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CX2SA > SATDIG 25.04.11 15:46l 888 Lines 31196 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: Icom D-Star (Diane Bruce)
2. Re: Icom D-Star (Edward R. Cole)
3. Re: Icom D-Star (i8cvs)
4. Re: Icom D-Star (Tony Langdon)
5. Today EK09 (David Maciel)
6. Re: Icom D-Star (Edward R. Cole)
7. Cat/Pin numbers NON Sat Question (Kevin Deane)
8. Endeavor's Alpha Magnetic Spectrometer (Clint Bradford)
9. Arrow and ELK Comparative Antenna Tests (John Kopala)
10. Congresswoman Giffords Will Attend ... (Clint Bradford)
11. XE3DX On EK08 (David Maciel)
12. Re: Icom D-Star (Ben Jackson)
13. 2m/70cm Quadrifilar Helix antenna Antenna Kit from
Antennas.us (vtnn43e@xxxxxxx.xxxx
14. Re: Arrow and ELK Comparative Antenna Tests (Gary "Joe" Mayfield)
15. Re: Arrow and ELK Comparative Antenna Tests (Mark L. Hammond)
16. Re: 2m/70cm Quadrifilar Helix antenna Antenna Kit from
Antennas.us (Mark L. Hammond)
17. Call for Papers--2011 ARRL/TAPR Digital
CommunicationsConference (Ford, Steve, WB8IMY)
----------------------------------------------------------------------
Message: 1
Date: Sun, 24 Apr 2011 15:18:55 -0400
From: Diane Bruce <db@xx.xxx>
Subject: [amsat-bb] Re: Icom D-Star
To: Sebastian <w4as@xxxxxxxxx.xxx>
Cc: amsat-bb <amsat-bb@xxxxx.xxx>
Message-ID: <20110424191855.GA34301@xxxxx.xx.xxx>
Content-Type: text/plain; charset=us-ascii
On Sun, Apr 24, 2011 at 02:36:37PM -0400, Sebastian wrote:
> Never heard of WSJT?
Never heard of it.
- 73 Diane VA3DB
--
- db@xxxxxxx.xxx db@xx.xxx http://www.db.net/~db
------------------------------
Message: 2
Date: Sun, 24 Apr 2011 11:49:15 -0800
From: "Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Icom D-Star
To: Diane Bruce <db@xx.xxx>
Cc: amsat-bb <amsat-bb@xxxxx.xxx>
Message-ID: <201104241949.p3OJnGKU013556@xxxxxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 11:18 AM 4/24/2011, Diane Bruce wrote:
>On Sun, Apr 24, 2011 at 02:36:37PM -0400, Sebastian wrote:
> > Never heard of WSJT?
>
>Never heard of it.
>
>- 73 Diane VA3DB
>--
Diane,
I'm surprised as involved in mw as you are.
Here is a link to the software:
http://physics.princeton.edu/pulsar/K1JT/
Joe Taylor, K1JT, was a professor (now emeritus) at Princeton and a
Noble Laureate for his work with Pulsars.
He first wrote FSK-441 as a digital mode for meteor scatter which has
essentially replaced high speed CW as the primary mode on ms. Then
he developed a weak-signal program for eme about 2002 (it is nearing
ten years). The group of programs was bundled into a suite called
WSJT (weak-signal JT). The prime mode for 2m eme is now JT-65; CW
has been largely replaced. JT-65 uses noise reduction algorithms
taken from the Reed-Solomon sw that is used for NR on DVD's. JT-65
is a very narrow band digital mode occupying only 4.7 Hz, thus it
demonstrates SNR > 10 dB over CW. It is a synchronous digital mode
so it requires precise timing and frequency. Most users use internet
sw to maintain their computer time <1 sec error.
One offshoot is the propagation beacon sw, WSPR "whisper", which is
very popular on HF for determining band conditions. Many stations
only run 1w or less with the sw.
http://wsprnet.org/drupal/
Maybe you have heard of these programs but not under the name of the
bundled suite (WSJT).
73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
EME: 50-1.1kW?, 144-1.4kw, 432-100w, 1296-testing*, 3400-?
