Only 1 tracker in rocket?

Discussion in 'Rocketry Electronics and Software' started by Locksmith, Apr 22, 2019.

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  1. Apr 22, 2019 #1

    Locksmith

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    Ive been in the hobby a couple years and invested in the Missileworks GPS system early on and it has never failed me.
    But
    My rockets are getting bigger, there getting faster and sometimes land farther away. At what point do you start to consider multiple trackers?
    Do any of you also only run 1 GPS or do you run a 2nd?
    Just curious, the RTX has never failed me but I would hate to lose a expensive rocket because I couldn't find it. But also don't want to waste my money on something I would never use.
     
  2. Apr 22, 2019 #2

    cwbullet

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    I have had rockets separate. I have used RF trackers in the top and bottom of a rocket or larger rockets (10 inches in diameter and 75 pounds). GPS in the middle.
     
  3. Apr 22, 2019 #3

    timbucktoo

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    I always use RF as backup whenever flying high altitude. For me that’s usually flights in the neighborhood of around 8k or more.
     
    Last edited: Apr 22, 2019
  4. Apr 22, 2019 #4

    blackjack2564

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  5. Apr 22, 2019 #5

    manixFan

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    I also generally fly an RF tracker as a backup to a GPS in high flights. (10k or so). Installation is trivial and takes up next to no room in a 54mm and larger rocket. However, if you lose the rocket (lawn dart or something similar) it is of course more costly. There’s always something to balance out the benefits it seems.


    Tony
     
  6. Apr 22, 2019 #6

    OverTheTop

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    I have never bothered with a second tracker in my rockets. I just put up a two-stage to 36k' and the telemetry went dark at the apogee charge. Maybe I should have had a second tracker so I don't have to wait for my rocket to turn up now. Next time...
     
  7. Apr 22, 2019 #7

    cwbullet

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    Isn’t that the way it always goes. The enemy is the statement “I don’t need no stinking tracker” or “it is only going 6000 feet”.
     
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  8. Apr 22, 2019 #8

    ksaves2

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    Folks, If you got the room use it. I did single tracker rockets just because they were too small for any other scenario. The other thing with a single tracker rocket is put it up on a lower impulse motor the first time to see how the tracker performs. If there is a problem with the installation, it might be apparent and you still recover your rocket within sight. I don't trust ground range tests as much unless they are incredibly impressive.
    Make sure the installation is solidly mounted, the airframe is radiolucent, the power source is solidly
    connected and the antenna is in good shape. if flying ham APRS trackers, toss in a 900Mhz tracker if there's space.
    Other tidbits: Avoid metallic paints. I know for a fact it attenuates 70cm Ham APRS. Rattle can rustoleum too! Ok to do a nose mounted tracker with non-metallic paint on the NC and paint the rest of the airframe metallic. I launched two Beeline GPS's in succession and that's how I know.
    The phenomena is likely frequency dependent so maybe 900Mhz not effected as much. Me? I'm making sure every rocket or NC mounted tracker bay is radiolucent. After not getting positions twice in a row 11 years ago I haven't had that repeated. Kurt
     
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  9. Apr 22, 2019 #9

    Banzai88

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    Another strange phenomenon is in the early phases of installing a tracker. Seems no matter what I do, once I got my RTX up and running and installed in universal nose bays, all of my rockets seem to be competing for the 'closest to the pads' recovery as though olympic gold was on the line!
     
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  10. Apr 22, 2019 #10

    Bat-mite

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    One tracker shared amongst all my rockets. Been to 13k' with it.

    I have a BRB900. I stick it in a piece of pipe insulation, then put that in a pill bottle, then duct-tape it to my harness. Aft end is better since that's where the motor is, and it is cheaper to replace a payload tube and NC.

    Last time I launched, the harness ripped through the duct tape. I was walking to the rocket via GPS. When I got there, the navigator said Ii was 250' away. Hmmm...

