Marco Polo Tracker - Great Bang for the Buck

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BSNW

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So I finally put my Marco Polo to use this weekend. In a word, it proved itself very worthy for rocketry use. I first loaned it to a friend who put it in his 5.5" kit on a K600 ex motor. I established a link to the tag before launch and the receiver kept a lock on it all the way up to around 2500 feet and all the way back down. I was encouraged that it maintained the lock between the tag and receiver.

I then put it in my PML Ariel for a slightly higher flight. Unfortunately, it did land in waist-deep soybeans about 3/4 of a mile away. I got in my car and drove to the edge of the field. In doing so I was actually going farther away from the tracker. I momentarily lost signal when I went behind a metal barn, but quickly regained signal when I came out past the building. I had to park my car pretty far away and began to track. All I can say is it walked me right up to the lost rocket. All I had to do was follow the arrow and % signal on the receiver. I would have never found it or taken hours to find it in the beans.....I was elated. I have lost rockets in soybeans and we all know how well they swallow up large rockets!

Talking to a guy at the flight line he told me he loaned his to a guy at a Tripoli-Mid Ohio launch for his L3 flight. He had a GPS and a Marco Polo. Guess he lost signal on both after launch. He looked for hours for his rocket. At long last, it was the Marco Polo that found this guys rocket in a wheat field! I guess he drove up the road a bit until it picked up the signal, then walked up to it.

The Marco Polo transmitter will send a signal for up to 3 weeks....plenty of time to find your rocket in crops, grass, thicket, etc. All I know is it works out of the box and is extremely affordable. A couple guys at the launch told me they are ordering one.

For MOST people this product is more than adequate. It was also very fun to track my rocket.....I truly recommend this tracker.

I got mine directly from Eureka Products, the maker of the Marco Polo. $220 for the complete setup. Easy to use....press 2 buttons and your tracking. Man, it took me losing my Mac-Performance Scorpion in tall grass to make me finally get one...I don't know how I ever launched without one now. The transmitter even can fit in a model rocket.....good times.


Andrew K
TRA 1272 L2
 
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BSNW

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I forgot to include some information.

Here is a link to their website: https://eurekaproducts.com/rc-model-tracking-and-recovery/

This is the system I got. Since I put my tracker tag into the rocket, I did not need the package that has the tag enclosed in a tough plastic "case". I just wrap mine in foam and put it in a nose cone bay or small empty payload section. You can even put it on a shock cord if you put it in something protective. Here is the link: https://eurekaproducts.com/ultralight-drone-category/

Enjoy!
Andrew
 

Buckeye

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This is RDF tracking on the 900 MHz band?
 

Tim Crabtree

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This is RDF tracking on the 900 MHz band?
Yes. The system uses frequency hopping on 50 frequencies between 902 and 906MHz. Transmit power is 250mW. The direction finding is pseudo Doppler. The transceiver on the rocket does not transmit until commanded to do so by the handheld locator so the system will not interfere with any other telemetry you may have onboard during flight.

Tim Crabtree
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Eureka Technology
 

BSNW

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I wish I had taken a photo of it on the ground. But just for fun, here is the lift-off shot. At that point, the wind had picked up. Despite my Chute-Release, it drifted very far into the beans. The 36" chute also did not help :). Anyway, the beans totally covered this rocket. I would have had to literally walk onto it to find it. In the truest sense, the Marco Polo Tracker saved the day.

IMG_2675.jpg
 

Handeman

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That's really a good price for a good RDF system. Can you use it in conjunction with a GPS system like the Missleworks T3?

I've been using a old Walston RDF system for quite a while but have been impressed with the T3 GPS recently. I like the smaller base unit than the Walston.
 

ksaves2

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The only problem I see with this system is if the ground Rf footprint is out of range of the receiver, one is screwed unless they were able to get a visual fix on the descent and are able to walk closer to the rocket. A continuous or periodic datastream without having to push a button would be more ideal. Still, I’m impressed with pseudo doppler location without GPS. That is really cool.

Depends upon how far ones rocket is going to fly. 250mW, 900Mhz band on the ground is halfway decent but I can tell you with 100mw GPS trackers one has to be pretty close to pick up an updated position on recovery with the rocket on the ground. The advantage to GPS is one knows where to go at the last known position. Likely one can get an updated position from there but if not, if they are using a live map, they can see the drift trend and proceed in the most likely direction of the rocket and eventually get within the ground footprint of the tracker and receive a final position fix. If the GPS doesn’t have a good look at the sky then there might not be a “good” final fix but this is where a noisemaker or “screamer” on the recovery harness will save the day! I’ve never had that happen yet though. Been usually able to get a terminal GPS fix as long as I was able to receive a signal. Our ears, as long as we don’t have a bad deficit, are great locators in recovery. I found that out in high flying modrocs that only had room for beepers and didn’t spend too much time in “outta sight land”.

