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CX2SA > SATDIG 10.12.08 03:33l 928 Lines 31293 Bytes #999 (0) @ WW
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Today's Topics:
1. SINAD Vs. Noise Figure Testing (Stan W1LE)
2. Re: SINAD Vs. Noise Figure Testing (Michael Heim)
3. Re: AO-51 (Andrew Glasbrenner)
4. RE : seed II (nader omer)
5. A great day in the Satellite Lab! (Robert Bruninga)
6. Re: AO-51 (n3tl@xxxxxxxxx.xxxx
7. Re: SINAD Vs. Noise Figure Testing (Glen Zook)
8. Re: SINAD Vs. Noise Figure Testing (i8cvs)
9. Re: PCSAT restoration maybe (Nate Duehr)
10. AO-51 uplink changed to 145.880 MHz (Gould Smith)
11. Re: SINAD Vs. Noise Figure Testing (Nate Duehr)
12. Frequency Stabilized Local Oscillators (Stan W1LE)
13. Fw: AO-51 uplink changed to 145.880 MHz (Raul Romero)
----------------------------------------------------------------------
Message: 1
Date: Tue, 09 Dec 2008 15:03:49 -0500
From: Stan W1LE <stanw1le@xxxxxxx.xxx>
Subject: [amsat-bb] SINAD Vs. Noise Figure Testing
To: AMSAT-BB@xxxxx.xxx
Message-ID: <493ECF25.5070106@xxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
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
------------------------------
Message: 2
Date: Tue, 9 Dec 2008 13:48:33 -0800 (PST)
From: Michael Heim <kd0ar@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing
To: Stan W1LE <stanw1le@xxxxxxx.xxx>, AMSAT-BB@xxxxx.xxx
Message-ID: <905012.57390.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
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
------------------------------
Message: 3
Date: Tue, 9 Dec 2008 17:17:38 -0500
From: "Andrew Glasbrenner" <glasbrenner@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51
To: <AMSAT-BB@xxxxx.xxx>
Message-ID: <F60F12621ABF4C63A72868AFCD130C3A@xxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
http://i139.photobucket.com/albums/q305/glasbrenner/FO-29QRM-1.jpg
This is a capture of FO-29 last night that shows the carriers on and
around
the 145.920 uplink. There may be some low level modulation on some of
them.
My guess is they are some of the same long distance phones that were
plaguing AO-27 and SO-50 a few years ago. Observations from myself and
others indicate they go LOS about the time the edge of the footprint
crosses
the mid Atlantic states. Notice the Doppler curve is different between the
three on the right.
Meanwhile, we plan to temporarily move the AO-51 main uplink to 145.88,
our
normal 2nd channel uplink. We'll post a message to the -bb as soon as the
change is made.
73, Drew KO4MA
------------------------------
Message: 4
Date: Tue, 9 Dec 2008 14:28:50 -0800 (PST)
From: nader omer <st2nh@xxxxx.xxx>
Subject: [amsat-bb] RE : seed II
To: amsat-bb@xxxxx.xxx
Message-ID: <231882.94629.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
?
HI? Ed -?KC9GWK
?
I?used Hamscope to decode CW ,HRD for Doppler correction ?with homebrew
CI-V
Then I?decode the received TLM text?by DK3WN's seed II decoder software
http://www.dk3wn.info/sat/afu/sat_seeds.shtml
You need to?type the received TLM at input line to get the sat status.
Take a look at my experiment at
http://www.st2nh.com/satellites
I hope this will help
?
73 -Nader - st2nh
?
?
?
------------------------------
Message: 5
Date: Tue, 9 Dec 2008 17:37:38 -0500
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] A great day in the Satellite Lab!
To: <amsat-bb@xxxxx.xxx>
Message-ID: <FD4935DBD64A4FF48212E427ED139201@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="US-ASCII"
A great day in the Satelliite Lab!
Not only did we hear ISS, and Command up PCSAT, but also on
today's last day of class, we distributed 5 LABsats throught the
campus in undisclosed locations hanging on strings so that the
students had to use Telemetry, and Command, and then the imager
and sun/magnetometer sensors to align the comm links and then
activate the on-board cameras to see where they were.
They were scored on how well they could align their best solar
panel to the sun, and how well they could change attitude to use
the camera.
The first link on this LABsat web page has this final 4 page lab
(a word doc): www.aprs.org/labsats.html that summarizes the
experiments.
Just a lot of fun on the last day of class. Over the semester
they incrementally assemble various components of these TNC
based satellites going through 33 lab periods and exercises
culminating in this final operations scenario.
