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CX2SA > SATDIG 07.03.20 13:45l 887 Lines 34380 Bytes #999 (0) @ WW
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Sent: 200307/1139Z @:CX2SA.SAL.URY.SOAM #:26348 [Salto] FBB7.00e $:AMSATBB1571
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: Center of the rotator (Scott)
2. Re: Center of the rotator (Thomas Schaefer)
3. Lower your power!!! (Joe KD2NFC)
4. Re: Lower your power!!! (Jeff Johns)
5. Re: Lower your power!!! (Michael Walker)
6. Re: Lower your power!!! (Mark D. Johns)
7. Re: Lower your power!!! (Gary)
8. Re: Lower your power!!! (Zach Metzinger)
9. Fwd: [Nouvel article] Rencontre Spatial Radioamateur 7 et 8
mars 2020 ? Diffusion des conf?rences sur Internet & sur le
satellite g?ostationnaire QO 100 (christophe.mcr)
10. Re: Lower your power!!! (Hasan al-Basri)
----------------------------------------------------------------------
Message: 1
Date: Fri, 6 Mar 2020 13:56:13 -0500
From: "Scott" <scott23192@?????.???>
To: <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Center of the rotator
Message-ID: <2C3B0E0236AC4C7D9186CA2965B70257@???????>
Content-Type: text/plain; format=flowed; charset="UTF-8";
reply-type=original
I'm not familiar with your exact hardware, but I use PSTRotator with a
G-5500 and practically speaking, there is no "stop".
Depending on whether the path of a satellite will cross the 0 or 180 degree
compass mark, PSTRotator will auto-set to "flip" mode and adjust the
pointing accordingly.
If needed to avoid the hardware limit of my rotator, PSTRotator will flip
the elevation of my array 180 degrees and reverse the AZ settings so that
the end result is proper tracking throughout the entire pass while avoiding
the rotation stop of the AZ rotator. Sure is nice to never have to give any
thought to that issue when planning a pass.
-Scott, K4KDR
===========================
-----Original Message-----
From: Mark D. Johns via AMSAT-BB
Sent: Friday, March 06, 2020 1:24 PM
To: Thomas Schaefer
Cc: amsat-bb
Subject: Re: [amsat-bb] Center of the rotator
For satellites, there's no perfect direction for the azimuth stop,
because most LEOs in near-polar orbits tend to pass along an arc to
the east or or an arc to the west, and only relatively rarely right
overhead.
For me, living in Minneapolis, I use a north stop because a lot of
things happen south of me. For example, passes of CAS-4A and CAS-4B
almost always go from west-southwest, through south, and on to the
southeast from my QTH. A south stop would require a flip or a complete
turn for every CAS-4x pass.
For you, down in Florida, a 180 degree stop may be of slight
advantage. You'd probably have to do a plot of several birds you plan
to use over a period of a couple weeks, and see how many of those
passes would require flipping.
--
Mark D. Johns, K?JM
AMSAT Ambassador & News Service Editor
Brooklyn Park, MN USA EN35hd
-----------------------------------------------
"Heaven goes by favor; if it went by merit,
you would stay out and your dog would go in."
---Mark Twain
On Fri, Mar 6, 2020 at 11:50 AM Thomas Schaefer via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> Hello all. Please forgive the novice question but I am new to dealing with
> Az/El rotator systems for satellites (always been the Armstrong method).
>
> I am finishing up the planning for my rotators. On my bench, I have my Az
> rotator and my elevations rotator (separate units ?both AlfaSpids). I am
> using a Green Heron RT21 AzEl controller.
>
> I have PSTRotator in between SatPC32 and the Green Heron since SatPC32
> does not control the GH AzEl directly.
>
> When I was testing, I went though a pass and when the Azimuth direction
> was 0, the rotator spun all away around since 0 was the bottom. That is no
> doubt a configuration point but it brings me to my question.
