#300990 - 29/07/2007 23:48
Long Distance wireless link
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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Ok, so I'm probably moving to a remote area of Belize within the next few months. The place I'm moving to does have a satellite internet connection powered by solar power, but I'd like to get a lower latency connection out there. Fortunately, we're right on the beach and there's a straight shot over the water to Belize City. In Belize City, we have an apartment with a DSL connection. I'm looking into the possibility of using highly directional antennae to shoot a wireless connection between my location and the apartment in the city. Added difficutly: even though we have line-of-sight, the distance between the two points is about 22.5 miles.
Having read some articles on the internet, it seems conceivable to get a reasonable connection over that distance. Also, since I don't have to worry about the FCC, perhaps boosting the signal strength is an option.
Does anyone have any experience with doing something like this?
Does anyone know the formula to figure out how tall the tower would need to be to account for the earth's curvature?
Does anyone know of a cheapish way to aim the antennae without using an expensive spectrum analyzer?
I'm sure I'll have some more questions as I work through putting this together....thanks in advance.
EDIT, approximate locations for the interested:
Where I'll be living:
17.185106, -88.305032
Apartment in Belize City:
17.490298, -88.186451
Edited by JBjorgen (29/07/2007 23:52)
_________________________
~ John
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#300991 - 30/07/2007 02:41
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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Quote:
Ok, so I'm probably moving to a remote area of Belize within the next few months.
And I'm so very sad about it. 
You've been such a fantastic web site host for me. I hate to see it go.
Guess it's time to start shopping around again. Ricin, you still hosting these days? 
I wish you the best of luck and success in Belize.
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#300992 - 30/07/2007 05:24
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 17/01/2002
Posts: 3996
Loc: Manchester UK
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Wow, what are you doing there?
I've set a couple of links up. I ended up using a cheap 2.4GHz video link and firing that over the link. I simply then aimed the dishes while looking at a portable TV, seemed to work really well.
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Cheers,
Andy M
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#300993 - 30/07/2007 06:44
Re: Long Distance wireless link
[Re: andym]
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carpal tunnel
Registered: 24/12/2001
Posts: 5528
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Quote:
I've set a couple of links up. I ended up using a cheap 2.4GHz video link and firing that over the link. I simply then aimed the dishes while looking at a portable TV, seemed to work really well.
Hmm. Thats a pretty neat trick. Aiming the dish is still going to be hard but at least you get a near enough instant indication that you're doing it right.
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#300995 - 30/07/2007 13:02
Re: Long Distance wireless link
[Re: andym]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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Quote:
Wow, what are you doing there?
Religious and charity work.
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~ John
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#300996 - 30/07/2007 15:10
Re: Long Distance wireless link
[Re: tman]
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pooh-bah
Registered: 15/01/2002
Posts: 1866
Loc: Austin
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Try a green laser to help aim! Just don't aim it at any planes.
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#300997 - 30/07/2007 15:29
Re: Long Distance wireless link
[Re: RobotCaleb]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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That was my first thought, too, but I can't imagine that any consumer laser will still be visible over 22.5 miles.
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Bitt Faulk
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#300998 - 30/07/2007 15:49
Re: Long Distance wireless link
[Re: wfaulk]
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pooh-bah
Registered: 15/01/2002
Posts: 1866
Loc: Austin
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And at that distance to keep it steady enough and to adjust it the minute distances need to make changes you'd need some sort of fancy worm-gear thingamabob. At least, that's what it looks like in my head.
Maybe a really wide laser beam would be better. Say, 2 feet wide?
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#301000 - 30/07/2007 16:07
Re: Long Distance wireless link
[Re: RobotCaleb]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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Holy crap. "Light cigars"?!? With a frickin' laser beam?
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Bitt Faulk
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#301001 - 30/07/2007 16:24
Re: Long Distance wireless link
[Re: RobotCaleb]
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carpal tunnel
Registered: 24/12/2001
Posts: 5528
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Quote:
Try a green laser to help aim! Just don't aim it at any planes.
Getting the laser aligned with your own dish will be an issue still. A tiny fraction of a degree out on your side and what the dish is pointing at and what your laser is pointing at will be totally different.
