Big Red Bee GPS

[cwbullet]

Can someone explain this system to me? I have thought about buying it. I understand you need a HAM license, but what is the difference between the 70cm and 2 meter versions? Does it work well?

 

[rdmmdr]

if you have a five hundred dollar ham radio and the decoder then the big red bee makes sense. and if you don't like playing with fiddly little wires. but this system will cost you 8-9 hundred by the time you buy the other hardware. not including the time it takes to pass the test. and you still have to have the laptop to read the signal

gspflight 1200$
ozark aerospace 670$



for two hundred fifty dollars
I just recieved two xbee pro modules "the replacement for the radio in the ozark system" and a droids usb adapter with a simple xbee board, i also got the "ls20033" gsp module.

Integration was as follows.

1.split the included 90 degree header in to four two segment units

2. solder the header two the usb board at the rx/tx port and the 3.3 volt ports.

3. solder the headers to the simple board at the rx/tx inputs and the 3.3 and ground

4. solder a nine volt clip / battery holder to the simple board at vin and gnd

5. take the cable that came with the ls20033, raid an old computer for the cables with the molex connectors on the end two strand is what you need. connect pins 1+6 to the positive and pin 2 to the gnd. connect pins 3+ 4 to the rx/tx.


6.put the solder iron away

7. plug the gps unit into the usb board/ the nice thing about this board it has pin out fo ttl level serial and 3.3 voltage

8. install the driver for the ubs board, see droids.it for the redirect. on my machine it installed a microsoft mouse drive that i had to disable in the control panel. Now your computer should talk to the usb module.

9. open up control panel and go to ports and make sure that the date rate is set to 9600

10. open minigps and set rate two 9600 with is the default rate for the unit and what com your computer assigned to the usb adapter. click connect and it should work. so at this point the gps is talking to the computer but it is not talking remotely

11. open x-ctu this is the config software for the xbee units. and close minigps since you wil be using the same channel

12. unplug the usb adapter from the computer remove the gps module and install the xbee module
read the module and change that address to something that is not zero. and change the baud to 9600. repete for other module.

13. insert xbee module in to simple board, connect gps module, connect battery

14. check leds on simple board once per sec flash tx

15. check led rx/usb board once per sec rv

16 open mini gps and it should work.

this will give you a gps telemetry module less then the size of a nine vollt battery that will run for a couple of hours offf a nine volt for about 200.00$

notes.

depending on how you mount every thing this could be made to fit in a 29 mm minimum dia

orientation is not a problem with the ls20033 vertical or horizontal it still maintians lock interferences from the xbee does not seem to be a problem with tracking. might be a problem with r/c autopilots however.

nine volts don't have the power to the unit i would suggest either high outputs or 3.7 volt lipos, for extended periods.

rick

 

[rdmmdr]

and if you want to hook it to the perfect flights and monitor them in flight all it takes is

configure perfect flight for realtime out. connect ground and tx from perfect flight to xbee ground and rx.

 

[cwbullet]

And no support. I kind of like going with a unit that has instructions and is set up for the purpose I want to use it for.

 

[WillMarchant]

Yes, you can spend $1k on a BeelineGPS ground station if you buy new top-of-the-line hardware. Or, if you want, you can:
-build an antenna for a few dollars
-buy a 2m or 70cm scanner radio for a few dollars at a flea market.
-use the sound card of your laptop computer to decode and map the data.
Or I suggest the approach of making friends with your local ham radio club and get them to come to the launches with their gear for free.

2m and 70cm are two different frequency block allocations for amateur radio use. 2m tends to be more crowded, but it does have a dedicated frequency (144.39 MHz) that many receiving stations pass on to Internet nodes for sharing. The 2m transmitter has much more power and so, probably, a longer range. But the 70cm unit has flown on amateur balloon flights to 100k+ feet without problems.

Greg's technical support is good.

As in most things in hobby rocketry their are many solutions each with their own pluses and minuses. The BeelineGPS works for me. The other product offerings may be better for others.

 

[troj]

For the BigRedBee GPS, you need...

1) HAM Radio License ($14 test fee and a few hours of your time to study; you can buy a study guide for $25 or find all the info you need, and then some, online)
2) BigRedBee GPS ($289 for the tracker, antenna, charger and programming interface)
3) A 70cm radio (lots of options; eBay is your friend if you don't want anything expensive - $50)
4) Yagi (build one for $20, buy a really nice 7-element Arrow for $60)
5) APRS decoder (laptop and free software, or a Byonics TinyTrak 4 with display for under $100)

So, assuming you buy everything....

