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Nose cone tracker question

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Mr G

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The 54mm Filament Wound Fiberglass Nosecone that came with my Wildman Wild Thang Jr kit had both a small 1/4" hex head bolt and a long eyebolt option to attach to the aluminum tip. At the other end is a separate coupler and lid that fits inside it. I thought maybe the eyebolt was for use with head-end deployment but maybe there are other uses.

The sustainer tube is already set up on the bottom end with traditional dual deploy electronics bay.

Given the pieces I have to work with, what would be a good way to install an Eggfinder tracker?
 

blackbrandt

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Shove the eggfinder and a battery into a short piece of bt-55, pack it in with foam, tape over the ends with duct tape, and zip tie it to the shock cord.

Problem solved.
 

ksaves2

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Shove the eggfinder and a battery into a short piece of bt-55, pack it in with foam, tape over the ends with duct tape, and zip tie it to the shock cord.

Problem solved.
That is a down and dirty way to do it and could very well be pulled off if placed on the apogee harness. The BT-55 should be long enough to encompass the EggFinder and the antenna. You don't want the antenna to get bent up or squished down or around.
An SMA or RP-SMA antenna would be more robust in that regard. Remember that carbon fiber tubes will attenuate the Rf off of a tracker significantly. Even the black "profusion" tubes though they are not CF have carbon black added to the substrate and that can attenuate a signal. Ejecting the tracker out at apogee into free air like Matt mentions above is ideal as far as range reception is concerned.

With the EggFinders, one might not get as many positions decoded on a dual deploy rocket that is at a distance and falling under drogue. For that reason, I set my main to blow at 800 feet or higher. Once the descent rate slows and the EggFinder antenna
is oriented more or less vertical, that's the time when the positions will start to come in more reliably and that's when you need 'em to get that initial and final location prior to touchdown.

I find the Ham APRS Trackers (BeeLine GPS/Ham band) have more robust packet/altitude reporting but that only is transmitted once every 5 seconds. I've tracked high flying rockets with APRS at 12k' under drogue and due to the vagaries of radio propagation
sometimes only receive position packets every 10 to 20 seconds instead of the expected once every 5 seconds. In that case too once the rocket is under the main chute at altitude, the decoding of the APRS packet can occur more reliably. The Beeline GPS tracker can of course store the positions at higher a rate to onboard memory for later download as a .kml file for Google Earth display. The once every 5 seconds transmission is more than adequate to get
a general track and find ones rocket.

I do both types of tracking and like them both. I have no reservation recommending the EggFinders to folks with no interest in getting a ham license but the technician's ticket opens up more options plus one will be able to learn
a lot about radio propagation. That does transfer to good use to rocket tracking.

I've used Windows software to track EggFinders in real time on a map and can get reasonable positions plotted but the reported altitudes are spotty. I saw some improvement when using a high gain receiving antenna but again the reception seems much more reliable once the rocket is under the main chute. The SirfIV GPS chipset used on the EggFinder is great for positioning but kinda sucky with altitude reporting with dynamic flight. The name is EggFinder and it does just that. It will find the rocket. Not advertised as an altitude reporting device. I've considered my WinBlows software might be at fault here and have a linux solution (Xastir) I am hoping to try with the EggFinders soon.

The TRS is a different bird here. If the packet is decoded the altitude from the baro chip is sent. I found with my one TRS flight when packets were decoded, the altitude seemed more reasonable as opposed to what
I've observed with the plain EggFinders. Then again, the behavior I describe above is generally what is seen with the TRS too. Once under main, the positions are more readily heard and decoded.

I've had three totally sight unseen Eggfinder flights with one ballistic and found them all. The ballistic was a glass rocket I walked up to the fincan sticking out of the ground. I would have had no idea where to go otherwise as that
last position got out at 50 feet above the ground was good enough to find the rocket. Kurt
 

cerving

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Here's the NC sled for my Double Shot, which is 54mm like the WM Jr. There are two short pieces of allthread epoxied into the NC coupler, you drill the bulkplate for them and just put on a couple of nylock nuts to hold it in. The actual sled is held on with two L brackets, with the U-bolt holding it onto the bulkplate. This particular one is going to have a TRS in it, I'm using the Main channel as a backup for the Quantum in the AV bay... that's what the charge well is for. The TRS is held on with some really strong servo tape... it ain't going nowhere. There's a 350 mAH 2S LiPo on the back side, that you can't see from this view.

