| |
CX2SA > SATDIG 10.01.16 00:24l 854 Lines 36270 Bytes #999 (0) @ WW
BID : AMSATBB119
Read: GUEST
Subj: AMSAT-BB-digest V11 9
Path: IW8PGT<IZ3LSV<ED1ZAC<CX2SA
Sent: 160109/2222Z @:CX2SA.SAL.URY.SOAM #:37313 [Salto] FBB7.00e $:AMSATBB119
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: Polarity (Burns Fisher)
2. Re: Polarity (Robert Bruninga)
3. Polarity (Roland Zurmely)
4. Pass Satellite Tracking - Rotor & Rigs (Pedro Converso)
5. fyi (Bob- W7LRD)
6. Re: It's so easy... (Greg D)
7. Regular Arrow vs. Alaskan Arrow (Dave Swanson)
8. Re: Regular Arrow vs. Alaskan Arrow (Lizeth Norman)
9. Re: Regular Arrow vs. Alaskan Arrow (Clayton W5PFG)
10. Video of ARISS between GB1SS and Sandringham school GB1SAN
(Ciaran Morgan)
11. Re: Polarity (R.T.Liddy)
----------------------------------------------------------------------
Message: 1
Date: Sat, 9 Jan 2016 12:39:48 -0500
From: Burns Fisher <burns@xxxxxx.xx>
To: Steve Kristoff <skristof@xxxxxxx.xxx>
Cc: amsat bb <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Polarity
Message-ID:
<CABX7KxVB9jX7ySL_8BGqtOLa+o4JAnif49K1zF8kD5GxAjtKQg@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Is the -1.5db vs -3db difference power vs voltage (which would be v**2/r
and thus the loss of power is the square of the loss of voltage, which is
double the db) ?
On Sat, Jan 9, 2016 at 12:34 PM, Steve Kristoff <skristof@xxxxxxx.xxx>
wrote:
> It makes sense (to me) that it follows a cosine function. So, if your
> antenna is horizontal and the signal is at 30 degrees above the horizontal,
> you should be getting about 87% of the signal, which figures out to a loss
> of about -.6dB. If the signal is coming in at 45 degrees, you're getting
> about 71% of the signal, for a loss of about -1.5 dB. If the signal is at
> 60 degrees above horizontal you'll get about 50% of the signal, which is
> the -3dB loss.
> At 80 degrees above horizontal, you'll get about 17% of the signal, which
> is a -7.6 dB loss
> I know that is not what the article says, but if you're going by cosines,
> which makes sense to me, those should be the numbers.
> (I think maybe)
>
> Steve AI9IN
>
> ----- Original Message ----- From: "Robert Bruninga" <bruninga@xxxx.xxx>
> To: "amsat bb" <amsat-bb@xxxxx.xxx>
> Sent: Saturday, January 09, 2016 12:05 PM
> Subject: Re: [amsat-bb] Polarity
>
>
> We all know that [matched polarity] = Zero db loss from cross
>>>
>> polarization.
>>
>>> And then in theory, the "Infinite loss" when cross polarized...
>>> [Pracically],it's more like 30 to 40 db or so [ or much less in the
>>>
>> presence of reflections]
>>
>>> Now does anyone know of a chart ... for every degree of something really
>>>
>> is?
>>
>>> Like 45 deg is 3 db down, 50 deg =? 55 deg =? etc.
>>>
>>
>> The cosine table works for all angles.. The cosine of 45 degrees is 1/2
>> which is -3 dB etc...
