GCARC Ballooning Adventure
Balloon Tracking Websites
GCARC Ballooning Adventure
Balloon Launch (2 Balloons)
Sunday, September 15, 2024 @ 1000 Hours
Weather Permitting
W2MMD Clubhouse
Click this link for more information
Balloon Launch : Sunday, September 15, 2024
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Successful launch of the SBS balloon with the ZachTek radio! It's now heading west and sending telemetry on 20 meters. It's W2MMD/1 and telemetry will start coming thru on Sondehub. We've got the ORBS balloon inflated and will connect the Traquito radio and launch it next. We're currently waiting for telemetry and gonna check Windy to see where it will go.
Balloon Launch : Saturday, August 24, 2024
Balloon Launch Update - Friday, August 23, 2024
Once again we're going to make an attempt to launch a balloon tomorrow morning, probably between about 11:00 AM and noon. Here's a quick summary of launches to date:
Flight 1: A Mylar party balloon that was unintentionally overinflated and vented at the bottom to allow gas to escape, carrying a Traquito transmitter and powered by a LiPo battery. Our goal for this flight was to understand the telemetry and launch process, and we expected this balloon to burst before reaching altitude. Result: The balloon rose to about 21,000 feet and then slowly descended, landing in the Atlantic Ocean slightly into international waters.
Flight 2: Similar to Flight 1 except that the balloon was carefully filled to give 7 grams of lift and sealed at the bottom. As before we didn't expect this balloon to survive but again wanted to test the telemetry tracking and launch process and find out what would cause the initial failure. Result: The balloon reached an altitude of about 29,000 feet before the LiPo battery froze and telemetry ceased. Several hours later telemetry resumed and showed the balloon on the ground in eastern Delaware.
Flight 3: An ORBS mylar balloon of a type that has been shown to successfully reach equilibrium in the upper atmosphere and circumnavigate the earth, carrying a Traquito transmitter and two 5 volt solar cells. It was carefully filled with helium to create 5 grams of lift. Result: The balloon cleared the trees on ascent, validating that 5 grams of lift is enough to get it rising. We never received telemetry from the transmitter, however, probably due to the misplacement of the solar cells.
Tomorrow's flight will be an ORBS balloon filled to create 5 grams of lift carrying a ZachTek tracker on which are mounted two 5V cells connected in parallel. The ZachTek also has diodes to prevent one solar cell's current from flowing into the other cell when unevenly lighted and also has two 1 farad supercapacitors to maintain voltage for a short period when the sun dims.
The goal for this flight will be to reach equilibrium at altitude (probably around 40,000 feet) and follow the wind currents for a long period, hopefully measured in weeks or months. Since the telemetry is powered by solar cells, and not by batteries as on the previous flights, we may not get telemetry data until the balloon has reached an altitude above any clouds and the sun angle on the cells is high enough to illuminate them brightly. Currently the prevailing winds at altitude are flowing toward the northeast so we'd expect the balloon to follow a path up the Atlantic coast north of Nova Scotia and then turn northeast, sweeping to the southeast and then ending up over England or France and hopefully continuing from there.
Once we've received telemetry we'll publish the links so that others can track. Hopefully this will be an interesting event for club members.
73 de Jon WB2MNF with Doug KD2VQA and Mike KG4JYA
Once again we're going to make an attempt to launch a balloon tomorrow morning, probably between about 11:00 AM and noon. Here's a quick summary of launches to date:
Flight 1: A Mylar party balloon that was unintentionally overinflated and vented at the bottom to allow gas to escape, carrying a Traquito transmitter and powered by a LiPo battery. Our goal for this flight was to understand the telemetry and launch process, and we expected this balloon to burst before reaching altitude. Result: The balloon rose to about 21,000 feet and then slowly descended, landing in the Atlantic Ocean slightly into international waters.