DUBUS Magazine USA Rep dubususa@xxxxxxx.xxx
======================================
------------------------------
Message: 3
Date: Sun, 24 Apr 2011 23:43:52 +0200
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Subject: [amsat-bb] Re: Icom D-Star
To: "Diane Bruce" <db@xx.xxx>, "Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
Cc: amsat-bb <amsat-bb@xxxxx.xxx>
Message-ID: <003101cc02c8$b4678660$0401a8c0@xxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
To: "Diane Bruce" <db@xx.xxx>
Cc: "amsat-bb" <amsat-bb@xxxxx.xxx>
Sent: Sunday, April 24, 2011 9:49 PM
Subject: [amsat-bb] Re: Icom D-Star
> The prime mode for 2m eme is now JT-65; CW
> has been largely replaced.
>
> 73, Ed - KL7UW, WD2XSH/45
Hi Ed, KL7UW
I am anxious about that because even on EME very soon
nobody will be able to use by hand a CW key and copy
Morse Code by ears.
I am sorry because I like very much the CW sound in my
ears.
CW is like music for me and after to eliminate the Radio
Officers over the ships we radio hams we actually should
be the last frontier for the CW existence.
73" de
i8CVS Domenico
------------------------------
Message: 4
Date: Mon, 25 Apr 2011 08:16:08 +1000
From: Tony Langdon <vk3jed@xxxxx.xxx>
Subject: [amsat-bb] Re: Icom D-Star
To: "i8cvs" <domenico.i8cvs@xxx.xx>, "Diane Bruce" <db@xx.xxx>,
"Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
Cc: amsat-bb <amsat-bb@xxxxx.xxx>
Message-ID: <4db4a130.e30d440a.1b2f.1386@xx.xxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 07:43 AM 4/25/2011, i8cvs wrote:
>I am anxious about that because even on EME very soon
>nobody will be able to use by hand a CW key and copy
>Morse Code by ears.
I don't think Morse is in any danger. I've seen an increase in
interest since the compulsory Morse exams were dropped in this part
of the world, particularly among younger people. I think it would be
a shame to see Morse go, and there's a real opportunity for those who
are proficient to show the newcomers the joys and elegant simplicity
of CW. I don't think you'll have a shortage of students, now that
Morse is both optional and something only in history outside of amateur radio.
>I am sorry because I like very much the CW sound in my
>ears.
>
>CW is like music for me and after to eliminate the Radio
>Officers over the ships we radio hams we actually should
>be the last frontier for the CW existence.
You can keep the torch burning. Unfortunately, I haven't had the
chance to get to a level I'd be comfortable using on air, that might
be a project for later in life, when there's less distractions, since
I find the idea of Morse very attractive also. It's a pity the old
exams emphasised slow speeds, I'd have done better had I learned at
more "useful" speeds. :/
73 de VK3JED / VK3IRL
http://vkradio.com
------------------------------
Message: 5
Date: Sun, 24 Apr 2011 15:54:15 -0500
From: "David Maciel" <xe3dx@xxxxxxx.xxx.xx>
Subject: [amsat-bb] Today EK09
To: <Undisclosed-Recipient:;>
Message-ID: <7DAFF58741414684A65D82647EDADC30@xxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi All, this day will be operating from ek09 in satellites AO-27 AO-51 and
SO-50 all passes
Dave
XE3DX
------------------------------
Message: 6
Date: Sun, 24 Apr 2011 15:02:57 -0800
From: "Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Icom D-Star
To: "amsat-bb" <amsat-bb@xxxxx.xxx>
Message-ID: <201104242302.p3ON2vJq071645@xxxxxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 01:43 PM 4/24/2011, i8cvs wrote:
>----- Original Message -----
>From: "Edward R. Cole" <kl7uw@xxxxxxxxx.xxx>
>To: "Diane Bruce" <db@xx.xxx>
>Cc: "amsat-bb" <amsat-bb@xxxxx.xxx>
>Sent: Sunday, April 24, 2011 9:49 PM
>Subject: [amsat-bb] Re: Icom D-Star
>
>
> > The prime mode for 2m eme is now JT-65; CW
> > has been largely replaced.
> >
> > 73, Ed - KL7UW, WD2XSH/45
>
>Hi Ed, KL7UW
>
>I am anxious about that because even on EME very soon
>nobody will be able to use by hand a CW key and copy
>Morse Code by ears.
>
>I am sorry because I like very much the CW sound in my
>ears.
>
>CW is like music for me and after to eliminate the Radio
>Officers over the ships we radio hams we actually should
>be the last frontier for the CW existence.
