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  1. #31
    Join Date
    26th November 2009
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    Quote Originally Posted by Bobfly View Post
    Hi All,

    I started using the Walston radio trackers years ago in Radio Control sailplanes. They saved a lot of planes over the years in our club. I use Vern Knowles GPS Multitronix “Kate” Tracker in all my 3” and larger rockets.

    The Missile Works GPS Tracker System fits in a 54 mm rocket. I have this system but have not flown it yet. You cannot beat these GPS trackers. They take you right to the rocket even if it lands miles away. The “Kate” unit tells you exactly how far the rocket is from your current position.

    Does anyone have a GPS tracker system that will fit in a 38 mm rocket?

    All the best,
    Bob
    Tele-GPS in a GoDevil 38 NC and folks do EF Minis.
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    I use three 2-56 PEM nuts in the coupler and buttonhead screws to hold the nosecone shroud to the coupler. The coupler is quite thick and I use a round router on the inside and epoxy the PEM nuts inside the coupler.
    Yeah the buttonhead screws show on the outside but I consider this viable in order to be able to easily get the tracker in there.

    Kurt


  2. #32
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    26th November 2009
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    Quote Originally Posted by Andrew_ASC View Post
    The Arrow antennas had a way to add external power if vehicle mounting to extend range of the receiving ground station communicating with the in flight GPS transceiver that communicates with the satellites. I think it would do light sub-orbital stuff no joke if externally powered ground station antenna, but that is beyond my experience level.

    What I noticed what gets people is a maximum velocity tracking a system can do. You want a system that can handle the rocket performance. Some are optimized for weather balloons and have epic altitudes but do not do high velocity supersonic tracking. I think people have modified egg timers and other 900Mhz systems but once you get into HAM stuff it's literally plug and play at a higher price tag. My experience was only limited to TeleGPS and a 440-5 antenna. User support was awkward and the forum helped more than Altus, but good device once you got used to it.
    No off the shelf GPS can do more than 1000knots and 59000 feet via treaty restrictions. Some chipsets do better at high G levels than others and some also will record to a reported 156,000 feet as long as the speed of 1000 knots isn't exceeded.

    Once the rocket is going less than 1000 knots (1200mph) and the G's lighten up one technically should see the positions coming in. Again, some chipsets do better than others. Kurt


  3. #33
    Join Date
    22nd September 2017
    Posts
    350

    This is why you want good tracker. I was on the YAGI the entire time plugged into an inverter, we had a four hour launch delay at VAST from weather.
    When you can't find it anymore visually. Story was the sustainer CATO'd for the low alt, we still got third, and I don't know how.
    Last edited by Andrew_ASC; 6th December 2017 at 03:59 AM. Reason: Your rocket can explode at SEDS and you can still win, LOL.

  4. #34
    Join Date
    18th October 2016
    Posts
    464
    Track all the things!!
    TRA L2. I-class record: "Vanish 29" with an I224, 14,596ft, Mach 1.92. Video here.

  5. #35
    Join Date
    18th January 2009
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    Toney, Alabama
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    I am following this thread as well, as I am going to be in need of some sort of tracking system... and right now I am about as fluent on trackers as a sack-O-hammers.
    "He who fights with monsters should look to it that he himself does not become a monster, and if you look long into an abyss, the abyss also looks into you." - Friedrich Nietzsche

    "The Future is Not Solid" - Korey Kline

    TRA# 08705 L3

  6. #36
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    15th October 2016
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    Huntsville AL
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    1,687
    Quote Originally Posted by DRAGON64 View Post
    I am following this thread as well, as I am going to be in need of some sort of tracking system... and right now I am about as fluent on trackers as a sack-O-hammers.
    If you come to the HARA meeting tomorrow night, I'll have my T3 there for examination. I'm thinking of picking up some sort of buzzer/screamer to get me that final 10 yards to the rocket.

