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CX2SA > SATDIG 29.06.15 04:03l 975 Lines 38242 Bytes #999 (0) @ WW
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Sent: 150629/0156Z @:CX2SA.SAL.URY.SOAM #:22814 [Salto] FBB7.00e $:AMSATBB10182
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: SpaceX Launch Failure Today (B J)
2. Re: uc: (John Brier)
3. Re: the SATgate donut effect (Robert Bruninga)
4. APRS Satgate Antenna page (More work needed) (Robert Bruninga)
5. DM05/DM06 TODAY SO-50 01:00Z LotW (Bryan Green)
6. Re: APRS Satgate Antenna page (More work needed) (Scott)
7. Re: the SATgate donut effect (jeff_griffin)
8. SO-50 help (Steve Kristoff)
9. Preamps and Circular Polarization Switch. (Jim Bennett)
10. Re: SO-50 help (Paul Stoetzer)
11. Re: APRS Satgate Antenna page (5/8 wave) (Robert Bruninga)
----------------------------------------------------------------------
Message: 1
Date: Sun, 28 Jun 2015 17:23:53 +0000
From: B J <va6bmj@xxxxx.xxx>
To: APBIDDLE@xxxxxxx.xxx
Cc: AMSAT-BB <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] SpaceX Launch Failure Today
Message-ID:
<CAP7QzkO1DwTZykK2kvV-AWpYU5jx5HiOPLbz0n9ePob5d6StFw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
On 6/28/15, Alan <wa4sca@xxxxx.xxx> wrote:
>
> http://preview.tinyurl.com/qfyz92n
>
> Key point: nobody hurt.
<snip>
The flight looked like it was proceeding normally until close before
the point when staging would have occurred. I watched the video and I
didn't hear a controller mention anything unusual until the mishap
occurred.
73s
Bernhard VA6BMJ @ DO33FL
------------------------------
Message: 2
Date: Sun, 28 Jun 2015 14:22:17 -0400
From: John Brier <johnbrier@xxxxx.xxx>
To: James Hickox <jameshickox@xxxxxxxxx.xxx>
Cc: volunteer <volunteer@xxx.xxx>, repair <repair@xxxxxxxxx.xxx>,
wa5vjb <wa5vjb@xxxxx.xxx>, mspencer <mspencer@xxxx.xxx>, amsat bb
<amsat-bb@xxxxx.xxx>, amayer <amayer@xxxx.xxx>, richdugger
<richdugger@xxxxx.xxx>
Subject: Re: [amsat-bb] uc:
Message-ID:
<CALn0fKONmzMaPUVO_F=AMP1OEfhJ+8nXZukDmdXznTepVO+7_w@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
This is probably spam. Don't click.
On Jun 28, 2015 6:26 AM, "James Hickox" <jameshickox@xxxxxxxxx.xxx> wrote:
>
>
> http://sunskie.com/0lf1g2t3r4w5q6z7x8p9o.php
>
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>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>He that would live in peace and at
> ease, must not speak all he knows nor judge all he sees.Karan Fama
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 3
Date: Sun, 28 Jun 2015 15:04:39 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] the SATgate donut effect
Message-ID: <0e0650ed2466b85e687d1c6263735c82@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
The donut hole is a problem... With two more APRS satellites to launch
this year, we need -more- Omni Satgates with *lower* antennas. The
vertical omni 1/4 or 3/4 wave satgate vertical antenna needs to be as low
as possible (to minimize the donut hole null and to reduce lightening
risk) while still seeing sky above 30 degrees.
See: http://aprs.org/aprs-satellite-igate-antennas.html
Once I deliver the last of these next two transponders, I hope to build
such a satgate with a D7 HT and document its performance. I can place the
HT at the base of the antenna with near zero coax, and being low, it is
not vulnerable to lightening compared to surrounding structures.