>
>73" de
>
>i8CVS Domenico
You can still do eme on CW, just it will take a bigger antenna array
and 1000w to be heard. JT-65 enables a station with a couple 10
element yagis or one longer yagi and 150w the ability to do eme on
2m. That is a huge attraction.
One takes about $5,000 and the other $500-800. You see the 10-dB
advantage applies to the cost as well! ;-)
CW is still prevalent on eme at 1296 and above. I still hear plenty
of CW around 14.020. It is the main mode used on LF and MW. but
digital modes are demonstrating they are superior in weak-signal as
well as emcomm.
WSPR on 10-MHz has been copied at 120 microwatts.
73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
EME: 50-1.1kW?, 144-1.4kw, 432-100w, 1296-testing*, 3400-?
DUBUS Magazine USA Rep dubususa@xxxxxxx.xxx
======================================
------------------------------
Message: 7
Date: Sun, 24 Apr 2011 19:22:27 -0700
From: Kevin Deane <summit496@xxxx.xxx>
Subject: [amsat-bb] Cat/Pin numbers NON Sat Question
To: <amsat-bb@xxxxx.xxx>
Message-ID: <COL107-W246A1194BA3C63D7537ABE83960@xxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
Does anyone know the pin numbers for the back of the computer/soundcard?
I have a new Yaesu FT-7900 cable and one of the wires is black instead of
blue like the manual says...
How do I know what number the pins are on the computer side of the cable
where I would connect the ends too I am sure that is standard?
Any help would be greatly appreciated, not having any luck looking it up on
the web.
Thanks
Kevin
KF7MYK
------------------------------
Message: 8
Date: Sun, 24 Apr 2011 20:22:19 -0700
From: Clint Bradford <clintbradford@xxx.xxx>
Subject: [amsat-bb] Endeavor's Alpha Magnetic Spectrometer
To: AMSAT BB <amsat-bb@xxxxx.xxx>
Message-ID: <7090AE4E-2699-47A7-B263-93D603D22329@xxx.xxx>
Content-Type: text/plain; charset=windows-1252
My wife and I "rate" books and articles on their topic sentences - the
initial declarative sentences - and whether or not that initial sentence
grabs and holds our attention or not. Those that do, we continue to read,
Those that do not, we dismiss and move on.
>From the Orlando Sentinel yesterday, here's one that grabbed me ...
"Stowed in the cargo hold of space shuttle Endeavour for its final launch
Friday is a science experiment that could upend astronomy in ways
unparalleled since the Hubble Space Telescope. Or ? if it flops ? it could
end up as a $1.5-billion hood ornament on the International Space Station."
Read more about the Alpha Magnetic Spectrometer at NASA's Web site.
Clint, K6LCS
------------------------------
Message: 9
Date: Sun, 24 Apr 2011 20:49:32 -0700
From: John Kopala <jkopala@xxxxx.xxx>
Subject: [amsat-bb] Arrow and ELK Comparative Antenna Tests
To: amsat-bb@xxxxx.xxx
Message-ID: <4DB4EF4C.30500@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On Saturday, April 23, Pat Stoddard (WD9EWK) and I did some antenna testing
in an attempt to answer
the questions about which is the best antenna for portable satellite
operation. We only tested the
antennas in receive mode to determine their relative gain. Time constraints
prevented us from
performing additional testing to determine if the transmitted output was
consistent with the receive
gain of the antennas. For the time being we will assume (and we all know
the dangers of doing so)
that the transmit performance closely matches the receive performance.
The antennas tested were an Arrow (3 x 7 elements), an ELK (4 elements), a
PortaFox configured for
145/435 operation (4 elements), and a Home Brew 4 by 9 element "arrow"
antenna. The standard Arrow
antenna was the only antenna equipped with duplexer, but not the basic
duplexer which is installed
in the handle. We did not measure the insertion loss of the duplexer on the
Arrow antenna, but this
was obviously not a significant factor in the overall performance. A
duplexer could still be
required depending upon the antenna chosen and the radio(s) to be used.
Using the Arrow antenna as the reference antenna and 145.300 MHz as our test
frequency, our
measurements indicated that the Arrow and the ELK antennas had identical
gain. The PortaFox antenna
showed 2db less gain than the Arrow and the ELK. The Home Brew 4/9 element
crossed yagi showed 2db
more gain than the Arrow and the ELK.
On 435.300 MHz, the Arrow antenna had 2db more gain than the ELK and 8db
more gain than the
PortaFox. The Home Brew 4/9 element had 3db more gain than the Arrow.
