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CX2SA > SATDIG 16.09.11 14:07l 910 Lines 35006 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. iPad App - HamSatHD (E. Michael McCardel)
2. fast 1 and fast2 (jerry keeton)
3. Re: iPad App - HamSatHD (Brandon Rasmussen)
4. Re: ARISSAT telemetry - no kursk frames (Alan Cresswell)
5. Re: Which Mobile Mag Mount? (Ted)
6. Re: Which Mobile Mag Mount? (Ted)
7. Re: Which Mobile Mag Mount (Clint Bradford)
8. Sat32PC Flex-5000A Satellite Mode B using 70 cm external
transverter and external 2M converter? (Bill Bordy, NJ1H )
9. Re: Which Mobile Mag Mount? (Clayton Coleman W5PFG)
10. K0BAM Road Trip (Jim Adams)
11. Re: iPad App - HamSatHD (Andy Kellner)
12. TNX for the help for the demo (Nick Pugh K5QXJ)
13. Re: Which Mobile Mag Mount? (Bob Bruninga)
14. Re: Which Mobile Mag Mount? (Bob Bruninga)
----------------------------------------------------------------------
Message: 1
Date: Thu, 15 Sep 2011 15:07:29 -0400
From: "E. Michael McCardel" <mccardelm@xxxxx.xxx>
To: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] iPad App - HamSatHD
Message-ID: <B99F9963-6D1B-4317-A401-86CF0F139C97@xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
I use HamSatHD with mixed results. I don't quite trust the keps used, but
lately I have had good luck. I especially like the graphic it displays for
the pass. I often set my iPad on the ground or a nearby elevated surface,
orient with the pass an just follow it along. One thing that I have noticed
is that my iPad isn't always in sync with the actual time so I have to be
sure that real time and iPad time are the same. A few minutes make a big
difference.
Another advantage of the iPad is I have successfully downloaded an ArisSat
SSTV image directly to the app, SSTV, for the iPad. There are also recording
capable apps that I have used to record passes. Both of these examples are
when NOT using the HamSatHD app. One app at a time.
If you have Internet access you can also visit Heavens-Above to get pass
information or to compare the keps with HamSatHD.
EMike, KC8YLD
Sent from my iPad
On Sep 15, 2011, at 1:01 PM, amsat-bb-request@xxxxx.xxx wrote:
> iPad App - HamSatHD
------------------------------
Message: 2
Date: Thu, 15 Sep 2011 14:12:34 -0500
From: "jerry keeton" <jkboxk@xxxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] fast 1 and fast2
Message-ID: <BDC718B9B33044939649D4137853FB51@xxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
With Fast 1 and Fast 2 being so far apart , are they still able to
communicate with each other ?
------------------------------
Message: 3
Date: Thu, 15 Sep 2011 13:40:50 -0500
From: Brandon Rasmussen <brandonbrasmussen@xxxxx.xxx>
Cc: Amsat BB <AMSAT-BB@xxxxx.xxx>
Subject: [amsat-bb] Re: iPad App - HamSatHD
Message-ID: <9F6DEF79-AC3F-4AAC-B8B7-A5C001BD55A0@xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
That's a great app. I actually have the ProSat version which has extra
non-ham stuff (rocket bodies and the like. Probably stuff I don't need.) but
I love the app. The latest version sports a radar view. You can enter base
frequencies, and it will calculate Doppler corrections for you.
I'd recommend the app. It works well.
Brandon
K7BBR
On Sep 15, 2011, at 5:52, Joel Black <w4jbb@xxxxxxx.xxx> wrote:
> The company I work for gave me a 16GB iPad for work and I can pretty much
put anything I want on it.
>
> There are not as many apps designed for the iPad as there are for the
iPhone (iPhone apps will work, but they're "screen space" small). However,
I found HamSatHD. There are no reviews on the App Store so I was wondering
if anyone here has used or is using it?
>
> I just want to track satellites not control anything while out-and-about.
>
> Developer webpage is www.vosworx.com.
>
> Thanks,
> Joel - W4JBB
------------------------------
Message: 4
Date: Thu, 15 Sep 2011 20:28:03 -0000
From: "Alan Cresswell" <alancresswell@xxxx.xx.xx>
To: "'Mike Rupprecht'" <mail@xxxxxxxxxxxxxx.xx>, <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: ARISSAT telemetry - no kursk frames
Message-ID: <7D7573EFA5344ABAA5E286CE769988D0@xxxxx>
Content-Type: text/plain; charset="us-ascii"
Hi Mike,
In the morning passes here when ARISsat came out of eclipse it would, after
the 15 minute delay, always send up to 20 telemetry frames before the KURSK
frames started up. Seems like it was normal behaviour.
