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How are you mounting your DC-30 dog tracker?

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n5wd

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Mike Konshak has published a couple of articles showing how to mount the DC-20 dog-tracker modules in rockets (see EXtreme Rocketry #70 March 2008 and Sport Rocketry July/Aug 2009) and has pix of his system on his web site http://telerover.com/. But, I've been unable to find any references to how folks are mounting the newer DC-30 modules.

I've got a couple of ideas, now that I've gotten mine in hand, but having learned to not reinvent the wheel any more than possible, anyone want to share their ideas, especially if it involves removing the module from the strap?

Just off hand, I think it would be easy to put the unit's strap through a nosecone U-bolt or traingle ring, feed it back through the buckle and duct tape the buckle so nothing comes loose, and just stuff the module down into the laundry for a quick-n-dirty ride. What else ya got? :)
 

cjl

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The first thing I did was remove the module from the strap. Once you've done that, you can simply mount it to a plate of G10/thin ply with some screws, and mount that in the nose. Of course, you could always give it a ride on the shock cord :)
 

cwbullet

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I mounted mine to the shock cord. I wraped it in kevlar sock and then zip tied the ends to the shock cord. It worked well.
 

quickburst

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Like the others, most of the time I see them mounted in nosecones. I have also seen them ride on the shock cord, without a problem.


I also saw one come loose and fall to the ground. Not sure how it was attached, but it was messed up from the impact. I think he was going to try to revive it ...... haven't heard anything.
 

n5wd

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...I have also seen them ride on the shock cord, without a problem.
It seems sturdy enough from the outside to do that, but just wanted some confirmation from others that it wouldn't fall apart the first time it took the ride.
 

n5wd

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The first thing I did was remove the module from the strap. Once you've done that, you can simply mount it to a plate of G10/thin ply with some screws, and mount that in the nose. Of course, you could always give it a ride on the shock cord :)
Yeah, I guess there's really only a couple of ways to mount 'em. Guess I'll try putting it in the Little Dog's nose cone first and take it down to Hearne weekend after next.
 

quickburst

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Yeah, I guess there's really only a couple of ways to mount 'em. Guess I'll try putting it in the Little Dog's nose cone first and take it down to Hearne weekend after next.
I'll be there in spirit.
 

n5wd

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The first thing I did was remove the module from the strap. Once you've done that, you can simply mount it to a plate of G10/thin ply with some screws, and mount that in the nose.
Well, I finally had a few minutes to take the DC-30 screws off the main unit and the antenna and was presented with a few new questions...
Did you take the GPS antenna (the squarish black box) connector off from the DC-30 main body? If so, was it slip fit on, screw on, or what? I can't see any way to get that cable out from under the strap without taking it off the main unit, but don't want to just start prying things off. Also, it looks like once you get the units separated from the collar, you're probably not going to be using the collar as a mount any more - no easy way to thread that coax back through the collar from what I could see.

Also, did you take off the main VHF antenna from the DC-30 main unit? Again, what kind of connector - looks like a right-angle, if it's an SMA.
 

cjl

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That GPS connector is just a snap on - I pried it carefully off to remove the collar from the GPS unit itself. You could also try to cut the collar off if you were really paranoid. As for the VHF antenna, as I said in the e-mail, it isn't an SMA. It actually has a screw holding it on, connected to the end of the antenna. I haven't removed it, so I can't give you any more details. The reciever VHF antenna is SMA though, so you could attach a higher gain antenna to the reciever if you needed a longer range.
 

lmt56

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I have one of these units on the way and would like to mount it to my shock cords.
Just wandering how much trouble users are having with the GPS transmitter interfearing with the altimiters and what steps they are taking to deal with it.
I plan to use it with a combination of the following alts.
PerfectFlight MAWD
ArtsII
MissleWorks RRC2 mini
 

cjl

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From what I know, talking to Mike Konshak (who has been flying Garmin GPS units longer than anyone else I know), if you want to put them in the same bay as your altimeters, there needs to be some sort of isolation between your altimeter and the Garmin unit. He had a couple of accidental deployments when he armed his altimeter due to that problem. However, if the GPS is a few feet away, it doesn't cause any trouble. I've mounted it in the nose cone with perfect success without needing any shielding or any extra precautions.
 

