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CX2SA > SATDIG 19.06.08 08:39l 538 Lines 22156 Bytes #999 (0) @ WW
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To : SATDIG@WW
Today's Topics:
1. Re: LEO's (Mark Vandewettering)
2. Re: Message from Tom Clark (Tom Clark, K3IO)
3. Re: DirecWav satellite internet useful? (Chris Hackworth)
4. Re: DirecWav satellite internet useful? (Chris Hackworth)
5. Re: FO-29 and Field Day? (Patrick STODDARD (WD9EWK/VA7EWK))
6. Airing Suitsat's dirty laundry (David Donaldson)
7. Re: LEO's (Andrew Koenig)
----------------------------------------------------------------------
Message: 1
Date: Wed, 18 Jun 2008 20:07:47 -0700
From: Mark Vandewettering <kf6kyi(AT)gmail.com>
Subject: [amsat-bb] Re: LEO's
To: "i8cvs" <domenico.i8cvs(AT)tin.it>
Cc: AMSAT-BB <amsat-bb(AT)amsat.org>
Message-ID: <1F4BBDF1-F678-4FC1-A9DD-AB970A14EA8F(AT)gmail.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
On Jun 18, 2008, at 5:38 PM, i8cvs wrote:
> ----- Original Message -----
> From: "Mark Vandewettering" <kf6kyi(AT)gmail.com>
> To: "AMSAT-BB" <amsat-bb(AT)amsat.org>
> Sent: Wednesday, June 18, 2008 9:49 PM
> Subject: [amsat-bb] Re: LEO's
>>
>> On Jun 18, 2008, at 2:46 AM, i8cvs wrote:
>>
>>> Hi Art, KC6UQH
>>>
>>> You are correct 100% because the HEO AO40 was very easy to work
>>> using any old TX capable to run about 50 to 100 watt into 70 cm CW
>>> and SSB
>>>
>>> A 3 to 4 foot dish with a 2400/144 MHz downconverter in the focal
>>> point and
>>> connected to any old 144 MHz CW/SSB receiver mounted on the balcony
>>> was
>>> sufficient to receive a nice downlink from all over the world by
>>> many users
>>> at the same time for many hours every day.
>>>
>>> No complicated TX/RX radios and special software was necessary to
>>> compensate
>>> for doppler just made by hand.
>>
>> Well, sure, if you want to reduce ham radio to just keying the mic,
>> leisurely yapping along for hours at a time, then by all means, let's
>> have more satellites in HEO. But where's the skill in that?
>>
> Hi Mark, KF6KYI
>
> The skill is in building about everyting by yourself like low noise
> preamplifiers for 2 meters, 70 cm, 13 cm and high dinamic range
> downconverters for the above bands plus an Automatic Noise Figure
> Meters to get the best Noise Figure, build transverters from 2
> meters up
> to the MW, build different type of feed for dishes having hours to
> test
> their efficiency through the HEO satellite in cooperation to many and
> many experimenters worldwide and discuss the problems with them
> improving your knoledge in radio-technique.
I can see that my attempt at sarcasm was apparently lost on some
people. I suppose I'll have to explain more plainly. I suppose that
means my little joke wasn't funny, since I have to explain it.
It's become trendy on this list to criticize LEO or FM sats. That's
okay, as far as it goes. Yes, they are frequently congested. Yes,
they have operators on occasion who are inexperienced, or what's
worse, just don't care very much about operating reasonably. And they
aren't up for very long, which often makes QSOs short. All of those
are at least to some extent somewhat reasonable criticisms. They are
reasonable in part because we can do something about them: we can
encourage better operating procedures and work to educate people on
the proper use of these satellites and thus ameliorate most of the
problems (except, perhaps the most basic ones: the satellites orbits
and transponders are what they are, and no amount of good operating
procedure is going to change that).
Which brings up the first _unreasonable_ criticism. Complaining about
either a) the fact that they are FM or b) the fact that they are LEO
satellites. No amount of complaining will make this fact change.
Ever. They are what they are. Those of you who would like to
endlessly revisit this question can point out, again and again if they
like, about how such FM/LEO birds are a waste of time. That has
served been at least one "benefit": AMSAT-NA isn't the least bit
interested in doing another FM satellite, or even a satellite in LEO.
You guys won! It's over! AMSAT-NA won't be sending any of those
birds up again, probably for my lifetime. Whether you thought ECHO
was a waste of time or not, at least it ruined the entire notion of
LEO permanently for AMSAT.