Now if this doppler system could be modified to do automatic periodic updates to give a more precise direction while ones rocket was in flight, that would be the cats meow. As opposed with having to push a button manually. Otherwise the utility is on par with that of GSM subscription tracking systems where one has to call the unit to “phone home”. If the ability to reach the tracker via Rf or cell tower is impaired, one is screwed. If there is a flight anomaly where the rocket hits “hard” and the tracker is “dead”, that last known GPS position from a GPS tracker is sometimes very close to where the rocket lies. Put a hardened noisemaker on the harness and one is in about the best position to perform a hard recovery.

Again, the major problem I see is if the rocket lands out of Rf range, out of sight and the flier has no idea where to proceed. Especially if one has to push a button on the receiver to get the transmitter to “send” out a signal. As long as the ground footprint of the tracker is within range of the receiver, this will work as described above. Land in a farrow in a cornfield and believe me the ground footprint stinks royally. The saving grace here is with a GPS tracker one can get within the decreased Rf footprint range and get a new fix. The three times this happened to me the fix wasn’t needed as I was able to get sight of the parachute/rocket on the ground.

I’d like to see the system that would send out a periodic or continuous signal that the receiver could pick up and interpret. Sure, in the early phases of launch, drogue deployment etc. the arrow would likely be pointing all over the place. Once the main chute is deployed, everything “slows down” an Rf doppler RDF would likely settle down and give a more accurate bearing. Even if at that point, the rocket transmitter is out of Rf range, one would have a decent bearing to track and eventually get within range to get a position fix “as long as the receiver locked in the last good bearing”. That is the key. If one has to manually interrogate the transmitter, if their timing is off they might be SOL.

Still, I’m impressed of the prospect of getting a bearing to an errant rocket sans the GPS system. No distance info but keep walking and you’ll find it. In order for this to work reliably with the dynamics of a rocket flight, the tracker would need to send out a periodic or continuous signal as opposed to the user ”pushing a button”.
An amateur rocket flight, especially a high powered one, things happen too fast to be manually pushing a button. With this Marco Polo system, one is depending upon the rocket to land within RF range. Most of us know that doesn’t happen all the time.

Again, if it sent out periodic fixes every 3 to 5 seconds it should be readily workable for rocket tracking as getting that last fix 50 to 100 feet in the air should be enough to do a recovery along with a noisemaker on the harness. Just get a good bearing to walk and one should be in good shape. Is there a GPS in the receiver?

Kurt Savegnago KC9LDH (for APRS tracking) :)
 
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BSNW

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The only problem I see with this system is if the ground Rf footprint is out of range of the receiver, one is screwed unless they were able to get a visual fix on the descent and are able to walk closer to the rocket. A continuous or periodic datastream without having to push a button would be more ideal. Still, I’m impressed with pseudo doppler location without GPS. That is really cool.

Depends upon how far ones rocket is going to fly. 250mW, 900Mhz band on the ground is halfway decent but I can tell you with 100mw GPS trackers one has to be pretty close to pick up an updated position on recovery with the rocket on the ground. The advantage to GPS is one knows where to go at the last known position. Likely one can get an updated position from there but if not, if they are using a live map, they can see the drift trend and proceed in the most likely direction of the rocket and eventually get within the ground footprint of the tracker and receive a final position fix. If the GPS doesn’t have a good look at the sky then there might not be a “good” final fix but this is where a noisemaker or “screamer” on the recovery harness will save the day! I’ve never had that happen yet though. Been usually able to get a terminal GPS fix as long as I was able to receive a signal. Our ears, as long as we don’t have a bad deficit, are great locators in recovery. I found that out in high flying modrocs that only had room for beepers and didn’t spend too much time in “outta sight land”.

Now if this doppler system could be modified to do automatic periodic updates to give a more precise direction while ones rocket was in flight, that would be the cats meow. As opposed with having to push a button manually. Otherwise the utility is on par with that of GSM subscription tracking systems where one has to call the unit to “phone home”. If the ability to reach the tracker via Rf or cell tower is impaired, one is screwed. If there is a flight anomaly where the rocket hits “hard” and the tracker is “dead”, that last known GPS position from a GPS tracker is sometimes very close to where the rocket lies. Put a hardened noisemaker on the harness and one is in about the best position to perform a hard recovery.

