Rocket trackers and altimeters: Right for Low Power, or a waste?

So I've been listening to "The Rocketry Show" podcast, and the eleventh and twelfth shows have dealt with how to range find and track a downed rocket.
It's all sounding pretty interesting, especially if your rocket has caught a thermal and is floating away, out of sight or over the horizon.

As the discussion in the show is wrapping up, the guest speaker says, something like, "Gee, you may feel that $300 to 400 dollars is too much, but the first time you lose a rocket packed with electronics, altimeter and gear, it quickly will pay for itself."

Gee, I think, I've never paid more than a couple of tenners for my low power rockets and another ten or so for motors.
Why would I want to invest in a $300 tracker system? Isn't there a cheaper way to do this? A low-cost beeper and receiver combo? Dirt cheap?

And then, there's the implication that an altimeter is terribly expensive.
All I'm interested in doing is maybe record what my highest flight on an "E" motor might have reached. Isn't there a cheap, penlight or key-chain altimeter to do that?

So I guess what I'm asking is what the cheapest amount one could spend to get an altimeter, and separately, a tracker and receiver system.
(Yes, before you ask, I AM a licensed HAM radio operator, and have a handheld HT with General privileges, but haven't progressed any deeper into that hobby. I do know what a Yaggi antenna is, and understand radio propagation and receiving theory and practice. Is there anyway to utilize the HT to track a downed rocket...or is the receiver end of this too specialized?)

If all you want is altitude then the best bang for the buck today (in my opinion) is the currently-out-of-stock PerfectFlite Firefly. Less than $25 and quite tiny. If you want more data then the Altus Metrum MicroPeak (which is even tinier) is the one.

For use outside a proper payload compartment the Jolly Logic devices are the way to go. Three choices - altitude only (AtimeterOne), lots of data (AltimeterTwo), and recording altimeter that pairs with your iOS or Android device via Bluetooth to plot and share data (AltimeterThree). They all work inside a payload section as well of course.

I can't offer any help on tracking yet. I have an EggFinder starter set kit which will be my intro to that world when I get there.

I would guess that the biggest obstacle you would have is size. likely bt50 size or larger tubes. followed by weight.
Rex

Rex R said:

I would guess that the biggest obstacle you would have is size. likely bt50 size or larger tubes. followed by weight.
Rex

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Walston (https://www.walstonretrieval.com/sub-2.htm) has a transmitter that weighs a couple of grams and the body is about the size of a dime. The antenna is flexible wire so can be, carefully, rolled to fit into a body tube for deployment.

The https://www.picoalt.com products are tiny and you can do very small dual-deploy rockets.

And keep an eye open for the Jolly Logic mechanical dual-deploy product.

So lots of fun stuff to do with low power, if you want.

If you want to try 2 meter RDF on the cheap and can design a rocket to handle the dipole, can't go wrong with the $15.00 XFM-1 https://www.jbgizmo.com/page30.htm
I get 1400' range on the ground with a 3 element Yagi. This offset attenuator isn't bad either: https://www.west.net/~marvin/k0ov.htm

I found I didn't have to activate the attenuator while the rocket was in flight. As I got closer, I had to switch on the attenuator to maintain the directivity. If you RDF, make sure you have a rig that has a true signal strength meter. Some of the cheap imports are either "full on" with a signal or "full off" without. Won't work for tracking.

Oh, if you crash or lose the XFM-1, you won't be out much dinero so it's fun to practice with. If the modroc goes down in standing corn the 1400' range I saw on the ground is very helpful in finding the rocket. Plus I was struck as to how well the attenuator worked when I needed to switch it in. The direction could be extremely sharp. With the right setting, go off to one side or the other and little or no signal. Have it pointed directly at the downed rocket and the strength increase is quite noticeable. Kurt

At last summer's World Spacemodeling Championships we used trackers on certain models in the Parachute Duration and Scale Altitude events, and found them quite helpful. There's a writeup of our experiences with the devices on the NAR website at:

https://www.nar.org/contest-flying/fai-spacemodeling/construction-techniques/recovery-beacons/

The trackers used were MUCH smaller than the Walston products mentioned earlier in this thread, having been designed for use on dragonflies and similar insects.