  7. #37
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    516
    I recommend this buzzer/screamer, only $7 shipped and very loud. You'll hear it from a lot further than 10 yards away.
    http://www.amazon.com/gp/product/B01...?ie=UTF8&psc=1

    L1 3/25/17 H135
    L2 8/12/17 J180

  8. #38
    Join Date
    5th December 2013
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    MD
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    Quote Originally Posted by DRAGON64 View Post
    I am following this thread as well, as I am going to be in need of some sort of tracking system... and right now I am about as fluent on trackers as a sack-O-hammers.
    You and I both. However, I'll share what little I do know.

    There are two categories of trackers: GPS and, um, the ones that "echo locate," sort of.

    There are two types of radios: 900 MHz, like cell phones and pagers, and does not require a HAM license; and other frequency bands that do require a HAM license.

    Trackers require two pieces: a transmitter and a receiver. Transmitter goes in rocket, receiver in hand.

    Transmitters and receivers come in two levels of difficulty: kits (requires soldering and good eyes), and already-built.

    GPS trackers report coordinates, which then also requires a navigator to get you to the rocket. Whereas the "echo location" thingies point you at the rocket via "pinging" volumes.

    Since it is clear and obvious that I do not have a HAM license and don't have a clue what I'm saying, I went with 900 MHz GPS. I bought a BRB900 transmitter and receiver (about $300), and a Magellan old school B&W hiking navigator ($20 on Ebay).

    The BRB900 receiver receives the coordinates of the rocket. I plug them into the Magellan, and it walks me to the rocket. It gets me within a 100' radius or so, which means it is still a drag in tall grass. Also, if the rocket gets blown around by the chute, its coordinates keep changing, which means I have to keep adjusting my Magellan.

    Anyway, this combo has successfully walked me to my rockets many times. But Gus P. also let me use his HAM pinger thingy at LDRS, and it looks like a great system if you want to get licensed and buy all the equipment. The nice thing about that is that it always points you at the rocket no matter what, and you don't need to be in range of a GPS satellite.

    John S. ---- NAR #96911 ---- TRA #15253 ---- MDRA #067 ---- BARC #028
    L1, 3/15/14: Aerotech Sumo, CTI H133BS
    L2, 6/21/14: Giant Leap Vertical Assault, CTI J240RL
    L3, 3/12/16: MAC Performance Radial Flyer, CTI M1101WH
    Altitude: 13,028', L3 flight; Speed: Mach ???, L3 flight

  9. #39
    Join Date
    31st May 2017
    Location
    Houston, TX
    Posts
    115
    Bat-mite,

    Very helpful! I am at the same level of understanding it seems lol. I guess the RF (?) style have distinct advantages, but they also seem like you need to buy more stuff. A radio, a transmitter, a yagi (uhh ?) - or I am a dummy and lost.
    TRA #17256
    Tripoli Houston
    L1 - 7/8/17

  10. #40
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    5th December 2013
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    MD
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    Quote Originally Posted by viciouspeanut View Post
    Bat-mite,

    Very helpful! I am at the same level of understanding it seems lol. I guess the RF (?) style have distinct advantages, but they also seem like you need to buy more stuff. A radio, a transmitter, a yagi (uhh ?) - or I am a dummy and lost.
    Eggfinder, BRB900, and Missileworks Telematics all use 900 MHz and report GPS coordinates. I suppose it matters where you launch, to know if there is sufficient GPS satellite coverage. Best thing to do is to talk to people at a launch and see what they use.

    John S. ---- NAR #96911 ---- TRA #15253 ---- MDRA #067 ---- BARC #028
    L1, 3/15/14: Aerotech Sumo, CTI H133BS
    L2, 6/21/14: Giant Leap Vertical Assault, CTI J240RL
    L3, 3/12/16: MAC Performance Radial Flyer, CTI M1101WH
    Altitude: 13,028', L3 flight; Speed: Mach ???, L3 flight

  11. #41
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    516
    "There are two categories of trackers: GPS and, um, the ones that echo locate, sort of."
    There are trackers that report the rocket's GPS location and trackers that just transmit a radio signal. In the latter case, you locate the rocket by homing in on it, using a receiver with a directional antenna and an attenuator. Slowly moving the antenna, you find the direction with the strongest signal and head in that direction. GPS will show you the rocket's exact location on a map and walk you to it, so it's usually easier to find the rocket this way, although as noted above sometimes a GPS tracker will "lose lock." Some trackers support both GPS and directional finding, these are the best so you have a backup. If the rocket lands hard, either type of tracker may go dead. In this case, a directional finder will do you no good, but the GPS tracker will hopefully give you the position shortly before landing.