Again, the major problem I see is if the rocket lands out of Rf range, out of sight and the flier has no idea where to proceed. Especially if one has to push a button on the receiver to get the transmitter to “send” out a signal. As long as the ground footprint of the tracker is within range of the receiver, this will work as described above. Land in a farrow in a cornfield and believe me the ground footprint stinks royally. The saving grace here is with a GPS tracker one can get within the decreased Rf footprint range and get a new fix. The three times this happened to me the fix wasn’t needed as I was able to get sight of the parachute/rocket on the ground.

I’d like to see the system that would send out a periodic or continuous signal that the receiver could pick up and interpret. Sure, in the early phases of launch, drogue deployment etc. the arrow would likely be pointing all over the place. Once the main chute is deployed, everything “slows down” an Rf doppler RDF would likely settle down and give a more accurate bearing. Even if at that point, the rocket transmitter is out of Rf range, one would have a decent bearing to track and eventually get within range to get a position fix “as long as the receiver locked in the last good bearing”. That is the key. If one has to manually interrogate the transmitter, if their timing is off they might be SOL.

Still, I’m impressed of the prospect of getting a bearing to an errant rocket sans the GPS system. No distance info but keep walking and you’ll find it. In order for this to work reliably with the dynamics of a rocket flight, the tracker would need to send out a periodic or continuous signal as opposed to the user ”pushing a button”.
An amateur rocket flight, especially a high powered one, things happen too fast to be manually pushing a button. With this Marco Polo system, one is depending upon the rocket to land within RF range. Most of us know that doesn’t happen all the time.

Again, if it sent out periodic fixes every 3 to 5 seconds it should be readily workable for rocket tracking as getting that last fix 50 to 100 feet in the air should be enough to do a recovery along with a noisemaker on the harness. Just get a good bearing to walk and one should be in good shape. Is there a GPS in the receiver?

Kurt Savegnago KC9LDH (for APRS tracking) :)
In the original post, I noted that the person who used this system DID indeed lose his signal on an L3 flight to over 10,000 feet. All he had to do is drive around and acquire his signal. Once he did the Marco Polo system walked him rite up to it. As I was told, the GPS failed on this flight and it was the Marco Polo that ultimately found the rocket a number of miles away. I am pretty sure he did not know where it went as he lost sight of it after launch. Based on wind direction, they had a general idea as to where it went.

For MOST people who track in thickets, crops, tall grass, or off-field, this tracker is perfect for such applications. Even better in wide open and flat deserts and praries!

There is no configuration, no Ham license, no 3d printed things to purchase to put hardware in, no cell phone/blue-tooth connection, no app to download, no receiver to buy, no yagi antenna to buy, no soldering.....just take it out of the box, press a few buttons and you are good to go. If one looks up the testimonials, one will learn this device to more than adequate for its intended use.

Andrew
 
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BSNW

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"In order for this to work reliably with the dynamics of a rocket flight, the tracker would need to send out a periodic or continuous signal as opposed to the user ”pushing a button”.

- Why is this? Once I press the button, the tracker searches and establishes a lock for 2 minutes. If a signal is lost, simply press the button again to search for the tag. 2 minutes in a rocket flight, is a long time. I simply press the button before launch (and get a lock) and I am good to go for most if not all of the flight!

"With this Marco Polo system, one is depending upon the rocket to land within RF range. Most of us know that doesn’t happen all the time."

- This is not true, the tag can be located if it lands out of range. This is the point of the system (fly away drones). All one has to do is get back within range of the tag and acquire the signal. You have three weeks to do it and you have to get within a mile. I like those odds. Again, the guy at Tripoli Mid-Ohio DID land out of range and did find his rocket with the Marco Polo....

The best $220 bucks I ever spent on rocketry...ever
 
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Scott_650

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I get both sides of this discussion - Kurt’s points are valid, if you’re spending the money anyway just spend a bit more, get your ham license and have a system that takes advantage of all the resources available and you’ll always find your rocket. OTOH, Andrew has a solid viewpoint - your initial cost is pretty much fixed and for most people who fly rockets the Marco Polo setup solves over 80% of their problem - finding a rocket in crops, grass, nearby woods, etc. If I had put a MP unit in my Estes MAV Saturday at the NOTRA launch I could’ve walked right into the bean field and picked up my rocket. A full on amateur radio/GPS tracker would’ve been overkill to find a rocket I tracked down but was swallowed up by the soybeans. If I was a HPR flyer and launched high altitude rockets on wide open ranges it could be well worth the cost/effort for a full system. As a LPR/MPR guy finding my model rocket in the corn with a simple RDF tracker might be worth the investment. Great discussion!
 