Flight 2: Similar to Flight 1 except that the balloon was carefully filled to give 7 grams of lift and sealed at the bottom. As before we didn't expect this balloon to survive but again wanted to test the telemetry tracking and launch process and find out what would cause the initial failure. Result: The balloon reached an altitude of about 29,000 feet before the LiPo battery froze and telemetry ceased. Several hours later telemetry resumed and showed the balloon on the ground in eastern Delaware.
Flight 3: An ORBS mylar balloon of a type that has been shown to successfully reach equilibrium in the upper atmosphere and circumnavigate the earth, carrying a Traquito transmitter and two 5 volt solar cells. It was carefully filled with helium to create 5 grams of lift. Result: The balloon cleared the trees on ascent, validating that 5 grams of lift is enough to get it rising. We never received telemetry from the transmitter, however, probably due to the misplacement of the solar cells.
Tomorrow's flight will be an ORBS balloon filled to create 5 grams of lift carrying a ZachTek tracker on which are mounted two 5V cells connected in parallel. The ZachTek also has diodes to prevent one solar cell's current from flowing into the other cell when unevenly lighted and also has two 1 farad supercapacitors to maintain voltage for a short period when the sun dims.
The goal for this flight will be to reach equilibrium at altitude (probably around 40,000 feet) and follow the wind currents for a long period, hopefully measured in weeks or months. Since the telemetry is powered by solar cells, and not by batteries as on the previous flights, we may not get telemetry data until the balloon has reached an altitude above any clouds and the sun angle on the cells is high enough to illuminate them brightly. Currently the prevailing winds at altitude are flowing toward the northeast so we'd expect the balloon to follow a path up the Atlantic coast north of Nova Scotia and then turn northeast, sweeping to the southeast and then ending up over England or France and hopefully continuing from there.
Once we've received telemetry we'll publish the links so that others can track. Hopefully this will be an interesting event for club members.
73 de Jon WB2MNF with Doug KD2VQA and Mike KG4JYA
Second Test Balloon Launch - Saturday, July 27, 2024
By Jon Pearce, WB2MNF
The Clubhouse was closed for general use today but Doug, Mike and I got there before 8 to set up another radio-carrying balloon test. Our objective this time was to use a sealed balloon (as opposed to the vented balloon in the last test) and to see how high it would go before failure. Failure could occur in one of three main ways :
We set up the balloon in the same way as last week's except that we sealed the inflation port with its own sealer and then wrapped in Kapton tape. We then took it outside and had a very successful launch, watching on a clear, virtually windless day as it disappeared into the sky to the southwest.
But back inside we heard no telemetry, which is broadcast every 10 minutes. It missed the 9:22, 9:32, 9:42 and 9:52 transmissions at which point we concluded that the battery had come unsoldered and the radio had quit. As we were castigating ourselves for not ground-testing the radios before launch when we suddenly received a WSPR signal at 10:02 followed shortly by a telemetry signal showing that the balloon had reached 13,780 feet and was moving south at about 45 mph. Recriminations ceased and we began tracking its course and watching the telemetry.
The balloon rose steadily for the next two hours, reaching a maximum altitude of 27,625 feet, far higher than last week. During that ascent we watched the reported temperature drop from 41 degrees F to 1.4 degrees F and the battery voltage dropped from 3.2 volts to 3.05 volts. After that telemetry ceased. We concluded that the battery had frozen as expected and that we might never hear from the balloon again unless we were fortunate enough to catch a transmission as it ultimately descended.
An hour later, though, another transmission appeared on the WSPRnet site that was picked up by two stations followed ten minutes later by a single reception from a station in Maryland. No telemetry accompanies those receptions (it takes two WSPR packets to send the identification and telemetry data) so we didn't know its altitude or location, but we did know that the battery had un-frozen sufficiently to allow transmission so it was much lower than previously.