>
> When I have used various rotor controllers for HF beams, 180 degrees is
> always the bottom which works for us in the northern Hemisphere. But with
> the current fleet of workable satellites, is there a direction that makes
> more sense to use at the ?bottom? of the rotator? I can rotate the
> AlfaSpid more than 360 degrees allowing for the coax loop. Is that the
> generally preferred way for maximum flexibility if one?s rotor supports
> it? Put another way, if I pick 180 as the ?bottom?, will I have as many
> passes that the rotator will have to turn all the way around to get from
> 179 degrees to 181 degrees as I would have to go from 359 degrees to 1
> degree?
>
> I am also using the Az rotator for a 6m beam so the usual sweep of 180 to
> 180 in a continuous arc is desirable but I was curious if I should allow
> an extra 90 degrees (to 470) for flexibility. The Green Heron will take
> care of not going too far from where it is programmed even though the
> AlfaSpid does not have limit switches in the Az rotator (but does in the
> elevation rotator).
>
> I hope that makes sense.
>
> Thanks,
>
> Tom NY4I
> Tom Schaefer, NY4I
> Blog: www.ny4i.com
> Madeira Beach, FL (Grid: EL87ot)
------------------------------
Message: 2
Date: Fri, 6 Mar 2020 14:00:58 -0500
From: Thomas Schaefer <ny4i@????.???>
To: Scott <scott23192@?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Center of the rotator
Message-ID: <84DC62FD-90D3-4841-B996-240F66EEC623@????.???>
Content-Type: text/plain; charset=utf-8
Unless you have a wireless connection between your radio and antenna, the
coax is usually the stop for the loop.
Tom Schaefer, NY4I
Blog: www.ny4i.com
Madeira Beach, FL (Grid: EL87ot)
> On Mar 6, 2020, at 1:56 PM, Scott via AMSAT-BB <amsat-bb@?????.???> wrote:
>
> I'm not familiar with your exact hardware, but I use PSTRotator with a
G-5500 and practically speaking, there is no "stop".
>
> Depending on whether the path of a satellite will cross the 0 or 180
degree compass mark, PSTRotator will auto-set to "flip" mode and adjust the
pointing accordingly.
>
> If needed to avoid the hardware limit of my rotator, PSTRotator will flip
the elevation of my array 180 degrees and reverse the AZ settings so that
the end result is proper tracking throughout the entire pass while avoiding
the rotation stop of the AZ rotator. Sure is nice to never have to give any
thought to that issue when planning a pass.
>
> -Scott, K4KDR
>
> ===========================
>
>
>
> -----Original Message----- From: Mark D. Johns via AMSAT-BB
> Sent: Friday, March 06, 2020 1:24 PM
> To: Thomas Schaefer
> Cc: amsat-bb
> Subject: Re: [amsat-bb] Center of the rotator
>
> For satellites, there's no perfect direction for the azimuth stop,
> because most LEOs in near-polar orbits tend to pass along an arc to
> the east or or an arc to the west, and only relatively rarely right
> overhead.
>
> For me, living in Minneapolis, I use a north stop because a lot of
> things happen south of me. For example, passes of CAS-4A and CAS-4B
> almost always go from west-southwest, through south, and on to the
> southeast from my QTH. A south stop would require a flip or a complete
> turn for every CAS-4x pass.
>
> For you, down in Florida, a 180 degree stop may be of slight
> advantage. You'd probably have to do a plot of several birds you plan
> to use over a period of a couple weeks, and see how many of those
> passes would require flipping.
> --
> Mark D. Johns, K?JM
> AMSAT Ambassador & News Service Editor
> Brooklyn Park, MN USA EN35hd
> -----------------------------------------------
> "Heaven goes by favor; if it went by merit,
> you would stay out and your dog would go in."
> ---Mark Twain
>
> On Fri, Mar 6, 2020 at 11:50 AM Thomas Schaefer via AMSAT-BB
> <amsat-bb@?????.???> wrote:
>>
>> Hello all. Please forgive the novice question but I am new to dealing
with Az/El rotator systems for satellites (always been the Armstrong method).
>>
>> I am finishing up the planning for my rotators. On my bench, I have my Az
rotator and my elevations rotator (separate units ?both AlfaSpids). I am
using a Green Heron RT21 AzEl controller.
>>
>> I have PSTRotator in between SatPC32 and the Green Heron since SatPC32
does not control the GH AzEl directly.
