Radio tracking - Basic help needed

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AKVP

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Hello all-

After trying to look up threads on the basics of radio tracking.....with little luck. I have decided to try this thread. I have been to Big Red Bee and Egg Finder and the problem I am having is the language and vernacular. I find myself having more questions and getting more confused the more I read. I know I am not an idiot but I am getting lost on the language you all use in the radio world. I was once able to program a transmission electron microscope (in a past life) but I am lost in all this radio talk.

What I am looking for is a person to explain it to me like I am a child (I have no shame here in asking like this). A guy I know was VERY generous to give me a yagi antenna to get me started. He also gave me a quick demonstration at a launch last weekend. I tried real hard to not appear dumb as he explained it all. I learned to go in the direction where the beeps got stronger etc. I also watched as he found a rocket deep in the corn that had drilled itself almost 2 feet into the mud....he FOUND IT and I was sold on all this tracking stuff.

What I am hoping to get is the Big Red Bee unit that does NOT require a HAM license. Can I use this antenna with the receiver that comes with this unit and track (via the beeps) my rocket?

I am totally lost now that I think of it. Like I said I need someone to explain this from the top using common vernacular so I can understand. This stuff is all fascinating and I DO want to learn more as I go. BUT now I just need to know what to get (without a HAM license) to simply just find my rocket by following the beeps or an arrow on a screen.

One other thing....I don't own nor want to get a smart phone (GASP!!!)

Help......please
 
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Hi Andrew,

Take it all slow. When you say radio tracking, are you referring to tracking using radio frequency only (RF tracking) or are you looking for gps and / or RF tracking. Big Red Bee has both. Things that transmit at around 900 MHz do not require a ham license. Most other frequencies do. As far as an antenna goes, antennas work for certain frequency ranges. You need to find out what frequency range your antenna is for. If you are looking to include gps, there are altimeters that include rf and gps. I hope that this helps you get started. Keep asking your questions. You will get a lot of help.
 
First off, the 900mhz unit is a GPS unit, so direction finding generally won't be necessary. It's still useful to know, in case the tracker fails to get a GPS lock. Second, what 4kids49 said about antennas only working for a certain frequency range isn't entirely true. In the case of yagi antennas, they are sized so that the driven element (the element the feedline is attached to) is resonant on the frequency range desired. For transmitting, it will only work well in that range. For receiving however, it will pick up signals far outside that range with ease. Lastly, getting an amateur license isn't hard. The technician license is all that's needed for rocket tracking. It's a 35 question test that's no harder than the L2 exam (The technical content is less involved than the L2 exam, IMO). Test sessions are administered by volunteers on behalf of the FCC, there's no need to visit an FCC field office. And finally, the Morse code requirement was eliminated in 2007.
There's a number of reasons I went for the Ham license, but perhaps the two biggest ones are that you have protection from interference that you wouldn't have in unlicensed spectrum, and that there are fewer users of the Ham bands overall. It's important to remember that at the frequencies that rocket trackers operate at, all propagation is line of sight. Therefore, as the altitude of the transmitting antenna increases, the farther a signal will propagate for a given power level. On the ground, a VHF or UHF signal will run into buildings, trees, hill etc, but in the air, there's nothing to block it. A tracker with a 5 mile range on the ground can easily have a 200 mile range while in the air. In any event, it sounds like you're interested in Radio Direction Finding (RDF). In the Ham radio world, this is often called Foxhunting. Foxhunting is basically a race to a hidden transmitter, which is found using RDF. I would recommend finding a Ham radio club that does a lot of foxhunting, you'll get quite an education. A website I'd recommend for RDF information is here:https://www.homingin.com/, and if you want to spring for a book on the subject, I'd recommend TRANSMITTER HUNTING Radio Direction Finding Simplified, By Joseph D. Moell, KØOV, and Thomas N. Curlee, WB6UZZ. For a general crash course in radio, The ARRL license study guides have a decent amount of info presented in an easy to digest format (make sure you get the full blown study guide and not the Q and Q book). Any other questions, just ask, I'm all ears.
 
