMSAT-BB" <amsat-bb@xxxxx.xxx>
Sent: Friday, September 25, 2009 6:53 AM
Subject: Re: [amsat-bb] Arrow antenna reconfiguration results - UPDATE
Jeff --
I really appreciate you doing this research for us. Two additional
ideas come to mind:
1. Those of us with FT-817s could configure its two RF ports to use
different bands and connect the rig directly to the beam's antenna
connectors, bypassing the duplexer. For this purpose, higher-quality
bnc terminated cable would be useful.
2. If I'm correct, your replacement duplexer is rather larger than the
one it is replacing. It would be a great topic for a Journal article
if someone with the necessary equipment and expertise were to design a
replacement with less loss.
73, Bruce
VE9QRP
On Fri, Sep 25, 2009 at 6:10 AM, Jeff Yanko <wb3jfs@xxx.xxx> wrote:
> Hi all,
>
> A quick update to my new project to improving the Arrow antenna,
> efficiency
> wise. I wanted to see how well it would perform on gaining and losing
> access during AOS and LOS. AO-27 is not a good choice since the timer is
> turned on when it is well above the AOS horizon and it is switched off
> before it reaches its LOS horizon. That leaves a dependable AO-51 to test
> it out.
>
> With the last setup, the OEM diplexer provided by Arrow Antenna, I would
> copy AO-51 about 3 minutes after AOS and lose it about 3 to 4 minutes
> before
> LOS. Not bad, but people were saying they worked the birds when they were
> 1
> degree off of the horizon. I have some pine trees that could be an issue
> but they are spaced far enough apart that I can work between them and I
> also
> have to deal with the McCollough Range to the SSE of me here in Las Vegas,
> NV. Today, there were 2 passes of AO-51, one at 12 degrees elevation, the
> other at 74 degrees. During both passes, I began to copy the downlink
> about
> a 1.25 minute after AOS. A considerable difference from 3 minutes. The
> downlink also improved down to about minute before LOS. On the last pass I
> worked KG6NUB at 0124z and LOS was 0125z and my downlink sounded fairly
> good, though I was fighting desense. (That's another issue I need to
> resolve.) Also, on both passes, I never once lost the downlink. No
> dropouts or fades. I'm still amazed.
>
> Another issue I came across was how wide the beamwidth is of the Arrow
> Antenna between the Arrow diplexer and the new diplexer. I was wondering
> if
> this was going to happen and it did. The reason that this happened was
> with
> the old diplexer, the signal attenuated so much that you had to be pointed
> right smack dab on the bird, a few degrees off and you lost the signal.
> Now, with the new diplexer, you can point the beam in the general
> direction
> and still copy the bird. In most cases I had to turn the beam 90 degrees
> before I completely lost the downlink! Twisting the antenna to make
> polarization changes makes absolutely no difference now. This also
> attributes to the fact that now I'm copying the entire pass without
> dropouts
> or fades. Makes sense. What I've regained over the lossy diplexer makes up
> for any polarization differences, etc. for a better copiable signal.
>
> Next weekend I will have to try more passes and get a feel of how much
> this
> system has changed.
>
>
> 73,
>
> Jeff WB3JFS
> Las Vegas, NV
> DM26
>
>
>
>
>
>
> _______________________________________________
> 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
>
------------------------------
_______________________________________________
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 4, Issue 499
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