73
Alan
ZL2BX
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Mike Rupprecht
Sent: Thursday, 15 September 2011 06:23
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] ARISSAT telemetry - no kursk frames
Hi all,
I had a 1 deg pass this morning and could grab 18 telemetry frames (!).
Interesting was that I received no one KURSK frame.
Can someone confirm this?
73, Mike
DK3WN
_______________________________________________
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------------------------------
Message: 5
Date: Thu, 15 Sep 2011 16:25:17 -0700
From: "Ted" <k7trkradio@xxxxxxx.xxx>
To: "'Bob Bruninga'" <bruninga@xxxx.xxx>, "'AMSAT BB'"
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Message-ID: <59B38C23A45547BBA538DA5E79864E56@xxxxxxxxxxx>
Content-Type: text/plain; charset="us-ascii"
Very interesting info...
I'm thinking maybe putting a mag mount with 19.5" of nice shiny wire on a
pizza pan would do as well as the Arrow (I hate the Arrow, even on a
tripod!)
73, Ted, K7TRK
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Bob Bruninga
Sent: Thursday, September 15, 2011 8:52 AM
To: 'AMSAT BB'
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Everyone's comments are correct and valid within their context. But the
original question was optimizing for the casual mobile operator in motion.
So here are some additional considerations...
> Second, any "vertical" antenna...will have a [null overhead]
> So, think about it: A GREAT pass of 90 degrees goes overhead
> your vertical is valueless during the middle of that great pass.
True, but when we put some actual numbers on that, the loss is quite
insignificant. Using AO51, only one pass every 5 days goes above 82
degrees, and the total duration above 82 degrees is 24 seconds, out of all
in view times. So we agree, the antenna is valueless, but for under 1% of
the time. The tradeoff is that it is 3 dB better most of the rest of the
time...
The measured elevation profile of a 3/4 wave vertical (a 19.5" whip on the
435 downlink) is shown 80% down the page http://aprs.org/astars.html. The
overhead null is only 10 dB down at 82 degrees... BUT the satellite is 10 dB
closer at that point, so you still hear it almost the same as when it came
above 25 degrees. So you get full sky coverage above 25 degrees > 99% of
the time with the vertical.
> Ideally - in a car - ... stopping and parking and getting a
> vertical perpendicular to the orbit of the satellite would
> give best results.
> Then maybe a Larsen mag mount... And bend - er, I mean,
> "re-form" that whip right at the base so that it is about
> 20" bent. you'll be more successful with the FM birds!
Yes, good idea, but now there is some directionality and so the car needs to
remain pointed towards the satellite during the pass. Otherwise there is
still the null, it is just in a different part of the sky.
> 1. If the satellite is circular polarization the 19.5 " whip looses 3 dB
of gain.
Yes, but most people have observed a polarization shift during overhead
passes. And in that case, the loss of a circularized antenna is much worse
than 3 dB... usually a complete fade. SO I agree, a circular antenna gets 3
dB better half the time, and much worse the other half the time. I prefer
the simplicity of the whip that does not give up more than 3dB no matter
what the polarization is. Mounting a quadrifilar on the roof of the mobile
is also problematic.
> 2. The common Quadrifilar Antenna is 1/2 wave 1/2 turn.
> The 1 wavelength, 1 turn Quadrifilar Antenna has its
> highest gain near or at the horizon depending on the
> length to diameter ratio.
But it is still only a 3 dB gain antenna out there, and so it is not going
to hear the satellite down on the horizon anyway because the satellite is
10 dB farther away and usually blocked for the mobile. So having gain on
the horizon for a mobile omni antenna is wasted. It either is not enough or
it creats additional nulls higher up. Better to move that gain higher up
but smooth where the satellite is closer and then have good contacts, than
waste gain where it is already insufficient or problematic.
Just different perspectives, but the devil is in the details...
Bob, Wb4APR
_______________________________________________
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: 6
Date: Thu, 15 Sep 2011 16:40:46 -0700
From: "Ted" <k7trkradio@xxxxxxx.xxx>
To: "'Bob Bruninga'" <bruninga@xxxx.xxx>, "'AMSAT BB'"
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Message-ID: <52B6CA92DE89452CA630BDBF45AB58B6@xxxxxxxxxxx>
Content-Type: text/plain; charset="us-ascii"
Bob, thanks for the great data.