Bob, WB4APR
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@xxxxx.xxxx On Behalf Of
kb2m@xxxx.xxx
Sent: Sunday, June 28, 2015 10:02 AM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] the donut effect
Is there anyway to get any APRS client to not Igate a packet with a path
of ARISS in it. I run a satgate here in NJ and the donut effect is causing
problems for several hams in the area that can't get a packet Igated after
it is digi'd by the ISS because it's a dup. My Igate hears the first
packet direct that then causes the ISS digi'd packet to be a dup. It
would seem to be a simple thing to set a filter to ignore a path of
ARISS, and accept everything else. I would think that this would fix the
problem of people who want to run Igates, but don't because of this. I
recently moved to Florida for the winter and had to shut my igate down in
NJ for this reason. Also, I noticed when down there that there is a lack
of satgates along the eastcoast. ISS,PSAT, and PCSAT are hearing stations
fine but no satgate's available until the bird's footprint move well
inland.
73 Jeff kb2m
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 4
Date: Sun, 28 Jun 2015 17:13:50 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] APRS Satgate Antenna page (More work needed)
Message-ID: <5e52b53af45057a3aaee6cbea9525306@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Well, someone with time to burn might want to check all these numbers.
Today I am getting inconsistent results and probably because to make a 9'
ground plane at 2m with good segment sizes, I need more than the 500 point
limit in EZNEC.
Also, to cover the USA with omni satgates with good gain above 25 degrees
will need almost 9 times as many satgates compared to the number with full
AZ/EL OSCAR arrays. But then the omni satgates are 10? Times simpler...
(just your HT while you are not actually using it)...
At this point we need to simply see what a 1/4 wave over a large ground
plane can actually HEAR. It is easy to just run it for days and see how
many PSAT packets are received per 24 hours. And then compare antennas
based on that number. If a 1/4 wave can hear down to 25 degrees, then there
is no need for the higher 3/4 wave gain at higher angles. Anyway, a great
opportunity for study.
-----Original Message-----
The gain of the 3/4 wave vertical is a real winner over the basic 1/4 wave
vertical for OMNI Satgates with no moving parts optimized for high elevation
gain above 30 deg. Low elevations are simply covered by more SATgates....
New: If we can get the angle down to 25 degrees then still need 9 times
more stations)
1/4 wave with radials: -2 at 30 and -6 at 60 ==> Basically a dipole
pattern
3/4 wave with radials: +2 at 30 and -1 at 60 ==> 4 to 5 dB better, 2 dBi
max
3/4 wave w 3' gndpln: +3 at 30 and +1 at 60 ==> 5 to 7 dB better, 3.3 dBi
max
3/4 wave w 6' gndpln: +2 at 30 and +3 at 70 ==> 4 to 9 dB better, 5.5 dBi
max
3/4 wave w 9' gndpln: +3 at 30 and +3 at 65 ==> 5 to 9 dB better, 5.3 dBi
max
3/4 wave perfect gnd: +3 at 30 and +3 at 68 ==> 5 to 9 dB better, 6.9 dBi
max
Even the 3/4 vertical with just the four 19" radials gives a huge 4 to 5 dB
improvement over a classic ground plane for omni satellite SATgate work.
Also, this antenna does not need to be high. Just see sky above 30 deg. In
fact, is better to be low to reduce terrestrial QRM.
Notice too that the Lilenblatt, eggbeaters, and all other "omni"s that try
to keep their gain down on the horizon, are equally as poor as the 1/4 wave
vertical at these higher elevations. This is OK for strong satellits like
the ISS with 5 to 10 watts, but abisimal when all that gain on the horizon
is completely wasted when you cannot hear the satellite anyway because it is
6 to 10 dB farther away! The result is these "omni's" give up the 4 to 9 dB
at higher elevations where the satellite is much stronger.
Ill eventually put all this on the Omni SATGATE page:
http://aprs.org/aprs-satellite-igate-antennas.html
Summary: The 3/4 wave vertical makes it so you CAN hear LEO satellites 5 to
9 dB better when they are closer and does this by giving up on hearing
them when they are so far away you can't hear them anyway!
THE BIG QUESTION though is What is the lowest elevation angle at which an
OMNI can hear PSAT?
Bob, WB4APR
-----Original Message-----
From: Robert Bruninga [mailto:bruninga@xxxx.xxxx
Subject: RE: [aprssig] APRS Satgate Antenna page
> One question,what constitutes a large ground plane?
> Is it 12"or 12'? Is it a multiple of the vertical whip?
Good question. Most people think that four 1/4 wave radials make a ground
plane. But if you model a 1/4 wave vertical over 1/4 wave radials, all you
get is the exact pattern of a DIPOLE. The radials are just providing a
"groundplane" to complete the electrical part of the antenna and give a good
match. They do not affect the pattern at all.