The icing on the cake was that today was also the first day of
PCSAT return to full sun, and also hearing the ISS crew on voice
all during the same lab. But PCSAT did not hold, and died on
the next orbit for the next class. We will resume restoration
attempts tomorrow.
These LABsats use nothing more than a KPC-3 TNC for all
telemetry, command and control, and an $88 Alinco HT for comms.
They use $75 2.4 GHz TV cameras for their imaging experiments.
Bob, WB4APR
USNA Satellite Lab
------------------------------
Message: 6
Date: Tue, 09 Dec 2008 22:47:14 +0000
From: n3tl@xxxxxxxxx.xxx
Subject: [amsat-bb] Re: AO-51
To: "Andrew Glasbrenner" <glasbrenner@xxxxxxxxxx.xxx>,
<AMSAT-BB@xxxxx.xxx>
Message-ID:
<120920082247.27417.493EF5720002C53900006B1922216128369B0A02D2089B9A019C
04040A0DBF049BCC02@xxx.xxx>
Content-Type: text/plain
Drew,
Thanks a bunch for doing this. Thanks to the whole control team for the
ongoing diligence and efforts.
73 to all,
Tim - N3TL
-------------- Original message from "Andrew Glasbrenner"
<glasbrenner@xxxxxxxxxx.xxx>: --------------
>
> http://i139.photobucket.com/albums/q305/glasbrenner/FO-29QRM-1.jpg
>
> This is a capture of FO-29 last night that shows the carriers on and around
> the 145.920 uplink. There may be some low level modulation on some of them.
> My guess is they are some of the same long distance phones that were
> plaguing AO-27 and SO-50 a few years ago. Observations from myself and
> others indicate they go LOS about the time the edge of the footprint crosses
> the mid Atlantic states. Notice the Doppler curve is different between the
> three on the right.
>
> Meanwhile, we plan to temporarily move the AO-51 main uplink to 145.88, our
> normal 2nd channel uplink. We'll post a message to the -bb as soon as the
> change is made.
>
> 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: 7
Date: Tue, 9 Dec 2008 14:53:17 -0800 (PST)
From: Glen Zook <gzook@xxxxx.xxx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing
To: Stan W1LE <stanw1le@xxxxxxx.xxx>, AMSAT-BB@xxxxx.xxxx
kd0ar@xxxxxxxxx.xxx
Message-ID: <644732.45409.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
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.
------------------------------
Message: 8
Date: Wed, 10 Dec 2008 00:15:53 +0100
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing
To: "Stan W1LE" <stanw1le@xxxxxxx.xxx>, "AMSAT-BB"
<amsat-bb@xxxxx.xxx>
Message-ID: <006301c95a54$15640940$0201a8c0@xxx.xx>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Stan W1LE" <stanw1le@xxxxxxx.xxx>
To: <AMSAT-BB@xxxxx.xxx>
Sent: Tuesday, December 09, 2008 9:03 PM
Subject: [amsat-bb] SINAD Vs. Noise Figure Testing
> 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
Hi Stan, W1LE
Tank you very much to share with us your very interesting report.
I have this letter copied in a file for record.
73" de
i8CVS Domenico
------------------------------
Message: 9
Date: Tue, 09 Dec 2008 16:29:03 -0700
From: Nate Duehr <nate@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: PCSAT restoration maybe
To: amsat-bb@xxxxx.xxxx John Grubbins <n0vse@xxxxxx.xxx>
Message-ID: <493EFF3F.9000307@xxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I was engrossed in other online discussions today and didn't see this
until 4:22 PM Mountain time on the AMSAT-BB list.
I'm pretty sure I can reach Rick KB0VBZ and get his beacon turned off.
Will try anyway.
He's local here (moved west into the mountains, but still "local" I
guess) and one of the former "lead guys" of the Colorado AMSAT Net.
----
John (N0VSE), do you have a current phone number for Rick to see if we
can get his unattended beacon to PCSAT turned off, so the control
stations can get into it successfully and command it?
I can't find one in either of the PC's here at the office, but I might
have something at home in CRA paperwork describing how to reach the
various Net Controllers for the various nets on the repeater system. I
won't be home until well after 6PM Mountain, though.
I'll give you a call too...
----
Nate WY0X
Alan Sieg WB5RMG wrote:
> WB4APR sez:
>> We restored PCSAT on the first orbit this morning at 1315z, but
>> it did not hold. On the next pass at 1500z, the one-good shot
>> at a restoration was consumed by someone still digipeating via
>> W3ADO-1 and his packet took all the power, and our logon was
>> unsuccessful.
