# GPS HELP

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#### thunderdog

##### Active Member
Hi All,
I have a great color hand held touch screen gps unit what do i need to put in the rocket to track? i fly low and med power so small i size and weight
thanks guys

#### troj

##### Wielder Of the Skillet Of Harsh Discipline, Potent
Your hand-held GPS isn't the part you fly.

Instead, you fly a GPS transmitter -- a device that picks up the GPS signal and transmits it to a receiver of some sort. Some folks have flown the Garmin Rhinos, although they're a bit bulky and require some work to keep from resetting under thrust.

-Kevin

#### BobCox

##### Well-Known Member
The latest issue of Sport Rocketry magazine has an article describing the Garmin Astro 220 receiver and the DC-20 or DC-30 transmitters. They are intended for tracking hunting dogs, but can be made to work well with rockets.

#### n5wd

##### Well-Known Member
what do i need to put in the rocket to track?
Kevin's correct - your bright, shiny handheld is good for pointing you in the right direction once you receive and decode the GPS coordinates from thetransmitter inside the rocket.

If you have, or can get, your amateur radio license, the Big Red Bee/GPS units are popular. If you're not a licensed ham, then Garmin's Astro is also popular, though they won't easily fit in most low and medium powered rockets. Probably, you're looking at a minimum of a 2.1 or 2.6 inch diameter rocket for the Astro.

#### cjl

##### Well-Known Member
Yep - the new Astro (DC-30) fits in a 54mm, and you need a bit bigger for the old DC-20 units.

#### rdmmdr

##### Well-Known Member
gps trackers come in many forms today while cell based trackers are avaible they are really not suited for this application.

gps flight has a nice unit but pricy
ozark also has a nice unit but pricy also
and there are a couple of others
but plan on eight hundred to 1200 $ham radio big red bee seems to be the cheapest way to go at about three hundred for the transmitter, but you need a receiver and packet decoder. with all of these systems you also need a handheld gps the garmin astro is a nice system after it is hacked a bit to fit the airframe and it has the hand held built in and no dragging out the laptops to talk with it. the best price i have seen is about 600 on ebay. or you can build one they are not that hard and can be done for about 200$ complete.

#### cjl

##### Well-Known Member
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#### timothyterpsalot

##### Well-Known Member
I'm probably getting the Astro and dog collar in December. To make sure I want it, my roommate works for Garmin and will borrow one and lend it to me. I just have to make sure I don't break it :eyepop:

#### Chrisn

##### Well-Known Member
Thats alot of money which could of been better spent on a ham radio licence, a beeline gps transmitter, second hand radio and gps handheld.

#### cwbullet

##### Obsessed with Rocketry
Staff member
Global Mod
I would agree the Astro is a better deal as long as you want to use it only in larger rockets. You are limited by tube size. I have heard of it in a 54mm tube. I would like to see this. I have only seen it in 3 inch or greater.

#### bobkrech

##### Well-Known Member
I guess if your ok with the lower specs. If you have a laptop you can do a beeline GPS system for under $500, so you dont need a GPS handheld. Reality check. Both systems cost over$500. The Garmin transmitter is $200 and the Big Red Bee is$300, and as rocket do sometimes crash, so to to make this financial commitment rationally, your rocket should be fairly expensive which in this case would be several times the value of the transmitter.

Both products work well, and perform as advertised, but the Garmin is less expensive and works right out of the box. The Big Red Bee requires a lot of other stuff and requires a fair bit of tinkerings. For a ham it's not a big deal, but for the average Joe it would be.

The retail street price for the complete Garmin system is ~$600, and you don't need to lug around a computer, and extra "rocket collars" are ~$200.

From my reading of both specifications, the only spec that the Big Red Bee can exceed the Garmin on is range because of the potentially 4 watt higher tranmitter power for the Big Red Bee versus the 2 watt transmitter power of the Garmin, and in reality the difference between the powers isn't really that big a deal. Otherwise, it's a wash on performance.

The Big Red Bee equipment is fine if you want to tinker, but after you purchase a $275 2-meter transmitter (plus the cost of the batteries you have to supply) (to be comparable to the Garmin 2-meter unit), you still need a ham receiver, antenna, decoder and a notebook. No matter how you look at it, it costs a good bit more more than the Garmin, and is not a plug and play. The Garmin is more user friendly when you are trying to get to your rocket. It contains a compass that will let you know what direction you are going, and shows a topo map so you can pick out the easiest path to your rocket, all without lugging a computer around with you. If you're a ham and have everything else, the the Big Red Bee makes a lot of sense, but if you're not a ham and want a simple to use system, the Garmnin is a better choice. Bob #### cjl ##### Well-Known Member I guess if your ok with the lower specs. If you have a laptop you can do a beeline GPS system for under$500, so you dont need a GPS handheld.
What lower specs? The Astro will do at least 5 miles line of sight straight out of the box, and significantly farther with the optional extended range antenna. You can download a 3d track from the Astro just like you can with the Beeline. The specs are nearly identical, and the Astro is easier to use. I fail to see why that is a worse option than the Beeline.