    Then I noticed the pill bottle wasn't on the harness. No problem. I followed the navigator to the pill bottle on the ground, 250' away. :)
     
  11. Apr 22, 2019 #11

    Chad

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    what would you say is the max. altitude for a non tracked flight? I'm planning on a flight in May that will likely end up between 5,000 and 5,500 feet or so. I really like the featherweight GPS setup but it's pretty pricey and so don't want to make the investment if I don't need it. After May, my next flight won't be until August due to family scheduling.
     
  12. Apr 22, 2019 #12

    Bat-mite

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    Depends on the size of the rocket, amount of wind, number of people watching, do you have binoculars, etc. I've launched big rockets to 7000' and seen them come down 1000' from the pad.
     
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  13. Apr 22, 2019 #13

    Nytrunner

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    In my personal opinion, altitude isn't a delineator but more like a contributing factor.

    How big is the rocket? How fast is it going (ie, ease of maintaining eye contact)? What color is the rocket (sky colored?, ground-clutter colored)

    A 2.5" blue/white rocket on a fast burn motor can disappear going only half a mile up (until the main charge popped and told us where it was)
    Contrast that, my 7' L2 rocket red/white/blue/gray/black was easily visible by eye on a 4k flight, and easily followed with binocs to 7k.

    Also, I'll +1 the tendency for tracker'd rockets to land obscenely close to the launch pads
     
  14. Apr 22, 2019 #14

    timbucktoo

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    For me it really depends on field size, conditions & terrain. But as a general rule anymore, if a tracker fits, it is going in the rocket. I recently lost a rocket that only went ~1000’ because in landed in really deep weeds only to be found a month later by the mighty bush hog.
     
  15. Apr 22, 2019 #15

    DaveW6DPS

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    If it fits, it flies. And I build some pretty small ones. So in any 24mm or larger rockets I use a tracker of some sort.

    If it is going over about 10K AGL I will use an APRS tracker (BRB) and add a DF beacon as a back up.

    Getting set up for DF tracking is pretty easy and cheap. GPS tracking is easier, but a bit more spendy. Some GPS receiver modules can interfere with each other, so you would not want them in the same e-bay.
     
  16. Apr 22, 2019 #16

    BBrown

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    If you want it back, put a tracker in it! It really is that simple. Without a tracker, you are relying on a bit of luck to recover your rocket.
     
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  17. Apr 22, 2019 #17

    boatgeek

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    It's reverse Murphy's Law. Now, if your tracker ever loses power, that'll be the flight that ends up 5 miles away.

    Reasonably good naked eyes can see 4" rockets at 5000 feet in decent weather conditions. I tracked my L1 cert (54mm, 2500-3000 feet) visually, so you can kind of scale that altitude by the diameter. Haze, clouds, sky-colored rockets, etc. reduce that distance somewhat. That's one half of the equation--the other half is the field. If you have nothing but wide open spaces in every direction and you'll be able to get a good bearing on the rocket as it nears the ground, you can probably just use those numbers. Just walk the bearing 25% further than you thought it would be and you'll find it just before turning around. If you have trees, property lines, etc. that you have to manage, you'll want a tracker sooner.
     
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  18. Apr 22, 2019 #18

    Locksmith

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    Looks like I should look into a RF as back up, any recommendations? Also do most receivers have ability to select the frequency? Maybe buy a RF transmitter then god for bid my GPS goes out I can beg borrow or steal the receiver from another flyer to track it down? just hard to justify spending $500+ on another tracker when its only a back up.

    Anyone use multiple 900Mhz in same rocket also? I have eggtimer GPS units just waiting for cream files so I can build them.
     
  19. Apr 23, 2019 #19

    timbucktoo

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    Com Spec transmitters are about $50. Com Spec receivers are about$250. Your club may have the receiver for loan.
     
  20. Apr 23, 2019 #20

    Exactimator

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    On anything going high I'll use my GPS and borrow an RF tracker from a friend that way if there's something that makes a GPS fail (distance or speed) the RF will cover it.

    My L3 cert flight had two GPSs and an RF.
     
  21. Apr 23, 2019 #21

    DaveW6DPS

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    If you have, or want to get a ham license, there are a number of good DF transmitters on the market. Most are very small and relatively inexpensive. For non-licensed equipment you are much more limited in options.