First off, the 900mhz unit is a GPS unit, so direction finding generally won't be necessary. It's still useful to know, in case the tracker fails to get a GPS lock.
You basically can't do direction finding on a BRB900 very easily, if at all. All conventional direction finding options AFAIK require a ham license.

The BRB900 (or other GPS spread-spectrum device, like the Eggfinder) is the only option for standalone license-free operation. You either get a receiver you plug into a computer or a handheld receiver that displays the location of the rocket in lat/lon, and then you need either a handheld GPS unit or a GPS smartphone application to actually go to that location.

There are also cell-phone-based units that text the location of the rocket periodically, but those require cell phone coverage at the rocket's final location.
 
The walston and Marshall are license free DF systems.

Yes they are and good quality too. Problem is the $$$$ one on a limited budget has to come up with. If Andrew gets a Tech license and concentrates on RDF tracking he would only need a 70cm Handi-Talkie, Beeline 70cm RDF beacon,
Yagi and a $30.00 attenuator like this: https://www.eham.net/reviews/detail/3064 to be in business. Only issue is to get a radio with a "true" signal strength meter and avoid the el cheapo Chinese radios that have an "all or none" meter.

One can get a kit together for far less than the above. Depends upon how much wants to spend. I went the GPS/APRS route when I priced the commercial RDF stuff and found it was very close to a Ham/APRS setup. I got a General ticket
and went at it. Kurt
 
You basically can't do direction finding on a BRB900 very easily, if at all. All conventional direction finding options AFAIK require a ham license.

The BRB900 (or other GPS spread-spectrum device, like the Eggfinder) is the only option for standalone license-free operation. You either get a receiver you plug into a computer or a handheld receiver that displays the location of the rocket in lat/lon, and then you need either a handheld GPS unit or a GPS smartphone application to actually go to that location.

There are also cell-phone-based units that text the location of the rocket periodically, but those require cell phone coverage at the rocket's final location.

Are all the 900mhz GPS trackers spread spectrum? I'd tend to think that's the greatest obstacle to DFing them. In any event, I regard the ability to DF a GPS transmitter as very important, in case a GPS lock can't be achieved (If you fail to find your rocket, it may be found by a combine harvester, and that could get expensive).
 
Yes they are and good quality too. Problem is the $$$$ one on a limited budget has to come up with. If Andrew gets a Tech license and concentrates on RDF tracking he would only need a 70cm Handi-Talkie, Beeline 70cm RDF beacon,
Yagi and a $30.00 attenuator like this: https://www.eham.net/reviews/detail/3064 to be in business. Only issue is to get a radio with a "true" signal strength meter and avoid the el cheapo Chinese radios that have an "all or none" meter.

One can get a kit together for far less than the above. Depends upon how much wants to spend. I went the GPS/APRS route when I priced the commercial RDF stuff and found it was very close to a Ham/APRS setup. I got a General ticket
and went at it. Kurt

One advantage to Ham band trackers is that the amateur radio service does not require operation in discrete channels, like most other radio services do. Unfortunately, most of the Ham band trackers on the market are rock bound (crystal controlled), and are hardwired to a single frequency. The BRB trackers, however, use a Variable Frequency Oscillator, which is continuously variable. From conversations with Gary Stroick at Off We Go Rocketry, the AIM XTRA GPS tracking system uses a VFO as well, but the software limits it to certain channels. The BRB GPS trackers use a technology developed by the Ham community called Automated Packet Reporting System (APRS), which has capabilities beyond position reporting, and has potential that IMO, is currently untapped by the rocketry community...
 
The walston and Marshall are license free DF systems.
Some debate about that, actually. The FCC forced Rocket Hunter/Com-spec to require licensing for their similar system.

Recall that the OP wanted the basics. Getting a license is fairly easy but will be a barrier to entry for some. I've used both GPS and RDF extensively and for a lot of flying, GPS with no RDF is perfectly fine.
 
For the OP...