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#301002 - 30/07/2007 17:02
Re: Long Distance wireless link
[Re: wfaulk]
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pooh-bah
Registered: 06/02/2002
Posts: 1904
Loc: Leeds, UK
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Quote:
Holy crap. "Light cigars"?!? With a frickin' laser beam?
SSSSSHHHHHH!!!!!!!! Don't let Godfrey hear you! He may start smoking them again if he knows you can light them with a laser beam 
Cheers
Cris
PS - After typing this I realised that boxer smoked a pipe not cigars, but you get the idea
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#301003 - 30/07/2007 17:49
Re: Long Distance wireless link
[Re: wfaulk]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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Quote:
Holy crap. "Light cigars"?!? With a frickin' laser beam?
There's a shot at the beginning of the Pink Floyd "Delicate Sound of Thunder" concert video of the lighting technician who runs the laser system doing exactly that.
The lasers they use for concerts are definitely that powerful.
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#301004 - 30/07/2007 20:01
Re: Long Distance wireless link
[Re: JBjorgen]
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addict
Registered: 02/04/2002
Posts: 691
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I'd have to climb up on the roof to check my antenna, but on the back of it they're 4 or 5 LEDs which act like a cell phone signal strength indicator. It took about 2 minutes to align my antenna, and I'm getting about 8ms of latency through it. I'm not on the longest run, I'm about 4 miles away, but these same antennas are going about 17 miles I think. They also do hardware channel hopping. I think they use one channel for upstream, another for downstream, and they rotate if any noise/interference is detected. I actually need to weld up a nicer mount, as one of the ice storms this winter caused it to drop from 95% signal strength to about 3%. Maybe I'll do that this week while the weather is still nice. Nothing like climbing around on an icy roof just for internet access
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Oliver
mk1 30gb: 129 | mk2a 30gb: 040104126
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#301005 - 30/07/2007 20:52
Re: Long Distance wireless link
[Re: oliver]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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The next logical question is, what antenna are you using?
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~ John
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#301006 - 30/07/2007 21:44
Re: Long Distance wireless link
[Re: tfabris]
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carpal tunnel
Registered: 13/02/2002
Posts: 3212
Loc: Portland, OR
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Quote:
Quote:
Holy crap. "Light cigars"?!? With a frickin' laser beam?
There's a shot at the beginning of the Pink Floyd "Delicate Sound of Thunder" concert video of the lighting technician who runs the laser system doing exactly that.
The lasers they use for concerts are definitely that powerful.
Well, given that one can cut and weld metal with lasers, I'd think that lighting a bit of flammable weed and paper isn't that much of a stretch. I'm more surprised at the portability, and accessibility, in general, of lasers with that much power.
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#301007 - 30/07/2007 23:47
Re: Long Distance wireless link
[Re: canuckInOR]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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Well, that's what I meant. Handheld laser powered by a few AA batteries.
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Bitt Faulk
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#301008 - 31/07/2007 12:35
Re: Long Distance wireless link
[Re: JBjorgen]
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pooh-bah
Registered: 13/01/2002
Posts: 1649
Loc: Louisiana, USA
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Hmm, maybe something like this?Stu
_________________________
If you want it to break, buy Sony!
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#301009 - 31/07/2007 13:26
Re: Long Distance wireless link
[Re: wfaulk]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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Quote:
Well, that's what I meant. Handheld laser powered by a few AA batteries.
Good point. Now that I look closer at the wickedlasers site, it looks like the ones that can light cigars (200-300mw) use Li-ion batteries, but same difference. I wouldn't think you'd be able to get that kind of power out of batteries. That's pretty impressive.
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#301010 - 31/07/2007 13:43
Re: Long Distance wireless link
[Re: tfabris]
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pooh-bah
Registered: 13/01/2002
Posts: 1649
Loc: Louisiana, USA
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You can fashion a similar performing laser by harvesting the diode from a high speed DVD burner.
Stu
_________________________
If you want it to break, buy Sony!
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#301011 - 31/07/2007 15:52
Re: Long Distance wireless link
[Re: maczrool]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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No. Seriously. A DVD burner's diode laser can operate at 200mw?