$14 + 289 + $50 + $60 + $100 = $513 worst case.

That gets you a really nice tracker setup that just works. On top of it, you get Greg's tech support which is very good -- he's responsive, knowledgeable and helpful.

If you drop the GPS and go with the BeeLine Tracker, you can knock the cost down to around $200 and have a really nice setup. Plus, it's a nice stepping stone to the GPS setup, if that's the route you want to go -- add the decoder and the GPS transmitter itself and you're set. Everything else (charger, radio, antenna, programming interface) works with both units.

-Kevin

 

[Chrisn]

You don't need a laptop, if you have a Garmin etrex that will also work

 

[n5wd]

Can someone explain this system to me? I have thought about buying it. I understand you need a HAM license, but what is the difference between the 70cm and 2 meter versions? Does it work well?

Chuck, lemme see if I can answer your so-far unanswered questions.

The Bee/GPS is a combination GPS receiver and either 2 meter (144-148 MHz) or 3/4 meter (420-450 MHz) transmitter. Unlike a consumer GPS unit, the Bee/GPS doesn't output to a screen, it sends GPS latitude and longitude and altitude data to the transmitter in what's known as APRS packets (APRS = Aut matic Packet Reporting System). APRS was invented by a ham named Bob Bruniga WB4APR who runs the Small Satellite Systems lab at the US Naval Academy. It was intended as a cheap way of letting other users know where a transmitter was, and allowing that transmitter to send brief status messages along with the location data. Kind of like SMS message plus.

The difference in frequencies is most obvious in the length of the antenna elements. The normal antenna for a VHF/UHF transmitter is measured in wavelengths - a 1/4 wavelength antenna is the standard antenna that most others are measured against - you'll often see it mounted on cars and trucks as a little "spike" -- for 2 meters, that length is about 19.5" - for the VHF High Band commercial radios, it's about 17-18", for the 446 MHz amateur radio band, it's about 7".

On a yagi antenna (the ones that look like your TV antenna, wires on eiher side of a boom and the end of the boom is pointed at the antenna), that means that the elements on a 2m antenna will be about 38-39" tip to tip, while the 440 MHz antenna's elements will be about 15" tip to tip. That can make a difference when you're crawling around in the bush or when you're swinging it in a populated area (ask me how I know that! :roll.

There are some other generalities about the difference in frequencies - it's generally thought that 2m will be less affected by foliage and slight rises/valleys and 440 is more "line of sight". In practical experience in the power levels we're talking about, you probably wouldn't notice that much difference.

One reason the folks who chose 2m transmitters do so is that there is an established network of APRS stations around the world listening on 144.390 MHz and a transmitter on that frequency stands a good chance of being heard by at least one of them and, if the transmitter is set up properly, any station hearing a signal will repeat it out so that others who might not have heard it originally will also relay the information. And it increases the chance that one of the stations hearing the re-transmitted packets will be an internet-gateway station and relay the "heard data" into the worldwide APRS tracking system.

If you're trying to track an 18-wheeler across the country, or a family taking a vacation, or a balloon that your school group has flown, or any number of things, that can be an advantage (getting it into the APRS network and on the internet).

If you're not interested in all that, though, you can either put the 2m Bee/GPS on a different transmit frequency or use the 440 Bee/GPS (the APRS network is not on 440 at all).

If you are starting from scratch, your selection then becomes a choice of whether you want to get involved in APRS or not. If not, then you don't need the 2m Bee/GPS, IMHO.

Either of them, though, paired with the proper receiving equipment (and that's another lecture, believe me! Let us know if you want more info on all of those choices) will work quite well.