>>
>> Bob, Wb4APR
>> _______________________________________________
>> 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
>>
>> Steve Kristoff
> skristof@xxxxxxx.xxx
>
> "A few chords strummed on a ukulele, enough to please a few others beside
> yourself, does more good in this world than the combined efforts of all the
> financiers and politicians that ever lived." - Frank Littig, Littig's New
> Harmony Self Instructor Chords for Ukulele, Banjuke or Taro Patch Fiddle,
> Chart Music Publishing House, Chicago, Illinois, 1924
> _______________________________________________
> 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: 2
Date: Sat, 9 Jan 2016 12:40:55 -0500
From: Robert Bruninga <bruninga@xxxx.xxx>
To: amsat bb <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Polarity
Message-ID:
<CALdCfNKaY2rs7iTSoN6WysLSp+5SprUBWQ8fsGOOsrTjFXGQfg@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Sorry, I should have elaborated.... dB is a reference to power. ANd power
is proportional to Voltage squared. So when the voltage of an RF field is
down by 0.707 squared it is down by one half. Or - 3dB.
And when we use the cosine law we are referring to the angle off axis. So
straight on is 0 angle and is 0 dB loss. 45 degrees is 3 dB down. But
going another 22.5 degrees or 67.5 degrees off axis is 0.38 squared which
is.144 which is -8.4 dB . Getting down to 90 degrees where the cosine is 0
might also seem confusing, but remember we are comparing "dB down" which is
a ratio of the full power available, lets say 1, divided by the smaller
power we would get at off angles. When we get to 90 degree off angle, and
a cosine of 0 then we are comparing "1" straight on, divided by the "0" we
get when we are cross polarized and so we get 1/0 which is infinitely
"down"...
I guess there is a better way to explain it... but I have not had my coffee
yet.
Bob
On Sat, Jan 9, 2016 at 12:20 PM, Steve Kristoff <skristof@xxxxxxx.xxx>
wrote:
> Well, the cosine of 45 degrees is actually 0.707. I suspect that the
> article is implying that the loss is linear. Since 45 degrees is half of 90
> degrees, then you lose half the power, or -3dB.
> Following that logic, at 22.5 degrees you'd half one-fourth the power or
> -6dB, etc.
>
> I have no idea if the article is correct, but the cosine of 45 degrees is
> 0.707
>
> Steve AI9IN
>
> ----- Original Message ----- From: "Robert Bruninga" <bruninga@xxxx.xxx>
> To: "amsat bb" <amsat-bb@xxxxx.xxx>
> Sent: Saturday, January 09, 2016 12:05 PM
> Subject: Re: [amsat-bb] Polarity
>
>
> We all know that [matched polarity] = Zero db loss from cross
>>>
>> polarization.
>>
>>> And then in theory, the "Infinite loss" when cross polarized...
>>> [Pracically],it's more like 30 to 40 db or so [ or much less in the
>>>
>> presence of reflections]
>>
>>> Now does anyone know of a chart ... for every degree of something really
>>>
>> is?
>>
>>> Like 45 deg is 3 db down, 50 deg =? 55 deg =? etc.
>>>
>>
>> The cosine table works for all angles.. The cosine of 45 degrees is 1/2
>> which is -3 dB etc...
>>
>> Bob, Wb4APR
>> _______________________________________________
>> 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
>>
>> Steve Kristoff
> skristof@xxxxxxx.xxx
>
> "A few chords strummed on a ukulele, enough to please a few others beside
> yourself, does more good in this world than the combined efforts of all the
> financiers and politicians that ever lived." - Frank Littig, Littig's New
> Harmony Self Instructor Chords for Ukulele, Banjuke or Taro Patch Fiddle,
> Chart Music Publishing House, Chicago, Illinois, 1924
> _______________________________________________
> 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: Sat, 9 Jan 2016 17:44:47 +0000 (UTC)
From: Roland Zurmely <py4zbz@xxxxx.xxx>
To: AMSAT <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Polarity
Message-ID:
<1767358981.2060239.1452361487379.JavaMail.yahoo@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
The theoretical value of the loss in dB as a function of the angle "alpha"
of bias error?for linear polarization is: ?20log(cos(alpha))
Examples:?for alpha= 45 degrees : ?20log(cos(45)) = 20log(0,707) = -3 dBfor
alpha= 60 degrees : ?20log(cos(60)) = 20log(0,5) = -6 dBfor alpha= 89
degrees : ?20log(cos(89)) = 20log(0,0174)= -35 dB
73 de Roland PY4ZBZ
------------------------------
Message: 4
Date: Sat, 9 Jan 2016 15:02:01 -0300
From: Pedro Converso <pconver@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Pass Satellite Tracking - Rotor & Rigs
Message-ID:
<CANTZqK=45Rc=F+PrZ5mrKFk+KDrbSVzaJh+zJRjPpKDfEKMzrw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
App available at http://amsat.org.ar/pass.exe for download.
