Rancho Seco Nuclear Power Plant.

The Sonde started out in Oakland and made steady progress until the balloon burst around 32,000 km, then it made an usual rapid descent into a country neighborhood known as Saddle Creek in a small town called Galt. It seems from the landing site that the parachute only partially deployed explaining the rapid descent. The parachute was not fully deployed because remnants of the balloon entangled the lines below the chute.

Sonde Path from Oakland to Galt.

Elevation Profile.

The output of r00ts RRS decoder software is shown below. This is a combination of data received from the home station and the mobile station. While in route to landing area, r00t informed me that the home system lost the signal. So I pulled over and pointed the 8 turn helical antenna to re-acquire the signal. This gave us some additional data points for r00t to know which neighborhood the landing will occur. The sonde landed while I was still 14 miles out from area.

Final Landing Location.

As you can see from the image below, as I entered the neighborhood (i have tracker so r00t can see my location) it was pretty easy to re-acquire the signal and get the exact location of the Sonde. It landed in someones backyard and I could see it from along the fence line. I found a neighbor that contacted the properly owner and obtained permission to enter the area and retrieve the Sonde.

Sonde Landing Location.

The recovered Sonde was in pretty good shape but did have a impact area on bottom due to rapid descent speed.

Recovered Sonde.

Hard Landing.

Here is short video about home receiving station, mobile setup and the recovery of this particular Sonde.

The switch is made of 4 independent relays that must be wired for proper group operation. The relays are controlled by a small embedded processor with a USB interface.

USB-4SPDT-A18 configured as SP5T (except for one missing jumper).

Since the relays have SMA connectors it is necessary to jumper to some additional SMA to N Female bulkhead adaptors for proper stress relief and cable management.

5 inputs and 1 output.

Bank od sma to N female bulkheads and grounding block.

The final placement, just before wiring. Note the station ground block, this will connect all receivers to station ground system (located near the coax entry area in another room).

Freshly installed microwave switch along with station grounding block.

Here is screenshot of the software I am using to control the relays. I plan to use an included DLL to customize a GUI for my own use.

The sample software from mini-circuits for relay control.

The Sonde was received on L-Band (1682 MHz) using a 1.2m dish and tracked using r00t’s RRS Sonde Decoding software (shown below).

Last received position data from Sonde#4 before going to retrieve.

Here is the recovered Sonde.

Sonde#4.

As you can see it had bit of a hard landing.

Sonde#4 showing an impact hit on landing.

Launch location, date and time.

Here is nice 3D position track of Sonde from point of first signal acquisition to the last received position before going mobile to retrieve. The position near Elk Grove is landing area.

3D plot of position data from Sonde#4.

The elevation profile is shown below, as you can see it was a quick and steep descent.

Elevation profile of Sonde#4 up until last signal was received.

As you can see from image below, r00t’s predicted landing spot was pretty close to the actual one. This was critical because once the Sonde lands the signal is attenuated quite a bit. I picked up the signal about 1.5 miles from actual landing position and luckily it was very close to a road in between fields.

Last, Predicted and Actual Landing Position of Sonde#4.

Ruggedized sonde setup.

ICOM IC-R8500 and SDR-IQ.

SDR-IQ is perfect SDR for mobile sonde hunting.

Although the batteries shown below are not exclusively for Sonde hunting, they will be used for that purpose.

Gel Batteries in Parallel

Click on the image below for more details.

The little CNC.

Click the image below for more details.

C-Band Downconverter in equipment box.

Photo by US Navy of the E-6B on ramp.

Shown below is a very strong PSK signal that I have confirmed on numerous occasions is emanating from the E-6B.

PSK Signal from E-6B.

The E-6B uses the callsign GOTO FMS on Mode-S with full position data (so it can be tracked).

Mode-S ICAO ID and Callsign.

POR 263.6250 on 02-16-13:

POR 263.6250 on 02-17-13:

Photo by afrc.af.mil. C-17 offloading in Antarctica.

I have ruggedized everything as a result of some bad weather last year. Lots of rain caused some damage to some of the equipment as a result of the moisture. The setup uses two 12V Gel batteries (in parallel), a Yaesu FT-8800 2m/70cm FM Radio, a Kantronics 9612 Plus TNC, a Stealth DC Computer and an Astron SRM-30M Switching Power Supply. Many of the components were made rack mountable using custom cut outs using a CNC.

A friend of mine helped out by creating the mounting system you see for the batteries below.

Mobile WinLink 2000 System.

Gel Batteries in Parallel

Batteries in OD Pelican Case.

However, Dragon has been transmitting on UHF (400.5 MHz) sending telemetry using it’s COTS UHF Communication Unit (CUCU) continuously. This seems to be a very low power transmitter, likely using an omni-directional antenna, perhaps just for Dragon/ISS command/control.

Below is a screenshot of this signal.

UHF Telemetry from Dragon.