to my AO-7 afictionados...what is the maximum distance one can work edge to edge, and how did you figure that out? 73 Bob W7LRD
Bob,
Since the height above ground varies due to the elliptical nature of orbits the max range also varies. Where the two stations are located relative to the apogee of the orbit can also come into play. If you are on the wrong side of the earth when the satellite is at its apogee that could be a problem. Here is my best shot at the range of max distances for AO-07 - compare them to numbers you get from other folks and let me know what you find. My numbers could be and are probably wrong.
73 W9KE tom...
On Mon, Oct 1, 2012 at 1:47 AM, Bob- W7LRD w7lrd@comcast.net wrote:
to my AO-7 afictionados...what is the maximum distance one can work edge to edge, and how did you figure that out? 73 Bob W7LRD _______________________________________________ Sent via AMSAT-BB@amsat.org. 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
Hi Bob,
Draw the ground circle on a lambert conformal chart, and you can measure the distance directly...From your location use the distance from you to the west end of Florida, according to my ANCIENT OSCAR LOCATOR....That will probably warm the cockles of some old timer's hearts...Who is still around??
Best 73 to all Dave WB6LLO
On 9/30/2012 11:47 PM, Bob- W7LRD wrote:
to my AO-7 afictionados...what is the maximum distance one can work edge to edge, and how did you figure that out? 73 Bob W7LRD _______________________________________________ Sent via AMSAT-BB@amsat.org. 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
Hi Dave, WB6LLO
I am also still around with my old OSCAR LOCATOR with aquisition circle and orbital track for OSCAR-7 ,it warm the cockles of my old timer heart !
I developed an OSCAR LOCATOR for the orbit of the first P3-A HEO satellite wich failed to go into orbit due to a malfunction of second stage engine on ARIANE-5 flight nr°6
In the time been, between P3-A and P3-B i.e. OSCAR-10, a software made for HEO satellites was developed by Tom Clark W3IWI and it was publisched into the ORBIT magazine and it's math is the fundamental base for all satellite traking programs to day.
Nice to remember the old days of the OSCAR LOCATOR my friend.
73" de
i8CVS Domenico
----- Original Message ----- From: "Dave Guimont" dguimon1@san.rr.com To: amsat-bb@amsat.org Sent: Tuesday, October 02, 2012 12:06 AM Subject: [amsat-bb] Re: maximum AO-7 distance
Hi Bob,
Draw the ground circle on a lambert conformal chart, and you can measure the distance directly...From your location use the distance from you to the west end of Florida, according to my ANCIENT OSCAR LOCATOR....That will probably warm the cockles of some old timer's hearts...Who is still around??
Best 73 to all Dave WB6LLO
On 9/30/2012 11:47 PM, Bob- W7LRD wrote:
to my AO-7 afictionados...what is the maximum distance one can work edge to edge, and how did you figure that out? 73 Bob W7LRD _______________________________________________ Sent via AMSAT-BB@amsat.org. 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@amsat.org. 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
On 10/01/2012 02:47 AM, Bob- W7LRD wrote:
to my AO-7 afictionados...what is the maximum distance one can work edge to edge, and how did you figure that out? 73 Bob W7LRD
Maximum communications distance:
MCD = 2 R arccos [ R / (R + h) ]
where R = Radius of earth (Spherical earth: 6371 Km) h = Height at apogee
(Eq 12.4, Sat. Experimenters Handbook 2nd Ed; Davidoff) All you need is the apogee height for the satellite in question, and a calculator. For AO-7 the apogee height USED to be 1460 Km, and probably hasn't altered much over the years. Therefore:
MCD = 2 * 6371 * arccos [ 6371 / (6371 + 1460) ] = 12756 * arccos [ 6371 / 7831 ] = 12756 * arccos [ 0.8135614864 ] = 12756 * 0.620545318575 = 7915.7 Km (4918.59 miles)
What is the "official" distance?
With a good station, the non-spherical earth working for you at your QTH and hoping for some sub-horizon love, who knows?
On 10/01/2012 02:47 AM, Bob- W7LRD wrote:
to my AO-7 afictionados...what is the maximum distance one can work edge to edge, and how did you figure that out? 73 Bob W7LRD
Did you spot the error in my math, deliberately made to test you? :)
No? Well Steve did. Hard to believe I actually used a calculator and STILL got that multiplication wrong. Thanks, Steve!
The correct calculations are:
MCD = 2 * 6371 * arccos [ 6371 / (6371 + 1460) ] = 12742 * arccos [ 6371 / 7831 ] = 12742 * arccos [ 0.8135614864 ] = 12742 * 0.620545318575 = 7,906.98 Km (4913.16 miles)
participants (5)
-
Bob- W7LRD -
Dave Guimont -
Gus 8P6SM -
i8cvs -
Thomas Doyle