>>
>> When I was testing, I went though a pass and when the Azimuth direction
was 0, the rotator spun all away around since 0 was the bottom. That is no
doubt a configuration point but it brings me to my question.
>>
>> When I have used various rotor controllers for HF beams, 180 degrees is
always the bottom which works for us in the northern Hemisphere. But with
the current fleet of workable satellites, is there a direction that makes
more sense to use at the ?bottom? of the rotator? I can rotate the AlfaSpid
more than 360 degrees allowing for the coax loop. Is that the generally
preferred way for maximum flexibility if one?s rotor supports it? Put
another way, if I pick 180 as the ?bottom?, will I have as many passes that
the rotator will have to turn all the way around to get from 179 degrees to
181 degrees as I would have to go from 359 degrees to 1 degree?
>>
>> I am also using the Az rotator for a 6m beam so the usual sweep of 180 to
180 in a continuous arc is desirable but I was curious if I should allow an
extra 90 degrees (to 470) for flexibility. The Green Heron will take care of
not going too far from where it is programmed even though the AlfaSpid does
not have limit switches in the Az rotator (but does in the elevation rotator).
>>
>> I hope that makes sense.
>>
>> Thanks,
>>
>> Tom NY4I
>> Tom Schaefer, NY4I
>> Blog: www.ny4i.com
>> Madeira Beach, FL (Grid: EL87ot)
>
> _______________________________________________
> 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: 3
Date: Fri, 6 Mar 2020 16:17:50 -0500
From: Joe KD2NFC <kd2nfc@?????.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] Lower your power!!!
Message-ID: <DAE0C5D0-FBBA-4B55-BF6E-A1FA71037456@?????.???>
Content-Type: text/plain; charset=utf-8
I was just on AO-7 and was told to lower my power from more then one person.
Sorry about that folks, just getting adjusted here, please be patient with a
satellite beginner.
Now that we are here I was curious what a lot of power in does to the linear
birds, does it ruin the passband for others? Also how much is a good amount
of power to start with or one shouldn?t exceed?
FM birds probably have similar operating rules as well right. I?m here to
learn :)
Joe
KD2NFC
Sent from my iPhone
------------------------------
Message: 4
Date: Fri, 6 Mar 2020 15:21:53 -0600
From: Jeff Johns <jeff30339@?????.???>
To: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Lower your power!!!
Message-ID: <6F9EF7D5-8CA9-4619-A76F-1D8AF4D43F92@?????.???>
Content-Type: text/plain; charset=utf-8
How much power were you using? SSB or CW? On SSB I usually use 2.5 watts and
haven?t had any issues making contacts.
Jeff WE4B
> On Mar 6, 2020, at 3:19 PM, Joe KD2NFC via AMSAT-BB <amsat-bb@?????.???>
wrote:
>
> ?I was just on AO-7 and was told to lower my power from more then one
person. Sorry about that folks, just getting adjusted here, please be
patient with a satellite beginner.
>
> Now that we are here I was curious what a lot of power in does to the
linear birds, does it ruin the passband for others? Also how much is a good
amount of power to start with or one shouldn?t exceed?
>
> FM birds probably have similar operating rules as well right. I?m here to
learn :)
>
> Joe
> KD2NFC
>
>
> Sent from my iPhone
> _______________________________________________
> 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: Fri, 6 Mar 2020 16:23:55 -0500
From: Michael Walker <va3mw@??????????.???>
To: Joe KD2NFC <kd2nfc@?????.???>, amsat-bb@?????.???
Subject: Re: [amsat-bb] Lower your power!!!
Message-ID: <34DE68C8-5D8A-405A-BC33-B14F0B5DD7FE@??????????.???>
Content-Type: text/plain; charset=utf-8
Hi Joe
Once you hear yourself start dialling down your power until you don?t hear
yourself.
then, increase it slightly.
Make sure you were wearing headphones.
Mike va3mw
> On Mar 6, 2020, at 4:18 PM, Joe KD2NFC via AMSAT-BB <amsat-bb@?????.???>
wrote:
>
> ?I was just on AO-7 and was told to lower my power from more then one
person. Sorry about that folks, just getting adjusted here, please be
patient with a satellite beginner.