#### Chrisn

##### Well-Known Member
No it wont cost over $500 for a lower end system Transmitter$300USD
Second hand scanner $100USD (some can be had for lower than this) OpenTracker$50

So if you already have a GPS system, and/or a laptop this is the cheaper set up. Most flyers at black rock should have GPS, where this system is widely used.

Also there will soon be a 70cm 4 watt version

http://www.bigredbee.com/blgps_hp.htm

#### timothyterpsalot

Bob, I somewhat disagree. Yes the Astro w/ DC-30 costs 500 bucks but the DC-30 costs $140. If the rocket fails, that's what you will be replacing. I talked to some guys at Garmin and they said they might be able to customize the system for me for free to do some experimenting. I will let you know what comes up with that, but that's a different thread. As for the DC-30 dimensions, it can fit in a much smaller space than the DC-20. It measures 1.4" x 1.17" x 3.3". The antenna now runs lengthwise across the unit vs. with the DC-20 it stuck straight out of it. This makes it fit in much smaller spaces than the DC-20. https://buy.garmin.com/shop/shop.do?pID=15512#specsTab #### new2hpr ##### Well-Known Member If you're with a club, share the burden. There are several Astro handhelds in our group, and DC-20 transmitters are cheap on Ebay. I picked up one new and a couple used ones (like new) for well under$100ea.

If there was a market, one could do come creative repackaging of the DC-20 into a 38mm. The board "ears" just barely go outside this size. CJL, you up for a Solidworks exercise? I'll take one apart for measurements. Maybe find someone to mill a few new housings out of Delrin?

Ken

#### bobkrech

##### Well-Known Member
No it wont cost over $500 for a lower end system Transmitter$300USD
Second hand scanner $100USD (some can be had for lower than this) OpenTracker$50

So if you already have a GPS system, and/or a laptop this is the cheaper set up. Most fliers at black rock should have GPS, where this system is widely used.

Also there will soon be a 70cm 4 watt version

http://www.bigredbee.com/blgps_hp.htm
The Garmin Astro is ready to go out of the box. It doesn't need anything else. There's no laptop required, not programing required, no interconnection of GPS, transmitter, Open Tracker, scanner, nada.

Even better, if a club or club member buys the package, other club members can simply buy a transmitter (street prices from $160-$200 for the DC-30 transmitter) and use the club's receiver to track up to 10 "dogs" at once. In fact just today, one of our club members just made this offer to our club's high power fliers. He also posted this on our club website,

"BTW, talking about rugged, at LDRS I brought the DC-30 in ballistic (ejection charge never fired) from about 3500 ft in an Aerotech Arcas and it was the only thing that survived the prang. Actually, about 30 seconds after the crash it transmitted to me that my dog (named Rocket) had "treed it's quarry" (i.e. it hadn't moved in 30 seconds). The handheld unit directed me right to what was left of the rocket in high planted field. "

I'm impressed.

Bob

#### bobkrech

##### Well-Known Member
Bob, I somewhat disagree. Yes the Astro w/ DC-30 costs 500 bucks but the DC-30 costs $140. If the rocket fails, that's what you will be replacing. I talked to some guys at Garmin and they said they might be able to customize the system for me for free to do some experimenting. I will let you know what comes up with that, but that's a different thread. As for the DC-30 dimensions, it can fit in a much smaller space than the DC-20. It measures 1.4" x 1.17" x 3.3". The antenna now runs lengthwise across the unit vs. with the DC-20 it stuck straight out of it. This makes it fit in much smaller spaces than the DC-20. https://buy.garmin.com/shop/shop.do?pID=15512#specsTab Tim I believe the orignal question was what GPS do I put in my rocket, and the respondents have been discussing the relative merits and costs of the Garmin Astro dog tracker and the Big Red Bee ham rocket tracker. I've seen both systems in action at our club launches and they both work. The big difference between the 2 is that the Astro is a complete, integrated COTS solution while the Big Red Bee is a DIY ham product that you have to assemble from a number of acquired components. No matter what, if you are starting from scratch, you will have to spend at least$500 to build your system. If you want plug-and-play instant gratification, buy the Astro. If your a tinkerer and/or have a big pile of electronic stuff or have the time and patience to find and buy second hand electronics and get a ham license, the Big Red Bee is your ticket.

If you crash and wreck your transmitter, you may have to replace it. The DC-30 can be had for ~1/2 the cost of Big Red Bee transmitter + the cost of a second GPS. I don't know how well the BRB crashes, but if you read my last post, the DC-30 is pretty rugged out of the box.