The Basics:

RDF (Radio Direction Finding): The transmitter in the rocket sends out a radio "beacon", you use a receiver with a directional antenna to find which way the rocket went. They are best for finding your rocket when it is on the GROUND and not moving, because it can be difficult to track the moving rocket (especially if you can't see it!) These systems can have a LOT of range... tens of miles in some cases.

GPS: The transmitter in the rocket sends you the latitude and longitude of it's location, which you can display with a computer, smart phone, or some kind of LCD display depending on which system you have. You may or may not get packets once it's on the ground (generally you won't with the license-free 900 MHz systems) but it doesn't matter because you only need the location right before landing. You plug the coordinates into some kind of mapping program (Garmin, smartphone, laptop) and it will take you right to it. As you get close, you will pick up the packets on the ground, so if it drifted a bit you can go right to the new location. The range on these systems generally isn't as high as a RDF system, but they are much easier to use because they literally tell you where to go to get the rocket.

(Full Disclosure: We make the Eggfinder GPS system, which we sell with either a "dongle" receiver (that connects to a laptop) or a portable LCD display for use with some kind of handheld mapping device. We only sell kits, so if you're not big on soldering then our products may not be for you, but they cost much less than other similar systems.)
 
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The antenna is designed for the 70cm (433 MHz (FM radio stations run from about 89 to 107)) band. As was mentioned above, antennas are designed for specific radio frequencies. Generally, higher frequencies have smaller antennas, lower frequencies have larger ones. The Yagi antennas are VERY directional- if used to transmit, they send a signal out in a beam off the end. As a receiver antenna they receive mostly only in the direction they are pointed. This is what makes the radio directional tracking work. The rocket transmits in all directions (like a light bulb scatters light) and we walk through the corn looking through a chunk of pipe, homing in on the bright spot.

The FCC regulates the use of the radio spectrum, doling it out to various users for various purposes. The 70cm band mentioned above is a ham radio band, so using it requires a ham radio license. Other slices of the pie don't require a license, for instance you don't need a license for your (not smart) cell phone, you don't need a license for a cordless phone or wireless internet router or or or...

Big Red Bee does make a non-license device, it's in the 900Mhz band. However, it's a different creature than the directional, home in on the signal approach. It's a GPS transmitter- the rocket receives signals from the Global Positioning System and sorts out where it is in Latitude and Longitude coordinates. This information is transmitted out as a digital signal (its a signal that contains data, when decoded, unlike the simple beeps you heard when we were tracking) to a receiver that decodes it and shows you the coordinates. In order to find your rocket, you need a GPS device that can show you where you are and where those coordinates are- a typical handheld unit will do this and will help guide you to the rocket. Since GPS information is "math-y", the handheld GPS can figure out how far away you are from the target, which way you should go, how long it'll take to get there..... etc.

BUT- the 900Mhz system is a different frequency- it's 900 instead of 433, so the antenna won't work... it's too big. The system BigRedBee sells includes the necessary antennas for transmit and receive. Someone mentioned an EggFinder- not a kitchen device, but a unit that functions in identical fashion- GPS in the rocket, reporting back where it is. Due to some technical mumbo-jumbo it's not really possible to home in on the transmitter from the GPS unit like we did at Geneseo. Since it IS transmitting, and in all directions, you'd think it would work, but it doesn't. And anyway- the receiver is decoding the data and telling you exactly where the rocket is, so why bother.

What to do? Well, I prefer the simplicity of RDF because it is very robust-- I can track a signal you can hardly hear in the static and that comes in handy. The GPS type thing wouldn't have been received from underground in the corn. Others prefer the simplicity of using the GPS and being able to see the rocket location on a map and most flights don't go underground!

Feel free to contact me directly, I think you have my email and I'm good at dumbing it down. I know I kind of buried you in details this weekend.

