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CX2SA > SATDIG 15.03.10 21:09l 409 Lines 14653 Bytes #999 (0) @ WW
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To : SATDIG@WW
Today's Topics:
1. Re: Non linear rotator (i8cvs)
2. Re: Road Trip (Air) to Turkey (w6zkh@xxxxxxx.xxxx
3. Re: use of PI in amsat development practice (Howard Long)
4. Re: use of PI in amsat development practice (Bruce Robertson)
5. YAESU G-5500 AZ-EL COMBO ROTOR 4Sale (Richard Meuse)
6. Re: Road Trip (Air) to Turkey (David Wing)
7. AO-51 Demo (Clint Bradford)
----------------------------------------------------------------------
Message: 1
Date: Mon, 15 Mar 2010 14:22:14 +0100
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Subject: [amsat-bb] Re: Non linear rotator
To: "Phil" <phillor@xxxxxxx.xxx>, "AMSAT-BB" <amsat-bb@xxxxx.xxx>
Message-ID: <003a01cac442$8787f3c0$0201a8c0@xxx.xx>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Phil" <phillor@xxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Monday, March 15, 2010 3:28 AM
Subject: [amsat-bb] Non linear rotator
> Thank you for reading this.
>
> I'm trying to devise an equation to correct the rotation of my non linear
> rotator. It's correct in the middle of its range but out at both ends of
its
> travel. I asked this same question ten years ago and someone kindly told
me
> about a simple Window application that did exactly want I wanted.
>
> I have searched through my e-mails back to 2000 and cannot find the reply.
> Can anyone, once again, suggest a suitable Windows or a Linux application?
>
> --
> Regards,
> Phil
>
Hi Phil,
I guess that your rotator is an azimuth rotator of the class G-400RC
or G-450XL using only two wires from the rotator potentiometer to the
control box terminals 2 and 3
In this type of rotator the non linear position using automatic traking
arise from the fact that the current flowing into the rotator potentiometer
is not a constant current but it depends on the antenna position.
If this is the case I have designed the hardware solution of the above
linearity problem adding a constant current regulator into the control
box that allow the current flowing into the rotator potentiometer to stay
constant for any antenna position.
If you are interested on it I can send to you the schematic diagram.
Best 73" de
i8CVS Domenico
------------------------------
Message: 2
Date: Mon, 15 Mar 2010 13:50:19 +0000 (UTC)
From: w6zkh@xxxxxxx.xxx
Subject: [amsat-bb] Re: Road Trip (Air) to Turkey
To: Rick - WA4NVM <wa4nvm@xxxxxxx.xxx>
Cc: AMSAT BB <amsat-bb@xxxxx.xxx>
Message-ID:
<421955469.2293391268661019931.JavaMail.root@xxxxxxx.xxxxxxxxxxx.xx.xxxx.xxxxx
xx.xxx>
Content-Type: text/plain; charset=utf-8
Just tell the locals you brought some Memphis BBQ with you, and you'll fit
right in, Rick.... Have a safe trip...
John W6ZKH
----- Original Message -----
From: "Rick - WA4NVM" <wa4nvm@xxxxxxx.xxx>
To: "AMSAT BB" <amsat-bb@xxxxx.xxx>
Sent: Sunday, March 14, 2010 8:47:18 PM GMT -08:00 US/Canada Pacific
Subject: [amsat-bb] Road Trip (Air) to Turkey
Hi all over the pond,
I will be operating as TA/WA4NVM from Turkey during my trip March 19 - April
2.
Time permitting, I will operate only on the FM birds. Below is a list of my
locations.
Date Location Grid
March 20-22 Istanbul, Turkey KN41
March 22-23 Canakkale, Turkey KN30
March 23-25 Kusadasi, Turkey KM37
March 25-27 Pamukkale, Turkey KM47
March 27-29 Antalya, Turkey KM56
March 29-31 Cappadocia, Turkey KM78
March 31-April 02 Istanbul, Turkey KN41
I hope to make some new friends on the birds.
73 all,
Rick WA4NVM - Memphis
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------------------------------
Message: 3
Date: Mon, 15 Mar 2010 15:30:52 -0000
From: "Howard Long" <howard@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re: use of PI in amsat development practice
To: "'Bruce Robertson'" <ve9qrp@xxxxx.xxx>, "'Samudra Haque'"
<samudra.haque@xxxxx.xxx>
Cc: 'Amsat-bb' <amsat-bb@xxxxx.xxx>
Message-ID: <003c01cac454$7f913480$7eb39d80$@xxx>
Content-Type: text/plain; charset="us-ascii"
Bruce
> What an interesting question! As many of you know, I'm having fun
> porting the G3RUH's Plan13 algorithm to the Atmel platform. One of the
> first things you want to be able to do in programs like this is to
> convert degrees to radians; and that means pi.