Although the ELK antenna shows slightly less (2db) gain on 435.300 MHz, it
does have one potential
advantage over the Arrow antenna. With the ELK, transmit and receive are in
the same plane. With
any satellites that have linear polarized antennas, such as AO-27, SO-50,
the ISS and maybe SO-67,
a crossed yagis can maximize the performance on one band while minimizing it
on the other. That
does not mean the Arrow won't work, as has been demonstrated by the
thousands of satellite QSO's
that are made on a regular basis using Arrow antennas. It just means that
when you rotate the
antenna to maximize the downlink signal, you may be significantly impacting
you uplink signal
strength in marginal situations.
Even though a satellite may have a circular polarized uplink and downlink,
don't assume that the
orientation of your station antenna as horizontal, vertical, or something in
between won't have a
significant effect on your signal strength. My experience operating
portable with my home brew
antenna has convinced me that my horizontally polarized Qagi should either
be remounted vertically
polarized or replaced with a circular polarized antenna. That is another
ongoing project.
In summary, unless you plan to build your own, the performance of the Arrow
crossed yagi antenna and
the ELK log periodic antennas are very comparable and should provide lots of
solid satellite contacts.
The overall results reflect the adage that bigger is better, but along with
more gain, you also get
a more bulky antenna that is harder to handle. The home brew crossed yagi I
built for portable
operation is tripod mounted, can be rotated on its axis, and disassembles
for storage in a roll up
case. But because of its size, it would be very tiring to attempt to use it
hand held for an
extended period of time. Pictures of the home brew crossed yagi antenna are
on my QRZ page.
John Kopala
N7JK
------------------------------
Message: 10
Date: Sun, 24 Apr 2011 21:04:39 -0700
From: Clint Bradford <clintbradford@xxx.xxx>
Subject: [amsat-bb] Congresswoman Giffords Will Attend ...
To: AMSAT BB <amsat-bb@xxxxx.xxx>
Message-ID: <2C4C4E63-9675-4D19-A59B-6EC840629776@xxx.xxx>
Content-Type: text/plain; CHARSET=US-ASCII
Rep. Gabrielle Giffords will attend husband Mark Kelly's space shuttle
launch in Florida on Friday, Kelly said, allowing the Arizona congresswoman
to travel for the first time since she was flown from Tucson to Houston more
than three months ago to recover from a gunshot wound to the head.
In an interview with CBS' Katie Couric, Kelly said Giffords' doctors had
given her permission to travel to Cape Canaveral, Fla., for the launch of
Endeavour, which is scheduled for 3:47 p.m. Friday. Kelly is the commander
of the shuttle mission.
There will not be a dry eye in the Bradford household on the 29th ...
Clint, K6LCS
------------------------------
Message: 11
Date: Sun, 24 Apr 2011 22:10:36 -0500
From: "David Maciel" <xe3dx@xxxxxxx.xxx.xx>
Subject: [amsat-bb] XE3DX On EK08
To: <Undisclosed-Recipient:;>
Message-ID: <5A7C8DF3A6F94411B29D79E6D1D6BD30@xxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi All, next Monday 25th and Tuesday 26th I'll be working from the Grid
EK08, State of Morelos in Mexico,
all contacts will be confirmed via LOTW or direct, I will work passes just
after 17:00z, I hope to hear soon.
David
XE3DX
EK08
------------------------------
Message: 12
Date: Mon, 25 Apr 2011 07:10:23 -0400
From: Ben Jackson <bbj@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: Icom D-Star
To: Gordon JC Pearce <gordonjcp@xxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <4DB5569F.2010408@xxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 4/23/2011 2:42 PM, Gordon JC Pearce wrote:
> On Sat, 2011-04-23 at 10:42 -0500, Gregg Wonderly wrote:
>> In the end, digital compression of spectrum space is going to happen more
and
>> more. AM style broadcast is hugely inefficient even though it is painfully
>
> Okay, but *why*? Why are we so obsessed with squeezing bandwidth down
> and down, at the expense of intelligibility?
You unfortunately provided data on why we should get ahead of crunching
down bandwidth: Because sooner or later, we're going to get squeezed for
bandwidth due to our spectrum being fairly empty and everyone and their
brother wanting to push IP to their new wireless toaster service.