The second _unreasonable_ criticism is to complain about how anyone
with an HT can push a button and work the FM satellites. That's not a
problem: that's a feature. Not everything that is easy is pointless,
and not everything that is hard is worthwhile. It's damned cool that
I can hit the ISS with 5w into an omnidirectional antenna on my car
roof, and use it for APRS messaging. It's cool that I can work
Hawaii, or Alaska, or the East Coast or deep into Mexico using my HT
and a handheld antenna, stuff I could toss into a backpack and go
hiking. Is it hard? No, not especially. It's not a snap though,
since I am operating with such low power. I find it kind of neat to
talk to NH7WN in Hawaii, each of us standing outside in the wind
holding handheld antennas and HTs on 5 degree passes. I could make it
harder. I could use smaller antennas or less power. I've had QSOs
over SO-50 with the lower power setting on my VX-3R before (300ish
mw). That actually wouldn't be that hard either, except for the high
power stations which like to transmit over others. But it isn't _hard_.
The fact is that there is _no actual reason_ that working linear
transponders in LEO need be hard either. It's hard mostly because
satellite communication is a niche market, so we have to make due with
what we can get. So, we cobble together downconverters, amplifiers,
preamps, computers and rotor controls together. Instead of a single
box with a microphone attatched, we have two separate radios, perhaps
each with their own amps/preamps and down/upconverters, and perhaps a
computer to drive it all and aim the antennas. It _could_ be in one
box. It _could_ use keplers to automatically correct Doppler for you,
so that tuning would be no more difficult than spinning a dial. But
nobody builds that box, and as near as I can tell, nobody in amateur
radio is really interested in building that box, because they think
that _the difficulty of something is what makes it valuable_. We see
this all the time, when people talk about Morse code and criticize
digital modes like PSK31 or the like. As engineers, we should be
_ecstatic_ that using radio is simple, but instead, we choose to laud
the efforts of doing things the same old hard way.
And here is the important thing that the AMSAT guys have discovered:
it's hard to convince government agencies like Homeland Security to
fund our launches in exchange for providing emergency communications
of we can't demonstrate that we can build _reliable, consistent ground
stations in reasonable numbers_. They aren't really interested in
helping you learn about radio or to talk to your friend in New
Zealand. They want a system for emergency communications. And if we
want their money, we are gonna have to _make_ satellite communications
easy.
Oh, and if we don't want their money? We aren't gonna get a launch.
We can't hold enough bake sales to make it happen.
> Probably to build about everyting by your self for a satellite for all
> like an HEO make you a real experimenter because if you are not
> succesfull you cannot send the equipment to the manufacturer but you
> are obliged to study your problem by your self looking and reasoning
> over your own schematic diagrams.
>
>
> When OSCAR-10, OSCAR-13 and AO40 where alive and well we all
> were assisted in solving our technical problems by some well know
> teachers
> and radio scientists every day on this BB like James Miller G3RUH,
> Charles Suckling, G3WDG and Tom Clark W3IWI now K3IO but
> unfortunately they actually desappeared from this BB because they are
> not anymore interested to discuss about the technical level and
> matters
> actually seen on this BB.
I suspect they are very interested in such things. I have great
admiration for all of these gentlemen. I first learned Tom Clark's
name when I found his Totally Accurate Clock project (GPS and
timekeeping are other interests of mine). James Miller's nifty Plan
13 paper led me to write my own satellite tracking code in Python, and
I'm working on a nifty idea to extend it. I'm less familiar with
Suckling's work, although I know he's a pretty familiar name in the
microwave community.
I suspect that what each is not interested in (and, in case you hadn't
figured it out, neither am I) is listening to a bunch of pointless,
idiotic complaining. Amsat-bb is incredibly high noise to signal
ratio. Complaining is a significant portion of that noise. It serves
no purpose at all.
> Read please into the AMSAT-BB archive and compare the importance of
> both
> technical and operating contents of messages at time in wich OSCAR-10
> OSCAR-13 and AO40 were operational and I am sure that you will learn
> more and more about the purposes of the Satellite Amateur Radio for
> the
> benefit of your own skill.
