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CX2SA > SATDIG 28.07.20 16:00l 641 Lines 20367 Bytes #999 (0) @ WW
BID : AMSATBB15306
Read: GUEST
Subj: AMSAT-BB-digest V15 306
Path: IW8PGT<IZ3LSV<IR1UAW<IK1NHL<CX2SA
Sent: 200728/1356Z @:CX2SA.SAL.URY.SOAM #:36225 [Salto] FBB7.00e $:AMSATBB15306
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. AMSAT Awards Update (Bruce)
2. (no subject) (Jim Davis)
3. Signal to Noise ratio (Albert Ozias)
4. Re: Signal to Noise ratio (Greg D)
5. Re: Easy and FUN Antenna Projects (Jeff Moore)
6. Re: Signal to Noise ratio (Zach Metzinger)
7. Re: Signal to Noise ratio (W3AB/GEO)
8. Re: Signal to Noise ratio (Leffke, Zachary)
9. Re: Searching AMSAT Archives Using Google 'Site:' Tool
(Clint Bradford)
10. Turning on a light (Michael Tondee)
11. Re: Signal to Noise ratio (Mike Seguin)
----------------------------------------------------------------------
Message: 1
Date: Mon, 27 Jul 2020 17:21:31 -0500
From: Bruce <kk5do@????.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] AMSAT Awards Update
Message-ID: <d29702bc-da06-5095-a995-023726239620@????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
Here are the awards issued in the last two months.
AMSAT Satellite Communicators Award for making their first satellite QSO
Anthony Rizi, NR1Z
Edward Hartzel, W3HMK
James Brooks, KB3EFH
Vilanova University ARC, W3YP
Robin Shelley, G8VVY
------
AMSAT Communications Achievement Award
Anthony Rizi, NR1Z, #628
Angus Alexander, KJ7KOJ, #629
------
AMSAT Sexagesimal Satellite Communications Achievement Award
Stephan Greene, KS1G, #187
Casey Tucker, KI7UNJ, #188
------
AMSAT South Africa Satellite Communications Achievement Award
Anthony Rizi, NR1Z, #US230
Casey Tucker, KI7UNJ, #US231
Angus Alexander, KJ7KOJ, #US232
------
AMSAT Robert W. Barbee Jr., W4AMI Award (1,000-4,000)
Mitchell Whitman, N4DCW, #110
Mark Johns, K0JM, #111
David Hoffman, KL1XI, #112
Phillip Sauvey, AK7DD, #113
Dennis Love, N7EGY, #114
Kell Bodholt, KI7UXT, upgrade to 2000
------
AMSAT Rover Award
Rover???????? Call
=====???????? ========
#054????????? N0TEL
#055????????? AK7DD
#056????????? KE0WPA
------
GridMaster Award
GridMaster???????? Call
==========???????? ========
#11??????????????? KO4MA
#12??????????????? N4UFO
#13??????????????? W5CBF
To see all the awards visit http://www.amsat.org and click on
Services then Awards.
73...bruce
--
Bruce Paige, KK5DO
AMSAT Director Contests and Awards
AMSAT Board Member 2016-2020
ARRL Awards Field Checker (WAS, 5BWAS, VUCC), VE
Houston AMSAT Net - Wed 0100z on Echolink - Conference *AMSAT*
Also live streaming MP3 at http://www.amsatnet.com
Podcast at http://www.amsatnet.com/podcast.xml or iTunes
Latest satellite news on the ARRL Audio News
http://www.arrl.org
AMSAT on Twitter http://www.twitter.com/amsat
------------------------------
Message: 2
Date: Mon, 27 Jul 2020 23:14:05 +0000 (UTC)
From: Jim Davis <ab5xs@?????.???>
To: <amsat-bb@?????.???>
Subject: [amsat-bb] (no subject)
Message-ID:
<E8AB86AF346920BA.BF6B420A-5C2C-4B77-BB13-68F49624660B@????.???????.???>
Content-Type: text/plain; charset=us-ascii
Department of Redundancy Dept.
------------------------------
Message: 3
Date: Tue, 28 Jul 2020 00:04:28 +0000
From: Albert Ozias <alozias@????.???>
To: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: [amsat-bb] Signal to Noise ratio
Message-ID:
<MWHPR02MB2414F908EA7E237454A74A99C0720@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="iso-8859-1"
Do preamps improve the signal to noise ratio or simply amplify signal and
noise?
------------------------------
Message: 4
Date: Mon, 27 Jul 2020 17:13:02 -0700
From: Greg D <ko6th.greg@?????.???>
To: Albert Ozias <alozias@????.???>, "amsat-bb@?????.????