I'm not a fan of proprietary codecs but our lack of an alternative back
in the 2000s caused D-STAR to be used with AMBE. Too bad, so sad. Don't
support it, probably not going to use it. My worry is that even though
we provided a alternative with Codec2, what cutting edge technology that
will be here five years from now are we not developing because we were
playing catch up?
--
Ben Jackson - N1WBV - New Bedford, MA
bbj <at> innismir.net - http://www.innismir.net/
------------------------------
Message: 13
Date: Mon, 25 Apr 2011 12:01:56 +0000 (UTC)
From: vtnn43e@xxxxxxx.xxx
Subject: [amsat-bb] 2m/70cm Quadrifilar Helix antenna Antenna Kit from
Antennas.us
To: AMSAT <amsat-bb@xxxxx.xxx>
Message-ID:
<1302090281.4329108.1303732916676.JavaMail.root@xxxxxxx.xxxxxxxxxx.xx.xxxx.xxx
xxxx.xxx>
Content-Type: text/plain; charset=utf-8
Antennas.us is selling a combo package of 2M and 70cm quadrifilar helix
antennas and a bias tee for $330.00. The 70cm antenna has a built-in 15db
LNA BTW.
http://www.antennas.us/store/p/391-UC-AMSAT-KIT-2-m-70-cm-Amateur-Satellite-An
tenna-Kit.html
The UC-AMSAT-KIT, 2 m / 70 cm Amateur Satellite Antenna Kit is a discounted
bundle combination of quantity 1 each of the following three antenna products:
UC-1464-433, VHF Amateur Satellite QFH Antenna, Passive
UC-4364-513, UHF Amateur Satellite QFH Antenna, with built-in LNA and SMA
Male connector
BIT-1500-385, UHF Bias Tee
I was wondering though what some of you on the list think of these antennas
for FM LEO users that are looking for fixed outdoor antennas?
73
Zack
N8FNR
------------------------------
Message: 14
Date: Mon, 25 Apr 2011 07:18:05 -0500
From: "Gary \"Joe\" Mayfield" <gary_mayfield@xxxxxxx.xxx>
Subject: [amsat-bb] Re: Arrow and ELK Comparative Antenna Tests
To: "'John Kopala'" <jkopala@xxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <COL114-DS186D7668A1EDCF77591C298A960@xxx.xxx>
Content-Type: text/plain; charset="us-ascii"
John,
Thank you for your objective, scientific comparison! I eagerly await
your article in the AMSAT journal ;-) This is really good stuff. If your
test stand is still available there is one more thing I would dearly love to
see tested. Antenna guru Kent Britain, WA5VJB, once commented the Arrow
seemed to be designed for the elements to be insulated from the boom, and
there might be something to be gained from doing just that. Testing the
Arrow with the elements in standard convention vs. insulated has been on my
to do list ever since but I never seem to be able to get around to it.
Again just a thought, and thanks for your awesome work already!
73,
Joe kk0sd
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of John Kopala
Sent: Sunday, April 24, 2011 10:50 PM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Arrow and ELK Comparative Antenna Tests
On Saturday, April 23, Pat Stoddard (WD9EWK) and I did some antenna testing
in an attempt to answer
the questions about which is the best antenna for portable satellite
operation. We only tested the
antennas in receive mode to determine their relative gain. Time constraints
prevented us from
performing additional testing to determine if the transmitted output was
consistent with the receive
gain of the antennas. For the time being we will assume (and we all know
the dangers of doing so)
that the transmit performance closely matches the receive performance.
The antennas tested were an Arrow (3 x 7 elements), an ELK (4 elements), a
PortaFox configured for
145/435 operation (4 elements), and a Home Brew 4 by 9 element "arrow"
antenna. The standard Arrow
antenna was the only antenna equipped with duplexer, but not the basic
duplexer which is installed
in the handle. We did not measure the insertion loss of the duplexer on the
Arrow antenna, but this
was obviously not a significant factor in the overall performance. A
duplexer could still be
required depending upon the antenna chosen and the radio(s) to be used.
Using the Arrow antenna as the reference antenna and 145.300 MHz as our test
frequency, our
measurements indicated that the Arrow and the ELK antennas had identical
gain. The PortaFox antenna
showed 2db less gain than the Arrow and the ELK. The Home Brew 4/9 element
crossed yagi showed 2db
more gain than the Arrow and the ELK.
On 435.300 MHz, the Arrow antenna had 2db more gain than the ELK and 8db
more gain than the
PortaFox. The Home Brew 4/9 element had 3db more gain than the Arrow.