FWIW I used 32 bit accuracy (equivalent to IEEE754 single precision) in my
PIC LVB Tracker 2 code (based on G3RUH Plan13 too) without any significant
difference in results over 64 bit. Although the accuracy did cause some
anomalies, they were small and inconsequential for amateur purposes,
typically a second or two in predictions. I tested this by running the same
code on a PC and carefully coding constants, stored values and datatypes
with #defines so I could recompile on demand and see the differences in the
results.
I was lucky, ISTR I had 3.5KB, but even that was a struggle, although I did
have the additional dimension of having to deal with manual bank switching
too of the PIC18 - you might not have this on your device. And the compiler
I used, although generating very compact code, wouldn't compile anything
slightly complex, so I had to manually split the statements into simpler
steps.
If I did it again, I'd head for at least a 16 bit and probably a 32 bit
device, and a different compiler. But five plus years ago we didn't have
such devices or capabilities!
73, Howard G6LVB
------------------------------
Message: 4
Date: Mon, 15 Mar 2010 13:20:08 -0300
From: Bruce Robertson <ve9qrp@xxxxx.xxx>
Subject: [amsat-bb] Re: use of PI in amsat development practice
To: Howard Long <howard@xxxxxxxxxx.xxx>
Cc: Amsat-bb <amsat-bb@xxxxx.xxx>, Samudra Haque
<samudra.haque@xxxxx.xxx>
Message-ID:
<49657a761003150920iaa2d67egc4d28369f76c082a@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
On Mon, Mar 15, 2010 at 12:30 PM, Howard Long <howard@xxxxxxxxxx.xxx> wrote:
> Bruce
>
>> What an interesting question! As many of you know, I'm having fun
>> porting the G3RUH's Plan13 algorithm to the Atmel platform. One of the
>> first things you want to be able to do in programs like this is to
>> convert degrees to radians; and that means pi.
>
> FWIW I used 32 bit accuracy (equivalent to IEEE754 single precision) in my
> PIC LVB Tracker 2 code (based on G3RUH Plan13 too) without any significant
> difference in results over 64 bit. Although the accuracy did cause some
> anomalies, they were small and inconsequential for amateur purposes,
> typically a second or two in predictions. I tested this by running the same
> code on a PC and carefully coding constants, stored values and datatypes
> with #defines so I could recompile on demand and see the differences in the
> results.
That's reassuring, and helpful (as was all your Plan13 LVB code!)
In October, I did something similar. In real-time, I compared a day's
results tracking a cubesat with Predict and my (32-bit) code compiled
on a PC, spitting SSP latitude and longitude into a spreadsheet. The
blog post (with spreadsheet) on the experiment is here:
http://ve9qrp.blogspot.com/2009/10/testing-plan13.html
The upshot was that they never differed in SSP by more than 35 km, and
I'm pretty sure some of the larger excursions were due to the computer
flipping over a second between doing the Predict calculation and the
P13 one.
More pragmatically, for the last two weeks I've had my latest project
revision hooked up to a FT-817 in the basement under our dining room
with the volume cranked up. Having 10 CW beacons programmed into it,
there are lots of opportunities to listen for tone shifts through a
pass, but I haven't noticed anything more than 100 Hz or so.
> I was lucky, ISTR I had 3.5KB, but even that was a struggle, although I did
> have the additional dimension of having to deal with manual bank switching
> too of the PIC18 - you might not have this on your device. And the compiler
> I used, although generating very compact code, wouldn't compile anything
> slightly complex, so I had to manually split the statements into simpler
> steps.
>
> If I did it again, I'd head for at least a 16 bit and probably a 32 bit
> device, and a different compiler. But five plus years ago we didn't have
> such devices or capabilities!
>
> 73, Howard G6LVB
You're absolutely right that these devices keep getting more capable.
I started with the Atmeg328, since its the basis of the Arduino
platform, in the hopes of making this a useful library for students
and so forth. Programming it feels less like a micro-controller, and
more like a microcomputer of my school days (Commodore 64 era)!
My final target may be a Atmega644p, which has a 4kB SRAM, 2kB of
EEPROM (good for about 20 satellites and their modes) and a luxurious
64kB of program space. That's an additional 32kB to doddle around in.
I'm wondering if Predict's algorithm can't be ported.