I modeled verticals over 6' or larger ground planes and only found that you
get the added "reflection" gain when the ground plane starts getting that
big or more. I wish I had time to use EZNEC to show the added gain
(skyward) versus the size of the ground plane. And how "radials" (above
actual ground) have nothing to do with the "pattern".
SO, the bigger the better. It should be worth 2 to 3 dB if you could make
it very large...
This is the page in question:
http://aprs.org/aprs-satellite-igate-antennas.html
Bob, WB4aPR
On 6/19/2015 3:57 PM, Robert Bruninga via aprssig wrote:
> Subject: APRS Satgate Antenna page
>
> Since the ideal APRS Satellite IGate OMNI antenna is exactly the
> opposite of the typical terrestrial IGaate antenna, I prepared the
> following WEB page:
>
> http://aprs.org/aprs-satellite-igate-antennas.html
>
> It shows how a vertical ? or ? wave VHF omni equals the performance of
> a full OSCAR class array (over half the sky) but does it with no
> moving parts.
> It makes up for the weak-signal horizon part of the sky by there
> simply being more omni-IGates. The APRS-IS cloud with all of its
> IGates is probably one of the largest spatially distributed satellite
> receiver system in the world (?).
>
> But with people used to the 10W transmitter on the ISS, just a few
> IGates can capture just about every packet from the ISS horizon to
> horizon on a whip. But with the 14 dB weaker signal from PSAT, we
> need more SatGates to make up for their smaller skyprint. For the USA
> we need more than a dozen such Omni-SATgates.
>
> To see the significance of the weaker downlink from PSAT, look at the
> successful IGates on the http://pcsat.aprs.org page compared to the IGates
> that hear the ISS packets on http://ariss.net Both are listening on
> 145.825 and passing along every packet they hear. But only TRACKING
> IGates or good vertical gain satgates hear PSAT. And since we want
> these running 24/7/365, we do NOT expect people wearing out motors
> when an omni will do fine (if we have enough).
>
> The page also shows how every SATgate with a HIGH and terrestrial type
> antenna actually creates a DEADZONE around it, effectively blocking
> any nearby user heaerd direct from appearing on any of the APRS-IS
> cloud satellite web pages. Hence, Omni-satgate antennas should be low
> to everything surrounding it w hile still seeing the sky above 30 degrees.
>
> If your TH-D7 HT is just sitting there, not in use 99% of the time,
> then just hook it to a vertical whip and let it be an IGate. With the
> low antenna it will also probably be safe from all weather lightening too.
> Put
> the UHF side on 435.350 and turn up the speaker. When PSAT PSK31
> comes into view, you can watch the PSK31 activity as a bonus!
>
> Bob, WB4APR
> _______________________________________________
> aprssig mailing list
> aprssig@xxxx.xxx
> http://www.tapr.org/mailman/listinfo/aprssig
------------------------------
Message: 5
Date: Sun, 28 Jun 2015 15:49:48 -0700
From: Bryan Green <bryan@xxxxx.xxx>
To: AMSAT-BB <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] DM05/DM06 TODAY SO-50 01:00Z LotW
Message-ID: <853FADE5-EEA2-44CD-899B-F2D8F55F362F@xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Will be active TODAY from DM05/DM06 line on SO-50 at 01:00Z TODAY
2015-06-29Z. LotW confirmation.
-- bag
Bryan KL7CN/W6
------------------------------
Message: 6
Date: Sun, 28 Jun 2015 18:46:30 -0400
From: "Scott" <scott23192@xxxxx.xxx>
To: "Robert Bruninga" <bruninga@xxxx.xxx>, <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] APRS Satgate Antenna page (More work needed)
Message-ID: <11CCDF05B67D41AA8C260C6F5E9E0F8F@xxxxxx>
Content-Type: text/plain; charset="UTF-8"
>>> At this point we need to simply see what a 1/4 wave over a large ground
>>> plane can actually HEAR. It is easy to just run it for days and see how
>>> many PSAT packets are received per 24 hours.
Greetings Bob and everyone!
If I am the only person following this thread with minimal satellite
experience, then please forgive the questions. But on the chance that there
are others like me who would be happy to contribute with just a little
guidance, I write today.
