Actually you need CP (circular polarization) so crossed yagi's or a
helical.
The antennas needed are about 2 meters long.
So you think tracking satellites is OT for Arocket? I disagree!
I agree piggybacking is not an option but a real network is viable and
useful.
It is true you can only track one sat at a time but with a big enough
network more satellites can be tracked and with some decision making and
organization it would still be a viable solution.
Higher bands and higher data rates are NOT needed with this type of
tracking network. THAT IS the reason for this type of network.
As I said before it could advance and develop over time as well.
I can't believe the bullshit over something truly useful to low cost
access to space, all I can do is LMAO.
True low cost access to space will have to be a combined effort and the
attitude I see here is exactly why we don't have it. We need to bring
space access CLOSER to the people in order to achieve that goal of low
cost access. The farther you raise the bar the farther you put low cost
access out of reach.
Why would anyone want to do that?
Wont be much longer and everyone will have it anyway. Just like North
Korea having the bomb sooner or later all countries will want one and
they will have them.
The problem is getting access to satellites to the people. They don't
even understand what they can do with satellites yet. Give people a
chance for even limited access and they will want more and more.
Even access via cups and string is enough to get the ball rolling. Your
view seems to be so narrow!
It seems like you don't realize that amateurs are going to need tracking
for launches to orbit some day! Someone is going to have to provide
tracking for them as well.
Some day soon I hope to have a network in place I can use for that very
thing!
These networks would also work for high altitude balloons as a form of
satellite.
I don't know about you but I want to bring space closer to everyone. To
do that you need to get MANY people involved! Even if it is at some much
lower level than many professionals would find useful.
A tracking network would indeed be useful for that.
Monroe
-------- Original Message --------
Subject: [AR] Re: "infrastructure" (was Re: Amateur solid rockets for
...)
From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
Date: Sun, December 10, 2017 10:50 am
To: Arocket List <arocket@xxxxxxxxxxxxx>
On Sun, 10 Dec 2017, Robert Clark wrote:
OK. But most cubesats or nanosats broadcast on VHF or UHF which can be
picked up by simple Yagi antennas.
Yep, but now we're talking about installing custom hardware, rather than
about the (faint) hope of piggybacking on masses of existing antennas.
Also, the VHF and UHF bands are already fairly crowded, and those simple
Yagi antennas have quite wide beams. If we're talking about lots and lots
of new cubesats, they may have to move up to higher frequencies just to
avoid spectrum clashes. And certainly they will have to move up if they
want high data rates (= wide spectrum bands).
On another forum it was discussed using Yagis with a tracking motor you
can receive the transmissions from a cubesat for up to 12 minutes.
That's perhaps a little optimistic but not ridiculously so -- for the rare
directly-overhead passes.
Now imagine covering the Earth with these same size circles, with a
ground station at the center. Because they are thousands of kilometers
wide, you would only need a few to completely cover the Earth.
Except that large parts of the Earth are water, some of it -- notably the
eastern Pacific and the southern Indian oceans -- very empty.
For an approximate 5,000 km wide disk on the surface, it would take 8 of
these to go around the circumference. So 8^2 = 64 would be enough to cover
the surface, though you would probably want more with overlap.
Bear in mind that each of those stations can only talk to one satellite at
a time. If you want near-continuous contact, this world-wide network can
serve only a handful of satellites before antenna conflicts will start to
appear.
Monroe wrote:
Say you spent $250 per station and there are 250 stations for $62,500
you would have a network.
Uh, a tracking VHF/UHF Yagi is a big chunk of antenna -- meters long --
and it needs tracking motors, and the whole thing typically has to be up
on a mast to give it room to point and to clear local obstructions. Plus
weatherproof electronics, access to power, and a network connection (all
of which are easy enough in urban areas, often not so easy elsewhere).
I think if you price all of this, you'll find that this *isn't* a $250
piece of hardware.
And all of this is getting very off-topic for Arocket...
Henry