    "Trackers require two pieces: a transmitter and a receiver. Transmitter goes in rocket, receiver in hand."
    Generally yes, and you will probably want to connect the receiver to a cell phone or tablet via bluetooth or USB cable to see the rocket on a google map. The exception is if you use a cell service tracker, as mentioned above in post #9 (only works if you have cell service at your launch field). In that case, the tracker on the rocket has a SIM card. Instead of transmitting its position on 900 mhz or a ham frequency, it does so via a cellular network. You don't need a receiver, just an app on your phone.

    "The BRB900 receiver ... gets me within a 100' radius or so."
    BRB is GPS and should get you much closer. How many satellites? My TeleMetrum sees around 9 sats at my launch sites and gets me within 15' every time.

    L1 3/25/17 H135
    L2 8/12/17 J180

  12. #42
    Join Date
    22nd September 2017
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    350
    Quote Originally Posted by viciouspeanut View Post
    Bat-mite,

    Very helpful! I am at the same level of understanding it seems lol. I guess the RF (?) style have distinct advantages, but they also seem like you need to buy more stuff. A radio, a transmitter, a yagi (uhh ?) - or I am a dummy and lost.
    Yagi is a fancy word for specialized antenna designed for frequency. You get a coaxial cable for the yagi and it screws into the reciever which can plug into a laptop as a groundstation if using Teledongle reciever hardware for an Altus metrum product. Then you have a hand-held HAM radio you tune to frequency you use for the FCC callsign stuff and to also receive info incase the GPS hit the fan. A UV-5R lets you say your callsign before using a frequency the only info received is beeps, it gets the data but a basic model won't decode into a range from you to gps/radio beacon or the heading to get to it. On the TeleGPS either a teledongle or a teleBt will transfer the GPS datalink data of everything literally to your phone or laptop running software depending on what you want that's what meant as ground station when connected to yagi ,handheld radio, and receiver. You hold a yagi to maximize range. Its analogous with a telescope for radio waves. Spacing, rod lengths, number of rods, and frequency are factors. A fancier handheld radio unit lets you directional find a dual GPS/APRS rocketry transreceiver through radiowaves with radio link APRS style data. The baud rate lower increases the data per second sent and also increases range, that's what the HAM units offer. It's a transceiver because it transmits the radio waves as an independent radio station. You are not dumb... Its a lot of "crap" to take in... And most of it seems foreign when you start. If you have solved a very basic circuits diagram that may help with the HAM exam. Most of the antenna questions are rules are a lot of memorize stuff then that just gets the tech liceunse for 10 years, and you have a lot to try practically to learn after exam. I still struggle with the HAM radio options and gear selection. You may need a BNC to coaxial to connect the yagi up. That's how dumb I was. Thankfully a prepper store of wackos with body armor and bunkers had the connector, because walmart won't. Dude at the counter knew, but said try radioshack. LOL...

    The eggfinder I've seen it have different YAGI. Its not required. The more gear crap you buy the better off your capabilities are. You are getting into optimizing a "overall" radio system with radio antennas for the electromagnetic radiation transfer between two locations. Many of the 900MHz systems are drop and go with a here's your ground station, here's your tracker, and antennas are already taken care of. The 434MHz systems are optimized for HAM operators, and often have easier to use interfaces with less assembly, but you need to know what gear to match with what to take full advantage.