>
> Now that we are here I was curious what a lot of power in does to the
linear birds, does it ruin the passband for others? Also how much is a good
amount of power to start with or one shouldn?t exceed?
>
> FM birds probably have similar operating rules as well right. I?m here to
learn :)
>
> Joe
> KD2NFC
>
>
> Sent from my iPhone
> _______________________________________________
> 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: Fri, 6 Mar 2020 15:26:30 -0600
From: "Mark D. Johns" <mjohns+K0JM@??????.???>
To: Joe KD2NFC <kd2nfc@?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Lower your power!!!
Message-ID:
<CAHKCqnCvrY-5cK6XgF=oXtL7K6=s+9ezjxvOkcTb6XtuG1tiOQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
AO-7 is a sick old bird. You can literally break it with too much
power. Not just affect other operators, but force it to change modes
so that no one can use it. Maybe better to start with a different
linear until you get your feet wet. And anything beyond 5 watts if
overkill. Usually less.
--
Mark D. Johns, K?JM
AMSAT Ambassador & News Service Editor
Brooklyn Park, MN USA EN35hd
-----------------------------------------------
"Heaven goes by favor; if it went by merit,
you would stay out and your dog would go in."
---Mark Twain
On Fri, Mar 6, 2020 at 3:18 PM Joe KD2NFC via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> I was just on AO-7 and was told to lower my power from more then one
person. Sorry about that folks, just getting adjusted here, please be
patient with a satellite beginner.
>
> Now that we are here I was curious what a lot of power in does to the
linear birds, does it ruin the passband for others? Also how much is a good
amount of power to start with or one shouldn?t exceed?
>
> FM birds probably have similar operating rules as well right. I?m here to
learn :)
>
> Joe
> KD2NFC
>
>
> Sent from my iPhone
> _______________________________________________
> 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: 7
Date: Fri, 6 Mar 2020 21:34:00 +0000
From: Gary <gary_mayfield@???????.???>
To: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Lower your power!!!
Message-ID:
<CH2PR13MB36715C44A258356B7FF0E46B8AE30@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="utf-8"
Power is meaningless without antenna information....
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Michael Walker via
AMSAT-BB
Sent: Friday, March 6, 2020 3:24 PM
To: Joe KD2NFC <kd2nfc@?????.???>; amsat-bb@?????.???
Subject: Re: [amsat-bb] Lower your power!!!
Hi Joe
Once you hear yourself start dialling down your power until you don?t hear
yourself.
then, increase it slightly.
Make sure you were wearing headphones.
Mike va3mw
> On Mar 6, 2020, at 4:18 PM, Joe KD2NFC via AMSAT-BB <amsat-bb@?????.???>
wrote:
>
> ?I was just on AO-7 and was told to lower my power from more then one
person. Sorry about that folks, just getting adjusted here, please be
patient with a satellite beginner.
>
> Now that we are here I was curious what a lot of power in does to the
linear birds, does it ruin the passband for others? Also how much is a good
amount of power to start with or one shouldn?t exceed?
>
> FM birds probably have similar operating rules as well right. I?m
> here to learn :)
>
> Joe
> KD2NFC
>
>
> Sent from my iPhone
> _______________________________________________
> 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: 8
Date: Fri, 6 Mar 2020 15:36:33 -0600
From: Zach Metzinger <zmetzing@?????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Lower your power!!!
Message-ID: <b36fb01b-8799-6e92-92a1-70ae96ba53db@?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
On 2020-03-06 15:23, Michael Walker via AMSAT-BB wrote:
> Once you hear yourself start dialling down your power until you don?t hear
yourself.
>
> then, increase it slightly.
>
> Make sure you were wearing headphones.
This seems wrong.
1. Listen for the beacon, which is warbly, but audible. If you can't
hear that, don't transmit. Listen for others on the bird, as that can
also give you a sense of what you expect to hear.
2. Make sure you use the one true rule for Doppler correction
(stationary frequency at satellite transponder input). Computer
correction is probably the best bet here, as it can tune as you do other
things.