    Almost all receivers a band or multiple bands of frequencies. For simple DF a hand-held scanner is usually fine, paired with a yagi antenna and usually an attenuator. With a scanner you can usually set up $100 to $150. With a smart phone and a simple cable the scanner can also receive two meter and 70 cm APRS (GPS) signals.

    Big Red Bee has 70cm beacon transmitters for $59.

    A company called Byonics has some great 2 meter beacon transmitters starting about $75.

    Com-Spec stuff works well, but the receivers are only useful for tracking, and due to the pulse modulation a normal FM receiver is not very useful. You are locked in to over $300 for a transmitter and 100 channel receiver.

    So for $300 or less you can set up for DFing your rocket for a pretty long range.

    Here is an article I wrote for our club, that explains a lot of the basics and some of the equipment on the market, with links.
     
  22. Apr 23, 2019 #22

    Locksmith

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    Link to article pls
     
  23. Apr 23, 2019 #23

    Chad

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    hah yeah i left out a few important details.

    3" diameter rocket traveling around mach 0.4, the body tube is painted a silver that looks very similar to aluminum with bright blue fins and nose cone. I guess, full disclosure, this will be 2 stage with a 4" booster. I'm not that worried about the booster just the sustainer. Plus, I'm not doing anything crazy, I'm trying to keep the altitude to a minimum but maintaining a safe velocity off the rail. The purpose of this flight is mostly about pre-launch and pad procedure plus refining some build techniques.

    at the end of the day, the featherweight gps is going in. I guess it came down to the ol' "if you have to ask.."
     
  24. Apr 23, 2019 #24

    cwbullet

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    Maybe someone can expand on what DF is? I assume Directional Finder.
     
  25. Apr 23, 2019 #25

    Titan II

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    direction finding

    you added " I assume Directional Finder" after I posted this response.
     
    Last edited: Apr 23, 2019
  26. Apr 23, 2019 #26

    boatgeek

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    If it's 2-stage, that's a whole 'nother ball of wax. At separation, everyone watching is going to have to choose whether to watch the booster or the sustainer. Murphy's Law says that enough people will choose one that the other will be lost, even if they have specific assignments. :)
     
  27. Apr 24, 2019 #27

    DaveW6DPS

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  28. Apr 28, 2019 #28

    blackjack2564

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    Yes I have had 2 900Mhz units in same rocket, worked fine.
    With RF you must track while flying just to get a general direction. If it lands in a gully, behind a slight rise in terrain or back side of tree...you will NOT get signal. You must track during flight not AFTER.
    Yes multiple freq.Choice. More the expense, more freq.choices.
     
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  29. May 2, 2019 #29

    ksaves2

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    I've ranted that way like Jim ever since I started GPS tracking with a 70cm Beeline GPS tracker, Kenwood D7A(g) and later a D72a coupled to a Garmin 60Cs or 60CsX mapping GPS in 2007. I was addicted after one flight being able to follow the rocket live on a map. The D72a can be set to display GPS altitude so one knows height and look on the 60Cs(X) screen to see location. Add field elevation (height that one sees with the rocket on the pad) to main deployment that one has set and they'll know where to look to try to get a visual on main deployment. Statement of fact: Even when using Rf tracking, a visual on descent is "golden" so it's nice to be looking in the right direction to try to catch it in the visual lobe of one's brain. True. It's not always possible with a small GPS tracked rocket to get a visual. I've had some flights pop a 36 inch main at 1/2 mile and not see a thing......... Except when I walk up and see the rocket on the ground with the main fully deployed and obviously a nominal flight. That's a head rush and sense of accomplishment.
    One doesn't have to send a pricey project up to 60,000 feet to have the satisfaction of a sight unseen recovery. A GPS tracked Wildman Jr. sent to 5 or 6k can generate a considerable sense of accomplishment too especially since there is a chance one won't get a visual on descent with the higher powered J motors.
    Oh, not dissing the non-licensed GPS solutions out there as I've used a few of the 900Mhz remedies (MW and EF). They're great for sport flying and with a bit of difficulty, can be interfaced for live map tracking too. Kurt
     
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