N
(antenna guy)
 
Hello All-

WOW! this has been ALL very helpful. I want to thank ALL of you that have replied. I need to dash off to work now but I wanted to send a thank you before I go to work. I guess I got bogged down and confused in all the information I was reading after I got back from the launch this weekend. After all I have read, I think I am going to stick with the radio tracking, as I think this is most robust. For some reason when I hear that GPS can stop receiving packets when the rocket is on the ground "scares" me. I think somebody said it will run off the last known position but most rocket flights are not long and if there is a recovery failure....making the flight even shorter...then I think...this could be a problem.

THANK YOU all for your input. I am learning a lot by all your posts. Thanks for your time.

The only thing now, is I have to get over my fear of trying to get a HAM license!!!

Have a good day all.
 
Many local amateur radio clubs offer classes. https://www.arrl.org/find-an-amateur-radio-license-class is one place to look.

And there are lots of online resources for studying for the exam. It's "multiple guess" and not that long. And the question pool (and answers) are published. So you can brute force memorize if necessary.

There is lots to do in amateur radio. High altitude balloons. Satellite operations. Emergency services. Or just using it for coordination at the local launch.
 
One advantage to Ham band trackers is that the amateur radio service does not require operation in discrete channels, like most other radio services do. Unfortunately, most of the Ham band trackers on the market are rock bound (crystal controlled), and are hardwired to a single frequency. The BRB trackers, however, use a Variable Frequency Oscillator, which is continuously variable. From conversations with Gary Stroick at Off We Go Rocketry, the AIM XTRA GPS tracking system uses a VFO as well, but the software limits it to certain channels. The BRB GPS trackers use a technology developed by the Ham community called Automated Packet Reporting System (APRS), which has capabilities beyond position reporting, and has potential that IMO, is currently untapped by the rocketry community...

APRS will give altitude direction and horizontal speed.............With an appropriate tracking program.

Problem is using a laptop out in the field. Can be difficult if one has to go after the rocket.

The EggFinder has a different encoding process than APRS and to simplify the discussion, it's like attaching a USB GPS receiver to a laptop to get 1/sec position position updates as long as the GPS has a lock and one is within range to receive the packet. APRS can carry more information and a nearly bullet-proof portable method of receiving can be had with a D72A/VX8GR and Garmin 60Cs or 60CsX handheld mapping GPS. Can walk right to the rocket with this arrangement.

A similar Android program called GPS Rocket Locator can do just about the same thing except the aerial pictures or map is not portable. Still, all one needs is two dots on a map with a line to walk.

For the adventurous, EggFinder data can be "injected" to the APRS tracking program Xastir as if the rocket was an
APRS station. Boy, a real pita to get working but is interesting to see the 1/sec updates instead of once every 5 secs. All of the information of direction, altitude, speed is displayed next to the EggFinder "based" icon on Xastir as if it were a native APRS "generator". All the information is in the EggFinder GPS output to extract.

The feature differences between the EggFinder and APRS are slim. The biggest $$$$ is a D72A and a Garmin 60CsX can be had used for a decent price and one can use Open Source Maps now.

One isn't tied to getting a Ham ticket now which wasn't the case a few years ago to do cost effective GPS tracking.
Yeah, there were a few unlicensed 900Mhz devices out there but they cost more than the 900Mhz Beeline unit.

I do both types a tracking and it isn't that limiting if one is tied to 900Mhz for sport flying. It's great and makes for fast recoveries and one shouldn't fret it.

Kurt
 
This is all you need: https://hamstudy.org/

Go there take the practice tests until you can get 90% on a regular basis. I got 34/35 on my first try taking the Technician's test after studying there fora couple nights.
 
This is all you need: https://hamstudy.org/

Go there take the practice tests until you can get 90% on a regular basis. I got 34/35 on my first try taking the Technician's test after studying there fora couple nights.

I had studied for a few months, did online tests and was going to try to take the Morse code test and pass under the "old" rules. I couldn't find the time to get the code up to snuff so just sat for both tests and passed. Did better on the General part.