    I only pass HAM by 1 question, mechanical engineer student here. Doing P=IV or V=IR on exam was easier than all the antenna satellite comms questions, LOL... HAMStudy.org. Failed practice twice than passed the real thing. You can take as many times as you want every 2 months. Sorry if I am rambling. I am new at it too. Overwhelming at first. Just overwhelming. Took 2 weeks of practicing to get to where I could use it. Then the FCC has GPS coordinate unit converters. You gotta enter the right format into a phone or GPS handheld if you wanna get to it. Thankfully the format was right on altus no converting.

  13. #43
    Join Date
    26th November 2009
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    4,721
    Quote Originally Posted by billdz View Post
    I recommend this buzzer/screamer, only $7 shipped and very loud. You'll hear it from a lot further than 10 yards away.
    http://www.amazon.com/gp/product/B01...?ie=UTF8&psc=1
    I have a few of those but be careful. The corner of that case has a little plastic post and that's all that holds the chain and the ring clip on. I was trying to figure out if there is a safe way to drill it out and put a piece of round metal rod there and still have
    battery access. True it's only $7.00 so if it rips off, no big financial loss.

    Not a solution for small rockets though and this thing is really LOUD. I haven't flown mine but I bet if deployed at an out of sight apogee, one might be able to hear it before they are able to see the rocket. Kurt

  14. #44
    Join Date
    22nd September 2017
    Posts
    350
    With a TeleGPS your out $214 for the unit if it crashes real stupid hard. Or if you solder a different antenna on. Granted it's a micro black box with live data feed and recording. You know where it is within ten to fifteen feet, where it's been, the altitude, coordinates, rocket heading updated constantly, mach, velocity, flight path 2D on map, and exportable data to 3D of flight route then 2D graphs on whatever parameters including satellite numbers, signal strength etc. That data with level of detail per second may help you diagnose if a fin fails in flight. And you don't need the GPS intact to extract that kind of data since it autosaves each flight with hours of memory. The issue is you have to manually clear the last flight or it won't record it on the board's memory.

    I think Raven has a neat 24mm system 900MHz. I would rather use the space for a spare tracker or even a HAM radio beacon on different frequency than a squealer. Squealer beats nothing. Paint, chalk, metallic streamers, and maybe even co2 dry ice in a small capsule are cheap tricks. Radio Beacons have good range for the price and I think they are under-rated. Low tech stuff is good backups.

  15. #45
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    11th February 2017
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    south Florida
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    Quote Originally Posted by ksaves2 View Post
    I have a few of those but be careful. The corner of that case has a little plastic post and that's all that holds the chain and the ring clip on. I was trying to figure out if there is a safe way to drill it out and put a piece of round metal rod there and still have
    battery access.
    I noticed that, so I have wrapped that corner of the screamer tightly with electrical tape, so far so good. This device was recommended by kcobbva on this forum.

    L1 3/25/17 H135
    L2 8/12/17 J180

  16. #46
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    26th November 2009
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    Quote Originally Posted by billdz View Post
    I noticed that, so I have wrapped that corner of the screamer tightly with electrical tape, so far so good. This device was recommended by kcobbva on this forum.
    I didn't say it wouldn't work but when I took one apart to see about the battery situation I saw how the chain was secured to the device. Little plastic post. With my luck, the thing would break off my harness and the rocket would likely land in standing corn or tall grass!! Well at least one could hear the screamer incoming!

    No doubt, not so bad to lose a $7.00 noise maker but if separation jepordizes finding the rocket that's the tough part! Kurt

  17. #47
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    18th January 2009
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    Quote Originally Posted by Nytrunner View Post
    If you come to the HARA meeting tomorrow night, I'll have my T3 there for examination. I'm thinking of picking up some sort of buzzer/screamer to get me that final 10 yards to the rocket.
    Alas, I have other obligations tonight, thank you for the invite all the same. It has been many years since I sat in on a HARA meeting I will admit. If you are recommending the T3 as a good start, then I will investigate the system further. Back when I knew nothing about altimeters (circa `98-`99) I broke down and just bought Missileworks first altimiter and taught myself, as I needed to start somewhere. Thanks again for the invite, maybe next month.
    "He who fights with monsters should look to it that he himself does not become a monster, and if you look long into an abyss, the abyss also looks into you." - Friedrich Nietzsche

    "The Future is Not Solid" - Korey Kline

    TRA# 08705 L3

  18. #48
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    19th January 2009
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    Stafford VA
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    6,971
    The two types of trackers you talk about are GPS and Radio Direction Finding (RDF).