Question: do you think your data/techniques have any application to using a
dual band HT with a long whip (e.g. Diamond SRH77CA - 15.5"long)
In other words would you be better off just holding the HT vertical and
fairly stationary during the pass (adjusting Doppler of course) or moving
the darn thing all over until you capture the bird. I realize it is not
duplex, etc. but it does seem to work on a strong pass. I just can't figure
out the best way to hold the radio
Thanks for any help
73, Ted, K7TRK
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Bob Bruninga
Sent: Thursday, September 15, 2011 8:52 AM
To: 'AMSAT BB'
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Everyone's comments are correct and valid within their context. But the
original question was optimizing for the casual mobile operator in motion.
So here are some additional considerations...
> Second, any "vertical" antenna...will have a [null overhead]
> So, think about it: A GREAT pass of 90 degrees goes overhead
> your vertical is valueless during the middle of that great pass.
True, but when we put some actual numbers on that, the loss is quite
insignificant. Using AO51, only one pass every 5 days goes above 82
degrees, and the total duration above 82 degrees is 24 seconds, out of all
in view times. So we agree, the antenna is valueless, but for under 1% of
the time. The tradeoff is that it is 3 dB better most of the rest of the
time...
The measured elevation profile of a 3/4 wave vertical (a 19.5" whip on the
435 downlink) is shown 80% down the page http://aprs.org/astars.html. The
overhead null is only 10 dB down at 82 degrees... BUT the satellite is 10 dB
closer at that point, so you still hear it almost the same as when it came
above 25 degrees. So you get full sky coverage above 25 degrees > 99% of
the time with the vertical.
> Ideally - in a car - ... stopping and parking and getting a
> vertical perpendicular to the orbit of the satellite would
> give best results.
> Then maybe a Larsen mag mount... And bend - er, I mean,
> "re-form" that whip right at the base so that it is about
> 20" bent. you'll be more successful with the FM birds!
Yes, good idea, but now there is some directionality and so the car needs to
remain pointed towards the satellite during the pass. Otherwise there is
still the null, it is just in a different part of the sky.
> 1. If the satellite is circular polarization the 19.5 " whip looses 3 dB
of gain.
Yes, but most people have observed a polarization shift during overhead
passes. And in that case, the loss of a circularized antenna is much worse
than 3 dB... usually a complete fade. SO I agree, a circular antenna gets 3
dB better half the time, and much worse the other half the time. I prefer
the simplicity of the whip that does not give up more than 3dB no matter
what the polarization is. Mounting a quadrifilar on the roof of the mobile
is also problematic.
> 2. The common Quadrifilar Antenna is 1/2 wave 1/2 turn.
> The 1 wavelength, 1 turn Quadrifilar Antenna has its
> highest gain near or at the horizon depending on the
> length to diameter ratio.
But it is still only a 3 dB gain antenna out there, and so it is not going
to hear the satellite down on the horizon anyway because the satellite is
10 dB farther away and usually blocked for the mobile. So having gain on
the horizon for a mobile omni antenna is wasted. It either is not enough or
it creats additional nulls higher up. Better to move that gain higher up
but smooth where the satellite is closer and then have good contacts, than
waste gain where it is already insufficient or problematic.
Just different perspectives, but the devil is in the details...
Bob, Wb4APR
_______________________________________________
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: Thu, 15 Sep 2011 17:37:28 -0700
From: Clint Bradford <clintbradford@xxx.xxx>
To: AMSAT BB <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Which Mobile Mag Mount
Message-ID: <E6E793AB-27DF-4508-86DF-2A01006A5E25@xxx.xxx>
Content-Type: text/plain; CHARSET=US-ASCII
>> ... can't figure out the best way to hold the radio ...
Get perpendicular.
Open your squelch up all the way, and get the improved HT's antenna in a
perpendicular relationship to the orbit of the satellite.
Clint Bradford
http://www.work-sat.com
------------------------------
Message: 8
Date: Thu, 15 Sep 2011 20:58:58 -0400
From: "Bill Bordy, NJ1H " <nj1h@xxxxxxx.xxx>
To: AMSAT <AMSAT-BB@xxxxx.xxx>
Subject: [amsat-bb] Sat32PC Flex-5000A Satellite Mode B using 70 cm
external transverter and external 2M converter?
