Technical Page

Pico Balloon, AA6DY launched on September 3rd 2022, has already gone around the world three times. While tracking this balloon, we found that we don’t always receive the necessary information to accurately track location, altitude and speed. Below is an explanation from Michael Seedman, AA6DY, on what we need to track our balloons.

Our tracker sends out one message on the 2’s (02, 12, 22, 32, 42, 52 after the hour), and one on the 4’s. Any ham station that hears our signal will post the message to a database over the internet. We need both pieces of the message to accurately locate the balloon. If we just receive the message sent on the 2’s (first packet), we can estimate our balloon’s location somewhere within a 7,000 square mile grid, and an altitude within 1,200 meters. If we also receive the message sent on the 4’s, we can locate our balloon to a 15 square mile grid and an altitude within 320 feet. The first message has a ham call included in the packet, but to save space in the packet, the second only has a hint of its sender.

The second packet is received as a code that is programmed in the tracker. It starts with a “Q”, “0” or “1” and a number from 0-9. That gives us a possibility of 30 different channels to set up our tracker.

AA6DY is programmed as Qx7xx. The Q and 7 are programmed by us, the last two digits provide the end of a 6 Grid Maidenhead. We enter it as Q_7% telling the program we’re looking for all Q’s, with a 7 as the 3rd digit.

Pico Balloon K9YO launched on October 10th 2022, has made it around the world three times and is being tracked on the 8’s and 0’s. K9YO is coded as 0x7xx and entered as 0_7%

We locate our balloons using primarily two programs; http://wspr.rocks/ and WSPR Spots

In “WSPR Spots” we enter the callsign of the balloon we’re following to receive 1st packet information.

In “WSPR Rocks” we enter the Tx call as Q_7% for AA6DY and 0_7% for K9YO to receive 2nd packet information. Every balloon we launch will have a different code and time slot.

To be able to track our balloons on APRS, we add a – and a number, AA6DY-15 K9YO-15 This extension is referred to as an SSID and also used to track other Pico Balloons around the world on Sondehub Amateur

Calculating the Altitude

WSPR Spots provides the altitude in both dBm and Watts (shown as Power), WSPR Rocks is shown in Watts (shown as W). The formula used to calculate the altitude in watts to convert to dBm is 10log(Watts/.001) Adding the data from (WSPR Spots + WSPR Rocks) will provide the accurate or true altitude.

Code of Federal Regulations 14 CFR Part 101

This is the section of the Code of Federal Regulations that allows us to fly Amateur Radio Pico Balloons 14 CFR Part 101.

Finding the Right Balloons, the right Gas

All of our balloons are advertised as a party balloon, so if you’re planning a big party or a wedding, we have a dual purpose balloon. We first wanted to make our own balloons but with an upcoming launch in September of 2021, we settled on the Qualatex 36″ party balloon which we used up until our December 2021 launch. We found that our early launches never flew more than a day. At the time we didn’t know if the balloon was leaking gas, have a sealing issue or if it was the balloon. What we discovered after filling it to burst in a test, that these balloons although work very well at ground level for lively parties, didn’t work for our Pico Project. We found that these balloons would reach altitude, then steadily lose altitude.

We were in a big learning curve from the start, what we didn’t know at the time was that there’s a science to calculating the gas fill based on size of the balloon.

Before we get too far into what works and what hasn’t, I’d like to recognize the Pico Balloon io group where we receive support on anything you want to know about our hobbly, I would recommend joining https://groups.io/g/picoballoon

The key to all of these balloons is they perform better if they’re pe strectched, and there’s a science to that as well, another reason to join the io group.

It was through the io group that we found the 36″ Chinese made balloon. That’s the best way we can describe this, it’s made in China, and it’s a couple of bucks, available in groups of 10 at a discount. 36″ clear party balloon, Aliexpress Party World Store 10 lot It takes a while to receive these so plan ahead.

The 36″ Chinese made balloon is round and flatter, we call it a pillow or pancake style. We flew this balloon for many long flights, it only needs to be heat sealed to secure. The issue is that we were limited in altitude to 32,000 feet. The balloon has stamina, we flew it on December 22nd for 19 days, spending 8 days touring the Marshall Islands.

To get to that magic altitude of 47,000 feet, we needed a round also known as a sphere balloon. We became aware of two different manufactured 32″ sphere’s and bought them both.

We found that our balloons will lose about 1/2 gram of gas overnight and each day before launch, so it’s critcal on the proper gas fill, and not to delay the launch.

The SAG Balloon, manufacturer is SAG, available at BalloonsOnline for around $16. If you buy 10, shipping is free, at least here in the U.S. Balloons Online 32″ Sphere

The Yokohama is $130 for 10, but they charge $100 for freight Yokohama 32″ Transparent Sphere

Both the SAG and the Yokohama are bargains for what we’re able to acheive.

We started using Helium gas in the beginning of our program and found the gas to be reliable but very expensive. We switched to Hydrogen starting in December of 2021.

Our current package of tracker, solar panels and dipole antenna weigh 9.2 grams we add about 8 grams of additional gas before sealing the balloon.

This is our tracker and 7 solar panel package with Dipole Antenna, secured to a cardboard flap for transport to launch site

This is our Low Sun-High Power Solar Panel and Tracker used on for Pico Balloon KD9UQB launched from Neumayer Station III, Antartica, November 24th 2022.