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#301012 - 31/07/2007 15:59
Re: Long Distance wireless link
[Re: tfabris]
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pooh-bah
Registered: 13/01/2002
Posts: 1649
Loc: Louisiana, USA
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Quote:
No. Seriously. A DVD burner's diode laser can operate at 200mw?
See here. I've tried it. It really does work.
Stu
_________________________
If you want it to break, buy Sony!
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#301014 - 01/08/2007 10:04
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 29/08/2000
Posts: 14496
Loc: Canada
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Quote:
Does anyone know of a cheapish way to aim the antennae without using an expensive spectrum analyzer?
Unlike lasers, radio waves spread out with distance. So ultra-precision isn't strictly necessary here.
A handheld GPS receiver can be used to measure the exact locations of the two antennas, assuming you can get a reasonably clear view of the sky from the city apartment (rooftop directly above the antenna?).
Once you have the GPS positions, that same handheld GPSr can tell you the exact bearing between them, which gives the angle at which they must be aimed to "see" each other.
Or use a telescope... mmm.. that might be the easiest here.
For height to avoid earth curvature, one of the math types here should know. I think 30' should be sufficient, though.
Cheers
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#301015 - 01/08/2007 12:32
Re: Long Distance wireless link
[Re: mlord]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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Quote:
Unlike lasers, radio waves spread out with distance. So ultra-precision isn't strictly necessary here.
That is not true in my experience. I've aligned a few wireless link antennas in my time and a few millimeters one way or another seems to make a big difference. This probably has far more to do with aligning the receiving dish than it does the transmitting antenna. The very fact that they do spread is probably what makes that alignment critical, as a few degrees off on a parabolic reflector can change the focus signficantly. I would imagine that a distance of about 22 miles would require a parabolic dish, but I could be wrong.
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Bitt Faulk
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#301016 - 01/08/2007 12:46
Re: Long Distance wireless link
[Re: wfaulk]
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carpal tunnel
Registered: 29/08/2000
Posts: 14496
Loc: Canada
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Quote:
Quote:
Unlike lasers, radio waves spread out with distance. So ultra-precision isn't strictly necessary here.
That is not true in my experience. I've aligned a few wireless link antennas in my time and a few millimeters one way or another seems to make a big difference. This probably has far more to do with aligning the receiving dish than it does the transmitting antenna. The very fact that they do spread is probably what makes that alignment critical, as a few degrees off on a parabolic reflector can change the focus signficantly. I would imagine that a distance of about 22 miles would require a parabolic dish, but I could be wrong.
I imagine that a pair of yagi or log antennas would do the trick nicely. And at 22km, the beam spread will be many metres, rather than a pencil (remember those?) eraser tip (laser).
Cheers
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#301017 - 01/08/2007 12:56
Re: Long Distance wireless link
[Re: mlord]
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carpal tunnel
Registered: 24/12/2001
Posts: 5528
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Quote:
pencil (remember those?)
You mean an AMD Athlon multiplier unlocking tool?
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#301018 - 01/08/2007 13:11
Re: Long Distance wireless link
[Re: mlord]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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Quote:
For height to avoid earth curvature, one of the math types here should know. I think 30' should be sufficient, though.
Ooh. That's a good one.
First, we need to determine the angle of the vertex at the center of the earth to one of the stations and the midpoint (that is, high spot) of the line connecting the two stations. We know the length of all three sides, so we can use the oblique triangle formula: a^2 = b^2 + c^2 - 2bc(cosA). b and c are the radius of the earth (call it r for easier calculations, and assume the maximum radius -- 6379km -- for head room) and a is half of the 22 miles (call it 18km for a little head room, shown as "d" in the picture). Give that b=c=r, the formula reduces to a^2 = 2r^2(1-cosA) and solving for cosA leaves cosA = 1 - (a^2/2r^2). Add in real numbers and you get cosA = 0.999996019... and then A = 0.1616749292 degrees. (Actually, because of the next step, we don't even need to resolve the actual angle.)
