Sadly disposable, the ones from the Michigan (usa) fall from the sky with postage and an envelop to send back to the weather station for reuse.

I have documented my progress in reverse engineering the RS41 in GitHub. KZfaq is a bit picky in me posting links here, but searching GitHub for RS41 will bring you there. RS41_Hardware - hardware reverse engineering with mostly complete theory of operation RS41_Decoding - radio transmission format reversing with mostly complete description of the transmission protocol

The water packs might just be to keep the batteries above 0°C. They can't get below that without freezing the water entirely first, which takes a huge amount of energy (*to be conducted out)

Beautiful video. Some remarks on the old RS92. Labelling: "D"=AA Batteries, "A"=AA Batteries, suitable for automatic launchers; "L"=Lithium battery pack; "W"=Water batteries. The A model has an on-off switch that would be punched in by the launch robotor. The RS92 did not process GPS coordinates onboard; this was down by a computer at the ground station. The realistic operating time with the RS41 and for the RS92 A and D models are about 10 hours.

i wish where i live it would ARM Dev Boards Falling From The Sky!

Dave, the RS41 sends full 10 hours. The 240 minutes are a very cautious statement in the data sheet.

I choose to believe the liquid is vodka, and it's for whomever finds the sonde :)

Nice teardowns and analysis Dave... 10/10

Jesus! A product of Finland! The Head office of the company is right next to my house :D

60mW may not sound like a lot, but with unobstructed line-of-sight, it can go a long ways (these often reach over 100,000 feet altitude). I've been able to receive and decode the signal from these at distances in excess of 300km!

went on a RS41 hunt recently. first two, someone else was faster. third one.. on a rooftop, fourth one fell into a river. fifth lost in the woods, sixth one i finally retrieved. it had a expansion port with a weird module fitted i couldnt informations about, looked like a barometric pressure sensor (1cm diameter metal can on ceramic substrate, hole in the bottom, qr code ontop).

A followup would be nice! Thanks for this interesting stuff.

Helical antennas look great ;-)

It's raining ARMs.

Now I WANT the Australian Meteorological Agency to make a platy-board with a custom platypus silk-screened chip!😂😂

I'd like to see a follow up on this to see how it can be programmed to do different things. Can't get one myself but would love to see it do things.

"It's up-side-down, so all the electrons have already all fallen out..." And this is why I watch your channel.

Does anybody know the partnumber and manufacturer of the battery holder? It looks very interesting and I want one :)

Those water containers will clamp the temperature to 0C until they froze completely.

For a radiosonde, they don't need to fully process the GPS data into a position as the sonde doesn't need to know where it is - they can send raw or intermediate data to be processed at the receiving end, saving on battery power and cost.

Hi, according to what I have read, these batteries (AA size)are not the "right" batteries used in a sonde so the organization must insert that sort of ballast (water containers) because the sonde must have the same weight compared to the others. The "right" batteries are ... water batteries: I mean they are activated by adding water a little before the launch (probably they are a sort of lead-acid batteries and this hypothesis justifies the considerable weight). A battery of that type can be stored (dry) even for years without problems. They use standard alcaline batteries pack in case the operator... "forgets" to prepare it or if for different reasons they have not the "right" batteries

It’s funny to see the same topology “chip” antennas for GPS and WiFi. They are nothing but a capacitive divider to resonate the inductive notch in the PCB. They will sell you one for several $ when it’s equivalent to two SMT capacitors.

Finally! I was waiting for this video since one of the sondes cam in, in a mailbag a year or so ago! Thanks a lot :)

And good thing about this is that you can just wiggle wiggle yeah..

Ha ha, i thought you went skydiving when i saw the title :D lol

in Australia, electrons fall out when the board is up straight

Is there some guard wireing going on? 15:38

I worked for u-Nav! I was an applications engineer, and I designed most of the eval and demo boards. Good times. u-Nav was bought by Atheros, then they were bought by Qualcomm. Three employers, same desk. I wasn't aware that anybody was using our front end without its matching baseband processor. But it makes sense that Vaisala would have used them without me ever hearing about it here in the USA, since they naturally would have interacted with our Finland office, where most of our software development was done.

We had to wait until 16:07 for Bob today *lol* - great vid as always!

Your teeny tiny inductance to ground is part of the RF output filter (band-pass?). May be more than 60mW output as there is a 4 legged transistor (or MMIC amplifier?) feeding into the filter.

I have found that lots of suppliers in China are happy to silkscreen the chips they send to you. :)

That is a good way to keep the battery stable even when the water freezes it won't drop below Oc.

I nearly didn't click this video because I thought it's just a Dev board. This is much more interesting!

Website for re-purposing is gone, is there another site?