Although the ELK antenna shows slightly less (2db) gain on 435.300 MHz, it
does have one potential
advantage over the Arrow antenna. With the ELK, transmit and receive are in
the same plane. With
any satellites that have linear polarized antennas, such as AO-27, SO-50,
the ISS and maybe SO-67,
a crossed yagis can maximize the performance on one band while minimizing it
on the other. That
does not mean the Arrow won't work, as has been demonstrated by the
thousands of satellite QSO's
that are made on a regular basis using Arrow antennas. It just means that
when you rotate the
antenna to maximize the downlink signal, you may be significantly impacting
you uplink signal
strength in marginal situations.
Even though a satellite may have a circular polarized uplink and downlink,
don't assume that the
orientation of your station antenna as horizontal, vertical, or something in
between won't have a
significant effect on your signal strength. My experience operating
portable with my home brew
antenna has convinced me that my horizontally polarized Qagi should either
be remounted vertically
polarized or replaced with a circular polarized antenna. That is another
ongoing project.
In summary, unless you plan to build your own, the performance of the Arrow
crossed yagi antenna and
the ELK log periodic antennas are very comparable and should provide lots of
solid satellite contacts.
The overall results reflect the adage that bigger is better, but along with
more gain, you also get
a more bulky antenna that is harder to handle. The home brew crossed yagi I
built for portable
operation is tripod mounted, can be rotated on its axis, and disassembles
for storage in a roll up
case. But because of its size, it would be very tiring to attempt to use it
hand held for an
extended period of time. Pictures of the home brew crossed yagi antenna are
on my QRZ page.
John Kopala
N7JK
_______________________________________________
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: 15
Date: Mon, 25 Apr 2011 08:34:36 -0400
From: "Mark L. Hammond" <marklhammond@xxxxx.xxx>
Subject: [amsat-bb] Re: Arrow and ELK Comparative Antenna Tests
To: John Kopala <jkopala@xxxxx.xxx>, amsat-bb@xxxxx.xxx
Message-ID: <boai1g00756cfur05oaiZr@xxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Thanks John and Patrick. Interesting results and a very nice study.
Question---what was your testing method? I can't glean that from the
information below.
Thanks!
Mark N8MH
At 08:49 PM 4/24/2011 -0700, John Kopala wrote:
>On Saturday, April 23, Pat Stoddard (WD9EWK) and I did some antenna testing
in an attempt to answer
>the questions about which is the best antenna for portable satellite
operation. We only tested the
>antennas in receive mode to determine their relative gain. Time
constraints prevented us from
>performing additional testing to determine if the transmitted output was
consistent with the receive
>gain of the antennas. For the time being we will assume (and we all know
the dangers of doing so)
>that the transmit performance closely matches the receive performance.
>
>The antennas tested were an Arrow (3 x 7 elements), an ELK (4 elements), a
PortaFox configured for
>145/435 operation (4 elements), and a Home Brew 4 by 9 element "arrow"
antenna. The standard Arrow
>antenna was the only antenna equipped with duplexer, but not the basic
duplexer which is installed
>in the handle. We did not measure the insertion loss of the duplexer on
the Arrow antenna, but this
>was obviously not a significant factor in the overall performance. A
duplexer could still be
>required depending upon the antenna chosen and the radio(s) to be used.
>
>Using the Arrow antenna as the reference antenna and 145.300 MHz as our
test frequency, our
>measurements indicated that the Arrow and the ELK antennas had identical
gain. The PortaFox antenna
>showed 2db less gain than the Arrow and the ELK. The Home Brew 4/9 element
crossed yagi showed 2db
>more gain than the Arrow and the ELK.
>
>On 435.300 MHz, the Arrow antenna had 2db more gain than the ELK and 8db
more gain than the
>PortaFox. The Home Brew 4/9 element had 3db more gain than the Arrow.
>
>Although the ELK antenna shows slightly less (2db) gain on 435.300 MHz, it
does have one potential
>advantage over the Arrow antenna. With the ELK, transmit and receive are
in the same plane. With
>any satellites that have linear polarized antennas, such as AO-27, SO-50,
the ISS and maybe SO-67,
>a crossed yagis can maximize the performance on one band while minimizing
it on the other. That
>does not mean the Arrow won't work, as has been demonstrated by the
thousands of satellite QSO's
>that are made on a regular basis using Arrow antennas. It just means that
when you rotate the
>antenna to maximize the downlink signal, you may be significantly impacting
you uplink signal
>strength in marginal situations.