3. Start at your rig's lowest power, and increase gradually until you
can hear yourself. As others have said, if you exceed 5W into a yagi,
there's probably something wrong with your setup.
4. Even a cheap SDR on the down-link, gives you ultimate situational
awareness. You can see the beacon, other people's signals, and your own.
You can then judge your relative power to the beacon.
Also see:
https://amsat-uk.org/beginners/how-to-work-ssb-satellites/
and N0AN just posted his recording (working XW-2D) a few days on this
list. Here is his video URL:
https://drive.google.com/open?id=1lKYvARp4SyHUraAX9u6HQRbmnCiamJAM
Grain of salt: I haven't worked linear birds in more than two decades.
However, time is freeing up now and I'm getting my own Az/El setup
going. Perhaps we'll make a contact on AO-7 soon!
--- Zach
N0ZGO
------------------------------
Message: 9
Date: Sat, 7 Mar 2020 08:08:46 +0100
From: "christophe.mcr" <christophe.mcr@?????.???>
To: amsat-f@???????????.???? amsat-bb@?????.???? hyperfr@???????.??
Subject: [amsat-bb] Fwd: [Nouvel article] Rencontre Spatial
Radioamateur 7 et 8 mars 2020 ? Diffusion des conf?rences sur Internet
& sur le satellite g?ostationnaire QO 100
Message-ID:
<CADF-Vj1J9X8ybpGZwQGbz0-KQ9hvuT2ty9S-oc1RSODNzM5zWA@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Xtophe a publi? :" Les conf?rences seront diffus?es en directe sur
internet et sur le satellite G?ostationnaire QO100 Diffusion sur des
conf?rences sur internet : https://www.youtube.com/user/ElectrolabFr
Diffusion des conf?rences sur QO100 "
Nouvel article sur *AMSAT Francophone*
<http://site.amsat-f.org/?author=2> Rencontre Spatial Radioamateur 7 et 8
mars 2020 ? Diffusion des conf?rences sur Internet & sur le satellite
g?ostationnaire QO 100
<http://site.amsat-f.org/2020/03/07/rencontre-spatial-radioamateur-7-et-8-mars
-2020-diffusion-des-conferences-sur-internet-sur-le-satellite-geostationnaire-
qo-100/>
par
Xtophe <http://site.amsat-f.org/?author=2>
<http://site.amsat-f.org/wp-content/uploads/2020/02/RSRtitre.jpg>
Les conf?rences seront diffus?es en directe sur internet et sur le
satellite G?ostationnaire QO100
Diffusion sur des conf?rences sur internet :
- https://www.youtube.com/user/ElectrolabFr
Diffusion des conf?rences sur QO100
- *Mode de transmission : DVB S2,*
- *Modulation : QPSK*
- *D?bit : 1M symboles/seconde,*
- *FEC : 1/2*
- *Format 720 p *
*Xtophe <http://site.amsat-f.org/?author=2>* | 7 mars 2020 ? 7 h 30 min |
Cat?gories : 2020 - Troisi?me rencontre spatial radioamateur
<http://site.amsat-f.org/?taxonomy=category&term=2020-troisieme-rencontre-spat
ial-radioamateur>
| URL : https://wp.me/p7txgd-uqS
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-2020-diffusion-des-conferences-sur-internet-sur-le-satellite-geostationnaire-
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Message: 10
Date: Sat, 7 Mar 2020 05:22:41 -0600
From: Hasan al-Basri <hbasri.schiers6@?????.???>
To: Joe KD2NFC <kd2nfc@?????.???>
Cc: AMSAT-BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Lower your power!!!
Message-ID:
<CAM4UQf2Y8nXM6tqC=E4=O+=51ie+T2OZbfwjRf_q2HikhCaojw@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Joe, (and other inexperienced sat operators). When I use the term 'you' in
this post it is not to be taken personally. If the shoe fits...well, then
yes, take it personally, otherwise just take it as a way to describe an
operating guide.
