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CX2SA > SATDIG 11.12.08 01:05l 778 Lines 29949 Bytes #999 (0) @ WW
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To : SATDIG@WW
Today's Topics:
1. Re: SINAD Vs. Noise Figure Testing (Stan W1LE) (RFI-EMI-GUY)
2. Re: AO-51 uplink changed to 145.880 MHz (Michael Heim)
3. ARISS Queries--Answered (Frank H. Bauer)
4. Re: AO-51 (Alan Sieg WB5RMG)
5. Re: ISS 9600 succeeded in digipeat (Bill)
6. info (w3vvp)
7. ISS 9600 changed to 145.825MHz (Mineo Wakita)
8. Re: SINAD Vs. Noise Figure Testing (Edward Cole)
9. Re: SINAD Vs. Noise Figure Testing (Edward Cole)
10. Re: AO-51 (Andrew Glasbrenner)
11. Re: AO-51 (Alan Sieg WB5RMG)
12. Re: AO-51 (Alan Sieg WB5RMG)
13. ESEO -The European Student Earth Orbiter - development gets
underway (Graham Shirville)
14. PCSAT little joy (Robert Bruninga)
----------------------------------------------------------------------
Message: 1
Date: Tue, 09 Dec 2008 20:39:38 -0500
From: RFI-EMI-GUY <Rhyolite@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing (Stan W1LE)
To: amsat-bb@xxxxx.xxx
Message-ID: <493F1DDA.4040802@xxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Stan; Thank you for sharing your results for those of us who have SINAD meters
but cannot afford a noise figure meter. I also thought your statement:
"An additional test was performed, adding a fixed 10 dB BNC attenuator after
the preamplifier and before the RX. The SINAD measurement did not change.
This indicated that at least 10 dB of excess gain was present and can be
eliminated.
It is always best to minimize system gains to maximize the ability to
handle strong signals and to reduce higher order intermodulation distortion."
is very appropriate for radio system designers. I work in the land mobile
radio field and many of the trunked systems use tower mounted preamplifiers
with excess gain. The use of an attenuator between the preamplifier and the
multicoupler to control IMD is often overlooked, misunderstood, and as you
demonstrated may have a tremendous impact on the performance of a radio
system.
Thanks for sharing this.
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"?
"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."
"Follow The Money" ;-P
------------------------------
Message: 2
Date: Tue, 9 Dec 2008 18:04:59 -0800 (PST)
From: Michael Heim <kd0ar@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51 uplink changed to 145.880 MHz
To: amsat-bb@xxxxx.xxx
Message-ID: <657456.31579.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Fantastic move! got in with 5 watts again! Thanks!
Michael Heim
ARS KD0AR
--- On Tue, 12/9/08, Gould Smith <gouldsmi@xxxxxxxxx.xxx> wrote:
> From: Gould Smith <gouldsmi@xxxxxxxxx.xxx>
> Subject: [amsat-bb] AO-51 uplink changed to 145.880 MHz
> To: amsat-bb@xxxxx.xxx
> Date: Tuesday, December 9, 2008, 6:45 PM
> As of 2340Z, 9 Dec 2008 the 145.92 uplink to the main FM
> repeater on AO-51, has been changed.
> This change was due to interference on uplink frequency.
>
> V/U FM Repeater
> Uplink 145.880 MHz
> Downlink 435.300 MHz
>
> 73,
> Gould, WA4SXM
> for the AO-51 command team
> _______________________________________________
> 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: 3
Date: Tue, 9 Dec 2008 21:06:04 -0500
From: "Frank H. Bauer" <ka3hdo@xxxxxxx.xxx>
Subject: [amsat-bb] ARISS Queries--Answered
To: <amsat-bb@xxxxx.xxx>
Message-ID: <000001c95a6b$dff0cab0$0301a8c0@xx.xxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
All,
The ARISS team has had a number of queries on several topics. It is hoped
that this e-mail will answer these for you.
1) 25th Anniversary of Ham in Space Special Event Certificate---Many have
asked how to receive the special certificate and what qualifies you for the
certificate.