BSNW

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I get both sides of this discussion - Kurt’s points are valid, if you’re spending the money anyway just spend a bit more, get your ham license and have a system that takes advantage of all the resources available and you’ll always find your rocket. OTOH, Andrew has a solid viewpoint - your initial cost is pretty much fixed and for most people who fly rockets the Marco Polo setup solves over 80% of their problem - finding a rocket in crops, grass, nearby woods, etc. If I had put a MP unit in my Estes MAV Saturday at the NOTRA launch I could’ve walked right into the bean field and picked up my rocket. A full on amateur radio/GPS tracker would’ve been overkill to find a rocket I tracked down but was swallowed up by the soybeans. If I was a HPR flyer and launched high altitude rockets on wide open ranges it could be well worth the cost/effort for a full system. As a LPR/MPR guy finding my model rocket in the corn with a simple RDF tracker might be worth the investment. Great discussion!
Thanks for your note, Scott-

I do appreciate your comments.

I also don't mean to keep repeating myself but this unit already has proven itself on at least one high altitude flight at a TMO launch where the rocket did go high and was recovered a number of miles away and over rolling terrain.....and after there was a LOS (which was recovered).

I don't understand any other situation (in rocketry ) that falls out of this type of scenario. I also don't understand why if it works in a mid-power rocket going to a respectable altitude it would not work in a high power rocket going a bit higher and land further away. The principles in play are the same.....distance, terrain, etc. With this unit all one has to do is re-establish a (potential) loss of signal and track.....do not the other, more "advanced" systems do the exact same thing? If this works in a wide-open field, why would it not work on the "playa of the Gods"? Or on the rocket prairie of Kansas? Again, a person has 3 weeks to re-establish a lost signal.

IMO I think the Marco Polo lacks the "Cool High Power Rocketry-Advanced Electronics-From a Rocketry Vendor" mystique (for now).

If so, I don't mind, as it seems like it can track with the best of them in 99% of the time for 99% of rocketeers...for much less money. I think a lot of questions and dare I say doubts...would be answered if folks try it. I also invite others to read the testimonials for others who have actually used it.

If I am showing my ignorance here, please forgive me

I would imagine there are far more planes and drones that have flown away or gotten lost over the same types of distances and terrain than rockets, as there are far more plane/drone folks than rocket folks. From what I hear from that group, they love it.

Andrew.
 
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Tim Crabtree

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All I can add here is some clarification of how the Marco Polo system works.

Both the handheld "Locator" and the remote "Tag" are transceivers with two-way communication capabilities. If the tag is powered up but the locator is off or in idle then the tag wakes up once every 10 seconds and scans the 50 frequencies used by the system for RF power. If nothing is found that matches the hopping pattern that is unique to the individual tag, then the tag goes into deep sleep for 10 seconds and then repeats the scan. The tag can do this for up to 15 days on a charge.

If the locator is "paging" a tag it is sending out data packets with synchronization information on a secession of channels which are, once again, unique to the tag being paged. A packet, or data frame, contains a payload of 6 bits which are encoded and forward error corrected into 24 bits to allow an 80% packet decode rate with a received SNR of 6dB. Each repeating set of data frames are organized in a "superframe" structure containing 53 frames, 1 frame is reserved for receiving the response of the tag being paged, the other two are reserved for transmission and reception of data to/from up to 7 other tags that have already had communication sessions started. Each of these tags is assigned a specific superframe to communicate with the locator in a "hyperframe" structure that consists of 16 superframes. Half of the superfames are dedicated to a single selected tag that is being tracked once every 4.7 seconds the remaining superframes are assigned to individual tags that are being "monitored". Much of this is designed to support other applications outside of rocketry, such as monitoring the proximity of 3 dogs and 2 cats and sounding an alarm if any of the animals exceeds an individual boundary that is established for them. The air protocol allows the locator to maintain communications with the 3 dogs and 2 cats while paging a 3rd cat and locking its tag into an unused superframe in the hyperframe. Once communications are established, the locator can select any tag to be the "active" (tracked) tag where it receives commands and responds on every other superframe or return the active tag to monitor status where it receives commands and responds on only one designated superframe in the hyperframe. The locator can also command tags to go back to idle status and then page and assign different tags to the idle superframe. Tags effectively have a 24-bit address (16M unique tags) and can be individually selected, even though the address is never sent over the air, in either direction, in normal operation.

I only drag you through all this because many people see or hear what Marco Polo does and they automatically think they know how it does it. Yet I doubt that anyone would have guessed the above explanation, which only covers the data communications, not the direction finding.