Nonetheless, if the OP goes for a Tech license there is a boatload of information available to read up on RDF/APRS tracking that is informative. Do that and they'll be all set. If that is found burdensome by all means, the 900Mhz GPS trackers will get the job done for "outta sight" sport flying. The Tech license gives more opportunities if so inclined and RDF/APRS tracking in the ham bands is available then. Kurt
 
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This article may help: https://rocstock.org/advanced/advanced-rocket-tracking-using-onboard-radio-transmitters/

If you have more question I can try to answer them.

I have been doing radio direction finding since the 1970s and GPS/APRS for about 15 years...

Dave
W6DPS

Nice article.



Missile works has a new RTx system coming out that is a gps system and works at 900 MHz. Not sure if that requires a ham license. Missile works is pretty cost friendly. Here is a link:
https://www.rocketryforum.com/showthread.php?126340-Missile-Works-RTx&highlight=telematics

Giant Leap Rocketry has a new easy to use GPS that is tied to a phone. I don't have the link for it now. I use a Com Spec RF tracker and have tech license. I like it a lot. I have the cheapest $250 receiver. You can move tracker easily from rocket to rocket by taping on shock cord. The antenna on the transmitter is 10 inches or so, which is a drawback on tight projects like 38 or 54 minimum diameter rockets. Some people use a Marshall transmitter with a 7 inch antenna with their com spec receivers, but you need a special com spec receiver not listed on the com spec site. I think the Marshal transmits at 433 MHz or something like that. Wildman has one for $450 or so that covers some legacy channels. This is a bit pricey, but you might want to consider what kind of projects that you want for your tracker. Also check to make sure that the frequencies of your transmitter and receiver match. The good news is that there are a lot of new things out there for fliers. Some are pricey. Egg finder is very affordable, but you have to solder your own electronics kits. I am adding gps to my tracking. I will get the Missileworks RTx when it comes out. Might get a Big Red Bee at some point.
 
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There is a lot to read here and in many cases I am trying to understand some of these replies and make sense of it all. I find it all kind of fun now but it is intimidating. I like it because it is adding a whole new dimension to my rocketry hobby. I am not the kind of guy who likes to let my rockets go out of site. If I stay at around 4500 feet I can see them and enjoy the flight. The reason I want to track is that I launch in Ohio and travel to Pa, and NY as well to launch. This means crops. I borrowed a tracker at the launch I went to last weekend and it was just great to notice a lowering of my anxiety when I launched in proximity to corn and soy beans. The tracker took the stress away more and i was able to enjoy the launching more. It is ALSO fun to actually track a rocket when needed (got to do this even though I knew where it was). I just wished I understood all this more.

OKAY. I listened to the Rocketry Show...an episode about tracking. Jim H. said he uses a transmitter that signals I think from 216-219 Mhz (whatever that is) This was mentioned to be non HAM frequencies. So it seems there are transmitters that operate at frequencies that do NOT require a HAM license !!!???? If so why are not more folks getting into these.

Are these transmitters just as good? anybody know who sells them? I found out that Communications Specialists dont sell them. Any thoughts from you all?
 
Andrew, you said you launch in NY. Any chance you plan on making METRA's next launch Sept 5th? If so I can walk you step by step through my Marshall TX (transmitter) and RX (receiver). The TX you linked is very good stuff but it is intended for bird tracking and uses frequencies set aside by the FCC for that use. I use their products on 70cm which requires a HAM license. That should not put you off, it's easy to get and kind of rewarding.

Keep asking until it starts to make sense. You are on the right track. RDF (radio direction finding) is the part of the hobby I enjoy the most. It has gotten to the point I launch rockets just to go hunt them down.
 
There is a lot to read here and in many cases I am trying to understand some of these replies and make sense of it all. I find it all kind of fun now but it is intimidating. I like it because it is adding a whole new dimension to my rocketry hobby. I am not the kind of guy who likes to let my rockets go out of site. If I stay at around 4500 feet I can see them and enjoy the flight. The reason I want to track is that I launch in Ohio and travel to Pa, and NY as well to launch. This means crops. I borrowed a tracker at the launch I went to last weekend and it was just great to notice a lowering of my anxiety when I launched in proximity to corn and soy beans. The tracker took the stress away more and i was able to enjoy the launching more. It is ALSO fun to actually track a rocket when needed (got to do this even though I knew where it was). I just wished I understood all this more.