Qualification: Those that have had 2 way communications with the ISS on
Voice, Packet (APRS), or through the voice repeater. And those that have
heard the ISS from space in any of the ARISS operations modes (Voice, SSTV,
School Contact, Voice Repeater, Digital). Valid dates to qualify for
certificate: November 30 to January 15.
Receiving the Certificate:
A) Please note on your QSL the ARISS mode of operation (e.g. SSTV, voice,
school, etc) and whether the contact with you was 1 way (receive only) or 2
way.
B) Send your SASE to the normal ARISS QSL volunteer distributor in your area
of the world.
C) On the outside of the QSL envelope, please include the words "25th
Anniversary Certificate"
D) Make sure your envelope is big enough to accept an 8.5 by 11 inch
certificate and includes the proper postage.
E) Go to www.ariss.org if you do not know where to send your QSL and please
use one of the standard international QSL distributors that are noted on the
Web page.
Important note: We will be sending your certificate to the volunteer
distributors in bulk AFTER the event is over. (This saves workload and
money). So do not expect to see it until 1-2 months after the event closes
on January 15.
2) Richard Garriott QSL Card---there are have several queries about the
final results of Richard Garriott's flight and how the QSL cards will be
handled.
QSO Results: Richard made over 500 voice QSOs during his flight, clearly
more than any single ham has made on-orbit during a short duration mission.
And he sent down about 1000 SSTV images during his flight.
QSL Card: Those that had a QSO with Richard can receive an ARISS QSL card
using the normal ARISS process. (See www.ariss.org). Richard Garriott is
also planning a personal card which is in development. Once it is
developed, they will be shipped to the ARISS international QSL distribution
volunteers for distribution. The current plan is that those that have
already sent in for an ARISS QSL card will also get a Richard Garriott
personal card once it is available. If you made a contact with Richard,
have not sent in your QSL, and would like Richard's personal QSL card,
please stand by for QSL distribution instructions until the QSL card is
ready. The distribution of this special QSL will parallel how we are
distributing the 25th Anniversary Certificate.
3) SSTV Operations Web Site---The ARISS team appreciated the special web
page support from UC Berkeley. They allowed us to use their server to
support SSTV operations during the Richard Garriott's flight. This was a
temporary solution. The web site is currently down while we move the web
pages from the Berkeley site to the AMSAT server. This should be completed
in the next few days. You will see a follow-on e-mail with details on
connecting up to the SSTV Operations server. We thank you for your
patience.
On behalf of the ARISS International team of volunteers, I thank you all for
your interest and participation in the ARISS Program.
73, Frank Bauer, KA3HDO
AMSAT V.P. for Human Spaceflight Programs
ARISS International Chairman
------------------------------
Message: 4
Date: Tue, 9 Dec 2008 21:32:27 -0600 (CST)
From: "Alan Sieg WB5RMG" <wb5rmg@xxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51
To: amsat-bb@xxxxx.xxx
Message-ID: <4030.192.168.121.31.1228879947.squirrel@xxx.xxx.xxx.xx>
Content-Type: text/plain;charset=iso-8859-1
KO4MA sez:
> Notice the Doppler curve is different between the three on the right.
As I see it, the one in the center of those three ( (435.881) indicated as
almost exactly in position to translate via AO-51 to the 145.92 downlink..)
is already more like ~2 min past TCA (at the base line).
I would expect anything coming out of FO-29's transponder to show the
same dopppler rate as the other signals, say the beacon at 435.795 ...
Unless it was going thru yet another satellite first ..!..
Or possibly not going thru FO-29 at all, but heard direct from a 2nd bird.
SO-50 was just ahead of AO-29 on that pass. Hummm...
Even tho the AO-51 uplink has already been changed,
I may try and grab a waterfall tonite centered on 435.850 ...
Just to see if there are two different doppler rates again.
Very Interesting . . .