lmt56

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From what I know, talking to Mike Konshak (who has been flying Garmin GPS units longer than anyone else I know), if you want to put them in the same bay as your altimeters, there needs to be some sort of isolation between your altimeter and the Garmin unit. He had a couple of accidental deployments when he armed his altimeter due to that problem. However, if the GPS is a few feet away, it doesn't cause any trouble. I've mounted it in the nose cone with perfect success without needing any shielding or any extra precautions.
Thanks for the info. I know the nose cone would be the prefered location but I plan on using it on some of my older builds.
Placing it on the shock cord would make it easy to move from one rocket to another. But that may cause it to be close to alt. bay once the rocket is flight ready.
Couple questions.
Can I expect problems if I have both the GPS transmitter and my radio tracker transmitter located close to each other?
I am not ready to give it up just yet and would like to have it as a back up.
I plan on doing as much ground testing as I can then a couple lower alt. test flights.
Second question is. What type of battery is in the GPS transmitter and how long does it last?
To me the price of the GPS transmitter at about $150 is not to bad.
My radio tracker transmitter cost that.
Any helpful hints and suggestion on using this GPS unit would be appreciated.
Just trying to cut down the learing curve.
 

n5wd

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I have one of these units on the way and would like to mount it to my shock cords.
Just wandering how much trouble users are having with the GPS transmitter interfearing with the altimiters and what steps they are taking to deal with it.
I plan to use it with a combination of the following alts.
PerfectFlight MAWD
ArtsII
MissleWorks RRC2 mini
Mike Konshak also wrote a good article (it appears in the July/August 09 issue of Sport Rocketry, sent to all NAR members - another good reason to join) that gave the results of an experiment where two DC-20's or a Rhino 110 (peer-to-peer GPS data) were put in close proximity to various altimeters to determine whether there was enough interference to cause a problem.

The Perfectflite MAWD had no problems with the DC-20, but the Rhino 110 produced a false launch detect on the MAWD.

The Missle Works RRC2 mini had false launch detects when any of the transmitters were within 6 inches.

The ARTS wasn't tested.

As always: test, test, test.
 

n5wd

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Just trying to cut down the learing curve.
Yep, we're all there, too!

lmt56 said:
I know the nose cone would be the prefered location but I plan on using it on some of my older builds. Placing it on the shock cord would make it easy to move from one rocket to another. But that may cause it to be close to alt. bay once the rocket is flight ready.
I'm thinking that a simple solution might be to do something like we do with the nomex shields for our shock cords & chutes - put a bit of aluminum foil or a cardboard bulkhead with aluminum tape on both sides between the ebay and the GPS/transmitter. Even a little bit of shielding may do the trick if you're getting falsing of the electronics when you test it out (did I mention: test, test, test?).

lmt56 said:
Can I expect problems if I have both the GPS transmitter and my radio tracker transmitter located close to each other? I am not ready to give it up just yet and would like to have it as a back up.
(a) Probably not or (b) not much chance at all: depends on what band your tracker is on. I have a Bee that operates on 446MHz - it's far enough away from the 151/154 MHz MURS channels that the Astro DC units transmit on that ther shouldn't be any problem, except maybe some weird mixing that puts a signal out somewhere around 315MHz and 597 MHz ( f1 + f2 = f3 and f1 - f2 = f3) when both of the units are transmitting at the same time (which shouldn't be enough to bother anyone).

If you have a receiver onboard that was operating in the 2m amateur band or VHF-High band, then I'd worry a bit.

Can't tell you much about the batteries.

IMHO I think you're right that the Garmin stuff is pretty cost-effective, especially when comparing the replacement cost of a DC-20 or a DC-30 to a Bee/GPS unit. The Bee/GPS has some advantages - but for personal use I think I'm going to get a lot of use out of this Astro system.
 
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