    The RDF is an older technology that was originally developed for wildlife tracking i.e. falcons. The Walston system is one example. The transmitters are very small and easy to put in small rocket, even 18mm. They are highly reliable. If the transmitter or antenna isn't damaged, it will transmit and can be tracked at some range. It might not be trackable from the LCO table after landing, but as you get close to the rocket down range, you will begin to pick up the signal. RDF tracking also takes some practice and skill to get really good at it, but when you do, if you put the transmitter where it will be exposed to the air after the apogee event, you can tell from the received signal when you've had an apogee event and the transmitter has come out of the rocket.

    GPS is a much newer technology and has some technical limitations. The receiver doesn't just have to receive the signal like RDF, it has to be able to read the data packets so it has to have a better RF connection between xmit and rcvr. The transmitters tend to be bigger, consume more power (bigger batteries) and are more delicate. The speed and altitude of the rocket can impede the transmission of data. If you lose data connection during flight, the whole tracking exercise can be compromised. An advantage is if you get a last data packet as the rocket drops to the ground, you have a pretty close location of where the rocket is located even if you never regain a xmit to rcvr connection.

    One of the differences between the two is that with GPS, you get a single location that will be + or - based on how many satellites are picked up by the xmit. If the xmit is face down and only getting 3 or 4 satellites, it might be + or - 100 ft or more. That is as good as you are going to get. With RDF, you can always back a little ways off and find the direction to the rocket, then move and find a new direction. Two or more times doing this will give you a location within a few feet of where the transmitter is.

    Which is better? That kind of depends on your skills and attitude. If you like new tech, the GPS is probably for you. If you are old school then RDF might be your go to system. Both systems have advantages and disadvantages. There are some that fly GPS because of the ease of use and location display but still put a RDF transmitter in the rocket as a backup for those times when the GPS fails which tends to be more often then RDF.

    With all of that, I never fly a rocket above about 1500 ft without a tracker unless the field/weather conditions are a sure thing and I know I can track it visually and see it on the ground. Flying at the same field over 10 years makes that an easier determination. It's part of what you learn as you move up in cert levels, flying the field.
    Handeman

    TRA #09903 L3 3/29/2015

    "If you don't use your head, you have to use your feet!" my Dad

    Tripoli Central Virginia #25 - BattlePark.org

  19. #49
    Join Date
    9th October 2013
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    San Jose, CA
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    Quote Originally Posted by ksaves2 View Post
    Tele-GPS in a GoDevil 38 NC and folks do EF Minis.
    Full-size Eggfinder (with the stock brass rod antenna) also fits, with a pretty big LiPo (900mAh, 2S). Been flying this combo in my Go Devil 38 NC since the very first flight, first as a simple FG sled, later as a 3D-printed one (linked post shows both versions).
    Will Ferry (Launches & Videos) NAR #96512 (L2) / TRA #15328 (L2) / LUNAR #2759
    L1: 9/2013 @ XPRS, GLR T-Bolt "Thunderbolt" (R.I.P.), H148R
    L2: 4/2016 @ TCC Helm, Binder Design Excel w/DD "dd2.xls", J315R
    Impulse flown (flights): 2013: 767Ns (2), 2014: 4298Ns (8), 2015: 7486Ns (16), 2016: 11693Ns (18), 2017: 11138Ns (16)

  20. #50
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    18th January 2009
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    Quote Originally Posted by Handeman View Post
    The two types of trackers you talk about are GPS and Radio Direction Finding (RDF).