/;^)
--
<- Licensed in 1976, WB5RMG = Alan Sieg * AMSAT#20554 ->
<- http://www.somenet.net * http://wb5rmg.somenet.net ->
<- http://www.linkedin.com/in/alansieg * My 'Day Job' ->
------------------------------
Message: 5
Date: Tue, 9 Dec 2008 13:01:01 -0800
From: "Bill" <bill@xxxxxxx.xxx>
Subject: [amsat-bb] Re: ISS 9600 succeeded in digipeat
To: <amsat-bb@xxxxx.xxx>
Message-ID: <001301c95a41$401aebd0$0b00a8c0@xxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Although I didn't get my TNC set up in time to get anything from me
digipeated,
I did monitor the following from ISS, now on 145.825 @ 9600:
p2 RS0ISS-5*>SGATE>WIDE>0P0PP0 (UI):
'vXl '/]APRS/BBS & Packet on.
p2 W4SV>RS0ISS-5*>STAN>CQ <UI>:
=4123.73N/08648.30Wx
Maybe on the next pass I'll see some of my packets digipeated.
If so, maybe someone will be around for a QSO?
> We confirmed ISS 9600 digipeat over Japan.
> The frequency is 145.800MHz, not 145.825MHz
------------------------------
Message: 6
Date: Tue, 9 Dec 2008 21:17:11 -0500
From: "w3vvp" <w3vvp@xxxxxxxxxx.xxx>
Subject: [amsat-bb] info
To: "amsat-bb" <amsat-bb@xxxxx.xxx>
Message-ID: <5B53F94C2EF740B1833BBC8BA871DDA1@xxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I'm looking for a 903 transverter w/144 if. Dem is only place I have found
one SSB does not have one. Does any one have one for sale or know of any
place that sells them. I hope this is not to far out of line for the BB. Any
info greatly appreciated. George
------------------------------
Message: 7
Date: Wed, 10 Dec 2008 13:08:30 +0900
From: Mineo Wakita <ei7m-wkt@xxxxxxxxx.xx.xx>
Subject: [amsat-bb] ISS 9600 changed to 145.825MHz
To: amsat-bb@xxxxx.xxx
Message-ID: <3CC95A7CF62E57ei7m-wkt@xxxxxxxxx.xx.xx>
Content-Type: text/plain; charset=us-ascii
ISS 9600 digipeat changed to 145.825MHz from 145.800MHz.
JE9PEL, Mineo Wakita
------------------------------
Message: 8
Date: Tue, 09 Dec 2008 22:49:01 -0900
From: Edward Cole <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing
To: AMSAT-BB@xxxxx.xxx
Message-ID: <200812100749.mBA7n1kc034077@xxxxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
As far as I know SINAD is only used for FM sensitivity measurements,
whereas the older standard that is used for AM is 20-dB quieting. Of
course SSB is another form of AM. But as an (relatively) inexpensive
tool for tuning RF stages for maximum sensitivity (which should
coincide with minimum NF) the SINADer should work fine. Most SSB VHF
receivers also include FM mode. Merely, tune for 12-dB SINAD and it
should result in the best sensitivity in for SSB, as well.
If you are wanting to know the absolute noise figure then you will
need to measure it using a NF meter or other standard method. But
since our goal is to achieve the best sensitivity, whatever NF that
results in, it seems to me that SINAD can be used for adjustments.
I have performed so many FM alignments over the years, I can tell
when I hear 12 dB SINAD without use of the meter with pretty good
accuracy. I perform probably 500+ of these a year. BTW state of the
art FM receivers run about 0.125uV these days (most ham VHF radios
are this sensitive). AT UHF they are often 0.25uV. The old standard
of 25-years ago was 0.35uV for VHF and 0.50uV for UHF. MOSFet
front-ends on commercial radios are pretty good. A good GasFet
preamp will achieve a NF of 0.5 dB which is about -145dBm at SSB
bandwidths. I don't convert dBm to uV much as my equipment has both
scales on them, but I know that 0.25uV = -119 dBm FM.