Finally two hours later we received a single decoded telemetry transmission showing that the balloon was on the ground in grid square FM29ef, which centers between Smyrna and Dover Delaware. It's on the ground or suspended somewhere down there. Unfortunately a 6-digit gridsquare is too broad for a search to be practical so we'll never see that balloon again (not that we expected to recover it anyway). Over the past few hours it has transmitted several times with the battery voltage again dropping to about 3 volts. It may continue to transmit occasionally until the battery runs out.
We've tried to estimate how high the balloon rose after the battery froze, and it's possible that it made it into the mid-30,000 foot altitudes with about 39,000 feet being proclaimed as the highest altitude generally attained by these types of balloons when filled with helium (hydrogen-filled balloons go a little higher). Our tracking was successful although we did learn the lesson of patience after declaring failure and then seeing the ultimate telemetry showing success.
The next balloon launch attempt will be next Saturday August 3, planned for noon weather and other factors permitting. We'll be launching one of the super-pressure balloons that we don't expect to burst along with the ZachTek tracker powered by two 5 volt solar cells. Come on out to the Clubhouse if you'd like to watch. If all goes well we'll email tracking information in case you'd like to check the status of this balloon yourself. And hopefully we'll have some good news to present at the General Membership Meeting on August 7.
73 de Jon WB2MNF with Mike KG4JYA and Doug KD2VQA
By Jon Pearce, WB2MNF
The Clubhouse was closed for general use today but Doug, Mike and I got there before 8 to set up another radio-carrying balloon test. Our objective this time was to use a sealed balloon (as opposed to the vented balloon in the last test) and to see how high it would go before failure. Failure could occur in one of three main ways :
- The Mylar® party balloon would definitely burst at some point since they're not strong enough to handle the pressure differential at high altitude
- The battery (which we're using for these tests because it's cheaper than solar cells and will give a consistent voltage to the telemetry radio) will run down, or
- The battery will freeze and stop working.
We set up the balloon in the same way as last week's except that we sealed the inflation port with its own sealer and then wrapped in Kapton tape. We then took it outside and had a very successful launch, watching on a clear, virtually windless day as it disappeared into the sky to the southwest.
But back inside we heard no telemetry, which is broadcast every 10 minutes. It missed the 9:22, 9:32, 9:42 and 9:52 transmissions at which point we concluded that the battery had come unsoldered and the radio had quit. As we were castigating ourselves for not ground-testing the radios before launch when we suddenly received a WSPR signal at 10:02 followed shortly by a telemetry signal showing that the balloon had reached 13,780 feet and was moving south at about 45 mph. Recriminations ceased and we began tracking its course and watching the telemetry.
The balloon rose steadily for the next two hours, reaching a maximum altitude of 27,625 feet, far higher than last week. During that ascent we watched the reported temperature drop from 41 degrees F to 1.4 degrees F and the battery voltage dropped from 3.2 volts to 3.05 volts. After that telemetry ceased. We concluded that the battery had frozen as expected and that we might never hear from the balloon again unless we were fortunate enough to catch a transmission as it ultimately descended.
An hour later, though, another transmission appeared on the WSPRnet site that was picked up by two stations followed ten minutes later by a single reception from a station in Maryland. No telemetry accompanies those receptions (it takes two WSPR packets to send the identification and telemetry data) so we didn't know its altitude or location, but we did know that the battery had un-frozen sufficiently to allow transmission so it was much lower than previously.
Finally two hours later we received a single decoded telemetry transmission showing that the balloon was on the ground in grid square FM29ef, which centers between Smyrna and Dover Delaware. It's on the ground or suspended somewhere down there. Unfortunately a 6-digit gridsquare is too broad for a search to be practical so we'll never see that balloon again (not that we expected to recover it anyway). Over the past few hours it has transmitted several times with the battery voltage again dropping to about 3 volts. It may continue to transmit occasionally until the battery runs out.
We've tried to estimate how high the balloon rose after the battery froze, and it's possible that it made it into the mid-30,000 foot altitudes with about 39,000 feet being proclaimed as the highest altitude generally attained by these types of balloons when filled with helium (hydrogen-filled balloons go a little higher). Our tracking was successful although we did learn the lesson of patience after declaring failure and then seeing the ultimate telemetry showing success.