It's not a bad suggestion, but it doesn't really justify the current
level of complaining we see on the list today, does it? It would be
great if AO-10, AO-13 and AO-40 were still in operation, and we had a
platform upon which to explore the various modes and capabilities they
had. But we don't. They are dead. And, barring an AO-7 like
miracle, they aren't coming back. You seem to imply that because they
are gone, there is nothing better for us to do than complain. I think
otherwise.
For instance, here's a little thought experiment I've been running.
I've been monitoring SEEDS telemetry. I've written a very simple
tracking application that drives my little FT-817 to track the signal
in doppler, and then just examine the telemetry. There are some
interesting bits inside: notably the various voltages, the current
produced by each of the six solar panels, and four different
temperature measurements. I noticed that the temperature swings are
fairly large depending on whether the satellite was illuminated or
not. That's hardly a profound observation: it's rather obvious. But
imagine you were designing a satellite, and wanted to know what the
likely swings in temperature were, and how that effected both battery
and solar panel performance. Well, that's a bit deeper question, and
it requires some careful thought and (for those like me whose training
isn't in spacecraft design) a bit of research. Phil Karn hinted at
some of the differences between LEO sats and HEO sats regarding
thermal control on the namaste-dev list which I found interesting.
I'm also _really_ anxious to hear how DELFI-C3 works out once it
shifts over to open amateur use. I am interested in what can be done
in these small form factor sats, and I think engineering a system
which runs without batteries on purpose (as opposed to AO-7) is really
intriguing.
That's what I'm having fun with. That's how _I_ am justifying my ham
radio license and its mandate to self train. And I wouldn't have
likely gotten here without the FM sats and cubesat launches. Indeed,
without those launches, we wouldn't have much to listen to AT ALL.
And, unless there is some news deep in the innermost chambers of the
AMSAT leadership that we are unaware of, it doesn't seem to be the
right time to start holding your breath for an HEO launch anytime soon.
>
>> Hell, you don't even need to know what Doppler is with these easy HEO
>> satellites. If you want to take the easy way out though...
>
> Every experimenter know what the Doppler is but if you like to make
> your
> life difficult with Doppler for a few minutes QSO having the time to
> only
> say.......Five.......Nine.......class.......class !
> and then come into this BB asking for the call letter of the guy you
> suppose
> have made a QSO then it is better to stay with the FM satellites !
Sigh.
Luckily, I don't need to take your advice about what I should or
shouldn't "stick with".
Mark KF6KYI
>
>
>>
>> Mark KF6KYI
>>
>
> Best 73" de
>
> i8CVS Domenico
>
>
>
>
>
>
------------------------------
Message: 2
Date: Wed, 18 Jun 2008 23:25:58 -0400
From: "Tom Clark, K3IO" <tom.k3io(AT)gmail.com>
Subject: [amsat-bb] Re: Message from Tom Clark
To: Stefan Wagener <stefan_wagener(AT)hotmail.com>
Cc: 'AMSAT BB' <amsat-bb(AT)amsat.org>
Message-ID: <4859D1C6.1030407(AT)verizon.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Stefan: thanks for the comments. It's good to know that this "tekkie" is
not a voice in the wilderness.
To all: I apologize for the blank "no subject" subject field. I thought
I had filled it in, but I guess I didn't.
73, Tom
------------------------------
Message: 3
Date: Wed, 18 Jun 2008 23:58:13 -0400
From: "Chris Hackworth" <n8phucjh(AT)gmail.com>
Subject: [amsat-bb] Re: DirecWav satellite internet useful?
To: AMSAT-BB(AT)amsat.org
Message-ID:
<298264bf0806182058t4d1ebdcfp64eda1a6d4e2e795(AT)mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
On Wed, Jun 18, 2008 at 10:14 AM, Chris Hackworth <n8phucjh(AT)gmail.com>
wrote:
> Hi Greg,
>
> I am a bit of a lurker, my name is Chris. I work professionally in
> the commercial satellite industry.
>
> What you have is a dish that was used as a Ku band up and downlink setup.
>
> 11.7 - 12.2 Ghz is the normal downlink band for Ku band transmissions
> in the U.S.. Transmit for the U.S. is 14.0 to 14.5 ghz. Also the feed
> horn assy. is linearly polarized, I.E. horizontal and vertical.
> Usually they are setup so that transmit and rcv are opposite
> polarities I.E transmit can be linear, but rcv is horizontal, or vice
> versa.This is done so that you can get 500 mhz of space on the
> horizontal pole, and still be able to use the same 500 mhz on the
> vertical pole. This is called frequency reuse.