73, Ed - KL7UW
At 12:48 PM 12/9/2008, Michael Heim wrote:
>Stan makes a good point here, especially for FM sensitivity. I
>worked in the 2-way business for a long time, and typically a sinad
>measurement would be something like the value of microvolts at the
>antenna input for 20 dB of quieting of the receiver. It is
>basically a measurement of FM receiver sensitivity. It will also
>show mis-aligned IF strips and detector, but for the sake of
>arguement in this case, lets say the receiver is functioning
>normally. The goal should be the minimum amount of signal input at
>the antenna connector quiets the receiver 20 dB.
>
>The way it works is this: an FM modulated carrier is injected into
>the receiver with a modulating frequency of 1000 Hz (at typically
>around 30% modulation). A sinadder is simply an audio level meter
>that has a deep notch at 1000 Hz. Therefore, any audio that it sees
>that is not on 1000 hz is read as noise (or distortion). As you
>increase signal strength, the noise drops off, and when the signal
>voltage reaches 1/10th of the unsquelched noise with no signal
>present, the amount of signal injected into the antenna connector is
>read. That would be the signal necessary to quiet the receiver 20 dB.
>
>A typical reading for sinad from a typical amateur (barefoot) rig
>today is such that .25 - .35 microvolts will quiet the receiver 20
>dB. It will be even lower with a preamp in line.
>
>I am not certain that a sinad reading would be of much use on an SSB
>receiver. Typically a similar measurement for an SSB receiver would
>be MDS, or "Minimum detectable Signal", which would be the amount of
>signal that is injected into the antenna connector that produces a
>faint but detectable signal in the receiver.
>
>Basically, SINAD and noise figure measurements produce the same
>result. They both are a measurement of receiver sensitivity,
>however sinad is reliable only for an FM receiver. A sinad meter is
>very easily constructed, and can be purchased much more
>inexpensively than a noise figure meter, so therefore, if your
>receiver is capable of FM reception, you can tune up your system by
>using a sinad measurement. The only difference that I can really
>think of between the two measurement systems is that noise figure is
>an absolute measurement that is applicable to all modes of
>operation, whereas sinad is only applicable to FM. If, however you
>place a generator at the preamp input, and monitor in the FM mode as
>you make adjustments to your preamp, you will also be tuning for
>best signal to noise, which will correspond to lowest noise
>figure. You just will not know what THAT value is, unless it can be
>calculated, which I do not know the formula if it is possible
> to do so.
>
>If I needed to tune a preamplifier for absolute best noise figure in
>a labrotory environment, then, yes, I would tune with the help of a
>noise figure meter, but for most amateur purposes, I see no reason
>why one could not tune up using sinad as the criterion.
>
>Michael Heim
>Chief Engineer, Forever Broadcasting
>New Castle PA
>WKST WJST WWGY
>814-671-0666
>Chapter Chair, SBE-122
>ARS KD0AR
>
>
>--- On Tue, 12/9/08, Stan W1LE <stanw1le@xxxxxxx.xxx> wrote:
>
> > From: Stan W1LE <stanw1le@xxxxxxx.xxx>
> > Subject: [amsat-bb] SINAD Vs. Noise Figure Testing
> > To: AMSAT-BB@xxxxx.xxx
> > Date: Tuesday, December 9, 2008, 3:03 PM
> > Hello The Net:
> >
> > Upon the suggestion of Domenico, I8CVS, I conducted some
> > tests to
> > compare SINAD to Noise figure testing.
> >
> > Noise figure testing was performed using a HP8970B with 346
> > noise source
> > on a ARR preamplifier,
> > one of their switched units, model SP144VDG.
> > Performance was optimized at 144 MHz. for a noise figure
> > of 0.9 dB and
> > gain of 25 dB.
> >
> > The preamp was added before the IC-910H, which was set to
> > 144.000 MHz in
> > a SSB (USB) mode.
> >
> > SINAD , SIgnal + Noise + Audio Distortion testing allows a
> > complete
> > receiver to be tested
> > from the RF input port, thru the IF's and demodulation
> > to audio.
> >
> > For SSB mode testing I injected a low level RF carrier, (~
> > -120 dBm),
> > no modulation, into the preamplifer with RX.
> > I tuned the RX frequency to 1000 Hz less than was actually
> > injected.