<amsat-bb@?????.???>
Subject: Re: [amsat-bb] Signal to Noise ratio
Message-ID: <a65a23f6-4918-c7a4-bab5-b7c00bc95e1c@?????.???>
Content-Type: text/plain; charset=UTF-8
"yes"
An amplifier can only amplify what it's fed, both signal and noise, and
adds a little noise of its own. If it's positioned at the antenna it
will work a lot better than if it's at the other end of the feed line at
the radio. You want to amplify the signal before the noise induced by
the coax can get in there.
Greg KO6TH
Albert Ozias via AMSAT-BB wrote:
> Do preamps improve the signal to noise ratio or simply amplify signal and
noise?
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
expressed
> are solely those of the author, and do not reflect the official views of
AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 5
Date: Mon, 27 Jul 2020 17:34:23 -0700
From: Jeff Moore <tnetcenter@?????.???>
To: Roy Dean <royldean@?????.???>, Amsat BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Easy and FUN Antenna Projects
Message-ID:
<CALx_moSA2mTAjoMBjsQjW9_7ChUoTQexr-993hOw=_3rgu0ELQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Who's "CLOGGING" the Internet now with this garbage??
Jeff Moore -- KE7ACY
On Mon, Jul 27, 2020 at 5:11 AM Roy Dean via AMSAT-BB <amsat-bb@?????.???>
wrote:
> Ok, Clint. Then I'll call it as I see it: Please stop clogging the
> internet with your personal web page propaganda.
>
>
> --Roy
> K3RLD
>
>
> > Roy Dean:
> >
> > You need a little education.
> >
> > ?Spam? is irrelevant or inappropriate messages sent indiscriminately to
> all audiences.
> >
> > ?Advertising? is the activity or profession of producing ads for
> commercial products or services.
> >
> > What do I offer on my Web site? Information. Free-of-charge. No product
> nor service that
> > benefits me personally.
> >
> > SO ? What I did - post ANTENNA PROJECTS to groups entitled ?antennas,?
> ?satellites,? and
> > ?DIY Projects? is really quite an appropriate use of the ?Net. No spam.
> Target audiences.
> >
> > Clint Bradford K6LCS
> >
> >
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 6
Date: Mon, 27 Jul 2020 19:37:36 -0500
From: Zach Metzinger <zmetzing@?????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Signal to Noise ratio
Message-ID: <ac3323bb-3889-8135-cdfb-ffadd4989c5c@?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
On 2020-07-27 19:04, Albert Ozias via AMSAT-BB wrote:
> Do preamps improve the signal to noise ratio or simply amplify signal and
noise?
Hello Albert,
No, a preamp cannot improve the SNR of the signal at its input terminal(s).
All amplifiers add noise to the signal that they are amplifying, and
that added noise can't be removed.
That's the key point: An analog signal's SNR only goes down, never up.
The RF energy intercepted by your antenna is immediately combined with
other sources of noise, mostly thermal noise, on the way to your radio
for eventual demodulation.
A LNA (low-noise amplifier) does this while adding a minimum of noise to
the signal. This prevents the SNR from degrading to a point where useful
information can no longer be recovered from the demodulated signal, be
it analog (voice) or digital (data).
Also note that your radio also adds its own measure of noise to the
incoming signal, degrading the SNR. However, if the SNR has been
preserved from the antenna through the LNA and coax, then the noise that
the radio adds will not degrade the SNR appreciably.
This topic is involved and sometimes complex, but rewarding!
--- Zach
N0ZGO
------------------------------
Message: 7
Date: Mon, 27 Jul 2020 20:10:07 -0700
From: W3AB/GEO <w3ab@?????.???>
To: Zach Metzinger <zmetzing@?????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Signal to Noise ratio
Message-ID: <d77e6ab3-aa0c-44da-8937-7f04367b910b@?????.???>
Content-Type: text/plain; charset=UTF-8
To add to the excellent info Zach gave, the LNA should be mounted as close
to the antenna as possible.
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
On Jul 27, 2020, 17:39, at 17:39, Zach Metzinger via AMSAT-BB
<amsat-bb@?????.???> wrote:
>On 2020-07-27 19:04, Albert Ozias via AMSAT-BB wrote:
>> Do preamps improve the signal to noise ratio or simply amplify signal
>and noise?
>
>Hello Albert,
>
>No, a preamp cannot improve the SNR of the signal at its input
>terminal(s).
>
>All amplifiers add noise to the signal that they are amplifying, and
>that added noise can't be removed.
>
>That's the key point: An analog signal's SNR only goes down, never up.