73, Bruce VE9QRP
--
http://ve9qrp.blogspot.com
------------------------------
Message: 5
Date: Mon, 15 Mar 2010 12:36:33 -0400
From: "Richard Meuse" <n1hid@xxxxxxx.xxx>
Subject: [amsat-bb] YAESU G-5500 AZ-EL COMBO ROTOR 4Sale
To: <amsat-bb@xxxxx.xxx>
Message-ID: <6CB2EE60C8F94F58BDCBEBB3EBAB0157@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="us-ascii"
I have this rotor that has been part of a field day satellite antenna setup
and need to sell for $375.00. I'm selling at this price because I've lost
the connections that go to the rotors and believe you can buy them off the
net. Shipping would be extra. Thanks Rick
------------------------------
Message: 6
Date: Mon, 15 Mar 2010 10:08:08 -0700
From: "David Wing" <david@xxxxxx.xxx>
Subject: [amsat-bb] Re: Road Trip (Air) to Turkey
To: <w6zkh@xxxxxxx.xxx>, "'Rick - WA4NVM'" <wa4nvm@xxxxxxx.xxx>
Cc: 'AMSAT BB' <amsat-bb@xxxxx.xxx>
Message-ID: <CF5689C5A1254D319B58A6687DC6EC46@xxxxx>
Content-Type: text/plain; charset="us-ascii"
Rick, have fun...the people there are very friendly and curious.
Oh, if you do take BBQ, make it beef ribs. I travelled there for a month
and never saw a pig anywhere ;>)
73
David
K6CDW
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of w6zkh@xxxxxxx.xxx
Sent: Monday, March 15, 2010 6:50 AM
To: Rick - WA4NVM
Cc: AMSAT BB
Subject: [amsat-bb] Re: Road Trip (Air) to Turkey
Just tell the locals you brought some Memphis BBQ with you, and you'll fit
right in, Rick.... Have a safe trip...
John W6ZKH
----- Original Message -----
From: "Rick - WA4NVM" <wa4nvm@xxxxxxx.xxx>
To: "AMSAT BB" <amsat-bb@xxxxx.xxx>
Sent: Sunday, March 14, 2010 8:47:18 PM GMT -08:00 US/Canada Pacific
Subject: [amsat-bb] Road Trip (Air) to Turkey
Hi all over the pond,
I will be operating as TA/WA4NVM from Turkey during my trip March 19 - April
2.
Time permitting, I will operate only on the FM birds. Below is a list of my
locations.
Date Location Grid
March 20-22 Istanbul, Turkey KN41
March 22-23 Canakkale, Turkey KN30
March 23-25 Kusadasi, Turkey KM37
March 25-27 Pamukkale, Turkey KM47
March 27-29 Antalya, Turkey KM56
March 29-31 Cappadocia, Turkey KM78
March 31-April 02 Istanbul, Turkey KN41
I hope to make some new friends on the birds.
73 all,
Rick WA4NVM - Memphis
_______________________________________________
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: 7
Date: Mon, 15 Mar 2010 11:51:12 -0700
From: Clint Bradford <clintbradford@xxx.xxx>
Subject: [amsat-bb] AO-51 Demo
To: AMSAT BB <amsat-bb@xxxxx.xxx>
Message-ID: <495C3D95-C73F-465A-8824-96D0A6D3E761@xxx.xxx>
Content-Type: text/plain; charset=us-ascii
Well, I "broke my own rules" back on March 9. I was demo'ing AO-51 for the
Apple Valley CA radio club, and we had a good pass of the sat at 5:01 PST
(01:01 GMT). I ususally don't even turn the radio ON until a few minutes
past breaking the horizon ... but I went ahead and turned my radio ON at the
start of the pass.
WOW! At a mere 4 degrees of elevation, stations were BOOMING into us. I
always tell folks, "Don't key the mic ... " 'till about two minutes AFTER
you hear voices well when working with low power. But I just HAD to try this
tonight ... and I worked many stations. Fresno, North Dakota, Oregon,
Montana, a grid square next door to me in California, and more. I was blown
away at the strength of AO-51's downlink! (There were THREE electronic QSL
cards waiting for me when I got home that night ... another in the mail over
the weekend!)
The fifteen folks in the parking lot for the demo were impressed!
Unfortunately, we also all heard some poor behavior from a couple operators.
A few minutes into the pass, there was a kid - sounded like a young girl -
attempting to work the sat. She never got in well, and I couldn't copy
anything she said. And she gave up after a minute or so. What was disturbing
was on-the-air comments made by two "old timers" regarding what they
perceived as "interference." "Must be from south of the border ... " one
operator stated. The guy he was talking to agreed that "those Mexicans" were
causing problems.
Their comments were totally unnecessary. They were racist in tone. And quite
ignorant: "Those guys" in Mexico have provided me MANY contacts, and several
ALWAYS send QSL cards. I have NEVER experienced any "nonsense" on the air
from those "south of the border."
No need to cite their callsigns here. The BEST thing we should have done is
backed off and try to copy the obviously low-power station. But these guys
trampled on her intentionally with their unnecessary and irrelevant rants.
It was a truly embarrassing situation. I have never had to apologize to a
crowd for the on-the-air behavior of others. I hope it doesn't not happen
again.
Clint Bradford, K6LCS
909-241-7666
------------------------------
_______________________________________________
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 5, Issue 123
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