>
>Even though a satellite may have a circular polarized uplink and downlink,
don't assume that the
>orientation of your station antenna as horizontal, vertical, or something
in between won't have a
>significant effect on your signal strength. My experience operating
portable with my home brew
>antenna has convinced me that my horizontally polarized Qagi should either
be remounted vertically
>polarized or replaced with a circular polarized antenna. That is another
ongoing project.
>
>In summary, unless you plan to build your own, the performance of the Arrow
crossed yagi antenna and
>the ELK log periodic antennas are very comparable and should provide lots
of solid satellite contacts.
>
>The overall results reflect the adage that bigger is better, but along with
more gain, you also get
>a more bulky antenna that is harder to handle. The home brew crossed yagi
I built for portable
>operation is tripod mounted, can be rotated on its axis, and disassembles
for storage in a roll up
>case. But because of its size, it would be very tiring to attempt to use
it hand held for an
>extended period of time. Pictures of the home brew crossed yagi antenna
are on my QRZ page.
>
>John Kopala
>N7JK
>_______________________________________________
>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: 16
Date: Mon, 25 Apr 2011 08:43:33 -0400
From: "Mark L. Hammond" <marklhammond@xxxxx.xxx>
Subject: [amsat-bb] Re: 2m/70cm Quadrifilar Helix antenna Antenna Kit
from Antennas.us
To: vtnn43e@xxxxxxx.xxxx AMSAT <amsat-bb@xxxxx.xxx>
Message-ID: <bojf1g00756cfur05ojfP0@xxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Interesting, Zack.
I would ask them about transmitting through the one with the preamp built
in. Can you do it? (i.e., is it RF-sensed/switched)
Or does the preamp make it a "receive only" antenna, with the accidental
transmission through it smoking the device :) It's bound to happen on a
dual band radio...
(I think you'd be better off building a pair of AA2TX style Lindenblads...)
Mark N8MH
At 12:01 PM 4/25/2011 +0000, vtnn43e@xxxxxxx.xxx wrote:
>Antennas.us is selling a combo package of 2M and 70cm quadrifilar helix
antennas and a bias tee for $330.00. The 70cm antenna has a built-in 15db
LNA BTW.
>
>http://www.antennas.us/store/p/391-UC-AMSAT-KIT-2-m-70-cm-Amateur-Satellite-A
ntenna-Kit.html
>
>The UC-AMSAT-KIT, 2 m / 70 cm Amateur Satellite Antenna Kit is a discounted
bundle combination of quantity 1 each of the following three antenna products:
>UC-1464-433, VHF Amateur Satellite QFH Antenna, Passive
>UC-4364-513, UHF Amateur Satellite QFH Antenna, with built-in LNA and SMA
Male connector
>BIT-1500-385, UHF Bias Tee
>
>I was wondering though what some of you on the list think of these antennas
for FM LEO users that are looking for fixed outdoor antennas?
>
>
>73
>Zack
>N8FNR
>_______________________________________________
>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: 17
Date: Mon, 25 Apr 2011 09:36:36 -0400
From: "Ford, Steve, WB8IMY" <sford@xxxx.xxx>
Subject: [amsat-bb] Call for Papers--2011 ARRL/TAPR Digital
CommunicationsConference
To: "RTTY Reflector" <rtty@xxxxxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>,
<vhf@xxxx.xxxxxxxx.xxx>, <psk31@xxxxxxx.xx.xxx.xx>,
<digitalradio@xxxxxxxxxxx.xxx>
Message-ID:
<145372871023544E98881538F29B1DFC030CB31E@xxxxxxxx.xxxxxx.xxx>
Content-Type: text/plain; charset="US-ASCII"
Technical papers are solicited for presentation at the 30th Annual ARRL
and TAPR Digital Communications Conference to be held September 16-18,
2011 in Baltimore, Maryland. These papers will also be published in the
Conference Proceedings (you do NOT need to attend the conference to have
your paper included in the Proceedings). The submission deadline is July
31, 2011. Please send papers to:
Maty Weinberg
ARRL
225 Main St
Newington, CT 06111
or you can make your submission via e-mail to: maty@xxxx.xxx
Papers will be published exactly as submitted and authors will retain
all rights.
73 . . . Steve, WB8IMY
ARRL
------------------------------
_______________________________________________
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 239
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