Now we need to find the length of the hypotenuse of a right triangle with one angle being A from above and the side adjacent to A being the radius of the earth. We know that cosA = adjacent/hypotenuse. So cosA = r/h. We know A and r, so solve for h: h = r/cosA. Plug in real numbers and you get h = 6379.025396, or 0.025396km longer than the radius of the earth. That's over 25 meters, or over 83 feet. Significant. That's 83 feet on each side. I hope you're living in a tall apartment building.
Edited by wfaulk (01/08/2007 13:25)
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Bitt Faulk
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#301019 - 01/08/2007 13:46
Re: Long Distance wireless link
[Re: wfaulk]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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I'll be lucky if I can get 25' on the apartment building side., so that means it'd need to be about 150' on the other side. Hmm...that may be cost prohibitive. We've got a building that's about 40' high and I was hoping to be able to just put a mast on top of it.
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~ John
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#301020 - 01/08/2007 14:33
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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You might want to have someone independently check my math.
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Bitt Faulk
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#301021 - 01/08/2007 14:41
Re: Long Distance wireless link
[Re: JBjorgen]
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pooh-bah
Registered: 13/01/2002
Posts: 1649
Loc: Louisiana, USA
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You may wish to consult this site. They have a calculator on there as well as some precalculated distances. Stu
_________________________
If you want it to break, buy Sony!
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#301022 - 01/08/2007 17:24
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 29/08/2000
Posts: 14496
Loc: Canada
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Quote:
I'll be lucky if I can get 25' on the apartment building side., so that means it'd need to be about 150' on the other side. Hmm...that may be cost prohibitive. We've got a building that's about 40' high and I was hoping to be able to just put a mast on top of it.
Note that since your hop is across salt water, Bitt's calculation suggests 83' above sea level (at high tide). Odds are very good that your apartment is already higher than this, though the beachfront spot likely is not.
cheers
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#301024 - 01/08/2007 18:49
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 10/06/1999
Posts: 5916
Loc: Wivenhoe, Essex, UK
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Quote:
I wonder how high that rocky island in the middle is, and who owns it. Hmm....
Dunno, but it doesn't look like a good place for shipping:
http://tinyurl.com/yr9p9v
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Remind me to change my signature to something more interesting someday
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#301025 - 01/08/2007 19:08
Re: Long Distance wireless link
[Re: andy]
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carpal tunnel
Registered: 13/07/2000
Posts: 4180
Loc: Cambridge, England
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Oh, that's where Belize is. Now I'm thinking that the relevant maths is: 83-foot mast, plus Gulf of Mexico hurricane season, equals severe packet loss Peter
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#301029 - 08/08/2007 15:14
Re: Long Distance wireless link
[Re: maczrool]
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carpal tunnel
Registered: 24/12/2001
Posts: 5528
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Quote:
Quote:
No. Seriously. A DVD burner's diode laser can operate at 200mw?
See here. I've tried it. It really does work.
Not quite as much destruction but you can get a violet laser diode out of a PS3 optical assembly. I got the donor parts off eBay for £40 exc shipping and it works pretty well. Probably not the safest thing to leave lying around tho. Must get some of the don't look into the laser beam with your remaining eye stickers made I think...
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#301030 - 08/08/2007 20:53
Re: Long Distance wireless link
[Re: tman]
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old hand
Registered: 20/07/1999
Posts: 1102
Loc: UK
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This thread inspired me, and I remembered I had a duff DVD-rw drive in the loft I had kept for exactly that purpose. So over the weekend I pulled it apart and scavenged the diode. With a little work, and the optics from a cheap (and non-functional) laser pointer, I produced the MEGApointer MK1  It's not quite finished yet, I still need to recess the screws and polish it! It's got a little PSU module inside that's designed for running CPU core voltages, set to 3.5V, and runs from 3 AAA cells in a holder I scavenged from an old LED head-torch. About 32mm in diameter and perhaps 100mm long. The laser optics are adjustable. Set to produce a parallel beam it gives a spot size of about 3mm, which still has enough energy to shrink heatshrink tubing! Focussed to a minimum spot size at perhaps a foot, the beam is only around 0.2mm across, and melts plastic so fast you can write your name with it. Wave it around on the antistatic mat it's on in the picture and it leaves a trail of smoke behind The beam diverges quickly after the focus point, and at 15 feet its about 3 inches across. I'd estimate the output power is at least 150mW. It's probably capable of more. Quite fun for a quick and dirty afternoons work. pca
Edited by pca (08/08/2007 21:07)
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#301031 - 08/08/2007 20:56
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 24/12/2001
Posts: 5528
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Quote:
This thread inspired me, and I remembered I had a duff DVD-rw drive in the loft I had kept for exactly that purpose. So over the weekend I pulled it apart and scavenged the diode. With a little work, and the optics from a cheap (and non-functional) laser pointer, I produced the MEGApointer MK1
Cool! Tried burning anything with it yet? 