> >
> > example: for a RF of 144.000 MHz, I tuned the RX, in a SSB
> > (USB) mode,
> > to 143.999 MHz.
> > SINAD instruments use a 1000 Hz tone for further
> > processing.
> >
> > Connecting the audio output to a SINAD meter, in my case a
> > Helper
> > Instruments, Inc. model Sinadder Linear 5,
> > I was able to get a SINAD reading from the meter.
> >
> > While monitoring the SINAD meter, I tweaked the
> > preamplifier tuning and
> > could not improve the original SINAD measurement.
> >
> > Conclusion: If the noise figure is optimized, the SINAD
> > measurement will
> > also be optimized.
> >
> > An additional test was performed, adding a fixed 10 dB BNC
> > attenuator after
> > the preamplifier and before the RX. The SINAD measurement
> > did not change.
> > This indicated that at least 10 dB of excess gain was
> > present and can be
> > eliminated.
> > It is always best to minimize system gains to maximize the
> > ability to
> > handle strong signals
> > and to reduce higher order intermodulation distortion.
> > Minimize system interstage gains until the system SINAD
> > sensitivity or
> > the noise figure is slightly degraded.
> >
> > In this example, if I was able to reduce 10 dB of excess
> > gain, this
> > would result in lowering
> > the 3rd order intermodulation distortion by 30 dB . !!!
> >
> > I hope this helps folks to consider SINAD testing of their
> > system, to
> > verify performance.
> >
> > Stan, W1LE FN41sr Cape Cod
> > _______________________________________________
> > 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
------------------------------
Message: 9
Date: Tue, 09 Dec 2008 23:14:26 -0900
From: Edward Cole <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing
To: AMSAT-BB@xxxxx.xxx
Message-ID: <200812100814.mBA8EQ4w060899@xxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
In this modern day, soundcard programs display very weak signals much
below what can be heard. The method described below can be modified
using a soundcard spectrum program whereby you can lower the signal
on the display to equal the noise floor and thus achieve very close
to S+N/N = 0. Measuring the signal in dBm that produces this level
will give one a good measure of sensitivity.
For example, my SDR-IQ is calibrated in dBm so I can see this
directly. Typically with 2.1 KHz wide SSB the SDR-IQ has a noise
floor of -130 dBm at 28-MHz into a 50-ohm load. On an antenna you
see a much higher noise floor that shows the amount of noise the RF
environment adds.
When I use a 144/28 MHz convertor before the SDR-IQ, the absolute
reading is likely shifted by the gain and NF of the convertor. Use
of a calibrated signal generator will give a good benchmark for
sensitivity. One must insert a test signal using a directional
coupler to know what actual sensitivity is when connected to an antenna.
73, Ed - KL7UW
At 01:53 PM 12/9/2008, Glen Zook wrote:
>The original SINAD was a 10 dB figure which was developed at least a
>couple of decades after the 20 dB quieting figure. The "proper" way
>to measure the 20 dB quieting point was to use an AC voltmeter
>utilizing a cupric oxide rectifier (which was what most of the "olde
>tyme" VOM units used - i.e. Simpson 260). With the squelch of the
>FM receiver "wide open" the voltmeter was placed across the speaker
>and the volume control adjusted for a convenient reading (1 volt was
>very common). Then an on-frequency unmodulated signal was applied
>from a signal generator having an accurately calibrated attenuator
>and the signal level was adjusted to the point where 1/10th the
>voltage was recorded on the VOM. Since a reduction in voltage by a
>factor of 10 represents a 20 dB reduction this point was referred to
>as the "20 dB quieting" point.
>
>Most experienced two-way radio technicians could actually make a 20
>dB quieting measurement "by ear" and did not require the use of an
>AC voltmeter. When verified by someone watching a voltmeter while
>the technician did the measurement by ear virtually always resulted
>in a measurement that was well within 1 dB which was "close enough
>for government work" for field measurements.
>
>Using a well calibrated dB meter (i.e. one made by Hewlett Packard)
>across the speaker will usually not result in the same reading as
>that done with a "plain old VOM" using the simple cupric oxide
>rectifier. The 20 dB quieting measurement was done by field
>technicians who often did not have such fancy test equipment as a
>calibrated dB meter.