James

James Duffy said:

At last summer's World Spacemodeling Championships we used trackers on certain models in the Parachute Duration and Scale Altitude events, and found them quite helpful. There's a writeup of our experiences with the devices on the NAR website at:

https://www.nar.org/contest-flying/fai-spacemodeling/construction-techniques/recovery-beacons/

The trackers used were MUCH smaller than the Walston products mentioned earlier in this thread, having been designed for use on dragonflies and similar insects.

James

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Ahhhhh, for an important contest or record attempt I can see it but $150.00 for a throw-away transmitter is a bit tough for a hobbyist to swallow.
That firm does indeed have some interesting devices though. I'd like something that I could replace the battery for usage longevity. Kurt

I think it is massive overkill for a low power rocket. No one wants to lose a rocket, but $300 buys a lot of low power kits.

I have been conversing (exchanging emails) with a person regarding a pair of transmitter and receivers for directional rocket hunting.
I thought the conversation was going well, and I was just about to order, when he dropped this line at the end of his last email...
"(typically, a JST pigtail since most 2S
LiPo's use JST's)."

This doesn't make much sense to me, since I do not recognize the abbreviations. I asked him to clarify, and I haven't heard from him since.
Can anyone make sense of this line for me. (To be fair, I told him right up front that I was a newbie...)[Maybe he had a stroke while typing?]

In the meantime, I have been following the great link that someone else provided to a $15 dollar cheap XFM1 Tracking Transmitter that appears to be compatible with my 2 meter HT ham radio set.
I am actively pursuing this alternative as a means of dipping my toe into the water. Whether to works well enough for me, or if it convinces me to invest in the larger pair of trmtr/recver unit, it will be well worth the investment for me now.

Have you checked out the https://bigredbee.com/BeeLine.htm product line?

WillMarchant said:

Have you checked out the https://bigredbee.com/BeeLine.htm product line?

Click to expand...

Had not heard of them. I will check them out...

Kirk G said:

I have been conversing (exchanging emails) with a person regarding a pair of transmitter and receivers for directional rocket hunting.
I thought the conversation was going well, and I was just about to order, when he dropped this line at the end of his last email...
"(typically, a JST pigtail since most 2S
LiPo's use JST's)."

This doesn't make much sense to me, since I do not recognize the abbreviations. I asked him to clarify, and I haven't heard from him since.
Can anyone make sense of this line for me. (To be fair, I told him right up front that I was a newbie...)[Maybe he had a stroke while typing?]

In the meantime, I have been following the great link that someone else provided to a $15 dollar cheap XFM1 Tracking Transmitter that appears to be compatible with my 2 meter HT ham radio set.
I am actively pursuing this alternative as a means of dipping my toe into the water. Whether to works well enough for me, or if it convinces me to invest in the larger pair of trmtr/recver unit, it will be well worth the investment for me now.

Click to expand...

JST has male and female connectors. You can look them up on Ebay. Example: https://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9683 for the female side.
I forgot to mention the XFM-1 is a kit, but it's an easy one. The advantage is it's cheap. Disadvantage is the low power, 3V batteries (in series for 6V) and accommodating the dipole antenna. I used it with an old Estes Super Nova Payloader that had plenty of room for the upper limb of the dipole and I just drilled a small hole in the hollow plastic transition to have the other end of the dipole go out the bottom. I wouldn't use it for the primary means of tracking on a high $$$$$ project but like I said, for the cost, it's fun enough. BRB stuff is extremely good too. I have several RDF and GPS devices from Greg. I recommend if you want APRS and can swing the cost. (For GPS that is. RDF is more manageable costwise) Kurt

I can get my Marshall transmitter into an 18mm tube with a bit of room to spare. I will put my tracker into low power kits simply because I already have one for my HP needs. I bought one of the LOC Mini Missiles so I can fly it on 24mm AT reloads pretty much to try to lose it just to track it. Tracking rockets is incredibly fun. I know they are expensive but they also add another dimension to flying that is often overlooked. I fly completely stress free, I don't freak out when my pride and joy goes higher than I used to feel comfortable with. I can't begin to tell you the rush you can get when you find your rocket is waste high grass knowing there would be no way you would have even known where to start looking unless you had the tracker. Honestly my tracker changed the way I fly.

