Radio location range

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Boy that's a loaded question. If you want to learn, become a Ham Radio operator and you'll learn most of the ins and outs.

2 meter band is better than 1.25 meters which is better than 70cm which is better than 33cm (the 900Mhz NMEA trackers) in a nutshell.

The unlicensed 100mW, 900Mhz (ISM band) trackers about 1/4 mile or a bit less while lying flat on the ground. Much higher up in the air.

But..................... A tumbling rocket can be a challenge for any receiver to decode the digitally encoded signal stream hence a higher powered
tracker feeding a properly sized (tuned) antenna will have better results. If you want to know what that is, study to become a Ham.
I'm not being an "elitist" here but the theory on antenna polarity takes some study and thought to understand. Take a look at the
"receiving" end of a Multitronix tracking system and you'll see a bit of antenna theory in action: https://www.multitronix.com/

Also keeping this in mind, blowing the main chute up as high as tolerated will constrain the descending stack and antenna positioning so it is easier to decode the position stream and recover more positions. Up high the range can be several miles say 1000 to 500 feet up with a 100mW tracker. As long as there is a clean line-of-sight of the signal. If the tracker is lying in a depression upon landing, the ground footprint is going to be a lot less than 1/4th mile.

Extremes? With APRS tracking and a Digipeater with a 100 foot tower 1200 feet away from me, I was able to "hear" and decode a position
beacon on a high altitude balloon at greater than 100,000 feet altitude, >400 miles away on the 2 meter, 144.390Mhz band. The balloon signal was "heard" by the local digipeater and the position retransmitted so I could decode it locally on my radio. I was essentially using the 100 foot antenna tower as a proxy for a 1 watt signal from the balloon.

So that will give you something to think about to start. Kurt
 
Well, I had a no-code tech (N8VHI) but I let it lapse when the World Wide Web came out.
I was thinking, if a high power launch sends the rocket five miles up and there's a good wind up there, will the beacon help you find it? Or will you have to buy a new kit?
 
Well, I had a no-code tech (N8VHI) but I let it lapse when the World Wide Web came out.
I was thinking, if a high power launch sends the rocket five miles up and there's a good wind up there, will the beacon help you find it? Or will you have to buy a new kit?

A beacon and experience using it definitely helps. In fact I don’t know anyone who would launch to that altitude without either an RDF beacon or a GPS telemetry system and possibly both on-board.


Steve Shannon
 
Last edited:
Oooops, I miscontrued the question. APRS, NMEA trackers vs. RDF. With entry level GPS trackers much cheaper than the purpose built RDF stuff of yore, sport fliers can successfully track via GPS now. Some fliers who have room will use a GPS tracker with
a separate RDF tracker where room allows and they have the equipment for RDF. To the OP I'd say get a Tech book, study and retake the test. Get a callsign and there are more options available then. Want to RDF? Get an H/T with a true signal strength
meter. (You might still have one on hand) An Arrow Yagi : https://www.arrowantennas.com/sub/arrowiiyagi.html and an electronic attenuator: https://www.west.net/~marvin/k0ov.htm. I cobbled my attenuator into a plastic box I can velcro to the beam of
a Yagi antenna. When I want, I can remove it and attach a TeleBT to the boom. Finally, get a Beeline RDF tracker: https://www.bigredbee.com/BeeLine.htm The above is a heckuv a lot cheaper than the commercial RDF stuff and will do most RDF chores
satisfactorily. Kurt
 
Depend on what full power of unit is.

My Marshall RDF flacon trackers claim range of 20 miles in air.
Their high power units claim 120 miles.

My ComSpec units has regularly tracked my rocket over 30,000ft

There are so many units out there now, you need to check specs and talk with those that use them.
Big Red Bee over 100,000
Kate over 100,000
Telemega 100,000
Egg finder over 20,000
Comm-Spec over 50,000
Marshal over 70,000
Missleworks over 30,000
Above are known actual flights for example

Aim Xtra don't know

all above may have higher limits, I just don't know of the flights.


On ground that's a different story. Depends on how flat terrain is and if you land behind a hill, in gully, trees etc.
My ground record is 7 miles standing in back of pick up truck, [standing on ground no signal.]

Higher the elevation you have receiver better the odds are.
 
Back
Top