This application is an upgrade on web app http://amsat.org.ar/pass.htm
To control Rotor/Rigs, run concurrently WispDDE Driver. (
http://www.mederoscnc.com/CX6DD/wispdde/wispdde.htm )
Thanks for fine comments and suggestions on pass.htm .
Congrats all for excellent satellite activity shown on amsat-bb.
If You care to try pass.exe, comments, changes, additions, welcome.
Enjoy,
Best 73,
lu7abf, Pedro Converso
------------------------------
Message: 5
Date: Sat, 9 Jan 2016 18:18:12 +0000 (UTC)
From: Bob- W7LRD <w7lrd@xxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] fyi
Message-ID:
<810332739.853993.1452363492806.JavaMail.zimbra@xxxxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Recently bought a short jumper cable for my Chinese HT radio from MPD
digital. Nice quality and reasonable price.
73 Bob W7LRD
------------------------------
Message: 6
Date: Sat, 09 Jan 2016 11:05:22 -0800
From: Greg D <ko6th.greg@xxxxx.xxx>
To: James Lea - WX4TV <james@xxxxx.xxx>, amsat-bb <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] It's so easy...
Message-ID: <569159F2.1070106@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Way to go Hope! Quite a pro already.
Greg KO6TH
James Lea - WX4TV wrote:
> ?a little girl can do it!
>
> https://youtu.be/13COZU957IU <https://youtu.be/13COZU957IU>
>
>
>
> _______________________________________________
> 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: Sat, 9 Jan 2016 13:10:06 -0600
From: Dave Swanson <dave@xxxxxxxxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Regular Arrow vs. Alaskan Arrow
Message-ID: <56915B0E.6010909@xxxxxxxxxxxxx.xxx>
Content-Type: text/plain; charset=utf-8; format=flowed
Hello Satellites friends and colleagues,
Since I started making videos a few months back of my portable satellite
operating, a lot of folks have picked up on the fact that I seem to use
the 'Alaskan' Arrow (AKA) pretty often. I also tend to use the AKA for
DX contacts and very long distance QSOs which always make it into my
movies. Questions about the AKA versus the regular arrow have become by
far the most asked topic of me from other operators. Clayton, W5PFG,
wrote an outstanding piece on his blog (
http://www.w5pfg.us/2015/10/my-thoughts-about-alaskan-arrow-146437.html
) with his thoughts on the AKA, after his experience with one this fall,
that I'd recommend that anyone interested in this topic also go read.
Since I don't have a blog though, this is the best forum I have to
express thoughts on the matter. If you have no intention of ever
operating portable, or are convinced some other design is superior, then
feel free to skip the rest of this thread. I'm not trying to make this
into anything other than an answer to frequently asked questions I get,
concerning the differences between the Regular Arrow and the Alaskan
Arrow, and to try and address the 'is it worth it' question that
inevitably follows the 'which one should I get' question.
So, to start, the regular arrow is great antenna. I have one, and I use
it for 95% of the passes I work. I used my regular arrow for my first
QSOs with Brazil, Alaska, Hawaii, Northern Ireland, and England, all of
which are between 5000km and 7200km from my home operating spots. It is
lightweight, effective, and will suit the needs of nearly every
satellite operator out there that seeks a portable antenna. If (and this
is a huge if, that's outside the scope of this post, but so so
important) you have a nice operating spot that has a clear view of the
horizon with nothing in the way. You can easily work all birds in the
sky AOS til LOS with the regular arrow, and be wildly successful. If I'm
not chasing 7000km+ DX, I'll be on my regular arrow. If I'm hanging my
arm out the window while /P in another grid? I'll be on my regular
arrow. Backyard 45? SO50 pass in the evening? Regular Arrow. Most of the
time, I'm on my regular Arrow. It probably doesn't look that way from
pictures and video, but I typically don't document my routine
operating.. no one wants to see that, they only wanna see the cool stuff.