    The RDF is an older technology that was originally developed for wildlife tracking i.e. falcons. The Walston system is one example. The transmitters are very small and easy to put in small rocket, even 18mm. They are highly reliable. If the transmitter or antenna isn't damaged, it will transmit and can be tracked at some range. It might not be trackable from the LCO table after landing, but as you get close to the rocket down range, you will begin to pick up the signal. RDF tracking also takes some practice and skill to get really good at it, but when you do, if you put the transmitter where it will be exposed to the air after the apogee event, you can tell from the received signal when you've had an apogee event and the transmitter has come out of the rocket.

    GPS is a much newer technology and has some technical limitations. The receiver doesn't just have to receive the signal like RDF, it has to be able to read the data packets so it has to have a better RF connection between xmit and rcvr. The transmitters tend to be bigger, consume more power (bigger batteries) and are more delicate. The speed and altitude of the rocket can impede the transmission of data. If you lose data connection during flight, the whole tracking exercise can be compromised. An advantage is if you get a last data packet as the rocket drops to the ground, you have a pretty close location of where the rocket is located even if you never regain a xmit to rcvr connection.

    One of the differences between the two is that with GPS, you get a single location that will be + or - based on how many satellites are picked up by the xmit. If the xmit is face down and only getting 3 or 4 satellites, it might be + or - 100 ft or more. That is as good as you are going to get. With RDF, you can always back a little ways off and find the direction to the rocket, then move and find a new direction. Two or more times doing this will give you a location within a few feet of where the transmitter is.

    Which is better? That kind of depends on your skills and attitude. If you like new tech, the GPS is probably for you. If you are old school then RDF might be your go to system. Both systems have advantages and disadvantages. There are some that fly GPS because of the ease of use and location display but still put a RDF transmitter in the rocket as a backup for those times when the GPS fails which tends to be more often then RDF.

    With all of that, I never fly a rocket above about 1500 ft without a tracker unless the field/weather conditions are a sure thing and I know I can track it visually and see it on the ground. Flying at the same field over 10 years makes that an easier determination. It's part of what you learn as you move up in cert levels, flying the field.
    Which begs the question; how here watching and providing feedback have lost there vehicle anyway due to GPS or RDF failure to locate (?) By that, I do not mean if it was lost to a rocket eating tree etc. I mean physically could not locate their rocket due to a loss of signal.
    "He who fights with monsters should look to it that he himself does not become a monster, and if you look long into an abyss, the abyss also looks into you." - Friedrich Nietzsche

    "The Future is Not Solid" - Korey Kline

    TRA# 08705 L3

  21. #51
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    30th July 2012
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    Quote Originally Posted by DRAGON64 View Post
    Which begs the question; how here watching and providing feedback have lost there vehicle anyway due to GPS or RDF failure to locate (?) By that, I do not mean if it was lost to a rocket eating tree etc. I mean physically could not locate their rocket due to a loss of signal.
    I use the Garmin dog collar GPS system. At LDRS 31, I lost contact with my GPS tracker during the drag race. A friend thought he saw it come down in a nearby field. I searched for a half an hour and found nothing. I decided to drive up the road toward the last reported position (about a mile away). When I got close enough, the handheld unit re-acquired the signal and rocket was recovered. Since then, I have never lost a signal in flight.

    I fly a tracker in almost everything now. I've wasted enough time searching for rockets by sight. I would rather walk right up to it, get back to base camp and fly some more or socialize versus searching for a rocket.
    David Sears
    TRA# 12944, L3
    NOTRA
    Tripoli Mid-Ohio

  22. #52
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    11th February 2017
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    south Florida
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    Quote Originally Posted by BalDave2 View Post

    I fly a tracker in almost everything now. I've wasted enough time searching for rockets by sight. I would rather walk right up to it, get back to base camp and fly some more or socialize versus searching for a rocket.
    +1
    And I use 2 trackers, or one tracker plus a screamer, on most HPR flights. No tracking system is fail-safe, a really hard landing will probably take out any tracker, and there can be other issues (dead battery, loose connection, hardware or software problem), but with GPS trackers I've already found several expensive rockets that otherwise I would have had little or no chance of finding.