Message-ID: <4E729F52.2020804@xxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I have a Flex-5000A with the extra receiver. I have a 70 cm transverter
connected to the main RX/TX via the transverter connectors and a 2M
converter into RX2. I am attempting to operate mode B satellite
operation, 70 cm TX up and 2M RX down using the Sat32PC tracking program
TS-2000 rig control. Unfortunately, the program sets the TX frequency on
VFOB and the RX frequency on VFOA. I want it the other way around. I
tried tricking the program by changing to mode J, 2M up, 70cm down, but
the doppler control is reversed then.
Has anybody been able to use Sat32PC successfully for full duplex
Flex-5000 with external transverters for frequency control? If so, how
did you configure it?
73,
Bill
NJ1H
------------------------------
Message: 9
Date: Thu, 15 Sep 2011 20:14:59 -0500
From: Clayton Coleman W5PFG <kayakfishtx@xxxxx.xxx>
To: Ted <k7trkradio@xxxxxxx.xxx>
Cc: AMSAT BB <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Message-ID:
<CAPovOwenwZmMdDJQytTTj4HDh99qrFvJHM0BiJChnyzBXu15Jw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Ted,
Regarding antenna orientation for handhelds, see the picture
associated with item #6 at this web page:
http://www.amsat.org/amsat-new/echo/EchoHT.php
Check this video out, too, for inspiration:
http://www.youtube.com/watch?v=FCFWrXzdgeM
When using an HT whip, the trick I use is to avoid any sudden movement
or adjustment of the antenna once you have a decent copy of the
downlink. Even then, it can be challenging as you will need to track
the bird. I own some of the commonly recommended antennas such as the
Pryme AL800. I don't own the Diamond you referenced but I have a
similar Comet SMA24 that is useable, albeit not ideal, for AO-51. My
experience has been that the "cat whisker" style whips tend to have
too much movement. I might try to make a video to demonstrate this
effect.
Even with a stock rubber dummy load, I can hear many passes of AO-51
and some overhead AO-27 passes.
K6LCS' web page has some good recommendations:
http://web.me.com/clintbradford/Work-Sat/Antennas.html
I recommend the AL800 and similar. I personally am most pleased with
cost and function of the Smiley 270A, which at $22 is a real bargain.
After some passes with this antenna used, I have listened to the
recording and been unable to distinguish my HT performance from that
of a full-bore home satellite station. Again, there are limitations
but it is a lot of fun to try!
73
Clayton
W5PFG
On Thu, Sep 15, 2011 at 6:40 PM, Ted <k7trkradio@xxxxxxx.xxx> wrote:
> Bob, thanks for the great data.
>
> Question: do you think your data/techniques have any application to using a
> dual band HT with a long whip (e.g. Diamond SRH77CA - 15.5"long)
>
> In other words would you be better off just holding the HT vertical and
> fairly stationary during the pass (adjusting Doppler of course) or moving
> the darn thing all over until you capture the bird. I realize it is not
> duplex, etc. but it does seem to work on a strong pass. I just can't figure
> out the best way to hold the radio
>
> Thanks for any help
>
> 73, Ted, K7TRK
>
> -----Original Message-----
> From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
> Behalf Of Bob Bruninga
> Sent: Thursday, September 15, 2011 8:52 AM
> To: 'AMSAT BB'
> Subject: [amsat-bb] Re: Which Mobile Mag Mount?
>
> Everyone's comments are correct and valid within their context. ?But the
> original question was optimizing for the casual mobile operator in motion.
> So here are some additional considerations...
>
>> Second, any "vertical" antenna...will have a [null overhead]
>> So, think about it: A GREAT pass of 90 degrees goes overhead
>> your vertical is valueless during the middle of that great pass.
>
> True, but when we put some actual numbers on that, the loss is quite
> insignificant. ?Using AO51, only one pass every 5 days goes above 82
> degrees, and the total duration above 82 degrees is 24 seconds, out of all
> in view times. ?So we agree, the antenna is valueless, but for under 1% of
> the time. ?The tradeoff is that it is 3 dB better most of the rest of the
> time...
>
> The measured elevation profile of a 3/4 wave vertical (a 19.5" whip on the
> 435 downlink) is shown 80% down the page http://aprs.org/astars.html. ?The
> overhead null is only 10 dB down at 82 degrees... BUT the satellite is 10 dB
> closer at that point, so you still hear it almost the same as when it came
> above 25 degrees. ?So you get full sky coverage above 25 degrees > 99% of
> the time with the vertical.