I have actually received APRS packets from the ISS and for that matter have
been digipeated using a simple 5/8 mag mount antenna oriented 90 degrees off
vertical. I only mention that to offer some background.
If someone would like to spell out exactly how to monitor the desired
frequency and in turn contribute any received packets to the study you refer
to, I would be most grateful. Of course I can receive signals all day, but
I'm not aware of how to forward anything useful to the database that
populates the map you provided a link to.
Many thanks for all of your informative posts,
-Scott Chapman, K4KDR
Montpelier, VA USA
------------------------------------------------------------------------------
--
------------------------------------------------------------------------------
--
----- Original Message -----
From: Robert Bruninga
To: amsat-bb@xxxxx.xxx
Sent: Sunday, June 28, 2015 17:13
Subject: [amsat-bb] APRS Satgate Antenna page (More work needed)
Well, someone with time to burn might want to check all these numbers.
Today I am getting inconsistent results and probably because to make a 9'
ground plane at 2m with good segment sizes, I need more than the 500 point
limit in EZNEC.
Also, to cover the USA with omni satgates with good gain above 25 degrees
will need almost 9 times as many satgates compared to the number with full
AZ/EL OSCAR arrays. But then the omni satgates are 10? Times simpler...
(just your HT while you are not actually using it)...
At this point we need to simply see what a 1/4 wave over a large ground
plane can actually HEAR. It is easy to just run it for days and see how
many PSAT packets are received per 24 hours. And then compare antennas
based on that number. If a 1/4 wave can hear down to 25 degrees, then there
is no need for the higher 3/4 wave gain at higher angles. Anyway, a great
opportunity for study.
-----Original Message-----
The gain of the 3/4 wave vertical is a real winner over the basic 1/4 wave
vertical for OMNI Satgates with no moving parts optimized for high elevation
gain above 30 deg. Low elevations are simply covered by more SATgates....
New: If we can get the angle down to 25 degrees then still need 9 times
more stations)
1/4 wave with radials: -2 at 30 and -6 at 60 ==> Basically a dipole
pattern
3/4 wave with radials: +2 at 30 and -1 at 60 ==> 4 to 5 dB better, 2 dBi
max
3/4 wave w 3' gndpln: +3 at 30 and +1 at 60 ==> 5 to 7 dB better, 3.3 dBi
max
3/4 wave w 6' gndpln: +2 at 30 and +3 at 70 ==> 4 to 9 dB better, 5.5 dBi
max
3/4 wave w 9' gndpln: +3 at 30 and +3 at 65 ==> 5 to 9 dB better, 5.3 dBi
max
3/4 wave perfect gnd: +3 at 30 and +3 at 68 ==> 5 to 9 dB better, 6.9 dBi
max
Even the 3/4 vertical with just the four 19" radials gives a huge 4 to 5 dB
improvement over a classic ground plane for omni satellite SATgate work.
Also, this antenna does not need to be high. Just see sky above 30 deg. In
fact, is better to be low to reduce terrestrial QRM.
Notice too that the Lilenblatt, eggbeaters, and all other "omni"s that try
to keep their gain down on the horizon, are equally as poor as the 1/4 wave
vertical at these higher elevations. This is OK for strong satellits like
the ISS with 5 to 10 watts, but abisimal when all that gain on the horizon
is completely wasted when you cannot hear the satellite anyway because it is
6 to 10 dB farther away! The result is these "omni's" give up the 4 to 9 dB
at higher elevations where the satellite is much stronger.
Ill eventually put all this on the Omni SATGATE page:
http://aprs.org/aprs-satellite-igate-antennas.html
Summary: The 3/4 wave vertical makes it so you CAN hear LEO satellites 5 to
9 dB better when they are closer and does this by giving up on hearing
them when they are so far away you can't hear them anyway!
THE BIG QUESTION though is What is the lowest elevation angle at which an
OMNI can hear PSAT?
Bob, WB4APR
-----Original Message-----
From: Robert Bruninga [mailto:bruninga@xxxx.xxxx
Subject: RE: [aprssig] APRS Satgate Antenna page
> One question,what constitutes a large ground plane?
> Is it 12"or 12'? Is it a multiple of the vertical whip?