The PTU probe is typically coated with a vacuum deposited aluminum. The aluminum helps reflect the IR and UV heat from the probe. If this tracks altitude, it will likely have some sort of temperature correction because it still absorbs some heat at higher altitudes

Is there a reason why the battery holder (at 13:57) has two gold-plated contacts and two non-plated ?

Neat! I had no idea so many of them go up there everyday.

I really wished I could get ahold of one of these.

Dave the 2 humidity sensors allows for 1 sensor to be heated and remove moisture while the other sensor is in use. they are switched back and forth. D= alkaline dry-cell battery L= lithium battery A= dry-cell for autosonde all 3 radiosondes measure pressure. temperature. and humidity .

I have documented my progress in reverse engineering the rs41 on github: hardware - github.com/bazjo/RS41_Hardware radio protocol - github.com/bazjo/RS41_Decoding

Do you remember (back in the days of analog) when these contained a vacuum tube (launched via weather balloon)?

Oh Dave you should had attached a probe on the RF output.

I wonder if these could be repurposed as a tracking device for model rockets or drones?

Nice. I have a potential application for these. May save me developing my own.

Most important Dave Vocabulary: 1) "Here you go" = "Bob's your uncle" 2) "Freehanging" = "Flapping around in the breeze" 3) "Fan" = "Aficionado" 4) "Let's take a look" = "Let's have a squiz" 5) "Look what we have here" = "look at these bobby dazzlers" 6) "That's pretty cool" = "That's sex on a stick right there!" 7) "This is way better than that" = This is non of that rubbish" 8) "We have opened the device" = "We're in like flyn"

Very nice video 👍

I wonder if they are doing there own GPS processing on chip because any off-the-shelf GPS modules shut down if you get above X height or over X speed due to USA restrictions to prevent GPS being used to guide missiles.

Not the usual EEVblog video ending... bummer.

If only that cloud could rain on my house!

I bet the slot around the temperature sensor also provides thermal separation from the rest of the PCB. That's actually a really good idea; I built a thermostat with an onboard thermal sensor - and think I'll add some similar sort of thermal gap for the next rev!

11:20 I believe the idea with the duplicate humidity sensors is that one is measuring while the other is heating (or cooling down to ambient afterwards), and so they can alternate.

cloud-based devices :D

LoL, was waiting for the 👮 police to arrive when you took the stup outside and got a GPS sink 😎 would have been fun!

DAVE Dave Dave, "Dave's not here man!" HEHEHE got your attention? Here is an update for you regarding my experience with Varta NMiH 15 minute rechargeable AA cells and Eneloop charged on the Varta charger. I have used 1 set of 1600 mAh Varta 15min (4 ea), and one set of Eneloop 2000mAh in White, recharging as necessary in the 15 minute charger since 2005. This model www.master-instruments.com.au/products/57780/57253%20201%20421.html (Varta 15 minute charge and go I-C3 type 57253 output 1.6 V DC 15 Amp) I also use an Energiser rechargable compact charger model CHM4AA, a 15 hour charger for two sets of Panasonic 2000 mAh and 1 set of Energizer 2300 mAh They were all used originally in a series of Digital still cameras like the Fujifilm AV215 and its predecessors, now they are used for clocks and PC mice, keyboards etc. There were times I needed quick charging of the Panasonic and Energizer, but one Panasonic failed after around 600 charges, and was discarded, it was replaced with another two Panasonic's. The Sony Eneloop's have been the most resilient as far as holding charge over long shelf times, and charge in 15 minutes the Varta set are still charging in 15 minutes and have over 1200 charge cycles. The Energizers had more power initially but after 14 years they are now down around 1500 mAh. The 15 minute charger seems to know which type of cell has been placed in it, and only charges the Varta and Eneloop at 15 minutes now, when the Panasonic's were new they also charged at 15 minutes but like I hinted at only for 600 cycles then the charger treated them like regular cells and does 15 hour charges on them now. As Panasonic has purchased Sony's battery division, Eneloops are now black and marked Panasonic. I do not have any of those. The above relates to AA cells. I have six sets of AAA cells two each of Panasonic and two of unbranded white sets from various test equipment, and one set of 'Solar' brand from solar lamps my neighbor discarded. All sets of four cells. I charge the Panasonic's in the 15 minute charger, and the rest in the Energizer. No failures at all after 10 years, I use them in remote controls, computer keyboards, and test equipment. I hope this is of some use to you Dave. Regards Andrew.

A bit of a "heads-up" Dave. Although the antenna has helical parts it isn't a helical antenna. It's what is know as a "turnstile". A true helical antenna is quite directive. A turnstile is designed to be quite onmi-directional.