>
>> Ideally - in a car - ... stopping and parking and getting a
>> vertical perpendicular to the orbit of the satellite would
>> give best results.
>> Then maybe a Larsen mag mount... And bend - er, I mean,
>> "re-form" that whip right at the base so that it is about
>> 20" bent. ?you'll be more successful with the FM birds!
>
> Yes, good idea, but now there is some directionality and so the car needs to
> remain pointed towards the satellite during the pass. ?Otherwise there is
> still the null, it is just in a different part of the sky.
>
>> 1. If the satellite is circular polarization the 19.5 " whip looses 3 dB
> of gain.
>
> Yes, but most people have observed a polarization shift during overhead
> passes. ?And in that case, the loss of a circularized antenna is much worse
> than 3 dB... usually a complete fade. ?SO I agree, a circular antenna gets 3
> dB better half the time, and much worse the other half the time. ?I prefer
> the simplicity of the whip that does not give up more than 3dB no matter
> what the polarization is. ?Mounting a quadrifilar on the roof of the mobile
> is also problematic.
>
>> 2. The common Quadrifilar Antenna is 1/2 wave 1/2 turn.
>> The 1 wavelength, 1 turn Quadrifilar Antenna has its
>> highest gain near or at the horizon depending on the
>> length to diameter ratio.
>
> But it is still only a 3 dB gain antenna out there, and so it is not going
> to hear the satellite down on the ?horizon anyway because the satellite is
> 10 dB farther away and usually blocked for the mobile. ?So having gain on
> the horizon for a mobile omni antenna is wasted. ?It either is not enough or
> it creats additional nulls higher up. ?Better to move that gain higher up
> but smooth where the satellite is closer and then have good contacts, than
> waste gain where it is already insufficient or problematic.
>
> Just different perspectives, but the devil is in the details...
>
> Bob, Wb4APR
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 10
Date: Thu, 15 Sep 2011 19:20:00 -0600
From: Jim Adams <jim9251@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] K0BAM Road Trip
Message-ID:
<CAD6RR8iogtbR+zwnH8sO3ZdWXcDq-AOsXFObHombYYk6iCfH4w@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
I'm wandering around various grids to the end of September (before the snow
starts), and will mail all contacts QSL cards the first week of October.
SASE not necessary. No plan on when and where I'll be so it will be as much
a surprise to me as you.
Jim Adams - K0BAM
------------------------------
Message: 11
Date: Thu, 15 Sep 2011 20:45:23 -0700 (PDT)
From: Andy Kellner <hawat1@xxxxx.xxx>
To: AMSAT-BB@xxxxx.xxx
Subject: [amsat-bb] Re: iPad App - HamSatHD
Message-ID:
<1316144723.28356.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
There is also GoSatWatch, which I like to predict / visualise passes.
--- On Wed, 14/9/11, Joel Black <w4jbb@xxxxxxx.xxx> wrote:
From: Joel Black <w4jbb@xxxxxxx.xxx>
Subject: [amsat-bb] iPad App - HamSatHD
To: "Amsat BB" <AMSAT-BB@xxxxx.xxx>
Received: Wednesday, 14 September, 2011, 10:52 PM
The company I work for gave me a 16GB iPad for work and I can pretty much
put anything I want on it.
There are not as many apps designed for the iPad as there are for the iPhone
(iPhone apps will work, but they're "screen space" small).? However, I found
HamSatHD.? There are no reviews on the App Store so I was wondering if
anyone here has used or is using it?
I just want to track satellites not control anything while out-and-about.
Developer webpage is www.vosworx.com.
Thanks,
Joel - W4JBB
_______________________________________________
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: 12
Date: Fri, 16 Sep 2011 03:20:45 -0500
From: "Nick Pugh K5QXJ" <quadpugh@xxxxxxxxx.xxx>
To: "'Nick Pugh K5QXJ'" <quadpugh@xxxxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] TNX for the help for the demo
Message-ID: <038e01cc7449$8bd0e6e0$a372b4a0$@xxx>
Content-Type: text/plain; charset="us-ascii"
A big thanks for the help in the demo to the middle school yesterday. You
had 20 kids excited. Next step is to get them licensed and the using there
radios.
nick
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Nick Pugh K5QXJ
Sent: Thursday, September 15, 2011 3:14 AM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] (no subject)
Hi AMSATERS
The kids at Paul Breaux Middle School in Lafayette, La are forming a school
radio club. Their first meeting will be at 10:20 AM CDT Thursday September
15th. If you could tune in on EchoLink node 370324 (the 146.82 W5DDL
repeater) at 10:30 for a quick demo it would be helpful. The younger you
are the more the kids will identify with you, but old guys like myself it is
O.K. If you can meet us on the air pleas reply to this email.