Good question. Most people think that four 1/4 wave radials make a ground
plane. But if you model a 1/4 wave vertical over 1/4 wave radials, all you
get is the exact pattern of a DIPOLE. The radials are just providing a
"groundplane" to complete the electrical part of the antenna and give a good
match. They do not affect the pattern at all.
I modeled verticals over 6' or larger ground planes and only found that you
get the added "reflection" gain when the ground plane starts getting that
big or more. I wish I had time to use EZNEC to show the added gain
(skyward) versus the size of the ground plane. And how "radials" (above
actual ground) have nothing to do with the "pattern".
SO, the bigger the better. It should be worth 2 to 3 dB if you could make
it very large...
This is the page in question:
http://aprs.org/aprs-satellite-igate-antennas.html
Bob, WB4aPR
On 6/19/2015 3:57 PM, Robert Bruninga via aprssig wrote:
> Subject: APRS Satgate Antenna page
>
> Since the ideal APRS Satellite IGate OMNI antenna is exactly the
> opposite of the typical terrestrial IGaate antenna, I prepared the
> following WEB page:
>
> http://aprs.org/aprs-satellite-igate-antennas.html
>
> It shows how a vertical ? or ? wave VHF omni equals the performance of
> a full OSCAR class array (over half the sky) but does it with no
> moving parts.
> It makes up for the weak-signal horizon part of the sky by there
> simply being more omni-IGates. The APRS-IS cloud with all of its
> IGates is probably one of the largest spatially distributed satellite
> receiver system in the world (?).
>
> But with people used to the 10W transmitter on the ISS, just a few
> IGates can capture just about every packet from the ISS horizon to
> horizon on a whip. But with the 14 dB weaker signal from PSAT, we
> need more SatGates to make up for their smaller skyprint. For the USA
> we need more than a dozen such Omni-SATgates.
>
> To see the significance of the weaker downlink from PSAT, look at the
> successful IGates on the http://pcsat.aprs.org page compared to the IGates
> that hear the ISS packets on http://ariss.net Both are listening on
> 145.825 and passing along every packet they hear. But only TRACKING
> IGates or good vertical gain satgates hear PSAT. And since we want
> these running 24/7/365, we do NOT expect people wearing out motors
> when an omni will do fine (if we have enough).
>
> The page also shows how every SATgate with a HIGH and terrestrial type
> antenna actually creates a DEADZONE around it, effectively blocking
> any nearby user heaerd direct from appearing on any of the APRS-IS
> cloud satellite web pages. Hence, Omni-satgate antennas should be low
> to everything surrounding it w hile still seeing the sky above 30 degrees.
>
> If your TH-D7 HT is just sitting there, not in use 99% of the time,
> then just hook it to a vertical whip and let it be an IGate. With the
> low antenna it will also probably be safe from all weather lightening too.
> Put
> the UHF side on 435.350 and turn up the speaker. When PSAT PSK31
> comes into view, you can watch the PSK31 activity as a bonus!
>
> Bob, WB4APR
> _______________________________________________
> aprssig mailing list
> aprssig@xxxx.xxx
> http://www.tapr.org/mailman/listinfo/aprssig
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 7
Date: Sun, 28 Jun 2015 20:11:38 -0400
From: "jeff_griffin" <jeff_griffin@xxxxxxx.xxx>
To: "'Robert Bruninga'" <bruninga@xxxx.xxx>, <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] the SATgate donut effect
Message-ID: <00a001d0b200$3073bd60$915b3820$@xxx>
Content-Type: text/plain; charset="us-ascii"
Bob,
I think it would get you a lot more Igates if you/we could convince the APRS
s/w authors to put in my simple fix. I mean really, how many people are
going to put in a 9 square foot ground mounted vertical? I couldn't in
either of my homes, the landscapers would take it out in no time, the only
place for a small vertical is mounted off the ground...
73 Jeff kb2m
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@xxxxx.xxxx On Behalf Of Robert
Bruninga
Sent: Sunday, June 28, 2015 3:05 PM
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] the SATgate donut effect
The donut hole is a problem... With two more APRS satellites to launch this
year, we need -more- Omni Satgates with *lower* antennas. The vertical omni
1/4 or 3/4 wave satgate vertical antenna needs to be as low as possible (to
minimize the donut hole null and to reduce lightening
risk) while still seeing sky above 30 degrees.