So, why do I own and use an AKA with everything I just wrote in mind?
First, I do operate terrestrial VHF/UHF, as well as satellites, from
mountain tops. For this type of work I'll physically attach the AKA with
only one set of elements installed to my mast, pop it up in the air, and
work folks in other grids on 2m or 70cm. If I'm Jeepin' to the mountain
top, my equipment has to break down into small enough pieces I can fit
it inside, or if I'm hiking, it needs to be small and lightweight enough
to carry up on my back. The AKA represents the highest gain, lightest
weight, most portable solution that I could find for my style of
mountain-topping.
Second, the AKA does have more gain, which is useful for working
satellites. It's not a lot more gain, and it's not required on most
passes, but I routinely work at < 0.5? in max elevation from elevated
positions while portable, and so every db counts. Most people are
probably not doing this... and judging by the considerable lack of
activity I hear in the birds on these passes, I think there's a fair
amount of evidence to support this theory. If you're routinely working
exceptionally low passes at and near the horizon portable, then an AKA
might be for you. If not, I wouldn't worry about it.
Third, as mentioned many times by others, the AKA is big and heavy. As
Jeff, NI3B, said a while back in a post "Holding one of those things up
in the air for fourteen minutes and your arms will look like Popeye the
Sailor Man at LOS." Combine this with my distaste for tripods, and you
can see where we've got an issue. While I don't care much for canned
spinach, I am a six-foot, 250 pound man, I split firewood by hand, and I
try to keep myself pretty strong and in shape. I can hold the AKA for an
entire pass without a huge issue, even thought my arms get pretty sore
after. I absolutely understand that others may not be capable, or simply
may not want to subject themselves to this kind of punishment. That's
fine, you don't have too. Get a regular arrow, and save your biceps..
you'll be just fine.
So in summary, If you're a mountain-top, multidisciplinary operator,
that wants superior portable performance, weight and muscle fatigue be
damned, then the AKA might be for you. If you're not, get the regular
arrow, you won't be sorry.
Feel free to ask questions, provide critiques.
73!
-Dave, KG5CCI
------------------------------
Message: 8
Date: Sat, 9 Jan 2016 14:35:37 -0500
From: Lizeth Norman <normanlizeth@xxxxx.xxx>
To: Dave Swanson <dave@xxxxxxxxxxxxx.xxx>
Cc: "<,amsat-bb@xxxxx.xxxxxxxx <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Regular Arrow vs. Alaskan Arrow
Message-ID:
<CAJUhCTNXQ7gF9HgfvmdeF4wA+hxXxswXEj65E4BwEhx_+zn2pQ@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Phased Elks work well. Airline portable. 2 pieces of coax the same
length and a tee. Only caveat is the horizontal spacing. Any antenna
pair could be driven the same way.
Shooting RF up and over the Andes (knife edge diffraction) and taking
advantage of ducting are two of the things that I've noticed with this
setup.
Fellow at Elk was kind enough to outline what I needed to know
regarding this and then push me out to the net to learn.. Look up
stacking antennas. Capture area. He thinks the elk has an elliptical
capture area. That follows from my in field testing.
It's not about gain (directionality, really), it's about more signal
to less noise. Noise levels in the rest of the world are high.
Example: Seaside VHF or UHF. Noise pointing over the ocean is much
less, s2. Point inland in any occupied area.. 20+S9. Cavity helps
somewhat with AGC lift.
I don't take this stuff to nowheresville without a reason.
Let me tell you about the dxpedition to Vieques that no one heard.