Thanks
nick
Office 337 593 8700
Cell 337 258 2527
Helping UL become a world Class Engineering and Educational School
_______________________________________________
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: 13
Date: Fri, 16 Sep 2011 08:58:02 -0400
From: "Bob Bruninga" <bruninga@xxxx.xxx>
To: "'Ted'" <k7trkradio@xxxxxxx.xxx>, "'AMSAT BB'"
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Message-ID: <020101cc7470$44c7dd90$ce5798b0$@xxx>
Content-Type: text/plain; charset="us-ascii"
> I just can't figure out the best way to hold the radio
By all means, you hold the radio to whatever works best. That is a MANY dB
advanatage over fixed antnenas, because the human ear-hand-feedback system
can respond in fractions of a second to always maintain the best signal at
any instant to match the instantaneous polarization of the satelite. No
mechanical mounting can do that.
Bob
-----Original Message-----
From: Ted [mailto:k7trkradio@xxxxxxx.xxxx
Sent: Thursday, September 15, 2011 7:41 PM
To: 'Bob Bruninga'; 'AMSAT BB'
Subject: RE: [amsat-bb] Re: Which Mobile Mag Mount?
Bob, thanks for the great data.
Question: do you think your data/techniques have any application to using a
dual band HT with a long whip (e.g. Diamond SRH77CA - 15.5"long)
In other words would you be better off just holding the HT vertical and
fairly stationary during the pass (adjusting Doppler of course) or moving
the darn thing all over until you capture the bird. I realize it is not
duplex, etc. but it does seem to work on a strong pass. I just can't figure
out the best way to hold the radio
Thanks for any help
73, Ted, K7TRK
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Bob Bruninga
Sent: Thursday, September 15, 2011 8:52 AM
To: 'AMSAT BB'
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Everyone's comments are correct and valid within their context. But the
original question was optimizing for the casual mobile operator in motion.
So here are some additional considerations...
> Second, any "vertical" antenna...will have a [null overhead]
> So, think about it: A GREAT pass of 90 degrees goes overhead
> your vertical is valueless during the middle of that great pass.
True, but when we put some actual numbers on that, the loss is quite
insignificant. Using AO51, only one pass every 5 days goes above 82
degrees, and the total duration above 82 degrees is 24 seconds, out of all
in view times. So we agree, the antenna is valueless, but for under 1% of
the time. The tradeoff is that it is 3 dB better most of the rest of the
time...
The measured elevation profile of a 3/4 wave vertical (a 19.5" whip on the
435 downlink) is shown 80% down the page http://aprs.org/astars.html. The
overhead null is only 10 dB down at 82 degrees... BUT the satellite is 10 dB
closer at that point, so you still hear it almost the same as when it came
above 25 degrees. So you get full sky coverage above 25 degrees > 99% of
the time with the vertical.
> Ideally - in a car - ... stopping and parking and getting a
> vertical perpendicular to the orbit of the satellite would
> give best results.
> Then maybe a Larsen mag mount... And bend - er, I mean,
> "re-form" that whip right at the base so that it is about
> 20" bent. you'll be more successful with the FM birds!
Yes, good idea, but now there is some directionality and so the car needs to
remain pointed towards the satellite during the pass. Otherwise there is
still the null, it is just in a different part of the sky.
> 1. If the satellite is circular polarization the 19.5 " whip looses 3 dB
of gain.
Yes, but most people have observed a polarization shift during overhead
passes. And in that case, the loss of a circularized antenna is much worse
than 3 dB... usually a complete fade. SO I agree, a circular antenna gets 3
dB better half the time, and much worse the other half the time. I prefer
the simplicity of the whip that does not give up more than 3dB no matter
what the polarization is. Mounting a quadrifilar on the roof of the mobile
is also problematic.
> 2. The common Quadrifilar Antenna is 1/2 wave 1/2 turn.
