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CX2SA > SATDIG 17.07.12 21:09l 332 Lines 10952 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.SAL.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: ao-7 antennas for portable use
(Patrick STODDARD (WD9EWK/VA7EWK))
2. Possible Delay For Mars Science Laboratory Landing Telemetry (B J)
3. Circularity question. (Tom Gentry)
4. Re: Circularity question. (Ib Christoffersen)
5. antennas for portable use (Thomas Doyle)
6. SkyCube launches Funding Campaign on Kickstarter (Trevor .)
7. WTB a "beater" FT-817 for sat rx (Clayton Coleman W5PFG)
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Message: 1
Date: Mon, 16 Jul 2012 13:28:57 -0700
From: "Patrick STODDARD (WD9EWK/VA7EWK)" <amsat-bb@xxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: ao-7 antennas for portable use
Message-ID:
<CAN6TEUf=YuMAU7e4Ai6Re9d-juLb7w-a-tTyNbtu2mhHu+DBBA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Norm,
I use an Elk log periodic for AO-7 and all my other satellite work. I am
able to work passes to the predicted LOS time, subject to local
surroundings.
I was only able to work down to 4 or 5 degrees elevation with my Arrow
dual-band Yagi, before I switched to the Elk. You can see this setup
in action working satellites - including AO-7 mode B - in some of
my videos at: http://youtube.com/va7ewk
For AO-7 in mode A, the Elk is my 2m antenna, and a Buddipole dipole
on its tripod and telescoping mast is used for the 10m downlink.
Since this requires more setup, and the 10m downlink is weaker
than the 2m downlink, I don't work mode A very much.
73!
Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
On Monday, July 16, 2012, Lizeth Norman wrote:
> Hi all!
> Just wanted some comments as to what ops are using for AO-7 portable.
> More importantly, some info on how they perform near loss of signal.
> Pictures of antenna arrays would be greatly appreciated.
> Norm n3ykf
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <javascript:;>. 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
>
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Message: 2
Date: Tue, 17 Jul 2012 00:25:23 +0000
From: B J <va6bmj@xxxxx.xxx>
To: amsat-bb <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Possible Delay For Mars Science Laboratory Landing
Telemetry
Message-ID:
<CAP7QzkOn1NgA0ovCFMoD=BdJqhMMg8_RYrc+hXnaXGcvcL0KYA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
http://spaceflightnow.com/atlas/av028/120716relay/
73s
Bernhard VA6BMJ @ DO33FL
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Message: 3
Date: Mon, 16 Jul 2012 22:10:59 -0500
From: Tom Gentry <t.gentry@xxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Circularity question.
Message-ID: <5004D7C3.7000305@xxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Do I go RHCP on the downlink and LHCP for the uplink or vice versa for
Mode B? I may add RH/LH switching later but for now my new antennas
will be fixed. Is there a reference that speaks to this issue?
73,
Tom K5VOU
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Message: 4
Date: Tue, 17 Jul 2012 09:51:38 +0200
From: "Ib Christoffersen" <oz1my@xxxxxx.xx>
To: <t.gentry@xxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Circularity question.
Message-ID: <5EF1A1CF871D4436B28C526069F27EBA@xxx.xx>
Content-Type: text/plain; charset="iso-8859-1"
Hi Tom,
For VO-52 it is best to use LHCP (2 meters) for the downlink and RHCP for
the uplink (70 cm).
AO-07 has linear antennas but LHCP seems to be best most of the time for the
downlink.
It all depends upon the satellite - not necessarily on the mode.
Adding switching is a good idea.
73 OZ1MY/Ib
-----Oprindelig meddelelse-----
Fra: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx P? vegne
af Tom Gentry
Sendt: 17 July 2012 05:11
Til: amsat-bb@xxxxx.xxx
Emne: [amsat-bb] Circularity question.
Do I go RHCP on the downlink and LHCP for the uplink or vice versa for
Mode B? I may add RH/LH switching later but for now my new antennas
will be fixed. Is there a reference that speaks to this issue?
73,
Tom K5VOU
_______________________________________________
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: 5
Date: Tue, 17 Jul 2012 07:00:53 -0500
From: Thomas Doyle <tomdoyle1948@xxxxx.xxx>
To: amsat-bb@xxxxxx.xxx
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] antennas for portable use
Message-ID:
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I did a lot of comparisons between my Elk and Arrow II. My results
were exactly the same as those of WD9EWK/VA7EWK but I was never sure
why the Elk performed better. Comparison tests I have been running
between a DIAMOND A430S10R and an Olde Antennas 7CP-70cm have given me
an insight as to why the Elk works so much better.
The tests between the Diamond and the Olde were the most inconclusive
tests I have ever run until suddenly my ancient grey cells managed to
figure it out. The Diamond has a longer boom which gives it more gain.