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#301033 - 08/08/2007 22:44
Re: Long Distance wireless link
[Re: tfabris]
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member
Registered: 06/04/2000
Posts: 158
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So that's what all the recent news stories about sharks being seen off the SW England coast were - secret pca prototypes...
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#301034 - 09/08/2007 00:13
Re: Long Distance wireless link
[Re: MarkH]
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carpal tunnel
Registered: 29/08/2000
Posts: 14496
Loc: Canada
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Quote:
So that's what all the recent news stories about sharks being seen off the SW England coast were - secret pca prototypes...
Ooooo...sharks with frickin' laser beams attached to their heads!
From PCA, of course!
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#301035 - 09/08/2007 15:45
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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May I just say, looking at your picture and reading your description, it's really only a short step away from a true ray gun. That shiny metal casing is just dying to have a pistol grip handle attached to it. Or even better, you could mount it inside one of these. On the other hand, you already said that it has a limited focal point, so what it truly needs is a proper collimating lens. You could mount the collimating lens on a sort of extension, making it truly look like a ray gun, such as this or especially this. *drool*
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#301036 - 10/08/2007 01:18
Re: Long Distance wireless link
[Re: JBjorgen]
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member
Registered: 06/04/2000
Posts: 158
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Would something like this mesh network work for you ? http://meraki.com/products/solar/Might be something which would provide extra services to the local community too. Regards Mark
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#301037 - 10/08/2007 01:47
Re: Long Distance wireless link
[Re: MarkH]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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That looks like it'd be a fantastic product to mount to the antennas. I was going to have to find something that would be weatherproof and powered by solar anyway. I'm waiting until my contacts that are there in Belize return to the location in Sept. to find out if there is any of the higher ground nearby that it would be conceivable for me to use as a midpoint to avoid having a 150 ft. tower. The closest hill or mountain is still several miles away and further inland, and then there's the problem of finding out who owns it and getting permission to put an antenna there. Prospects not looking so good at the moment
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~ John
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#301038 - 10/08/2007 14:44
Re: Long Distance wireless link
[Re: maczrool]
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carpal tunnel
Registered: 08/03/2000
Posts: 12344
Loc: Sterling, VA
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Wasn't sure if anyone had run across this yet. It also showed up here.
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Matt
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#301039 - 10/08/2007 15:20
Re: Long Distance wireless link
[Re: Dignan]
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old hand
Registered: 14/04/2002
Posts: 1172
Loc: Hants, UK
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Yeah, I spotted that on the same day as reading Patrick's post - amazing coincidence!
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#301040 - 13/08/2007 09:05
Re: Long Distance wireless link
[Re: tfabris]
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old hand
Registered: 20/07/1999
Posts: 1102
Loc: UK
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It's already got a collimating lens, but I tweaked it to come to a point at a foot or so. It can be untweaked, and gives a nice parallel beam thats quite impressive in the dark. One problem is that at 650nm the human eye isn't all that sensitive, so the beam doesn't look as powerful as it really is. It hits peak brightness quite early on, and more power doesn't appear visibly brighter. The impressive bit is when you expand the beam out to about 6 inches across and it's STILL much brighter than an ordinary laser pointer It makes a damn impressive red flashlight if you widen the beam enough! A spot six feet across on trees two hundred feet way is easily bright enough to make out all the details. After this success, I bought another 10 surplus DVD writers at a radio rally yesterday for £15. Now I just need to figure out the best method of combining all the outputs into one beam pca
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Experience is what you get just after it would have helped...