>
> Normal operation of this setup is the modem inside the house uses a
> I.F. freq range of 950-1550 Mhz (L band) for both transmit and
> receive.
>
> There is a set of articles on the net that explain how the satellite
> end of things work, here are the links :
>
> http://www.uhf-satcom.com/misc/satloop/
>
> http://www.uhf-satcom.com/misc/satellitebeacons/
>
> The LNB might be able to be modified for use in the 10Ghz range. I
> have seen a few articles on the net about conversion of LNA's to 10
> Ghz, so a LNB might be do able.
>
> The transmitter is usually in the range of 14 - 14.5 Ghz and usually
> is only 2 to 4 watts out. I wouldn't think this would be a hard
> conversion, but I haven't heard of anybody having done it, Maybe you
> could be the first!
>
> Good luck, there is a lot of this stuff starting to become dumpster
> fodder, maybe we can convert it for ham use...
>
> Chris N8PHU
> Chief of Transmitters and RF
> SES-Americom, Washington International Teleport
> Alexandria Va.
>
>
> On Wed, Jun 18, 2008 at 1:19 AM, Greg D. <ko6th_greg(AT)hotmail.com> wrote:
>>
>> Hi folks,
>>
>> An update on my Ku dish, the result of some lite poking around. Links to
pictures, below.
>>
>> The receive LNB has a sticker on it claiming "11.7-12.2 ghz", so this is a
bit outside of the ham band. Judging from the construction, it looks like
it's circularly polarized, and is fed with about a 3/4" round waveguide.
According to another Ham, it appears to have what he called a "ceramic
oscillator" or something like that, feeding a mixer for a low-gHz IF. He
guesses the IF out is in the 1 to 2 ghz range. Since there's not a lot of
filtering, and nothing is crystal controlled, we suspect that it should not be
too hard to re-tune down to the 10-10.5 ghz range. It somewhat depends on
whether the LO injection is on the high or low side, hopefully low. He's also
worried if the waveguide is the right size.
>>
>> The transmit side of things appears to be linearly polarized, and at a
higher frequency (guessing by the constrictions in the feed pipe). I haven't
opened the full Tx module (didn't have a Torx screwdriver handy), so I don't
know what's under the shield inside. Outside the shield are a bunch of parts,
nothing resembling a transmitter... Their website talks about it putting out
a couple of watts.
>>
>> I haven't opened up the control box yet.
>>
>> Some pictures, below. Any additional hints would be appreciated!
>>
>> The whole dish. Looking on the website, the new ones seem to be round;
hopefully, they haven't changed the electronics part...
http://home.wavecable.com/~ko6th/IMG_0115.JPG
>>
>> Side view of some of the plumbing. LNB is at the left, and the back of the
feed horn is to the right. The transmitter is piped in from below. We are
guessing that the lumps in the plumbing between the "T" and the LNB is a
filter of some sort, keeping the Tx from frying the Rx. The crud on the parts
is the remains of a rather large wasp nest that was waiting for me inside the
plastic hood. http://home.wavecable.com/~ko6th/IMG_0123.JPG
>>
>> Outside of the LNB, with the round flange for the waveguide, and one of the
feed probes. The other one is on the back side of the PCB, coming down from
the top (up from the bottom on the next picture).
http://home.wavecable.com/~ko6th/IMG_0131b.JPG
>>
>> Inside the LNB, with the cover and shield removed. The feed is on the
right, and we believe the LO is the round doughnut thing just to the lower
left of center. There's a set screw on the shield cover that comes down over
the ring, to adjust the frequency. There's one filter section in the middle
that might need tweeking. The IF comes out the upper left.
http://home.wavecable.com/~ko6th/IMG_0130b.JPG
>>
>> Transmit module, with the inside shield still on. Haven't done much
analysis on this yet... Where did I put that Torx?
http://home.wavecable.com/~ko6th/IMG_0132b.JPG
>>
>> So, I turn it back to you guys... Any further thoughts?
>>
>> Greg KO6TH
>>
>>
>> ----------------------------------------
>>> From: ko6th_greg(AT)hotmail.com
>>> To: amsat-bb(AT)amsat.org
>>> Date: Tue, 27 May 2008 21:42:21 -0700
>>> Subject: [amsat-bb] Re: DirecWav satellite internet useful?