See: http://aprs.org/aprs-satellite-igate-antennas.html
Once I deliver the last of these next two transponders, I hope to build such
a satgate with a D7 HT and document its performance. I can place the HT at
the base of the antenna with near zero coax, and being low, it is not
vulnerable to lightening compared to surrounding structures.
Bob, WB4APR
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@xxxxx.xxxx On Behalf Of
kb2m@xxxx.xxx
Sent: Sunday, June 28, 2015 10:02 AM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] the donut effect
Is there anyway to get any APRS client to not Igate a packet with a path of
ARISS in it. I run a satgate here in NJ and the donut effect is causing
problems for several hams in the area that can't get a packet Igated after
it is digi'd by the ISS because it's a dup. My Igate hears the first packet
direct that then causes the ISS digi'd packet to be a dup. It would seem to
be a simple thing to set a filter to ignore a path of ARISS, and accept
everything else. I would think that this would fix the problem of people who
want to run Igates, but don't because of this. I recently moved to Florida
for the winter and had to shut my igate down in NJ for this reason. Also, I
noticed when down there that there is a lack of satgates along the
eastcoast. ISS,PSAT, and PCSAT are hearing stations fine but no satgate's
available until the bird's footprint move well inland.
73 Jeff kb2m
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 8
Date: Sun, 28 Jun 2015 19:42:07 -0400
From: "Steve Kristoff" <skristof@xxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] SO-50 help
Message-ID: <04C9C5016F48474DA923C4848B72D78F@xxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
I could use some help here. For the third time this week, I've gone outside
during what was supposed to be a nice high pass of SO-50, pointed my Arrow
in (what I think is) the right direction and I hear nothing. Just now, I was
supposed to have a max elevation of 80 degrees at EM79. Should have been an
easy one. But I hear nothing.
In the past I've had QSOs on SO-50 with some of you, so you know I know how
to point the antenna and use the radios.
Does anyone else use the Pass Predictions on the AMSAT page? That's what
I've been using, but it's starting to seem like the satellite isn't where
the prediction says it is.
I'd really appreciate some replies on this one. If other folks are finding
the AMSAT Prediction Page for SO-50 to be correct, then I'll know it's me
and I'll check all my radios and connections one more time.Thank you.
Steve Kristoff AI9IN
skristof@xxxxxxx.xxx
------------------------------
Message: 9
Date: Sun, 28 Jun 2015 20:27:35 -0400
From: "Jim Bennett" <jlb3nn@xxxxxxxxx.xxx>
To: "'Amsat'" <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Preamps and Circular Polarization Switch.
Message-ID: <008a01d0b202$66a51d00$33ef5700$@xxx>
Content-Type: text/plain; charset="us-ascii"
Hey guys.
I just took a lighting strike the other day. Wipe out the big stick in the
air. Also took out one preamp and possible a circular polarization switch
on the sat antennas alone with both PCs that I had, a power supply, plus my
network. The pair of KLM appear ok. So I am going to redo my tower layout.
New coax(probably hard line), new preamps, new cp switch and new control
cable to the preamps and CP switches. Rotor cables appear good, but will
check to make sure.
I put this system together about 20 years ago. So I am starting out fresh
trying to find the stuff. Is Lanwear amps still available? If not, what is
the next best. Are there any shelf available CP switches. The ones I have
were on the antennas when purchased. And they appear home built.
Any suggestions are appreciate.
Jim
Ke4kol
------------------------------
Message: 10
Date: Sun, 28 Jun 2015 21:20:59 -0400
From: Paul Stoetzer <n8hm@xxxx.xxx>
To: Steve Kristoff <skristof@xxxxxxx.xxx>
Cc: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] SO-50 help
Message-ID:
<CABzOSOrcBz67bU81tEUTpHvUGXn_XXWa6+MfLNZRRa-_rdUDBg@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Steve.
Describe your setup. Are you using the Arrow diplexer?
73,
Paul, N8HM
On Sun, Jun 28, 2015 at 7:42 PM, Steve Kristoff <skristof@xxxxxxx.xxx> wrote:
> I could use some help here. For the third time this week, I've gone
outside during what was supposed to be a nice high pass of SO-50, pointed my
Arrow in (what I think is) the right direction and I hear nothing. Just now,
I was supposed to have a max elevation of 80 degrees at EM79. Should have
been an easy one. But I hear nothing.
