Altimeter post flight audio siren feature

[Dave S.]

I noticed that the StratologgerCF has a feature where post flight there is an audio siren beacon that goes off to help you locate your rocket.

Didn’t see this feature listed on a chart comparing different rocket altimeters.

Anyone know of other altimeters that have this feature?

 

[cerving]

Yes, I do. However, calling those little buzzers a "siren" is a bit of a stretch... their outdoor range is very limited, unless it's VERY quiet and you have really good high-frequency hearing (they resonate at about 3 KHz).

 

[StreuB1]

Most adults have a 4khz notch in their hearing causing hearing loss at or around 4khz. Notice that is very close to the resonant frequencies of the PCB mount piezo electric buzzers that are generally used, as Cris stated. You will hear them up close, but as distance increases and ground cover perpetuates, your chance of hearing them falls off dramatically. Not to mention if the buzzer lands facing down. They just don't create enough physical energy to overcome the local means of attenuation.

Like Cris stated, these noise makers aren't very effective, especially in areas where there is foliage and other background noise.

Now what might be a little more effective would be something that sweeps a range of FQ's but again, the amount of energy that these can produce is the limiting factor.

 

[ksaves2]

But...... Used in conjunction with a tracker, the tracker can get one to "hearing" range and man o' man one's ears can really localize the source. Flew a rocket with a GPS tracker with a mapping program on my laptop but without a beeper. Map showed I was on top of the rocket but I couldn't find it. I had to "zoom" in the map to show I was 20 feet away. I started flying beepers or noisemakers with my trackers thereafter if room allows.

 

[BEC]

Anyone know of other altimeters that have this feature?

The PerfectFlite Pnut also does this.

 

[Dave S.]

Fantastic! Thanks to all of you for your info and suggestions.

 

[Steve Shannon]

As I recall, the Raven can also be programmed to enable an output on landing. That output could be used to power up a panic alarm. Of course it’s just as easy to simply use a panic alarm separately.

 

[cerving]

One other issue is that your altimeter is going to be tucked inside an AV bay that's sealed except for a few small vent holes, so there's really nowhere for the sound waves to get out. If you fly in places with crops, clipping a pull-pin alarm to the shock cord is cheap recovery insurance. Even if you have GPS, you will probably hear the alarm way before you get close to the rocket.