1. Yes running too much EIRP aka Effective Radiated Power, (power plus
antenna gain - feedline loss) ruins operations for other operators. It may
also cause a malfunction of AO-7, to include FM'ing on SSB or shutting down
the xponder entirely.
AO-7 is a particularly sensitive case. So, let's set it to the side for the
moment.
On the other linear (SSB/CW) birds like CAS-4A, 4B, XW-2A, 2B, 2D (again),
and 2F here are the issues:
The downlink power (the sat's transmitter) is shared. It is shared in
proportion to the strength of the uplink signal from each individual
station. So, if a station is running *excessive EIRP,* they capture the
vast majority of the available downlink power and everyone else's signal is
driven into the noise floor. This happens at a syllabic rate on voices
(heard by others running proper power levels as a pumping up and down of
their signal at the speech rate of the offending signal). On cw, it is even
worse, with each keyed character driving all the other signals into the
noise floor at the keying rate.
Saying, "I'm only running 5 watts" is NOT an acceptable answer. It also
demonstrates that those saying it have no idea how to considerately operate
on a satellite.
*There is one simple rule: You should never be louder on the downlink than
the strength of the CW beacon, period.*
It is the ops responsibility to stay within this limit. No excuses, no
explanations, just do it.
Unfortunately, this pumping/power robbing happens frequently on all birds,
because operators either:
1. Have no idea what they are doing....or
2. Don't care that they are ruining the operation for others.
I have many hours of 15 minute pass MP4 recordings of these situations and
have been tempted to publish them. I have resisted publishing them because
so many of them seem to be the result of "innocent" mistakes.
So, what is excessive EIRP and how do we avoid it? For simplicity's sake,
I'm going to refer to EIRP as power.
You should adjust your uplink power so that it *NEVER *exceeds the strength
of the CW beacon you are hearing *AT THAT TIME*. Simply looking at the
beacon once in an entire 15 minute pass does not reflect what is happening
throughout the pass. The beacon reference needs to be repeatedly checked
during the pass to see if you need to power down. It's a LOT easier to tell
if you have enough power (you can hear yourself), but a lot harder to pay
attention to the fact you are too loud.
I cannot tell you how many times I have witnessed a QSO where one op tells
the other, "*You have a great signal*"....yeah, 8 dB above the beacon,
stealing the downlink power from the considerate operators who have kept
their uplink power low enough to stay no stronger than the beacon. Yes,
they are loud. But on this shared resource we call a satellite downlink
passband, being an Alligator (big mouth, poor ears) is not something to be
proud of, nor should we be complimenting operators for this lack of either
1) awareness; or 2) consideration, for the other operators.
Also, you may sound weak because of poor receiver performance on your end,
so you are tempted to turn up your transmit power to make up for your poor
ears. *This is a constant problem on the birds as they are being used
lately. *Many ops seem unaware of how poorly they are hearing and it has
little or nothing to do with their bright and shiny new rig. :-)
Someone else mentioned, that if you can't hear the beacon, don't
transmit. *Truer
words were never spoken*. If your rx performance is so bad that you cannot
hear a signal that is easily 15 to 25 dB above the noise, then don't
transmit, all you are going to do is power rob others.
The truth is, all of the linear birds on mode B (2m downlink), have beacons
that consistently run 15 to 25 dB above the noise floor. If you don't
hear them that strong, fix your receiver setup. Add a preamp, use better
coax, increase your receiver antenna gain. etc.
Another simple test: do you hear passband noise from the satellite? When it
comes into view, you should be able to hear a marked increase in your
receive noise. At the peak of the pass you should be able to hear it
easily. If you don't, your rx performance is poor. 9700 and SDR users will
see a marked 'hump' shape of the passband if they are set to a wide
panoramic view.
Turning up your transmit power is not the solution and you will, indeed,
ruin other people's qsos.
In another post, I mentioned a simple and dirty way to tell if you have
adequate receiver performance. It requires no test equipment.
1. Disconnect your antenna.
2. Connect a 50 ohm dummy load (a simple 47 Ohm resistor works fine) to the
antenna input of your radio. You will not be transmitting.