On Sat, Jan 9, 2016 at 2:10 PM, Dave Swanson <dave@xxxxxxxxxxxxx.xxx> wrote:
> Hello Satellites friends and colleagues,
>
> Since I started making videos a few months back of my portable satellite
> operating, a lot of folks have picked up on the fact that I seem to use the
> 'Alaskan' Arrow (AKA) pretty often. I also tend to use the AKA for DX
> contacts and very long distance QSOs which always make it into my movies.
> Questions about the AKA versus the regular arrow have become by far the most
> asked topic of me from other operators. Clayton, W5PFG, wrote an outstanding
> piece on his blog (
> http://www.w5pfg.us/2015/10/my-thoughts-about-alaskan-arrow-146437.html )
> with his thoughts on the AKA, after his experience with one this fall, that
> I'd recommend that anyone interested in this topic also go read. Since I
> don't have a blog though, this is the best forum I have to express thoughts
> on the matter. If you have no intention of ever operating portable, or are
> convinced some other design is superior, then feel free to skip the rest of
> this thread. I'm not trying to make this into anything other than an answer
> to frequently asked questions I get, concerning the differences between the
> Regular Arrow and the Alaskan Arrow, and to try and address the 'is it worth
> it' question that inevitably follows the 'which one should I get' question.
>
> So, to start, the regular arrow is great antenna. I have one, and I use it
> for 95% of the passes I work. I used my regular arrow for my first QSOs with
> Brazil, Alaska, Hawaii, Northern Ireland, and England, all of which are
> between 5000km and 7200km from my home operating spots. It is lightweight,
> effective, and will suit the needs of nearly every satellite operator out
> there that seeks a portable antenna. If (and this is a huge if, that's
> outside the scope of this post, but so so important) you have a nice
> operating spot that has a clear view of the horizon with nothing in the way.
> You can easily work all birds in the sky AOS til LOS with the regular arrow,
> and be wildly successful. If I'm not chasing 7000km+ DX, I'll be on my
> regular arrow. If I'm hanging my arm out the window while /P in another
> grid? I'll be on my regular arrow. Backyard 45? SO50 pass in the evening?
> Regular Arrow. Most of the time, I'm on my regular Arrow. It probably
> doesn't look that way from pictures and video, but I typically don't
> document my routine operating.. no one wants to see that, they only wanna
> see the cool stuff.
>
> So, why do I own and use an AKA with everything I just wrote in mind?
>
> First, I do operate terrestrial VHF/UHF, as well as satellites, from
> mountain tops. For this type of work I'll physically attach the AKA with
> only one set of elements installed to my mast, pop it up in the air, and
> work folks in other grids on 2m or 70cm. If I'm Jeepin' to the mountain top,
> my equipment has to break down into small enough pieces I can fit it inside,
> or if I'm hiking, it needs to be small and lightweight enough to carry up on
> my back. The AKA represents the highest gain, lightest weight, most portable
> solution that I could find for my style of mountain-topping.
>
> Second, the AKA does have more gain, which is useful for working satellites.
> It's not a lot more gain, and it's not required on most passes, but I
> routinely work at < 0.5? in max elevation from elevated positions while
> portable, and so every db counts. Most people are probably not doing this...
> and judging by the considerable lack of activity I hear in the birds on
> these passes, I think there's a fair amount of evidence to support this
> theory. If you're routinely working exceptionally low passes at and near the
> horizon portable, then an AKA might be for you. If not, I wouldn't worry
> about it.
>
> Third, as mentioned many times by others, the AKA is big and heavy. As Jeff,
> NI3B, said a while back in a post "Holding one of those things up in the air
> for fourteen minutes and your arms will look like Popeye the Sailor Man at
> LOS." Combine this with my distaste for tripods, and you can see where we've
> got an issue. While I don't care much for canned spinach, I am a six-foot,
> 250 pound man, I split firewood by hand, and I try to keep myself pretty
> strong and in shape. I can hold the AKA for an entire pass without a huge
> issue, even thought my arms get pretty sore after. I absolutely understand
> that others may not be capable, or simply may not want to subject themselves
> to this kind of punishment. That's fine, you don't have too. Get a regular
> arrow, and save your biceps.. you'll be just fine.