IMG_1634.jpg
 

Mr G

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Good to know about Eggfinder antennas and when to expect a solid signal. The tube attached to the shock cord eliminates a bunch of structural considerations. Cardboard, right?

Thanks, ksaves2 for the extensive background info. My assembled Eggfinder is about to show up and I am still trying to understand what is required to make it perform properly. Can you explain more about various makes of antennas to a total tracker noob? Sounds like I need to buy something more. Pictures are worth a thousand words.

Hopefully, there is a way to program/use the Eggtimer with an Apple system - no option for a PC system.
 

cerving

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Hopefully, there is a way to program/use the Eggtimer with an Apple system - no option for a PC system.
The only thing that's PC-specific with an Eggtimer Classic or TRS is the Win-AVR program that's used to upload firmware, the actual programming and downloading is done with a serial terminal program. There's plenty of them out there for every OS, look at the docs on the web site for details. There is also apparently an Apple version of Win-AVR too, somebody did a thread on it about a year or two ago.

For an Eggfinder, there is nothing Apple-specific at all... no firmware.
 

Swissyhawk

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Here's some pictures that might help.

The first is a nose cone tracker in a 54 mm Tomach. I put 1" machine screws into 10-24 coupling nuts. I then epoxied the machine screws onto the inside of the nose cone coupler. I didn't directly epoxy the coupling nuts to the coupler because I was afraid there wouldn't be enough adhesion. It's a little tight and I've had to play around with my sled to get it to work. If I did it again, I might use smaller coupling nuts or maybe just use 2 of them instead of 4. Also, I really like Chris' idea of epoxying small sections of all thread to the NC coupler instead of the coupling nuts like I did. I might do that next time. The sled is attached to the eye-bolt running through the bulk plate. There is no all-thread support the sled.

The second picture is my tracking tube for attaching it to the harness. I used a length of 29 mm motor tube and put Estes retainers on both ends for easy access. I glued small plywood circles into the retaining rings to seal it off. The sled is just the width of the tube, so it doesn't move around much but I still put some small pieces of foam in there under the sled just to keep things from moving around.

IMG_0290.JPGIMG_0291.JPG
 

Crazyrocket

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So I am assuming that the second picture just gets taped to the shockcord? I was thinking about doing something similar.
 

michigander

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I made a sled in nc , this is old school gps with the switch , picture is before the couple was glued into NC

gps.jpg


IMG_2297.jpg
 

Swissyhawk

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So I am assuming that the second picture just gets taped to the shockcord? I was thinking about doing something similar.
Tape would work. So would zip ties. For a while I had a loop of Kevlar epoxied to one end of the tube to clip to or pass the shock chord through. You could also put an eye-bolt in the end.
 

cerving

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Just don't use electrical tape... it melts. (No, it wasn't MY mistake...)
 

ksaves2

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I made a sled in nc , this is old school gps with the switch , picture is before the couple was glued into NC
Old school? Yeah, it's v1 but not that old! I'm stealing that design! Brilliant. All thread runs from centering ring aft to the bulkhead which is secured by nuts of some type. Antennas are above that centering ring so no all-thread interference.
Like I said, brilliant. Perhaps a dollop of threadlocker or epoxy so those nuts on the centering ring don't come loose? Kurt
 

michigander

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Old school? Yeah, it's v1 but not that old! I'm stealing that design! Brilliant. All thread runs from centering ring aft to the bulkhead which is secured by nuts of some type. Antennas are above that centering ring so no all-thread interference.
Like I said, brilliant. Perhaps a dollop of threadlocker or epoxy so those nuts on the centering ring don't come loose? Kurt
yep those nuts inside and outside got rocketpoxy , wing nuts for removal :)

IMG_2293.jpg
 
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