>
>The RF energy intercepted by your antenna is immediately combined with
>other sources of noise, mostly thermal noise, on the way to your radio
>for eventual demodulation.
>
>A LNA (low-noise amplifier) does this while adding a minimum of noise
>to
>the signal. This prevents the SNR from degrading to a point where
>useful
>information can no longer be recovered from the demodulated signal, be
>it analog (voice) or digital (data).
>
>Also note that your radio also adds its own measure of noise to the
>incoming signal, degrading the SNR. However, if the SNR has been
>preserved from the antenna through the LNA and coax, then the noise
>that
>the radio adds will not degrade the SNR appreciably.
>
>This topic is involved and sometimes complex, but rewarding!
>
>--- Zach
>N0ZGO
>
>_______________________________________________
>Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>to all interested persons worldwide without requiring membership.
>Opinions expressed
>are solely those of the author, and do not reflect the official views
>of AMSAT-NA.
>Not an AMSAT-NA member? Join now to support the amateur satellite
>program!
>Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 8
Date: Tue, 28 Jul 2020 13:28:49 +0000
From: "Leffke, Zachary" <zleffke@??.???>
To: AMSAT <AMSAT-BB@?????.???>
Subject: Re: [amsat-bb] Signal to Noise ratio
Message-ID:
<MN2PR05MB70379E704E3B65434DF0B375DF730@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="utf-8"
An EXCELLENT topic of conversation, and one I keep circling back to over and
over and over.......
But to keep this one short, if interested in the math behind why a preamp
close to the antenna terminals is important, I invite you to read this
article from Wikipedia: https://en.wikipedia.org/wiki/Friis_formulas_for_noise
The key point here is the G1 value (gain of first device) is in the
denominator of every term in the equation......this is why you want a high
gain preamp, to keep those terms small. The Noise Factor of the first
device, F1, (linear version of noise figure) is the first term in the
equation and is NOT normalized by any other gain term.......this is why you
want a low noise figure for the preamp. The first device in the above
equation tends to set the *system* noise figure.....this is why you want
that first device to be a high gain, low noise amplifier. The antenna is
not included in the above equation, but requires some more description to
get to *system* noise figure (required for things like link budget analysis
and computing SNR).
The Friis noise equation gives you what I like to call the 'component' noise
factor (which can be converted to noise figure and then to noise
temperature), referred to the INPUT of the preamp (output of the antenna).
Then there's the antenna noise temperature (insert lots of other math
here.....a good first cut for antenna noise, without doing all the
integrals....is around 200 Kelvin, a bit less than 'warm earth' at 290K).
'component' noise temp, plus 'antenna' noise temp = 'system' noise temp
(all in Kelvin). system noise temp can then be converted to system noise
figure, NF_sys (dB).
When computing noise floor (aka Minimum detectable signal, MDS), the
equation is: MDS [dBm]= -174 dbm/hz + 10log10(receiver/signal bandwidth in
Hz) + NF_sys [dB].
As a quick side note, it is common to refer things to the antenna terminals.
This is somewhat arbitrary, but its important that the reference point be
tracked. This is also why you do not include things like preamp gain, coax
loss, IF gain, etc. in the figure of merit calculation (also galled G/T).
The Friis Equation above already accounts for all of that in the computation
that is referred to the input of the preamp. So once you get noise
temperature, all you have to do is take antenna gain over the *system* noise
temperature to get *system* G/T. G/T is a simple way to compare one ground
station to another, whoever has a large G/T has a larger SNR (and it doesn't
matter how they achieved that G/T....whether they have cryogenic LNAs, or
huge antenna gain......G/T is G/T). If your station has 3 dB more G/T than
my station, you've got 3 dB more SNR than my station.
There's lots of details I skipped.....but fun topic! Excellent question. I
once asked a similar question (about Eb/No....digital version of SNR) on a
research contract of some of my colleagues...and got to see three PhDs argue
over what the 'meaning' of SNR (and Eb/No) is for over an hour......super
informative and fun to watch!
-Zach, KJ4QLP
--
Research Associate
Aerospace & Ocean Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of W3AB/GEO via AMSAT-BB
Sent: Monday, July 27, 2020 11:10 PM
To: Zach Metzinger <zmetzing@?????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Signal to Noise ratio
To add to the excellent info Zach gave, the LNA should be mounted as close
to the antenna as possible.
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
On Jul 27, 2020, 17:39, at 17:39, Zach Metzinger via AMSAT-BB
<amsat-bb@?????.???> wrote:
>On 2020-07-27 19:04, Albert Ozias via AMSAT-BB wrote:
>> Do preamps improve the signal to noise ratio or simply amplify signal
>and noise?