>
> So in summary, If you're a mountain-top, multidisciplinary operator, that
> wants superior portable performance, weight and muscle fatigue be damned,
> then the AKA might be for you. If you're not, get the regular arrow, you
> won't be sorry.
>
> Feel free to ask questions, provide critiques.
>
> 73!
>
> -Dave, KG5CCI
>
> _______________________________________________
> 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: 9
Date: Sat, 9 Jan 2016 14:07:19 -0600
From: Clayton W5PFG <w5pfg@xxxxx.xxx>
To: AMSAT-BB <amsat-bb@xxxxx.xxx>, "Dave Swanson
<dave@xxxxxxxxxxxxx.xxx>; Lizeth Norman" <normanlizeth@xxxxx.xxx>
Subject: Re: [amsat-bb] Regular Arrow vs. Alaskan Arrow
Message-ID: <56916877.6020601@xxxxx.xxx>
Content-Type: text/plain; charset=utf-8; format=flowed
One factor that is often overlooked in planning a good portable
operation is the location's height above average terrain and the
surrounding noise level. Dave KG5CCI certainly knows how to pick a good
location.
In a very low-noise, high plain area where I operate occasionally
(DM95ae/DM985xe,) a short 2 element 2m yagi and 4 element 70cm yagi
allow me to operate to the horizon in all directions on all of our
current LEO satellites. That antenna choice is not applicable everywhere.
Another factor is the portability of the station itself. In many cases,
I drive a vehicle with my portable gear. With air travel, larger yagis
or multiple antennas can be problematic. I have had no trouble flying
domestically or internationally with a full size Arrow and/or Elk.
I'd opt for a better operating location than bigger antenna almost any
day. Larger and more complex stations reduce your ability to be agile
and adapt to unexpected situations encountered in the field. Plus,
increased complexity creates opportunity for failure.
It is always interesting to read from others how they operate portable.
The variations in technique and equipment provides others a stepping
stones on which to perfect their own portable stations.
73
Clayton
W5PFG
On 1/9/2016 13:35, Lizeth Norman wrote:
> Phased Elks work well. Airline portable. 2 pieces of coax the same
> length and a tee. Only caveat is the horizontal spacing. Any antenna
> pair could be driven the same way.
>
> Shooting RF up and over the Andes (knife edge diffraction) and taking
> advantage of ducting are two of the things that I've noticed with this
> setup.
>
> Fellow at Elk was kind enough to outline what I needed to know
> regarding this and then push me out to the net to learn.. Look up
> stacking antennas. Capture area. He thinks the elk has an elliptical
> capture area. That follows from my in field testing.
>
> It's not about gain (directionality, really), it's about more signal
> to less noise. Noise levels in the rest of the world are high.
>
> Example: Seaside VHF or UHF. Noise pointing over the ocean is much
> less, s2. Point inland in any occupied area.. 20+S9. Cavity helps
> somewhat with AGC lift.
>
> I don't take this stuff to nowheresville without a reason.
>
> Let me tell you about the dxpedition to Vieques that no one heard.
>
> On Sat, Jan 9, 2016 at 2:10 PM, Dave Swanson <dave@xxxxxxxxxxxxx.xxx> wrote:
>> Hello Satellites friends and colleagues,
>>
>> Since I started making videos a few months back of my portable satellite
>> operating, a lot of folks have picked up on the fact that I seem to use the
>> 'Alaskan' Arrow (AKA) pretty often. I also tend to use the AKA for DX
>> contacts and very long distance QSOs which always make it into my movies.