OKAY. I listened to the Rocketry Show...an episode about tracking. Jim H. said he uses a transmitter that signals I think from 216-219 Mhz (whatever that is) This was mentioned to be non HAM frequencies. So it seems there are transmitters that operate at frequencies that do NOT require a HAM license !!!???? If so why are not more folks getting into these.

Are these transmitters just as good? anybody know who sells them? I found out that Communications Specialists dont sell them. Any thoughts from you all?

FCC allows unlicensed operation above 200mhz if the field strength is very low.
https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf
However to be below this limits the output power of the transmitter is well below 1mw. If you above the allowed power limit you need to be licensed for the whatever frequency you will be transmitting on. HAM licenses your only practical option if you are transmitting with decent power.

The Marshall transmitters have a line that operates below the FCC power limit making them legal unlicensed use. However to get them to work you will need state of the art Marshall receivers with the incredible sensitivity to make these low power transmitters useful.
 
This is what I am talking about.

https://marshallradio.com/north-ame...conry-transmitters/item/122-scout-transmitter

Does anybody know where I can get a good receiver and antenna for this unit? What are your thought on this? As I understand this transmitter does not require a HAM license.

Marshall sells receivers for them. The receiver probably has its own antenna. Pricey though. Not sure if requires a ham license or not. The 216 - 219 frequencies are in the legacy frequencies that may not require a ham license, but you need to check that. I think that Crazy Jim uses the Scout with his Com Spec receiver, but this is a special Com Spec receiver that has legacy frequencies. Check with Jim or Wildman about this. I wish that i had the capabilities on my receiver to use the Marshall transmitters, but so far have not wanted to pay for the receiver. Don't be intimidated to get a ham tech license. Just get a current study book, or test questions. It is pretty easy if you study.
 
I think I will follow the prevailing wisdom and pursue my HAM permit. Thank you for the link to all the resources to that end. You all have been very helpful. I will continue to keep asking questions as they come up. Now it is time to study.

As far as going to METRA I would love to come out and take you up on your offer. I will certainly try and make it if I can! THANKS!!!
 
Here is the link to the receiver on the Wlidman site

https://www.wildmanrocketry.com/ProductDetail.aspx?product=2884

I am pretty sure that this is the Communication Specialist receiver that is like the R-300A receiver but also has a number of legacy frequencies. If you are interested, don't guess about the transmitter and receiver. Make sure that your frequencies match.

I have the PR-100 A Communications Specialist receiver:

https://www.com-spec.com/rocket/index.html

The R300A receiver is also at this site. These receivers have their own antennas. All of this stuff can be a bit intimidating and pricey. There are a number of different products out there. Take your time and see what is right for you and your pocket book. There are some expert flyers out there who use RF only. Everything has pros and cons. But gps availability and pricing has become attractive. For a strict RF budget, the $100 transmitters and $250 PR-100A Com Spec receiver are pretty good. Requires a ham license. Egg Finder is attractively priced. There is a guy on the forum who will assemble your Egg Finder kits for a small fee.
 
Hello Chris-

I emailed Com-Spec and asked if the PR-100A receiver can track frequencies of 216-219 MHz and this was his reply:

Hi Andrew, Only the PR-100 Export Version, will cover 216.025 thru 219.080, in 25KHz steps. The US PR-100 version covers 218.025 thru 219.300, in 25KHz steps, as well as the HAM frequencies 222.250MHz thru 223.290, in 20KHz steps.

As I understand, then, the receiver can work with the Marshal transmitter.....I think....yes?
 
As I understand, then, the receiver can work with the Marshal transmitter.....I think....yes?
Check with CJ on this. I know he uses a Com-Spec receiver with a Marshall TX. I also think Rick Comshaw has started doing this too. There is a thread CJ had where he shows you what he is using but I can't find it right now.
 
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