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CX2SA > SATDIG 29.04.13 21:16l 155 Lines 4629 Bytes #999 (0) @ WW
BID : AMSATBB8137
Read: GUEST
Subj: AMSAT-BB-digest V8 137
Path: IZ3LSV<F1OYP<ON0AR<ON4HU<PY1AYH<PY1AYH<CX2SA
Sent: 130429/1909Z @:CX2SA.SAL.URY.SA #:5694 [Salto] FBB7.00e $:AMSATBB8137
From: CX2SA@CX2SA.SAL.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: Path to HEO (Robert Bruninga)
2. Re: Path to HEO (Stefan Wagener)
3. Re: G5500 Rotor motor Question (Thomas Doyle)
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Message: 1
Date: Mon, 29 Apr 2013 14:34:02 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: Stefan Wagener <wageners@xxxxx.xxx>, M5AKA <m5aka@xxxxx.xx.xx>
Cc: AMSAT BB <Amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Path to HEO
Message-ID: <0492a0559fb4155273e3727aa0752da8@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
> Going from 310 to 700km in a year is not doing us anything.
Im not following this closely, but that statement misses the most
important reason for doing this...
*to*stay*in*orbit!
The lifetime of a cubesat at 310km is only a few weeks at most. The life
time at 700km is tens of years.
The minimum requirement then for an ION thruster, then, is to be able to
at least be slightly greater than the loss on every orbit. Then it is
worth its weight in gold!
Bob, Wb4APR
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Message: 2
Date: Mon, 29 Apr 2013 13:38:17 -0500
From: Stefan Wagener <wageners@xxxxx.xxx>
To: Robert Bruninga <bruninga@xxxx.xxx>
Cc: AMSAT BB <Amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Path to HEO
Message-ID:
<CAKu8kHAA1_zrpiG9p19Kg_trzt1p5JfLAg0NjSQ5ays1dseDTg@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Thanks Bob,
That's why it is important to read the complete conversation.
This is NOT about Cubesats, staying in orbit, etc. It is about getting into
an HEO beyond 20000km.
On Mon, Apr 29, 2013 at 1:34 PM, Robert Bruninga <bruninga@xxxx.xxx> wrote:
> > Going from 310 to 700km in a year is not doing us anything.
>
> Im not following this closely, but that statement misses the most
> important reason for doing this...
>
> *to*stay*in*orbit!
>
> The lifetime of a cubesat at 310km is only a few weeks at most. The life
> time at 700km is tens of years.
>
> The minimum requirement then for an ION thruster, then, is to be able to
> at least be slightly greater than the loss on every orbit. Then it is
> worth its weight in gold!
>
> Bob, Wb4APR
>
------------------------------
Message: 3
Date: Mon, 29 Apr 2013 13:59:05 -0500
From: Thomas Doyle <tomdoyle1948@xxxxx.xxx>
To: David Palmer KB5WIA <kb5wia@xxxxx.xxx>
Cc: AMSAT <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: G5500 Rotor motor Question
Message-ID:
<CAHnRQR+wjTo1QGgstodZExkKvGVg5++OcATMjgQ5C0J9MsQueQ@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Has anyone measured the gear reduction used in the rotor to compute the raw
speed of the motor. I have always been a fan of checking theoretical
calculations with actual measurements to make sure we stay within the
ballpark.
Fortunately I have never had to take my G5500 apart so have never checked
the gear ratio.
W9KE Tom Doyle
On Mon, Apr 29, 2013 at 11:29 AM, David Palmer KB5WIA <kb5wia@xxxxx.xxx>wrote:
> Oh, I didn't measure the rotation speed of the motor during my rebuild,
> unfortunately. In all the research I did prior to the rebuild (=scrambling
> to find an equivalent motor) I didn't see any published specs on the unit
> either. I'd think Domenico's calculations would probably be the closest,
> since it is a simple 2-pole AC motor.
>
> 73! Dave KB5WIA
>
> On Sun, Apr 28, 2013 at 2:31 PM, Gregory Beat <gregory.beat@xxxxxxx.xxx
> >wrote:
>
> > You could ask Dave Palmer, KB5WIA if he noted that spec.,
> > when he rebuilt his Yaesu motor last year (March 2012)
> > http://kb5wia.blogspot.com/2012/03/yaesu-g5500-rotator-motor-repair.html
> >
> > w9gb
> > ==
> > From: "Mike Hoblinski"
> > To: <amsat-bb@xxxxx.xxx>
> > Subject: [amsat-bb] G5500 Rotor motor Question
> >
> > Anybody know what the rpm of the AC motors are. I know from the Yaesu
> > specs that after all of the gear reduction they list EL as 67 seconds for
> > EL
> > and 58 Seconds for AZ.
> >
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
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>
--
Sent from my computer.
tom ...
------------------------------
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Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
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End of AMSAT-BB Digest, Vol 8, Issue 137
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