>
> Looks like maybe a couple of 'unattended' beacons . . .
> Maybe someone has an email address or phone number for these guys .??.
> They obviously have not gotten the word.
>
>
> (raw packets via http://www.findu.com/cgi-bin/pcsat.cgi?absolute=1 )
> 20081209163914 : KB0VBZ]SYSWUS,W3ADO-1*,qAS,KC0WIF-1:`r[Rl `/]=SYSWUS
>
> 20081209163710 : KB0VBZ]SYSWUS,W3ADO-1*,qAR,WM5Z-1:`r[Rl `/]=SYSWUS
>
> 20081209163435 : KB0VBZ]SYSWUS,W3ADO-1*,qAS,W7XZ-6:`r[Rl `/]=SYSWUS
>
> 20081209163424 :
> W3ADO-1]BEACON,SGATE,qAS,W7XZ-6:T#002,138,136,136,137,214,11111111,0001,1
>
> 20081209163023 :
> W3ADO-1]BEACON,SGATE,qAS,W7XZ-6:T#001,030,089,055,028,214,11111111,0000,1
>
> 20081209145842 : W3ADO]APRS,W3ADO-1*,qAR,KI4HDU-2:Ping...# 1
>
> 20081209145645 :
> VE3FFR]APRS,W3ADO-1*,SGATE,WIDE,qAR,KI4HDU-2:=4416.01N/07629.01W- (UIV32N)
>
> 20081209145532 : KB0VBZ]SYSWUS,W3ADO-1*,qAR,NK8X-3:`r[Rl `/]=SYSWUS
>
> 20081209145437 : KB0VBZ]SYSWUS,W3ADO-1*,qAR,K9DRX:`r[Rl `/]=SYSWUS
>
> 20081209145131 : KB0VBZ]SYSWUS,W3ADO-1*,qAR,XE1KK-1:`r[Rl `/]=SYSWUS
>
> 20081209132317 :
> NODIGI]BEACON,SGATE,qAo,VE2DMA:T#020,159,160,061,209,214,00110111,0111,1
>
> 20081209132121 :
> PCSAT-11]BEACON,SGATE,qAR,KC2APG-1:T#005,136,054,056,063,215,00110111,0000,1
>
>
> Thanks /;^)
------------------------------
Message: 10
Date: Tue, 9 Dec 2008 18:45:22 -0500
From: "Gould Smith" <gouldsmi@xxxxxxxxx.xxx>
Subject: [amsat-bb] AO-51 uplink changed to 145.880 MHz
To: <amsat-bb@xxxxx.xxx>
Message-ID: <7D241029346C4D479EF6200B058D761F@xxxxxxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
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
------------------------------
Message: 11
Date: Tue, 09 Dec 2008 17:01:23 -0700
From: Nate Duehr <nate@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: SINAD Vs. Noise Figure Testing
To: AMSAT-BB@xxxxx.xxx
Message-ID: <493F06D3.8080908@xxxxxxxx.xxx>
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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.
<http://www.repeater-builder.com/tech-info/20dbquieting.html>
Often times folks building repeaters and/or doing other weak-signal
(contesting) work at VHF and above have great documentation and
information that applies just as much to satellite operation.
It's always worth "popping our heads up" from our own little RF worlds
and looking around a bit once in a while. (Like Prairie Dogs.)
I agree with you, a SINAD measurement on an SSB receiver is kinda not
the right idea. It'll show you something, but what... I'm not quite
sure. It CAN be used for a comparison measurement for changes, though.
Thus, the best thing about learning how to make a SINAD measurement,
measuring or at least calculating Noise Figure, or WHATEVER measurements
is this:
You can make CHANGES and see if you made things better or worse.
Why is that important?
It changes your hobby from subjective ("that sounds better") to
quantitative ("I made my home VHF setup 3dB more sensitive on VHF
today"), which is a sign you're trying harder than the majority to have
a great receiver setup and antenna system.
Another useful measurement is to find the receiver's sensitivity while
injecting the test signal while connected to an outside antenna, after
doing it without... to see how local noise/intermod/etc., affects your
receiver.
A home-made "Iso-Tee" set up for a known amount of loss on your test
setup, or a directional coupler with a known amount of loss are needed
for that test.