>> Questions about the AKA versus the regular arrow have become by far the
most
>> asked topic of me from other operators. Clayton, W5PFG, wrote an
outstanding
>> piece on his blog (
>> http://www.w5pfg.us/2015/10/my-thoughts-about-alaskan-arrow-146437.html )
>> with his thoughts on the AKA, after his experience with one this fall, that
>> I'd recommend that anyone interested in this topic also go read. Since I
>> don't have a blog though, this is the best forum I have to express thoughts
>> on the matter. If you have no intention of ever operating portable, or are
>> convinced some other design is superior, then feel free to skip the rest of
>> this thread. I'm not trying to make this into anything other than an answer
>> to frequently asked questions I get, concerning the differences between the
>> Regular Arrow and the Alaskan Arrow, and to try and address the 'is it
worth
>> it' question that inevitably follows the 'which one should I get' question.
>>
>> So, to start, the regular arrow is great antenna. I have one, and I use it
>> for 95% of the passes I work. I used my regular arrow for my first QSOs
with
>> Brazil, Alaska, Hawaii, Northern Ireland, and England, all of which are
>> between 5000km and 7200km from my home operating spots. It is lightweight,
>> effective, and will suit the needs of nearly every satellite operator out
>> there that seeks a portable antenna. If (and this is a huge if, that's
>> outside the scope of this post, but so so important) you have a nice
>> operating spot that has a clear view of the horizon with nothing in the
way.
>> You can easily work all birds in the sky AOS til LOS with the regular
arrow,
>> and be wildly successful. If I'm not chasing 7000km+ DX, I'll be on my
>> regular arrow. If I'm hanging my arm out the window while /P in another
>> grid? I'll be on my regular arrow. Backyard 45? SO50 pass in the evening?
>> Regular Arrow. Most of the time, I'm on my regular Arrow. It probably
>> doesn't look that way from pictures and video, but I typically don't
>> document my routine operating.. no one wants to see that, they only wanna
>> see the cool stuff.
>>
>> So, why do I own and use an AKA with everything I just wrote in mind?
>>
>> First, I do operate terrestrial VHF/UHF, as well as satellites, from
>> mountain tops. For this type of work I'll physically attach the AKA with
>> only one set of elements installed to my mast, pop it up in the air, and
>> work folks in other grids on 2m or 70cm. If I'm Jeepin' to the mountain
top,
>> my equipment has to break down into small enough pieces I can fit it
inside,
>> or if I'm hiking, it needs to be small and lightweight enough to carry up
on
>> my back. The AKA represents the highest gain, lightest weight, most
portable
>> solution that I could find for my style of mountain-topping.
>>
>> Second, the AKA does have more gain, which is useful for working
satellites.
>> It's not a lot more gain, and it's not required on most passes, but I
>> routinely work at < 0.5? in max elevation from elevated positions while
>> portable, and so every db counts. Most people are probably not doing
this...
>> and judging by the considerable lack of activity I hear in the birds on
>> these passes, I think there's a fair amount of evidence to support this
>> theory. If you're routinely working exceptionally low passes at and near
the
>> horizon portable, then an AKA might be for you. If not, I wouldn't worry
>> about it.
>>
>> Third, as mentioned many times by others, the AKA is big and heavy. As
Jeff,
>> NI3B, said a while back in a post "Holding one of those things up in the
air
>> for fourteen minutes and your arms will look like Popeye the Sailor Man at
>> LOS." Combine this with my distaste for tripods, and you can see where
we've
>> got an issue. While I don't care much for canned spinach, I am a six-foot,
>> 250 pound man, I split firewood by hand, and I try to keep myself pretty
>> strong and in shape. I can hold the AKA for an entire pass without a huge
>> issue, even thought my arms get pretty sore after. I absolutely understand
>> that others may not be capable, or simply may not want to subject
themselves
>> to this kind of punishment. That's fine, you don't have too. Get a regular
>> arrow, and save your biceps.. you'll be just fine.
>>
>> So in summary, If you're a mountain-top, multidisciplinary operator, that
>> wants superior portable performance, weight and muscle fatigue be damned,
>> then the AKA might be for you. If you're not, get the regular arrow, you
>> won't be sorry.
>>
>> Feel free to ask questions, provide critiques.
>>
>> 73!