There are lots of different ways to add tracking to a rocket - The Com-Spec setup talked about on the Rocketry show podcast runs $350 for the transmitter and receiver - and requires at least a BT60 or larger rocket. There are some cheaper ways to get started.


The Estes Digital Altimeter is only $24 at AC Supply. You can have a lot of fun finding out how high your rocket goes with an inexpensive altimeter.

It's also great fun to fly a key chain video camera on a low power (C,D,E) rocket. The video you get is surprisingly good for a tiny camera that costs about $20 bucks.

I think it's very possible to recover rockets WITHOUT using lots of expensive tracking gear. Having a few friends help you spot the rocket always helps.


For me, tracking is more important when the cost increases. You really don't want to loose that Leviathan ($30) when you fly it on a G64 ($50 Hobbyline case) with an AltimeterTwo ($70) and a #16 HD video Camera ($50)

The potential loss is now $200 - added up quickly, didn't it. :shock:

Adding a $90 tracker (Eggfinder starter set) to make sure you get your $200 rocket back every time- seems like a smart plan

Bee Line transmitters are another way to get started tracking @ around $60-$90...

A personal security alarm (screamer) will blast a loud continuous High-Pitch tone (think sonic beacon) and a small one is about the same size as an altimeter - Cost is usually under $10

I've seen a lot of LPR/MPR with electronics in it, mainly altimeters. The TARC flyers do it all the time, they have to, mainly to get the apogee but the flight profiling helps them pick the "right" motor/delay/chute size. If you want to play around with both flight data recording and GPS tracking, the Eggtimer TRS is a relatively cheap way to do it, it's $140 with the handheld LCD receiver. You don't need to enable the deployments, just use it to record the flight data and to get your rocket back. The catch is that you have to solder it together, so it may or may not be your cup of tea depending on your electronic skills. [Full disclosure: I make the Eggtimer products.]

Good news, The XFM1 tracker transmitter kit arrived, and I assembled it in one evening. Ran into a little trouble with what turned out to be a solder bridge that prevented it from beeping... but the designer/supplier was extremely helpful in giving pointers that led me to the trouble. Transmitter programmed with my callsign too!

Then I tackled a flexible Yagi antenna made from a broken tape measure, PVC pipe, hose clamps and a short run of RG58 coax and BNC connector. I'm finishing that tonight!

Kirk G said:

Good news, The XFM1 tracker transmitter kit arrived, and I assembled it in one evening. Ran into a little trouble with what turned out to be a solder bridge that prevented it from beeping... but the designer/supplier was extremely helpful in giving pointers that led me to the trouble. Transmitter programmed with my callsign too!

Then I tackled a flexible Yagi antenna made from a broken tape measure, PVC pipe, hose clamps and a short run of RG58 coax and BNC connector. I'm finishing that tonight!

Click to expand...

If you get serious, you might need an attenuator like this: https://www.west.net/~marvin/k0ov.htm or look up something homemade online. With the rocket at altitude I find I had good directivity without any attenuation. When my rocket landed, it was about 2000' away, easily seen by me on the ground and of course no signal was heard. As I walked closer, I began hearing the signal at about 1400' and without the attenuator inline still had excellent direction bearing.
As I drew closer, the ability to detect the direction was lost as the receiver became saturated with the stronger signal. I of course could see the rocket on the ground in this instance and put the attenuator inline and adjusted the gain. In concert with the signal strength meter, direction bearings and nulls were easily detected and could be kept sharp by adjusting the gain.

Being able to keep a good bearing as one gets closer is important if your project is sucked up by tall grass or corn. Make sure your radio has a true signal strength meter. If it is made by a major manufacturer like ICOM, Alinco, Yaesu or Kenwood you should be O.K. If it's a Chinese import, you'll need to look it up online and make sure it's not a full deflection on with a signal and full off without one. No good for RDF.

Only issue with the XFM-1 is it's at its best with the full dual wire dipole accommodated in the rocket. With my old Super Nova Payloader, that wasn't a problem. But then again, for $15.00 not bad to experiment with. Kurt