Did you plan to reuse these components ? I ask because they are special and free 👍 thumbs up 👍

Made to be disposable, their probably not concerned for anyone reverse engineering these especially with packaging that's not designed to protect the insides, just keep it functioning in the extreme cold. Those packs are definitely for warming, the upper atmosphere can get so cold it will not only freeze batteries but it can freeze i/c's too. Looks to do the basic function of collecting data and sending it out and that's about it.

very interesting... I might start going deeper into this, perhaps building a few receivers and go fox hunting like in the old days!

At 15:58 upside down chip and all electrons falling out? huh?? #easylab4kids cracking up!! :P

Did it pump out any RF packets when you got a GPS lock?

"Isn't that sex on a stick." - LOL!!!!

Looks like "BRR" chip is "TPS6120x Low Input Voltage Synchronous Boost Converter", costs whole 1$

At 16:45 you mention the totem pole... I can't be sure, but maybe this is a receiver circuit. The sondes power themselves up when they are sat on their ground check devices. At a guess this is a coil that receives the initial initialization and processing signals before the transmitter is bought online later in the ground check sequence.

It's not a data out connector but it's the programming connector also used for calibration. Please do not create interference turning on Radiosondes near launch site.

Oh nice, Finnish stuff.

Should we be discussing that knife, Mr. Dundee?

Surprised at the high energy consumption. Emptying two primary AA lithium batteries in one flight seems a lot. I would have hoped an efficient design could have used less with a more energy hungry base station. For example a motorized directional tracking antenna to maximize SNR, gold code modulation (like in GPS L1 signals, these can be demodulated at extreme low signal levels), strong ECC to overcome noise (ECC decoding is the energy intense part, but again base station).

Finally I can go to my grave knowing what this module is I picked up at the local flea market, I recognized the RF components of the module, that's the reason I purchased it for a few penny's, but I could not find any information on it's function until this video.

I just wonder why they don't extend the plastic to protect the sensors as well, leaving some small holes for them

nice t-shirt, i was just busy with an opamp circuit yesterday

It uses the GPS signal for windfinding. Bet you didn't know that!

lol, i though the title was just clickbait, but i thought...'im ahhh clickin' it just cause its that crazy aussie guy. plus i like to see dave constantly balls it up with those envelope packages and get crap everywhere lol

Looking forward to the continuing videos on this subject....especially how to hack them to use on Ham Radio frequencies. 73 WB4RHA

Stmicro samples stuff like crazy lol, its basically like falling from the sky

RF people: if the "duffle winkle topology" is not a thing make it happen!!!

Poke around on the GPS chip see if you get anything out of it. Could be interesting :) Would it spit NMEA sentences out, or raw timing data?

OMG, your Rhohde & Schwarz is as big as mine!

Could you do a thorough review of the Micsig STO1104C? Battery life, etc.

Word of the day "platypus"

Love your letter opener😎.

I found one of those once. It landed in the parking lot of the hotel I was staying at.

Thanks for sharing😀👍

That would hurt...

Maybe it is a transponder. You need the signal from the base station to waken the sonde and send back the data.

What is doofereink topology?

Now if only they were shaped like an EPO glider and in the end of the voyage they would fly to the nearest radiosonde launch station, though... :D

Everyone and their dog knows a dupawinkle topology! Come on Dave, don't underestimate us!

Does anyone remember the meteorological sonds that had a couple of subminiture tubes? They had a plate battery that was soaked in water just before takeoff for activation.

There is PLL inside the STM32 chip, the chip can do 72MHz from this little 24MHz crystal.

Were they programmed to self-destruct, like the tape recorders in Mission Impossible, emitting 'magic smoke' ?

nice! i want one!...unfortunatly theres hardly ever going to be any falling from the sky around here...from the info ive seen the closest launches are from Williamstown..would be very lucky to get one travel north north-east from there i think!...may have some chance of getting one the from the east, Lord Howe Island...if it makes it across 600kms of ocean! LOL..but no car to go hunt it down...so ill probably never see one :(

Michael and I did a conference presentation on how we track and recover these, which is available here: kzfaq.info/get/bejne/j6ipYMWJqr2-lYE.html

The water keeps the RH sensor damp. RH is figured by the difference between a wet bulb thermometer and a dry bulb.

How much do these things cost ? How much would it cost if someone were to make a replica of these, the parts value ? Possibly PCM, phase change material instead of water ? If it were me I'd heat up the water/PCM and the batteries.

Looking a little sun burned Dave!

What the heck are "Eclipse" batteries? ;-)

I'm curious to know how much these things cost, especially since they are only used once.

The letter opener.... XD

When I first saw it I thought that thermometer was a hot wire anemometer. Then again there's not really much point to one of those as any wind would just blow the whole device around.

Bit sunburnt ?