Wayne

 

[n5wd]

... and you still have to have the laptop to read the signal

Rick,

Actually no, you don't. There are two ways to do it without a laptop:
1. Use a radio with a built-in TNC to decode the APRS packets. There are two hand-held options for that, plus another one that's bigger, intended for mounting in a car:
(a) the Kenwood TH-D7 decodes the APRS and displays it on its LCD screen in lat/long format. You can manually input it into a handheld GPS or, with the proper cable, pass the NMEA GPS$ strings into a GPS directly (the Garmins do this quite nicely all the way back to my monochrome Garmin 12 up to the current full color with maps Etrex mode. It's no longer in production, so your only option is to find one that's lost on the back shelf or buy a used one, and they're seeming to go for about $150-200 in the used market.
(b) the Yaseu VX-8R also decodes the packets directly and displays them on the LCD. If you add the optional GPS antenna module to the handheld, it'll give you distance and bearing information so you can walk to it, but it doesn't apparently output the NMEA data to another GPS receiver (i.e. one with maps).
2. take a scanner or HT that doesn't have a TNC built in and output the audio into one of the little APRS decoders available. There are several made (about $100 or so) that will display the packet information on an LCD screen or, with the proper cabling, will output the data to a handheld GPS.

This is more than academic for me, by the way, since I'm sponsoring a team that's participating in the NASA Student Launch Initiative this school year, and one of the requirements is to have tracking for the rocket to assist in recovery. Right now, I'm thinking that we'll probably have a UHF B/GPS in the payload section, and a BRB transmitter in the booster section, both on separate frequencies. A portable receiving station (maybe using the Kenwood D700, the mobile radio I mentioned earlier) feeding a laptop so everyone can see where the payload is, and the chase team with handhelds (maybe the VX8R or a TH7/handheld GPS if we can swing it) for the recovery.

From what i'm reading about the system you're using, it's not that portable, or is it?

 

[rdmmdr]

if i lose signal it it holds the last known good lock. i enter that in the handheld gps and drive right to it.
rick

 

[JAllen]

Rick,

Actually no, you don't. There are two ways to do it without a laptop:
1. Use a radio with a built-in TNC to decode the APRS packets. There are two hand-held options for that, plus another one that's bigger, intended for mounting in a car:
(a) the Kenwood TH-D7 decodes the APRS and displays it on its LCD screen in lat/long format. You can manually input it into a handheld GPS or, with the proper cable, pass the NMEA GPS$ strings into a GPS directly (the Garmins do this quite nicely all the way back to my monochrome Garmin 12 up to the current full color with maps Etrex mode. It's no longer in production, so your only option is to find one that's lost on the back shelf or buy a used one, and they're seeming to go for about $150-200 in the used market.
(b) the Yaseu VX-8R also decodes the packets directly and displays them on the LCD. If you add the optional GPS antenna module to the handheld, it'll give you distance and bearing information so you can walk to it, but it doesn't apparently output the NMEA data to another GPS receiver (i.e. one with maps).
2. take a scanner or HT that doesn't have a TNC built in and output the audio into one of the little APRS decoders available. There are several made (about $100 or so) that will display the packet information on an LCD screen or, with the proper cabling, will output the data to a handheld GPS.

This is more than academic for me, by the way, since I'm sponsoring a team that's participating in the NASA Student Launch Initiative this school year, and one of the requirements is to have tracking for the rocket to assist in recovery. Right now, I'm thinking that we'll probably have a UHF B/GPS in the payload section, and a BRB transmitter in the booster section, both on separate frequencies. A portable receiving station (maybe using the Kenwood D700, the mobile radio I mentioned earlier) feeding a laptop so everyone can see where the payload is, and the chase team with handhelds (maybe the VX8R or a TH7/handheld GPS if we can swing it) for the recovery.

From what i'm reading about the system you're using, it's not that portable, or is it?

I have been in contact with Yaesu, and was told that it is possible to output the data to a GPS device. They also indicated which connector I should purchase to do so. Of course, I need to figure out how to rewire this connector for the inputs on the computer and GPS units.

 

[n5wd]

I have been in contact with Yaesu, and was told that it is possible to output the data to a GPS device. They also indicated which connector I should purchase to do so. Of course, I need to figure out how to rewire this connector for the inputs on the computer and GPS units.

Joe,

I really am hoping they told you the right stuff and that you get it to work. Please keep us informed of your progress.

The only reason I question whether it's practical (not just possible - if you have to hang a 5x5" minibox off the HT to hold all the converter logic or the PIC, well.... )is that by looking at the message traffic on a couple of other forums, no one seems to have gotten this to work yet. I've been holding up buying one till I see whether someone else has gotten things to work.