Back to this problem domain; a tag must, of course, be powered on before flight. When in the idle mode the tag only cycles its receiver on once every 10 seconds to listen for transmissions from a locator. So in idle mode the tag does not transmit any RF energy and can be co-located with any other RF transmitters or receivers used during flight. This is popular with drone users since they have often have multiple RF links running during flight. The tag can also be activated by the locator before or during flight and once locked into a tracking session with the locator it will receive and respond to commands from the locator once every 4.7 seconds, the locator will then measure the RSSI and compute the angle of arrival of the signal for display after each communication. Each tag transmission is 50 msec in duration on a pseudo randomly selected frequency repeating every 50 transmissions. Thus the dwell time on any one frequency is 50 msec once every 4 minutes. If you have telemetry that would suffer interference from the tag's transmissions (or the locator's, since it is basically doing the same thing on the ground) then I would leave the tag in idle. In most cases I would suspect that you would start the tracking session before launch and track the rocket during descent so you have a bearing from the launch point to guide you in a search. if the signal is lost when the tag in on the ground then the handheld locator will enter searching (paging) mode and reestablish communications when you get within the ground-to-ground range of the system. Getting to higher ground helps a lot when trying to establish communications, even standing on the bed of a truck makes a noticeable difference. We have military customers that track payloads ejected from high flying drones, I think they do have GPS coordinates as a starting point. All I know is that they tell me they "have never lost one yet."

Tim Crabtree
 

Scott_650

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About a third of all this only makes sense to me as it connects to the other 2/3 of the info - in other words I can “logic” out how it fits together but I’d never be able to explain the science of how it works ;)

But I find it all fascinating - spent a hunk of my afternoon down the rabbit hole reading about frequency allocations, history of amateur radio, strengths/weaknesses of all the variations of LF and HF frequencies, impact of RDF aircraft navigation...dang, this is one of the reasons I LOVE this hobby!

Thanks to Andrew, Tim, Kurt for a fun session of skull sweat 😓!!
 

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BSNW, Congrats on your successful tracks. It is a rush when your device leads you to your rocket! Nobody is calling your baby ugly though, so no need to be offended. There are several tracking technologies out there, each with pros and cons. The Marco Polo is a nice addition to the space.

Personally, I like numbers and I like maps, so I go for GPS. Unregulated GPS, to be exact.
 

BSNW

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BSNW, Congrats on your successful tracks. It is a rush when your device leads you to your rocket! Nobody is calling your baby ugly though, so no need to be offended. There are several tracking technologies out there, each with pros and cons. The Marco Polo is a nice addition to the space.

Personally, I like numbers and I like maps, so I go for GPS. Unregulated GPS, to be exact.
Thank you very kindly for your reply Buckeye.

However, I was indeed not offended. I was a tad frustrated...yes....as I was trying to explain that the very things I was being told it could not do....I actually experienced and was told (already) that it could do. Either way, it's all good. I am sure as this catches on with more rocketeers people will be surprised as to is capabilities and like the affordability and ease of use.

I know and respect the many other options out there. But that was not my point. I just felt (maybe incorrectly) that this product was initially being dismissed for its perceived limitations in lieu of actual observed performance. This was the source of my frustration.

Thanks!
Have a great day all.
 

Handeman

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This is certainly much more complicated and technically dependent on the technology working than a simple RDF system. The price point is good, but I find the difference between this and a GPS system not much different when it comes to dependency on the technology working. Certainly it preserves battery life way past what a GPS locator would have transmitting packets every few seconds. I still don't think it would out last the simple RF burst from a true RDF transmitter as far as longevity. Of course with the RDF, the directional detection is all up to the user. An experience user can detect apogee ejection if the system is set up right.
Certainly worth considering as a tracking system.
 

Tim Crabtree

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This is certainly much more complicated and technically dependent on the technology working than a simple RDF system. The price point is good, but I find the difference between this and a GPS system not much different when it comes to dependency on the technology working. Certainly it preserves battery life way past what a GPS locator would have transmitting packets every few seconds. I still don't think it would out last the simple RF burst from a true RDF transmitter as far as longevity. Of course with the RDF, the directional detection is all up to the user. An experience user can detect apogee ejection if the system is set up right.
Certainly worth considering as a tracking system.
Man, you guys know your stuff. Way different than the woman with 5 cats that says, "Oh, does this use radio signals? Is that why it didn't work well when I was standing between 2 dumpsters in the school parking lot?" Or, "Red LED? You mean the red light? Why didn't you just say red light???"
 
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