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#301041 - 13/08/2007 10:49
Re: Long Distance wireless link
[Re: pca]
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veteran
Registered: 21/03/2002
Posts: 1424
Loc: MA but Irish born
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#301042 - 13/08/2007 15:06
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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Quote:
Now I just need to figure out the best method of combining all the outputs into one beam
See? See? Told you so.
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#301043 - 13/08/2007 15:09
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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Quote:
It's already got a collimating lens, but I tweaked it to come to a point at a foot or so
So, from someone who doesn't know much about lasers or optics, is it possible to make a lens assembly that focuses the beam at a point like you did, only have that point be the entire length of the beam (a true parallel beam)?
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#301044 - 13/08/2007 15:38
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 13/02/2002
Posts: 3212
Loc: Portland, OR
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Quote:
Now I just need to figure out the best method of combining all the outputs into one beam
And, once you're done that, see if you can get a red laser, a green laser, and a blue laser to focus in one spot, so you can build a laser-TV from it...
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#301045 - 13/08/2007 15:41
Re: Long Distance wireless link
[Re: tfabris]
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old hand
Registered: 20/07/1999
Posts: 1102
Loc: UK
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Um. Given a perfect lens and a perfect vacuum in the complete absence of gravity or magnetic fields, I think it's possible. A little fiddly, in other words pca
_________________________
Experience is what you get just after it would have helped...
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#301046 - 13/08/2007 16:27
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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Quote:
Now I just need to figure out the best method of combining all the outputs into one beam
"Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light."
_________________________
Bitt Faulk
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#301047 - 15/08/2007 01:25
Re: Long Distance wireless link
[Re: tfabris]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Quote:
Quote:
It's already got a collimating lens, but I tweaked it to come to a point at a foot or so
So, from someone who doesn't know much about lasers or optics, is it possible to make a lens assembly that focuses the beam at a point like you did, only have that point be the entire length of the beam (a true parallel beam)?
You use the multiple laser diodes to pump another gain medium causing it to laze.
http://www.llnl.gov/nif/psa/sshcl.html
Edited by gbeer (15/08/2007 01:40)
_________________________
Glenn
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#301048 - 21/08/2007 08:11
Re: Long Distance wireless link
[Re: JBjorgen]
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carpal tunnel
Registered: 13/07/2000
Posts: 4180
Loc: Cambridge, England
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Quote:
[Belize] Both locations are within 10 ft of sea-level.
Yow. I guess as of today they're still within 10ft of sea-level, but below, not above? Hope you (and/or your colleagues, if you're not out there yet) are OK. Looks like they might be needing more charity work than you thought...
Peter
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#301049 - 21/08/2007 13:23
Re: Long Distance wireless link
[Re: pca]
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veteran
Registered: 21/01/2002
Posts: 1380
Loc: Erie, CO
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Can you mount the laser in a plane, hack into the system and change the coordinates for the test firing and cook up a monster batch of popcorn in your professor's house? If so, I will be the Kent to your Knight.
"I want to see more of you in the lab"
"Ok, I'll gain weight"
Obscure?
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#301050 - 21/08/2007 14:50
Re: Long Distance wireless link
[Re: cushman]
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pooh-bah
Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
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Real Genius. Great old movie.
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#301051 - 21/08/2007 15:04
Re: Long Distance wireless link
[Re: lectric]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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"I quote Socrates, when he said... 'I drank what?'"
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#301052 - 21/08/2007 15:32
Re: Long Distance wireless link
[Re: cushman]
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addict
Registered: 25/06/2002
Posts: 456
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Quote:
Can you mount the laser in a plane, hack into the system and change the coordinates for the test firing and cook up a monster batch of popcorn in your professor's house?
Oh, I think you have to. It's a moral imperative.
If you don't you'll rue the day!
(Yet another in a long series of diversions in an attempt to avoid responsibility.)
Just make sure to clean your optics....
Actually, I just re-watched this a month or two ago.