>>
>> -Dave, KG5CCI
>>
>> _______________________________________________
>> 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: 10
Date: Sat, 9 Jan 2016 21:42:34 +0000
From: "Ciaran Morgan" <ciaran@xxxxxxxxxxx.xx.xx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Video of ARISS between GB1SS and Sandringham
school GB1SAN
Message-ID: <20160109214816.2660886C4@xxxxxxxxxx.xxxxx.xxx>
Content-Type: text/plain; charset="Windows-1252"
The full video of the web stream from Fridays contact between Sandringham
school and Tim Peake is now available on YouTube.
The video is a complete copy of everything that was web streamed from the
school by the UK ARISS team.
Please search for the "ARISS UK Team" and you will find a channel that I
have set up.
It currently contains the video from the Richard Garriott contact in Oct
2008 with Budbrooke School and the Sandringham contact.
Over time, it will be populated with videos of the previous UK contacts.
As further contacts with Tim occur, they will be uploaded to this YouTube
channel.
Enjoy!
73s
Ciaran - M0XTD
------------------------------
Message: 11
Date: Sat, 9 Jan 2016 22:20:40 +0000 (UTC)
From: "R.T.Liddy" <k8bl@xxxxxxxxx.xxx>
To: AMSAT BB <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Polarity
Message-ID:
<2044500797.2676069.1452378040434.JavaMail.yahoo@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
It seems to me that a live test of these theories and calculations?would be
easy to perform.
In an open space, separate two radios with dipole antennas. Onone radio
transmit and read the receive level on the other radiowhile turning one of
the antennas to a variety of polarizations.
Be careful to avoid ground effects and Fresnel Zones.
Let us know the results. ? ;o)
GL/73, ? ? ?Bob K8BL
From: Steve Kristoff <skristof@xxxxxxx.xxx>
To: amsat bb <amsat-bb@xxxxx.xxx>
Sent: Saturday, January 9, 2016 12:34 PM
Subject: Re: [amsat-bb] Polarity
It makes sense (to me) that it follows a cosine function. So, if your
antenna is horizontal and the signal is at 30 degrees above the horizontal,
you should be getting about 87% of the signal, which figures out to a loss
of about -.6dB. If the signal is coming in at 45 degrees, you're getting
about 71% of the signal, for a loss of about -1.5 dB. If the signal is at 60
degrees above horizontal you'll get about 50% of the signal, which is
the -3dB loss.
At 80 degrees above horizontal, you'll get about 17% of the signal, which is
a -7.6 dB loss
I know that is not what the article says, but if you're going by cosines,
which makes sense to me, those should be the numbers.
(I think maybe)
Steve AI9IN
----- Original Message -----
From: "Robert Bruninga" <bruninga@xxxx.xxx>
To: "amsat bb" <amsat-bb@xxxxx.xxx>
Sent: Saturday, January 09, 2016 12:05 PM
Subject: Re: [amsat-bb] Polarity
>> We all know that [matched polarity] = Zero db loss from cross
> polarization.
>> And then in theory, the "Infinite loss"? when cross polarized...
>> [Pracically],it's more like 30 to 40 db or so [ or much less in the
> presence of reflections]
>> Now does anyone know of a chart ... for every degree of something really
> is?
>> Like 45 deg is 3 db down,? 50 deg =? 55 deg =?? etc.
>
> The cosine table works for all angles..? The cosine of 45 degrees is 1/2
> which is -3 dB etc...
>
> Bob, Wb4APR
> _______________________________________________
> 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
>
Steve Kristoff
skristof@xxxxxxx.xxx
"A few chords strummed on a ukulele, enough to please a few others beside
yourself, does more good in this world than the combined efforts of all the
financiers and politicians that ever lived." - Frank Littig, Littig's New
Harmony Self Instructor Chords for Ukulele, Banjuke or Taro Patch Fiddle,
Chart Music Publishing House, Chicago, Illinois, 1924
_______________________________________________
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 11, Issue 9
***************************************
Read previous mail | Read next mail
| |
