WA Radio Scanner Users' Group

Anybody tracking weather balloons? Apparently it's easy to do if you know the frequency they use (somewhere around 403 MHz). From what I can find out, they launch at 7am and 7pm locally from YPPH.
There's a demo on youtube of a guy tracking one in NZ with ordinary radio gear and PC software. I couldn't see or hear any signal like that over the last two days (watching 399 - 406 MHz)

Try 401.5MHz. That is a frequency assigned to the Met Bureau for FM data transmissions. Info below is from the ACMA register

137408-102801 401.5000000 MHz 350KF1D Met Bureau Site Airport PERTH (49793)

Very interesting. 401.5MHz is the frequency. I listened at 7pm for a while and nothing heard. I went back at 8pm and heard the radiosonde. In fact it was still just audible at 8:38pm when I stopped.

Next, just for fun will be trying to decode it to see if I can. I installed the software to decode it but never managed to today, but running the youtube video of receiving the radiosonde I was able to get some data streams appear in the software. I think perhaps I might be just too far away and need a stronger signal. Maybe take the laptop mobile closer to the airport one day before the software trial runs out.

401.5 is where I was watching for the most part (SDRSharp). I think the problem is I was expecting to see the same signal as in the video. I spotted something else there I thought was just an artefact but probably was the radiosonde. It's 8.20am now and is there again faintly. The signal is quite wide, maybe 80k and looks like a tyre track on the waterfall. The frequency also wanders quite a bit which could explain the 350k emission designator. Using a low angle antenna for 70cm isn't helping though. This calls for a plain 1/4 wave. What antenna did you use Monday night?

Edit. Didn't notice this before "This licence authorises the use of 400.5 MHz or 402.5 MHz as an alternative in the event of a failed launch on 401.5 MHz"

I took a video of my screen and received audio. http://vimeo.com/57429578, it's not a great video.

The radiosonde in the video you mentioned was a digital radiosonde where the analog ones appear to be used here. So the signal is a musical tone of 6 tones not the raspy sound of digital. It is also as you said a WFM signal. I could not hear much of anything in normal narrow FM mode. A better video of what the audio sounds like is this one from Brisbane http://youtu.be/lboBEToLLhE

My antenna was a Diamond X-300, 5.5 metres above ground.

Will have to do a bit of reading up on it but as you will hopefully see in the video, the graphs come up ok but they have no figures assigned so unless there is some form of values that can be assigned you don't know what each is indicating so basically useless information. Being analog, I don't think there is any GPS info so no maps or tracking.

Early days yet and will have to read up a bit more but at this stage I don't think I would continue after the 21 day trial of the software is over.

I haven't tried to decode what I heard but it certainly sounds the same as in your video and the Brisbane one once he got the frequency right.
Trying again in about 70 minutes with FT-7800

robbage wrote: Trying again in about 70 minutes with FT-7800

Does that do wide FM?

I don't know if the 9600 port is wide enough but it's decoding something right now (since about 11.25 UTC) Lots of pretty coloured lines. No scale.
It's showing values on the Data screen.
I'm listening to the 9600 port and it doesn't sound anything like the radio speaker. Lots of very high pitched tones.

It stopped decoding around 12:20 when the audio started cracking up and lost audio tones completely around 12:35
The data doesn't seem to be useful to the user of the application. There's no lat/long or altitude either (maybe that's only digital)

Same conclusion I came to. Unless there is some way to add a scaling to the coloured lines they don't tell you much. Well I concluded the humidity was fairly stable not moving too much as that line on the graph was fairly straight. Lat/Long is only available on digital transmissions from what I can gather.

There must be thousands of these payloads and remnants of balloons out there somewhere. Almost like sanctioned littering. They must be cheap.

It's something I can say yeah I have done that, but as you say pretty useless without the relevant info, just a colourful graph and on the raw data screen lots of numbers.

Will do some goggle reading to see if anything can be found but I think after the 21 day trial it will be uninstalled if not before.

By the way 9pm and it's still going strong. Can still hear the musical tones clearly.

Blinky wrote:There must be thousands of these payloads and remnants of balloons out there somewhere. Almost like sanctioned littering. They must be cheap.

Check this out. "... each flight would cost less than $100 including the technical equipment and staff time." I can't see how it could be that cheap. I read somewhere else there is a bounty on recovered units. I wonder what condition they are after the balloon burst.
I was hoping for position reports from these things at least. Oh well.

I would imagine there would be a please return if found message on the radiosonde, but then again they are probably just classified as disposable items. I would have expected more than $100 myself, as you say including wages, the balloon and hydrogen. Using the $100 as the base, that would be $2.92 million per year total for all sites. I suppose in this day and age you can understand wanting to save $1.4 million from their budget by one launch per day. Can't have kicked in yet, still 2 per day here.

I dare say the analogs are cheaper (no GPS) and probably from a country up north and cost cents to produce.

I found some pictures of a radiosonde, but the variety with GPS. Would you believe you can buy off ebay for $11, brand new sealed in the packet. http://tinyurl.com/cojr69z

We used to find them on my sisters farm at Beverley quite often during the 80's, mostly not in good order but occasionally we'd find one in fairly good nick. The "electronic" bits and pieces usually held together but as expected the balloons and lightweight foil fins never fared the landing well

I'm pretty sure everything is disposable with no rewards offered

For what it's worth, monitoring the local balloons works a lot better with a decent receiver.


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