    L1 3/25/17 H135
    L2 8/12/17 J180

  23. #53
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    26th November 2009
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    Quote Originally Posted by DRAGON64 View Post
    Which begs the question; how here watching and providing feedback have lost there vehicle anyway due to GPS or RDF failure to locate (?) By that, I do not mean if it was lost to a rocket eating tree etc. I mean physically could not locate their rocket due to a loss of signal.
    Sure, ballistic flight and loss of power to the tracker. Ballistic flight though if one has one position when the rocket is coming in that's close to the ground (perhaps 500 feet AGL or less) one stands a better chance of finding the hole or the pieces.
    RDF if completely sight unseen very little chance one can hold an accurate bearing once the tracker dies.

    Sure, if a main at apogee comes out at 10k might not be able to follow along and track long enough to get to where the rocket lies. RDF or GPS it could be a challenge. If using a 2 meter Ham Band APRS tracker on 144.390Mhz,
    on the national APRS frequency and using a WIDE 2-1 path one might be able to get away with it except the APRS Nazis get ticked off with someone hitting a digipeater once every 5 seconds. For the uninitiated Digipeaters are
    ham radio stations that "listens" for a position packet and will re-transmit it and possibly gate it to the internet: https://aprs.fi/#!mt=roadmap&z=11&ca...3600&tail=3600 KB9YVN is a
    digipeater. Any Ham radio operator could setup a digipeater and if ones rocket went way out of range locally, if it was within range of a digipeater on 144.390Mhz, one could look online for the track.
    Again, the only problem here is the APRS Nazis consider it poor form to be "hogging" the national frequency once every 5 seconds. One might be able to pull it off for a relatively
    short rocket flight but if the rocket lands in an inaccessible place and hits a digipeater every 5 seconds that could be a problem. If there is no digipeater nearby then not a problem or if one uses say 144.600Mhz off the
    national APRS frequency to track locally only would not jerk anyone's ire.

    Use a 100mW 33cm (900Mhz) tracker in a very high flying screamer that lands 5 miles away. If it's out on the playa that would be even worse. You want to be able to get within the ground foot print of the tracker which out on the playa is not good.
    Even in farmland, if the tracker lands in a natural depression the ground footprint can be zilch. With sport rockets that isn't much of a problem because you are likely to get a position while the rocket is 50 to 100 feet in the air. It will probably be lying
    nearby so it will be close enough for you to find. Using a screamer like Mr. Handeman suggests is a good idea if it can fit.

    RDF failures are more likely if the rocket goes out of sight and you lose the bearing. Sure if you see it coming in at a distance that gives you someplace to start your search but if it goes "way out there", you can't hold a bearing, you don't see where it went
    it could be a challenge.

    Also beware that some deployment devices don't play well with Rf trackers. The newer ones with opto-isolation do well but older devices need to be tested. That is bare contained ematches, stand the rocket up and turn on the tracker. Let sit for an hour.
    If the altimeter doesn't, shutdown, or reset, or blow the matches during the test one is likely in good shape.

    One definitely should avoid a deployment device where the maker says it doesn't play well with Rf. ie. AIM USB 2.0 (Not the GPS tracker version but just the deployment device) it says in the instructions not to use an Rf tracker. Adept 22's have seized with 150Mhz 2 watt dog trackers.

    I just had to get a PICO AA2 'cause I respect Robert DeHate's work. Yeah not as fancy and a bit out of date maybe but I wanted an accel/baro based device without issues. Found out one of my USB cables Cris Cerving sent for his EggTimers/Finders works fine with this. Bottom pin is + plus and the top pin is - negative. The remaining two pins are tx and rcv. I got the +/- right and one usually doesn't cause any harm with crossing the signal cables. If it doesn't work one way, switch the two and that's how I got it to work. You don't want to do reverse polarity as that can kill a device.

    If I decide to try to fly it with a tracker, I'm going to do testing to prove it will be reliable in an Rf field. Or if many folks report they've had stellar results I might be a little lax........ Naaaaahhhhh!! Kurt


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