> In the past I've had QSOs on SO-50 with some of you, so you know I know
how to point the antenna and use the radios.
> Does anyone else use the Pass Predictions on the AMSAT page? That's what
I've been using, but it's starting to seem like the satellite isn't where
the prediction says it is.
> I'd really appreciate some replies on this one. If other folks are finding
the AMSAT Prediction Page for SO-50 to be correct, then I'll know it's me
and I'll check all my radios and connections one more time.Thank you.
>
> Steve Kristoff AI9IN
> skristof@xxxxxxx.xxx
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 11
Date: Sun, 28 Jun 2015 21:54:36 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] APRS Satgate Antenna page (5/8 wave)
Message-ID: <22fcbbb1f8a3a1c2a9463674b365b49d@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
> I have actually received APRS packets from the ISS and for that matter
have been digipeated using a simple 5/8 mag mount antenna oriented 90
degrees off vertical. I only mention that to offer some background.
Ah, but the ISS is 10W compared to PSAT?s 0.3W, so it is 15 dB stronger and
any piece of wire as an antenna can hear ISS, even in the very strong NULL
that a 5/8 wave antenna has above 15 degrees. All of my comments are
trying to help SatGates hear the weak ones?
> I'm not aware of how to forward anything useful to the database that
populates the map you provided a link to.
That is simple or hard. Depending on your patience with software. Any
APRS software just about automatically becomes a SatGate if you leave your
radio tuned to 145.825 and leave your PC running th software connected to
the internet. Then your station feeds the pcsat.aprs.org satellite
downlink data base.
Hope that helps.
Bob, WB4aPR
------------------------------
------------------------------
----- Original Message -----
*From:* Robert Bruninga <bruninga@xxxx.xxx>
*To:* amsat-bb@xxxxx.xxx
*Sent:* Sunday, June 28, 2015 17:13
*Subject:* [amsat-bb] APRS Satgate Antenna page (More work needed)
Well, someone with time to burn might want to check all these numbers.
Today I am getting inconsistent results and probably because to make a 9'
ground plane at 2m with good segment sizes, I need more than the 500 point
limit in EZNEC.
Also, to cover the USA with omni satgates with good gain above 25 degrees
will need almost 9 times as many satgates compared to the number with full
AZ/EL OSCAR arrays. But then the omni satgates are 10? Times simpler...
(just your HT while you are not actually using it)...
At this point we need to simply see what a 1/4 wave over a large ground
plane can actually HEAR. It is easy to just run it for days and see how
many PSAT packets are received per 24 hours. And then compare antennas
based on that number. If a 1/4 wave can hear down to 25 degrees, then there
is no need for the higher 3/4 wave gain at higher angles. Anyway, a great
opportunity for study.
-----Original Message-----
The gain of the 3/4 wave vertical is a real winner over the basic 1/4 wave
vertical for OMNI Satgates with no moving parts optimized for high elevation
gain above 30 deg. Low elevations are simply covered by more SATgates....
New: If we can get the angle down to 25 degrees then still need 9 times
more stations)
1/4 wave with radials: -2 at 30 and -6 at 60 ==> Basically a dipole
pattern
3/4 wave with radials: +2 at 30 and -1 at 60 ==> 4 to 5 dB better, 2 dBi
max
3/4 wave w 3' gndpln: +3 at 30 and +1 at 60 ==> 5 to 7 dB better, 3.3 dBi
max
3/4 wave w 6' gndpln: +2 at 30 and +3 at 70 ==> 4 to 9 dB better, 5.5 dBi
max
3/4 wave w 9' gndpln: +3 at 30 and +3 at 65 ==> 5 to 9 dB better, 5.3 dBi
max
3/4 wave perfect gnd: +3 at 30 and +3 at 68 ==> 5 to 9 dB better, 6.9 dBi
max
Even the 3/4 vertical with just the four 19" radials gives a huge 4 to 5 dB
improvement over a classic ground plane for omni satellite SATgate work.
Also, this antenna does not need to be high. Just see sky above 30 deg. In
fact, is better to be low to reduce terrestrial QRM.