>
>Hello Albert,
>
>No, a preamp cannot improve the SNR of the signal at its input
>terminal(s).
>
>All amplifiers add noise to the signal that they are amplifying, and
>that added noise can't be removed.
>
>That's the key point: An analog signal's SNR only goes down, never up.
>
>The RF energy intercepted by your antenna is immediately combined with
>other sources of noise, mostly thermal noise, on the way to your radio
>for eventual demodulation.
>
>A LNA (low-noise amplifier) does this while adding a minimum of noise
>to
>the signal. This prevents the SNR from degrading to a point where
>useful
>information can no longer be recovered from the demodulated signal, be
>it analog (voice) or digital (data).
>
>Also note that your radio also adds its own measure of noise to the
>incoming signal, degrading the SNR. However, if the SNR has been
>preserved from the antenna through the LNA and coax, then the noise
>that
>the radio adds will not degrade the SNR appreciably.
>
>This topic is involved and sometimes complex, but rewarding!
>
>--- Zach
>N0ZGO
>
>_______________________________________________
>Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>to all interested persons worldwide without requiring membership.
>Opinions expressed
>are solely those of the author, and do not reflect the official views
>of AMSAT-NA.
>Not an AMSAT-NA member? Join now to support the amateur satellite
>program!
>Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________
Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
to all interested persons worldwide without requiring membership. Opinions
expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 9
Date: Tue, 28 Jul 2020 06:34:46 -0700
From: Clint Bradford <clintbradford@???.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Searching AMSAT Archives Using Google 'Site:'
Tool
Message-ID: <4C8630CD-4B23-4246-ABC1-B5C3C19A2F33@???.???>
Content-Type: text/plain; charset=utf-8
Hmmm ... never tried that. List messages are included in regular Google
searches - but I am not sure if the more current years are included, or just
the ones on the ?old system? are being searched.
Clint Bradford K6LCS
Sent from my iPhone
------------------------------
Message: 10
Date: Mon, 27 Jul 2020 20:10:13 -0400
From: Michael Tondee <mat_62@???????.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] Turning on a light
Message-ID: <dd593a1c-93fe-6266-6637-ea38d9097634@???????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
The AMSAT membership has obviously long been in the dark about how the
organization operates and what's involved in the finances and various
decision making processes. Michelle and Patrick are trying to turn on a
light and get some clarity and transparency. Despite the rancor it's
caused and the fact that it's painful, it's becoming more and more
undeniable how necessary it was and I fail to see how it's a bad thing.
I'd love to go back to discussing satellites too but sometimes you have
to go through the bad to get to the good. That's life.
73,
Michael, W4HIJ
------------------------------
Message: 11
Date: Tue, 28 Jul 2020 09:45:50 -0400
From: Mike Seguin <n1jez@?????????????????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Signal to Noise ratio
Message-ID:
<bd42798a-ac8c-cdf6-2705-910badf852ee@?????????????????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
And here's a short text from Ian, GM3SEK about adjusting preamp gain. No
test equipment needed. Too much gain can be a bad thing...
====
Here's a method that requires no test equipment at all. It comes from
G4DGU, who designed all the original muTek transverters and outboard
preamps to have adjustable gain. This method uses the sharp threshold
effect of FM detectors at low S/N ratios, and it allows you to optimize
the preamp/transverter gain for your local band noise conditions.
1. Turn the transverter/preamp gain well up.
2. Find a very weak but steady unmodulated carrier (off-air, not from a
signal generator or a local birdie). Rotate the antenna until you can
just detect the signal in FM mode.
3. Reduce the preamp/transverter gain until you hear the noise increase.
The FM threshold is sensitive to a small fraction of a dB in S/N.
4. Increase the gain just a little,to the point where you can't hear the
quieting improve much.
5. Switch back to a real DX mode.
Remember that every dB of unnecessary preamp/transverter gain will
probably subtract almost 1dB from your system intermod intercept!
The penalty of adjusting the gain correctly is that you're living just
above the "knee" where S/N will begin to deteriorate rapidly if
something changes. It's worthwhile to repeat this test every few months
- especially just before a contest.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
On 7/28/2020 9:28 AM, Leffke, Zachary via AMSAT-BB wrote:
> An EXCELLENT topic of conversation, and one I keep circling back to over
and over and over.......
>
> -Zach, KJ4QLP
--
73,
Mike, N1JEZ
"A closed mouth gathers no feet"
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@?????.???.
AMSAT-NA makes this open forum available to all interested persons worldwide
without requiring membership. Opinions expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT member? Join now to support the amateur satellite program!
https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 15, Issue 306
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