> The 1 wavelength, 1 turn Quadrifilar Antenna has its
> highest gain near or at the horizon depending on the
> length to diameter ratio.
But it is still only a 3 dB gain antenna out there, and so it is not going
to hear the satellite down on the horizon anyway because the satellite is
10 dB farther away and usually blocked for the mobile. So having gain on
the horizon for a mobile omni antenna is wasted. It either is not enough or
it creats additional nulls higher up. Better to move that gain higher up
but smooth where the satellite is closer and then have good contacts, than
waste gain where it is already insufficient or problematic.
Just different perspectives, but the devil is in the details...
Bob, Wb4APR
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------------------------------
Message: 14
Date: Fri, 16 Sep 2011 09:00:43 -0400
From: "Bob Bruninga" <bruninga@xxxx.xxx>
To: "'Ted'" <k7trkradio@xxxxxxx.xxx>, "'AMSAT BB'"
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Message-ID: <020201cc7470$a48c7790$eda566b0$@xxx>
Content-Type: text/plain; charset="us-ascii"
> I'm thinking maybe putting a mag mount with 19.5" of nice
> shiny wire on a pizza pan would do as well as the Arrow..
The pizza pan is assumed to be the size of your car roof to get the full
gain of the 3/4 wave vertical. Also, if you have the arrow, then you can
more than double your contact time because you can point it low on the
horizon.
The 19.5" whip in the center of your car roof is the no-muss-no-fuss
approach, for operating while mobile, but it does not compare to having a
good beam.
Bob, Wb4APR
73, Ted, K7TRK
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Bob Bruninga
Sent: Thursday, September 15, 2011 8:52 AM
To: 'AMSAT BB'
Subject: [amsat-bb] Re: Which Mobile Mag Mount?
Everyone's comments are correct and valid within their context. But the
original question was optimizing for the casual mobile operator in motion.
So here are some additional considerations...
> Second, any "vertical" antenna...will have a [null overhead]
> So, think about it: A GREAT pass of 90 degrees goes overhead
> your vertical is valueless during the middle of that great pass.
True, but when we put some actual numbers on that, the loss is quite
insignificant. Using AO51, only one pass every 5 days goes above 82
degrees, and the total duration above 82 degrees is 24 seconds, out of all
in view times. So we agree, the antenna is valueless, but for under 1% of
the time. The tradeoff is that it is 3 dB better most of the rest of the
time...
The measured elevation profile of a 3/4 wave vertical (a 19.5" whip on the
435 downlink) is shown 80% down the page http://aprs.org/astars.html. The
overhead null is only 10 dB down at 82 degrees... BUT the satellite is 10 dB
closer at that point, so you still hear it almost the same as when it came
above 25 degrees. So you get full sky coverage above 25 degrees > 99% of
the time with the vertical.
> Ideally - in a car - ... stopping and parking and getting a
> vertical perpendicular to the orbit of the satellite would
> give best results.
> Then maybe a Larsen mag mount... And bend - er, I mean,
> "re-form" that whip right at the base so that it is about
> 20" bent. you'll be more successful with the FM birds!
Yes, good idea, but now there is some directionality and so the car needs to
remain pointed towards the satellite during the pass. Otherwise there is
still the null, it is just in a different part of the sky.
> 1. If the satellite is circular polarization the 19.5 " whip looses 3 dB
of gain.
Yes, but most people have observed a polarization shift during overhead
passes. And in that case, the loss of a circularized antenna is much worse
than 3 dB... usually a complete fade. SO I agree, a circular antenna gets 3
dB better half the time, and much worse the other half the time. I prefer
the simplicity of the whip that does not give up more than 3dB no matter
what the polarization is. Mounting a quadrifilar on the roof of the mobile
is also problematic.
> 2. The common Quadrifilar Antenna is 1/2 wave 1/2 turn.
> The 1 wavelength, 1 turn Quadrifilar Antenna has its
> highest gain near or at the horizon depending on the
> length to diameter ratio.
But it is still only a 3 dB gain antenna out there, and so it is not going
to hear the satellite down on the horizon anyway because the satellite is
10 dB farther away and usually blocked for the mobile. So having gain on
the horizon for a mobile omni antenna is wasted. It either is not enough or
it creats additional nulls higher up. Better to move that gain higher up
but smooth where the satellite is closer and then have good contacts, than
waste gain where it is already insufficient or problematic.
Just different perspectives, but the devil is in the details...
Bob, Wb4APR
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 6, Issue 524
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