>
>An easy to make and a very meaningful sensitivity measurement is the
>LDS (least discernible signal) which involves turning on the BFO,
>tuning the receiver for maximum signal strength, and then reducing
>the signal level (using a well calibrated attenuator on the signal
>generator) to the point at which the signal can just be detected by
>ear. The reading in microvolts from the signal generator is the
>LDS. Of course reducing the bandwidth does affect the LDS. By
>doing an LDS measurement you are measuring the weakest signal that
>the receiver is capable of receiving through the noise generated
>within the receiving system.
>
>Glen, K9STH
>
>Website: http://k9sth.com
>
>
>--- On Tue, 12/9/08, Michael Heim <kd0ar@xxxxxxxxx.xxx> wrote:
>
>From: Michael Heim <kd0ar@xxxxxxxxx.xxx>
>
>Stan makes a good point here, especially for FM sensitivity. I
>worked in the 2-way business for a long time, and typically a sinad
>measurement would be something like the value of microvolts at the
>antenna input for 20 dB of quieting of the receiver. It is
>basically a measurement of FM receiver sensitivity. It will also
>show mis-aligned IF strips and detector, but for the sake of
>arguement in this case, lets say the receiver is functioning
>normally. The goal should be the minimum amount of signal input at
>the antenna connector quiets the receiver 20 dB.
>
>I am not certain that a sinad reading would be of much use on an SSB
>receiver. Typically a similar measurement for an SSB receiver would
>be MDS, or "Minimum detectable Signal", which would be the amount of
>signal that is injected into the antenna connector that produces a
>faint but detectable signal in the receiver.
>
>
>
>
>
>_______________________________________________
>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: 10
Date: Wed, 10 Dec 2008 07:59:29 -0500
From: "Andrew Glasbrenner" <glasbrenner@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51
To: "Alan Sieg WB5RMG" <wb5rmg@xxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <E1FAF3D9F4524FE4A345E22788EDF696@xxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
>
> I would expect anything coming out of FO-29's transponder to show the
> same dopppler rate as the other signals, say the beacon at 435.795 ...
I may be misunderstanding your statement, but transmitters in different
locations on the ground will show different curves. Remember you have
Doppler on both the uplink and downlink too, so the beacon should be
different than any uplinked signal (unless someone was running full Doppler
tuning).
73, Drew KO4MA
------------------------------
Message: 11
Date: Wed, 10 Dec 2008 08:31:13 -0600 (CST)
From: "Alan Sieg WB5RMG" <wb5rmg@xxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51
To: amsat-bb@xxxxx.xxx
Message-ID: <3047.198.119.224.78.1228919473.squirrel@xxx.xxxxxxx.xxx>
Content-Type: text/plain;charset=iso-8859-1
>> I would expect . . . .
>
> I may be misunderstanding your statement, but transmitters in different
> locations on the ground will show different curves. Remember you have
> Doppler on both the uplink and downlink too, so the beacon should be
> different than any uplinked signal (unless someone was running full Doppler
> tuning).
>
> 73, Drew KO4MA
Point well taken Drew - Thanks for your thoughts.
I figured there would be some slight differences in uplink doppler as
a function of ground location relative to TCA. Comparing the other traces
to that of the presumed beacon, there appear to be two slopes - either
matching closely or not. That made me suspect an additional transmitter.
The 145 MHz doppler I would expect to be less pronounced than the 435 ...
I suppose with a really clean display and accurate measurements and .. .. ..
I'm sure that an entire team of experts is involved in this type of
spectral fingerprinting every day. Wish I had more time and tools, it
could be a lot of (admittedly geeky) fun. Unfortunately the only
waterfall I can get is an audio passband-width ala MixW or similar. The
wideband waterfall you showed looks like an interesting tool. I'm envious.
Anyway, changing the uplink solves the immediate issue, but still leaves
the question - could it have been a terrestrial carrier, relayed by FO-29
or possibly a spur from some other transmitter on a different bird...