Nate WY0X
------------------------------
Message: 12
Date: Tue, 09 Dec 2008 19:29:39 -0500
From: Stan W1LE <stanw1le@xxxxxxx.xxx>
Subject: [amsat-bb] Frequency Stabilized Local Oscillators
To: AMSAT-BB@xxxxx.xxx
Cc: apollo@xxxx.xxx
Message-ID: <493F0D73.6090704@xxxxxxx.xxx>
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Hello The Net:
Steve Hicks, N5AC, is designing frequency stabilized local oscillators
that can be used
in the (Down East Microwave Inc.) DEMI transverters or RX only, block
down converters.
Frequency stability is achieved by locking to a external 10 MHz house
reference standard
which could be a GPS disciplined oscillator, a OCXO, or a compact Rb
reference oscillator.
The Trimble Thunderbolt GPSDO is a very popular 10 MHz reference.
We could use your help in disclosing what RFs and IFs you are using for
present and proposed satellite
transponders. Then we can calculate the local oscillator frequencies
needed for the DEMI transverters.
This stabilized LO can be used in place of the DEMI standard MICROLO pcb.
The MICROLO pcb is used on transverters 900 MHz and higher.
Most will use a "low beat" RF/IF mixer scheme, but if you use a "high
beat" mixer scheme, let us know.
A new design by Steve will allow factory programming for 256 different
frequencies, in memory.
Just change the jumpers for the pre-programmed LO freq you need for your
satellite application.
The objective of this inquiry is to determine what those 256 programmed
frequencies should be.
The DEMI transverter uses 2 pcbs, the MICROLO pcb and the transverter pcb.
The transverter pcb multiplies the LO from the MICROLO pcb then mixes it.
The transverter pcb LO multiplier on the 2,304 band is X2, for 3,456 MHz
band is X3,
for 5,760 MHz band is X5, for 10,368 MHz band is X9
Examples: (low beat mixer scheme)
2,401.0 MHz RF, RX only, block down converter with a 145.0 MHz IF
output, low beat,
2,401.0 - 145.0 = 2,256.0 MHz, divided by 2 = 1128.0 MHz
2,400.0 - 432.0 = 1,968 MHz, divided by 2 = 984.0 MHz
2400.0 - 50.0 = 2,350.0 MHz, divided by 2 = 1,175.0 MHz
2439.0 - 144 = 2,239.0 MHz, divided by 2 = 1,147.5 MHz
3,400.0 MHz RF downlink with a 144 MHz IF: 3400.0 - 144.0 = 3256.0 MHz,
divided by 3 = 10.85.333 MHz
3,400.0 - 432.0 = 2,968.0 MHz, divided by 3 = 989.333 MHz
5,668.0 MHx RF uplink with a 144 MHz IF: 5668 - 144 = 5,524 MHz
10,451.0 MHz RF downlink with a 144 MHz IF, LO =
10,451.0 - 144.0 = 10,307.0 MHz, divided by 9 = 1145.222 MHz
for a 432 MHz IF, 10,451.0 - 432.0 = 10,019.0 MHz, divided by 9 =
1,113.222 MHz
10,386.0 MHz RF for terrestrial ops, 145.0 MHz IF,
10,368 - 145 = 10,223 MHz, divide by 9 = 1,135.888 MHz
10,368.0 MHz RF with 144.0 MHz IF, 10,368 - 144 = 10,224 MHz, divided by
9 = 1,136.0 MHz
Look to: http://www.n5ac.com/blog/?page_id=19 for the N5AC
products
Look to: http://www.downeastmicrowave.com/A32.htm for more
details on the synthesized LO pcb
I will summarized your RF/IF combinations.
(Hopefully there are not too many typos here)
Stan, W1LE FN41sr Cape Cod
------------------------------
Message: 13
Date: Tue, 9 Dec 2008 22:20:54 -0300
From: "Raul Romero" <ce3soc@xxxxx.xxx>
Subject: [amsat-bb] Fw: AO-51 uplink changed to 145.880 MHz
To: "Amsat-BB@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Message-ID: <0C6755D57F61469C88FC144AB55C6788@xxxxxxxx>
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its ok up 145.880 up 435.300 DW
73 Raul
CA3SOC
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> ----- Original Message -----
> From: "Gould Smith" <gouldsmi@xxxxxxxxx.xxx>
> To: <amsat-bb@xxxxx.xxx>
> Sent: Tuesday, December 09, 2008 8:45 PM
> Subject: [amsat-bb] AO-51 uplink changed to 145.880 MHz
>
>
>> 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.
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>
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End of AMSAT-BB Digest, Vol 3, Issue 642
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