Notice too that the Lilenblatt, eggbeaters, and all other "omni"s that try
to keep their gain down on the horizon, are equally as poor as the 1/4 wave
vertical at these higher elevations. This is OK for strong satellits like
the ISS with 5 to 10 watts, but abisimal when all that gain on the horizon
is completely wasted when you cannot hear the satellite anyway because it is
6 to 10 dB farther away! The result is these "omni's" give up the 4 to 9 dB
at higher elevations where the satellite is much stronger.
Ill eventually put all this on the Omni SATGATE page:
http://aprs.org/aprs-satellite-igate-antennas.html
Summary: The 3/4 wave vertical makes it so you CAN hear LEO satellites 5 to
9 dB better when they are closer and does this by giving up on hearing
them when they are so far away you can't hear them anyway!
THE BIG QUESTION though is What is the lowest elevation angle at which an
OMNI can hear PSAT?
Bob, WB4APR
-----Original Message-----
From: Robert Bruninga [mailto:bruninga@xxxx.xxx <bruninga@xxxx.xxx>]
Subject: RE: [aprssig] APRS Satgate Antenna page
> One question,what constitutes a large ground plane?
> Is it 12"or 12'? Is it a multiple of the vertical whip?
Good question. Most people think that four 1/4 wave radials make a ground
plane. But if you model a 1/4 wave vertical over 1/4 wave radials, all you
get is the exact pattern of a DIPOLE. The radials are just providing a
"groundplane" to complete the electrical part of the antenna and give a good
match. They do not affect the pattern at all.
I modeled verticals over 6' or larger ground planes and only found that you
get the added "reflection" gain when the ground plane starts getting that
big or more. I wish I had time to use EZNEC to show the added gain
(skyward) versus the size of the ground plane. And how "radials" (above
actual ground) have nothing to do with the "pattern".
SO, the bigger the better. It should be worth 2 to 3 dB if you could make
it very large...
This is the page in question:
http://aprs.org/aprs-satellite-igate-antennas.html
Bob, WB4aPR
On 6/19/2015 3:57 PM, Robert Bruninga via aprssig wrote:
> Subject: APRS Satgate Antenna page
>
> Since the ideal APRS Satellite IGate OMNI antenna is exactly the
> opposite of the typical terrestrial IGaate antenna, I prepared the
> following WEB page:
>
> http://aprs.org/aprs-satellite-igate-antennas.html
>
> It shows how a vertical ? or ? wave VHF omni equals the performance of
> a full OSCAR class array (over half the sky) but does it with no
> moving parts.
> It makes up for the weak-signal horizon part of the sky by there
> simply being more omni-IGates. The APRS-IS cloud with all of its
> IGates is probably one of the largest spatially distributed satellite
> receiver system in the world (?).
>
> But with people used to the 10W transmitter on the ISS, just a few
> IGates can capture just about every packet from the ISS horizon to
> horizon on a whip. But with the 14 dB weaker signal from PSAT, we
> need more SatGates to make up for their smaller skyprint. For the USA
> we need more than a dozen such Omni-SATgates.
>
> To see the significance of the weaker downlink from PSAT, look at the
> successful IGates on the http://pcsat.aprs.org page compared to the IGates
> that hear the ISS packets on http://ariss.net Both are listening on
> 145.825 and passing along every packet they hear. But only TRACKING
> IGates or good vertical gain satgates hear PSAT. And since we want
> these running 24/7/365, we do NOT expect people wearing out motors
> when an omni will do fine (if we have enough).
>
> The page also shows how every SATgate with a HIGH and terrestrial type
> antenna actually creates a DEADZONE around it, effectively blocking
> any nearby user heaerd direct from appearing on any of the APRS-IS
> cloud satellite web pages. Hence, Omni-satgate antennas should be low
> to everything surrounding it w hile still seeing the sky above 30 degrees.
>
> If your TH-D7 HT is just sitting there, not in use 99% of the time,
> then just hook it to a vertical whip and let it be an IGate. With the
> low antenna it will also probably be safe from all weather lightening too.
> Put
> the UHF side on 435.350 and turn up the speaker. When PSAT PSK31
> comes into view, you can watch the PSK31 activity as a bonus!
>
> Bob, WB4APR
> _______________________________________________
> aprssig mailing list
> aprssig@xxxx.xxx
> http://www.tapr.org/mailman/listinfo/aprssig
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@xxxxx.xxx.
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!
http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 10, Issue 182
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