3. If you can turn the agc off in your rx, do so. If not, set it to Fast.
4. Noise Blanker or Noise Reduction OFF
5. Now....turn up the volume so the noise coming out of the speaker is
quite obvious, but not ear splitting.
Remember how loud it sounds.
6. Quickly disconnect the resistor and replace it with your satellite
antenna.
Did the noise jump up considerably compared to the noise caused by the 50
ohm resistor?
If not, your rx performance is poor. You need to fix it, as above.
If it did jump up, at least a bit, you are probably in a relatively quiet
RF location for noise and that is really good...and the fact that you can
hear environmental noise above your receiver's internally generated noise
is very good.
If it jumped up a very large amount, then your locally generated
environmental noise is high, which is NOT good, because you will end up
turning up your transmit power (uplink) to the birds to overcome it...and
of course, the rest of the people using the satellite will be driven down
into the noise floor, or power modulated by your speech rate or cw keying.
So, what do we do about all of this?
1. Exercise some real care about your operating practices. Take time to
learn how your station performance varies by the nature of a pass (shallow,
moderate, very high) and during a pass ((current elevation and polarization
fading).
Using linear birds considerately requires skill and operator attentiveness.
This is completely different than FM birds and is much more demanding of
operator intervention.
*Most importantly, during the pass itself check the beacon strength several
times and adjust your uplink power such that your received signal does not
exceed the strength of the CW beacon.*
Those with the nice shiny new Icom 9700 have no excuse for ever being
stronger than the beacon. They can simultaneously monitor the beacon level
and their own signal (as well as others in the passband) with the
panadapter feature of the 9700. Set your rx width on the panadaptor to +/-
25 kHz and center it so the PSK beacon is at the left edge of the display
and the right edge is above the op of the satellite passband (and you will
see the CW beacon just above (to the right) of the PSK beacon and the
normal passband just above (further to the right) of the CW beacon). This
should be on your display all the time. Then you can always see if you are
too strong. It will be obvious.
2. If you have access to an SDR dongle like the FunCube Pro +, run software
like SDR Console v3 (free). You will be able to see every signal in the
passband in real time from the PSKBeacon to the CW Beacon to your signal
and all the others.
When you can see what poor operating practices do to the satellite passband
and everyone trying use it, you will be amazed.
Since more and more of the serious satellite ops are getting 9700s and
SDRs, I find that the first thing I tell someone when I'm working them is
how strong their signal is (in relative dBm) and how strong the beacon is
(in relative dBm) . If they are exceeding he beacon, I ask them to reduce
power. It's that simple.
I'd really like to not have to:
1. Chase people all over the birds asking them to reduce their signal
because they are 6 to 10 dB over the beacon and are "power modulating"
every signal on the satellite.
2. Get on their freq and politely call them....only to have to chase them
all over the passband because they can't hear themselves and they continue
to transmit anyway.
As the popularity of satellites, especially the linear birds, has
increased, we are coming under more and more pressure to clean up our
operating habits. These are NOT FM birds. *Getting on one freq and
capturing the downlink with one signal with all the juice you can put out
is not an acceptable operating technique on the linear birds*.
It is inconsiderate and destructive.
Hopefully, the directness of these explanations will help and not offend
new satellite ops. It has gotten bad enough, that something needed to be
said. We want all of you on the birds, just play nicely.
73, N0AN
Hasan
On Fri, Mar 6, 2020 at 3:19 PM Joe KD2NFC via AMSAT-BB <amsat-bb@?????.???>
wrote:
> I was just on AO-7 and was told to lower my power from more then one
> person. Sorry about that folks, just getting adjusted here, please be
> patient with a satellite beginner.
>
> Now that we are here I was curious what a lot of power in does to the
> linear birds, does it ruin the passband for others? Also how much is a good
> amount of power to start with or one shouldn?t exceed?
>
> FM birds probably have similar operating rules as well right. I?m here to
> learn :)
>
> Joe
> KD2NFC
>
>
> Sent from my iPhone
> _______________________________________________
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> to all interested persons worldwide without requiring membership. Opinions
> expressed
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> 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
>
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@?????.???.
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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!
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------------------------------
End of AMSAT-BB Digest, Vol 15, Issue 71
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