One of my faves.
Believe it or not, Val Kilmer has signed on to do Real Genius 2.
As I really like goofy Val Kilmer comedies, I'm hoping for the best.
And even if it's not so great, it will be a fun trip down memory lane.
P.S. Would you classify that as a launch problem or a design problem?
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#301053 - 21/08/2007 20:24
Re: Long Distance wireless link
[Re: music]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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Well, it looks like "home" in Belize is still there after Dean passing through. We should get more info within the next day or so as to its condition.
EDIT: Looks like the grounds are torn up but the buildings are ok for the most part and the flooding was minimal. Yay.
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#301054 - 21/08/2007 23:53
Re: Long Distance wireless link
[Re: JBjorgen]
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addict
Registered: 25/06/2002
Posts: 456
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Do you know yet if you lost much "stuff" to water or wind damage?
I am glad you're OK and I hope your possessions are relatively unscathed as well.
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#301055 - 22/08/2007 19:35
Re: Long Distance wireless link
[Re: music]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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Actually, I haven't moved down there quite yet, I'm still in the states. It'll probably be at least a few more months 'til I get down there due to financial contraints. Which is why I'm trying to figure out things like internet and solar air-conditioning and water heating now.
I'm not too sure about the "stuff" yet. All the buildings except one are on piers. The one that isn't does have a washer and dryer on the ground floor. The only other things I can think of that might be damaged on the ground level are a large diesel generator and some water pumps and an old 15 passenger van. I'm not sure how much surge there was onsite, so I don't know if any of those things were damaged at all. I'll ask my friend who is onsite next time we talk.
_________________________
~ John
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#301056 - 23/08/2007 19:14
Re: Long Distance wireless link
[Re: JBjorgen]
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addict
Registered: 25/06/2002
Posts: 456
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Quote:
probably be at least a few more months 'til I get down there due to financial contraints. Which is why I'm trying to figure out things like internet and solar air-conditioning and water heating now.
Ah, I wasn't paying attention. I thought you were partially moved and partially still stateside. I.e., stuff in jeopardy, body in U.S.
(Hmmmm, would that be a good name for an album? ...no probably not.)
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#301057 - 24/08/2007 18:08
Re: Long Distance wireless link
[Re: pca]
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old hand
Registered: 20/07/1999
Posts: 1102
Loc: UK
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I got a laser power meter today, and measured the megapointer. With fresh batteries, 198mW Even with a couple of hours running it's still ofer 150mW. Not at all bad for an essentially free laser. pca
_________________________
Experience is what you get just after it would have helped...
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#301058 - 24/08/2007 18:49
Re: Long Distance wireless link
[Re: pca]
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carpal tunnel
Registered: 20/12/1999
Posts: 31602
Loc: Seattle, WA
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Fortunately, I've met you, and know you to be a peace-loving person.
But you know what they say: "Power corrupts, absolute power is kind of neat."
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#301059 - 24/08/2007 23:49
Re: Long Distance wireless link
[Re: tfabris]
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old hand
Registered: 20/07/1999
Posts: 1102
Loc: UK
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Thanks. I stripped down a few more dvd drives. Hint: NEC and Panasonic ones are good, Hitachi-LG ones not so much, they have weird diodes in, with way too many pins. Some sort of integrated laser/pattern reader I think. All the diodes measured at least 250mW @ 3.3V, one of them was over 300mW! I have over a watt worth of laser diodes on the bench at the moment, and I still have 5 drives to ruin Now to figure out the best, or al least prettiest, way to combine all the beams. I'm thinking some sort of sub-miniature death star sort of arrangement, which would look pretty cool in a darkened room with some smoke in... pca
_________________________
Experience is what you get just after it would have helped...
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#301060 - 25/08/2007 19:18
Re: Long Distance wireless link
[Re: pca]
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member
Registered: 02/03/2002
Posts: 134
Loc: Bendorf, Germany
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Quote:
I'm thinking some sort of sub-miniature death star sort of arrangement, which would look pretty cool in a darkened room with some smoke in...
pca
Is this actually going to be on display during the meet in Manchester?
-Peter
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