The fact that you saw energy on that frequency, with doppler could
fairly well rule out a ground-based signal on the 145 MHz uplink, reckon ?
Thanks /;^)
--
<- Licensed in 1976, WB5RMG = Alan Sieg * AMSAT#20554 ->
<- http://www.somenet.net * http://wb5rmg.somenet.net ->
<- http://www.linkedin.com/in/alansieg * My 'Day Job' ->
------------------------------
Message: 12
Date: Wed, 10 Dec 2008 08:44:31 -0600 (CST)
From: "Alan Sieg WB5RMG" <wb5rmg@xxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51
To: amsat-bb@xxxxx.xxx
Message-ID: <3105.198.119.224.78.1228920271.squirrel@xxx.xxxxxxx.xxx>
Content-Type: text/plain;charset=iso-8859-1
>> I would expect ...
> I may be misunderstanding your statement ...
I'm easily mis-understood. Like in my 'just-sent' reply - I said...
> The fact that you saw energy on that frequency, with doppler could
> fairly well rule out a ground-based signal on the 145 MHz uplink, reckon ?
Too few words failed to express what I thought I was thinking.
I'll try again.
The fact that you saw energy on that 435.xx, with doppler could
fairly well rule out a ground-based signal on 435.xx as the source of
interference to the AO-51 uplink. I think that is what you were confirming.
Maybe thats better. Maybe additional coffee may be required ..
/;^)
--
<- Licensed in 1976, WB5RMG = Alan Sieg * AMSAT#20554 ->
<- http://www.somenet.net * http://wb5rmg.somenet.net ->
<- http://www.linkedin.com/in/alansieg * My 'Day Job' ->
------------------------------
Message: 13
Date: Wed, 10 Dec 2008 17:00:26 -0000
From: "Graham Shirville" <g.shirville@xxxxxxxxxx.xxx>
Subject: [amsat-bb] ESEO -The European Student Earth Orbiter -
development gets underway
To: <amsat-bb@xxxxx.xxx>
Message-ID: <EF647FE6234A42F1954F8C0D7750D899@xxxxxxx.xxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi all,
The ESA Education website now has this interesting page concerning the ESEO
satellite mission:
http://www.esa.int/SPECIALS/Education/SEMYQ2STGOF_0.html
Slightly greater technical information is also available on the AMSAT-UK
website here:
http://www.uk.amsat.org/content/view/677/68/
We are not able to be more precise at this time as detailed discussions about
the communications sub-system have still to take place - hopefully we will
have some firm decisions within a few weeks so that design, development and
manufacture of the hardware can commence quickly.
We promise to keep information about this project flowing as much as we can.
best 73 from the AMSAT-UK team!
Graham
G3VZV
------------------------------
Message: 14
Date: Wed, 10 Dec 2008 12:08:55 -0500
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] PCSAT little joy
To: <amsat-bb@xxxxx.xxx>
Cc: 'TAPR APRS Mailing List' <aprssig@xxxx.xxx>
Message-ID: <21CBC666EC1F4B5BA8455F747C6FDEE2@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="US-ASCII"
PCSAT not useable. No joy today.
Like yesterday, on the first ascending pass, we got a successful
logon and restore commands, but they did not hold to the next
rev.
Again, I almost got in on the second pass, but a QRM packet took
the energy I was hoping for. Third pass to the NW was too high
in latitude so she was already dead.
Will try again tomorrow. The only time we can get in is on an
ascending pass, with some solar sun on the south panel, and this
only occurs on an ascending pass, in the local morning in the
Northern Hemisphere, in the winter, between the latitudes of
about 30 to 40 deg and only when the orbit's ground track is in
line with the terminator.
Because PCSAT is magnetically stabilized, the angles work out
just right only for a few minutes a day a few days per winter.
Below that latitude there is not enough sun on the bottom panel
(faces down in the southern hemisphere). Near that latitude
there is some southern sun on this panel, but above that
latitude, the best solar panel is pointing to space.
Bob, WB4APR
------------------------------
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End of AMSAT-BB Digest, Vol 3, Issue 643
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