 

[bigredbee]

Sure am glad I didn't see this post when it was made. Lots if dis-information here. :y:

Troj: Forget the yagi -- don't need it. Adrian tracked his just fine to 57k agl using just the rubber duck on his TH-D7

AND he had real-time alltitude and telemetry data indicating drogue and main deployment.

AND he had a 3d track recorded of the entire flight.

AND he didn't have to solder any wires.

AND he didn't need a laptop

I'm working on a standalone TNC w/ radio receiver and LCD display, that should make for a much cheaper / non-laptop solution....just need more time

SLI Teams: If it's not too late, you get a 15% education discount on BigRedBee equipment.

-- Greg

 

[troj]

Troj: Forget the yagi -- don't need it. Adrian tracked his just fine to 57k agl using just the rubber duck on his TH-D7

Holy cow! I didn't know you could pick 'em up from that far away.

I'm working on a standalone TNC w/ radio receiver and LCD display, that should make for a much cheaper / non-laptop solution....just need more time

Very cool -- keep me posted, I'm very interested, and I know several others who are looking at GPS options who would be, as well!

-Kevin

 

[n1lul]

I like the BRB GPS unit, looks like a good unit at an excellent price.

I have a HT already. I am planning to get the TinyTrack4 with the tested display and cables and the cable for the HT to Tiny Track.

https://www.byonics.com/tinytrak4/

Price assembled is around $125. I save more if I put some if it together, but I get the feeling that there assemblers soldering skill is better than mine.

This will display basic GPS coordinates. To get the whole show real time it is just one more cable to the laptop, or I could wait until I retrive the rocket and down load the data.

 

[cwbullet]

I would like to see a 900 mhz unit.

 

[bigredbee]

Just curious, why 900 Mhz? ARTS and GSFlight are 900 Mhz, and use FCC licensed modules so you don't need a ham license.

 

[Adrian A]

I'm working on a standalone TNC w/ radio receiver and LCD display, that should make for a much cheaper / non-laptop solution....just need more time

-- Greg

Any progress on this? I'm looking at different GPS solutions for flights this summer.

I don't mind taking a laptop to the field, but I don't want to hike with it. I'd feel better being able to read the GPS data after a long walk that gets me close enough to where I could pick up the signal again.

On a different topic, what are the speed and altitude capabilities of the BRB GPS?

 

[bigredbee]

well, as usual, time is my enemy. I've got a prototype running, but the range is dismal -- measured in 100's of feet instead of miles.

Not sure you need to lug the laptop in the field -- just go to the last reported position -- surely that will be close enough unless you're on the other side of a mountain?

Speed / altitude? The BeeLine GPS has gone above 100K feet in a balloon, and well above mach in rockets. There's a question as to what happens if you exceed both of the COCOM limits (515 m/s and 18000 meters) but so far, no ones tested that for me yet

- Greg

 

[Adrian A]

well, as usual, time is my enemy. I've got a prototype running, but the range is dismal -- measured in 100's of feet instead of miles.

Not sure you need to lug the laptop in the field -- just go to the last reported position -- surely that will be close enough unless you're on the other side of a mountain?

Speed / altitude? The BeeLine GPS has gone above 100K feet in a balloon, and well above mach in rockets. There's a question as to what happens if you exceed both of the COCOM limits (515 m/s and 18000 meters) but so far, no ones tested that for me yet

- Greg

I would expect that the last reported position would normally be good enough. It would just be kind of unsatisfying to go to the last reported position, not see the rocket, and not be able to get a GPS update. But if at that point I can hear a signal that I would like to decode, I should be able to use RDF to get a direction and use it like a simple beeline transmitter. And if I can hear a signal but I'm still stumped I could go back and get the laptop.

From what I have heard from other people using GPS systems, the last reported position is almost always within sight of the rocket, but not having used one yet, I'd like to make sure that all the bases are covered.

 

[bigredbee]

When I track down my rockets, I always punch the last reported coordinates that I heard at the pads into my handheld GPS . I've never had to do it again once I got to that location, even in one case when it DID go behind a ridge. At that point, the rockets tend to be falling pretty vertically unless you've got a pretty stiff wind.....

I did have to resort to RDFing the GPS signal one time: "too much thrust" resulted in premature separation of the fins, and the parts rained down. Found everything but the GPS transmitter which was hiding in the sage brush. GPS got me close, but had to break out my yagi to ID which bush it was hiding in.

-- Greg