The Olde has a very short boom but is circularly polarized. I had them
mounted on opposite ends of the cross boom with a switch for quick
comparisons. During part of a pass the Diamond would work better.
During other parts of the pass the Olde would work better.
The chart at the top of the SV1BSX web page holds the answer.
http://sv1bsx.50webs.com/antenna-pol/polarization.html
When the orientation of the sat antenna lines up with the Diamond it
works better and continues to work better until the sat rotates to the
point where the cross polarization loss cancels the gain advantage the
Diamond has over the Olde at which point the Olde works better...
What has this to do with the Elk - Arrow comparison. Since the 2M and
70cm antennas on the Arrow are mounted at right angles to one another
we have a problem when working linear polarized sats. If the Arrow is
turned to maximize the downlink signal it is automatically turning the
uplink antenna to the angle that will maximize the uplink cross
polarization loss of up to 30 dB.
I do my testing on the linear sats and listen to my own downlink
signal. When the Arrow is rotated to maximize the the received signal
my best guess is that it is turned off the angle of the sat antenna.
This would spread the cross polarization loss between the uplink and
downlink antennas. The exact offset angle would depend on transmit
power, receive sensitivity and a ton of other things.
There is nothing wrong with the Arrow II it just can not work as well
as the Elk on linear sats unless you have a quick wrist and rotate the
antenna between transmit and receive. Even if you have very quick
wrists resulting from a miss spent youth playing foosball there still
is a problem. Trying to figure out the angle to turn the antenna
during transmit is all but impossible. Since the sat is rotating the
angle for transmit is not always 90 degrees from the angle for
receive. All antennas work to some degree and all this stuff is only
important if you are trying to maximize performance.
73 W9KE Tom Doyle
On Mon, Jul 16, 2012 at 3:28 PM, Patrick STODDARD (WD9EWK/VA7EWK)
<amsat-bb@xxxxxx.xxx> wrote:
> Norm,
>
> I use an Elk log periodic for AO-7 and all my other satellite work. I am
> able to work passes to the predicted LOS time, subject to local
> surroundings.
> I was only able to work down to 4 or 5 degrees elevation with my Arrow
> dual-band Yagi, before I switched to the Elk. You can see this setup
> in action working satellites - including AO-7 mode B - in some of
> my videos at: http://youtube.com/va7ewk
>
> For AO-7 in mode A, the Elk is my 2m antenna, and a Buddipole dipole
> on its tripod and telescoping mast is used for the 10m downlink.
> Since this requires more setup, and the 10m downlink is weaker
> than the 2m downlink, I don't work mode A very much.
>
> 73!
>
>
>
>
> Patrick WD9EWK/VA7EWK
> http://www.wd9ewk.net/
>
>
> On Monday, July 16, 2012, Lizeth Norman wrote:
>
>> Hi all!
>> Just wanted some comments as to what ops are using for AO-7 portable.
>> More importantly, some info on how they perform near loss of signal.
>> Pictures of antenna arrays would be greatly appreciated.
>> Norm n3ykf
>> _______________________________________________
>> Sent via AMSAT-BB@xxxxx.xxx <javascript:;>. 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
--
Sent from my computer.
tom ...
------------------------------
Message: 6
Date: Tue, 17 Jul 2012 16:28:51 +0100 (BST)
From: "Trevor ." <m5aka@xxxxx.xx.xx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] SkyCube launches Funding Campaign on Kickstarter
Message-ID:
<1342538931.67678.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
The ArduSat CubeSat project recently succeeded in raising donations of
$106,330 in just 30 days on Kickstarter.
Now another amateur radio CubeSat project SkyCube is using Kickstarter to
raise $82,500
See http://www.uk.amsat.org/?p=8955
73 Trevor M5AKA
AMSAT-UK International Space Colloquium Guildford takes place Sept. 15-16
http://www.uk.amsat.org/colloquium/twelve
AMSAT-UK News on Twitter: http://twitter.com/AMSAT_UK
----
------------------------------
Message: 7
Date: Tue, 17 Jul 2012 12:03:08 -0500
From: Clayton Coleman W5PFG <kayakfishtx@xxxxx.xxx>
To: AMSAT <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] WTB a "beater" FT-817 for sat rx
Message-ID:
<CAPovOwd45TJjqnS80YPN5yCKE5ppLXUZR9fpeCzBTVzNyXyp9Q@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
I'm looking for an inexpensive FT-817 (don't care it's a "D" or "ND"
model.) It doesn't need to be cosmetically pretty. I don't
necessarily need any of the accessories. Not interested in "packages"
with all the accessories and after market accessories unless it's
really, really cheap.
Need it for a satellite-related project. Email off-list please.
Thanks & 73
Clayton
W5PFG
------------------------------
_______________________________________________
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 7, Issue 225
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