Bob

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#### ttabbal

##### Well-Known Member
If you crash and wreck your transmitter, you will have to replace it. The DC-30 can be had for ~1/2 the cost of Big Red Bee transmitter + the cost of a second GPS. I don't know how well the BRB crashes, but if you read my last post, the DC-30 is pretty rugged out of the box.
I don't know about crashes, but I shredded a rocket with a beeline transmitter in it. It was damaged, but the manufacturer was able to repair it for $10. Not bad for a bare PCB taped to the shock cord. There are good and bad things about both systems. The lower transmitter cost for the Garmin system is nice though. #### rdmmdr ##### Well-Known Member The astro looks to be the best for the non electronically inclined. If some one takes one apart i can cad up a case drawing for it. the days of the big red bee are not long for this world with a company the size of garmin putting out a product like this. If they add a telemetry channel i will hang up my soldering iron. I paid the same for my comm spec tracker with the crapy antenna. And a lot less range. It is still nice for little stuff so it will stay in the range box. for every body worried about range unless you are flying to 25000 and poping at apogee in a 20 knot wind you are fine. For those of us planning on playing nasa, the zbee xtend units kick it up to one watt, or twenty miles, but you are homebuilding again. #### cjl ##### Well-Known Member No it wont cost over$500 for a lower end system

Transmitter $300USD Second hand scanner$100USD (some can be had for lower than this)
OpenTracker $50 So if you already have a GPS system, and/or a laptop this is the cheaper set up. Most flyers at black rock should have GPS, where this system is widely used. Also there will soon be a 70cm 4 watt version http://www.bigredbee.com/blgps_hp.htm I'm sorry if I don't see the appeal of saving$50 for a system that's far less convenient than the Astro. The difference between $450 and$500 is not that significant, and as pointed out above, the Astro has a cheaper transmitter cost and is absolutely ready to go out of the box. Don't get me wrong - the Beeline is a nice product, but the Astro is in a whole new category for easy rocket tracking.

#### Chrisn

##### Well-Known Member
I'm sorry if I don't see the appeal of saving $50 for a system that's far less convenient than the Astro. The difference between$450 and \$500 is not that significant, and as pointed out above, the Astro has a cheaper transmitter cost and is absolutely ready to go out of the box. Don't get me wrong - the Beeline is a nice product, but the Astro is in a whole new category for easy rocket tracking.
Apology accepted

I don't like taking the easy way though. I build a rocket and then fly it, not fly it without doing any work. :2:

#### cwbullet

##### Obsessed with Rocketry
Staff member
Global Mod
I personally feel the garmin is better if you are using big rockets. It is easier to set up and use. It is idiot proof. The red bee is not. But then again, the red bee fits in a smaller rocket.

#### n5wd

##### Well-Known Member
This argument (OK, discussion! :confused2 about whether the Garmin Astro system or the Bee/GPS is better reminds me of two kids fighting over game systems. Let's face it, guys, both the Astro and the Bee/GPS, when they're set up with the right support, will work to help you locate a rocket, and neither one is inexpensive to begin with.

If you're starting from scratch and want the most turn-key solution for a 4-5" rocket or larger, the Astro would seem to be the logical choice. If you're wanting to pack it into a smaller diameter rocket, you're going to have to do some surgery on the DC-transmitter (or did someone say they could put a DC-30 into a 3" tube without opening the case?). We'll put the little legality about the MURS antenna height restrictions aside because, really, the chances of that becomming an issue on a rocket launch are slim to none. That is a very good reason, though, why you're not hearing about the Astros being used for the high altitude balloon launches - when you take over one of the five MURS frequencies for five states, the FCC DOES begin to notice! :shock:

If you're a ham, though, and want to use the APRS capabilities of the Bee/GPS for something besides tracking rockets, or you're into public service communications, or if you've already got most of the equipment to use the Bee/GPS system (a receiver, a TNC, something to put the GPS coordinates into, whether it's a laptop or a handheld GPS), then the Bee/GPS makes sense. An average ham already has a 2-meter or 440 HT and probably a laptop. Make an interface cable from the HT to the laptop and run the AGWPE software, and the laptop decodes the APRS packets and squirts 'em out into UI or APRS-View or any number of applications.

But, it's really no harder to use than mounting an altimeter and doing a little bit of configuration. Really. It's not rocket science! (Pun intended)

Getting a ham license to track rockets is dangerous, though - you might just find out there's a lot of other things in ham radio that interests you and that could dilute your time for rockets! And as far as the license being too hard for a person of average intelligence... I hope no one's still thinking that way.

I know that I'm going to add a Bee/GPS system to the rocket my kids will be flying for the NASA-SLI program this year simply because we can use the data to generate a visual map track on so many different things, besides the hand-held units that the recovery crew will have, and will also use the data for post-flight analysis as well, unlike the Garmin (unless I've missed anyone who's said they can receive and display the MURS data on anything but the Astro handheld).

But, I'm also about to purchase an Astro system, as well.

Both work - both have pro's and con's.

So c'mon, folks...

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#### cjl

##### Well-Known Member
The DC-30 will fit in as little as a 54mm tube (I've tried) with minimal effort, unlike the old DC-20, which required slight modifications for 3" and more significant surgery for anything less.

Staff member