>>>
>>>
>>> Hi all,
>>>
>>> Well, it's been saved from the dumpster, at least for now. But, I kind of
don't care much about the dish itself - it's probably a bit big /heavy for my
Az/El rotor setup, though it's hard to tell with the huge steel support mount
still attached. I nearly wrenched my back out carrying it over to my side
yard this morning. (I think the Advil is wearing off... oow)
>>>
>>> But, back to the pre-amp and other electronics pieces... I found a
reference to the Hughes DirecWay (not wav) service on the Web. Looks like the
stuff runs in the Ku Band (11-14.5 ghz, according to Wikipedia), and has a
0.5-2 watt transmitter, depending on model. Sounds like it's possibly a good
bit out of band for P3E needs, and I'm not much good with microwave hacking.
Am I better off taking another two pills and putting it back on the pile, or
is there a reasonable chance that I can do some simple (think "Drake")
modifications to get it to work?
>>>
>>> Greg KO6TH
>>>
>>>
>>> ________________________________
>>>> From: w7lrd(AT)comcast.net
>>>> To: ko6th_greg(AT)hotmail.com; kc6uqh(AT)cox.net; amsat-bb(AT)amsat.org
>>>> Subject: Re: [amsat-bb] Re: DirecWav satellite internet useful?
>>>> Date: Tue, 27 May 2008 17:14:01 +0000
>>>>
>>>> Greg- They seem to be an off center feed antenna, similar to the old
primestar dish of which I have been successfully using for several years. If
it's free you can't beat the price.
>>>> 73 Bob W7LRD
>>>>
>>>> --
>>>> "if this were easy, everyone would be doing it"
>>>>
>>>> -------------- Original message --------------
>>>> From: "Greg D."
>>>>
>>>>>
>>>>> Hi Art,
>>>>>
>>>>> The DirectWav is an Internet link - data, not TV - but good point about
LO
>>>>> stability being an unknown.
>>>>>
>>>>> But, my base question was whether any of the pieces can be used, and it
sounds
>>>>> like it's worth saving. Thanks!
>>>>>
>>>>> Greg KO6TH
>>>>>
>>>>>
>>>>> ----------------------------------------
>>>>>> From: kc6uqh(AT)cox.net
>>>>>> To: ko6th_greg(AT)hotmail.com; amsat-bb(AT)amsat.org
>>>>>> Subject: Re: [amsat-bb] DirecWav satellite internet useful?
>>>>>> Date: Mon, 26 May 2008 22:20:55 -0700
>>>>>>
>>>>>> Greg,
>>>>>> These dishes are used on 10 GHz and lower frequencies. Designed to
operate
>>>>>> in Ku Band ~12 GHz they will give ~30 dBof gain. The LNB and feed can
be
>>>>>> used , at least the LNA section. As the intended use is television the
LO is
>>>>>> not stable enough for Amateur Satellite work.
>>>>>>
>>>>>> Art,
>>>>>> KC6UQH
>>>>>> ----- Original Message -----
>>>>>> From: "Greg D."
>>>>>> To:
>>>>>> Sent: Monday, May 26, 2008 8:23 PM
>>>>>> Subject: [amsat-bb] DirecWav satellite internet useful?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hi folks,
>>>>>>
>>>>>> My neighbor appears to be tossing their Hughes "DirecWav" satellite
internet
>>>>>> dish and associated dish-mounted electronics. By any stroke of luck, is
>>>>>> this stuff reasonably convertable for use with any of the the proposed
P3E
>>>>>> up or downlinks? I have no idea what frequency it runs. It appears to
have
>>>>>> both transmit and receive capabilities (based on the warnings posted).
>>>>>> There are no model numbers tha t I can find on the electronics.
>>>>>>
>>>>>> I've got my AO-40 S-band receive setup, but nothing for the higher
bands.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Greg KO6TH
>>>>>> _________________________________________________________________
>>>>>>
>> _________________________________________________________________
>> The i'm Talkathon starts 6/24/08. For now, give amongst yourselves.
>> http://www.imtalkathon.com?source=TXT_EML_WLH_LearnMore_GiveAmongst
>> _______________________________________________
>> 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
>>
>
>
>
> --
> Chris N8PHU
> ET1(SW) USN (Ret)
> Chief transmitter Heavy SES-Americom
>
--
Chris N8PHU
ET1(SW) USN (Ret)
Chief transmitter Heavy SES-Americom
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