The next balloon launch attempt will be next Saturday August 3, planned for noon weather and other factors permitting. We'll be launching one of the super-pressure balloons that we don't expect to burst along with the ZachTek tracker powered by two 5 volt solar cells. Come on out to the Clubhouse if you'd like to watch. If all goes well we'll email tracking information in case you'd like to check the status of this balloon yourself. And hopefully we'll have some good news to present at the General Membership Meeting on August 7.
73 de Jon WB2MNF with Mike KG4JYA and Doug KD2VQA
The First Balloon Flight!
By Jon Pearce, WB2MNF
We finally flew our first BCAR (Balloon Carrying Amateur Radio)! Here’s how that happened.
Background
As most readers know, we were approached several months ago to develop a STEM (Science, Technology, Engineering, Mathematics) program for the Woodruff Middle School in Cumberland County. After discussions with the staff we proposed a project involving launching high-altitude balloons carrying Amateur Radio as a core topic from which many others could be derived. Once committed to that concept, though, the Club team determined that we needed to launch one or more balloons in advance of the beginning of the school project to develop the skills and experience needed for successful launches. We acquired many of the items needed, built a team, set up an active Discord discussion group and did lots of research. Now we were ready for the first launch.
First Flight Objective
Although our overall objective is to build a balloon that will circumnavigate the earth we decided to take an incremental approach by setting more modest goals along the way that would allow us to use less costly materials. By substituting Mylar® party balloons for the more durable super-pressure balloons and using batteries instead of solar panels we saved significant cost, but also knew that there was no chance for a long duration flight. A shorter flight would still allow us to test many of the balloons and radio preparation steps, check out the telemetry and have some initial success. After some discussion we set a modest goal of declaring success if we could monitor the balloon up to an altitude of 10,000 feet.
Approach
The SBS balloons that we obtained for the actual launches are quite durable but also quite costly, so Doug Dersch KD2VQA picked up a few 36 inch Mylar® balloons for a few dollars that we decided to try. When completely filled with helium these balloons generated almost 150 grams of lift, so since our payload was slightly more than 50 grams we attempted to partially fill the balloon to create this much lift and no more.
Partially inflating the balloon would allow some expansion as the balloon reached thinner air, but we also tried another approach to lessen the chance of the balloon bursting as the pressure in the balloon exceeded that of the ambient air surrounding it. In the inflation port of the balloon we inserted a soda straw holding a small piece of a cotton mop found in the Clubhouse. We reasoned that this would allow some gas to escape from the balloon and thus would lessen its chance the bursting. (In actuality that approach may have hastened its demise, as described later.)
Several months ago we purchased two balloon tracking units from ZachTek (https://www.zachtek.com), which were described in previous CrossTalk articles. While we still expect to use these for actual flights, we also identified a lower cost alternative that utilizes a Raspberry Pi Pico combined with an add-on board containing a GPS receiver, power converter and 20 meter transmitter that together cost about $11. Mike Thompson KG4JYA figured out how to configure these devices by selecting a “channel” that defines the transmit frequency, timing, and several parameters in a spoofed call sign that allow specific identification of the WSPR packets since these devices send data that doesn’t conform to the WSPR protocol.
We decided to use a battery instead of solar cells for this launch, partly to save cost and partly because we haven’t yet decided how to fasten solar cells to this radio. An additional benefit to using batteries is that they provide a constant source of power for the radio telemetry units, meaning that we would get a telemetry update every 10 minutes. Solar cells only provide power in direct sunlight, so we might miss getting telemetry in the early stages of the launch if the balloon passed through a cloud and solar cells weren’t brightly lit. We used a 2200 mAh LiPo battery to power the radio after doing some testing with that 1100 mAh battery and finding that the smaller battery would power the radio for about 24 hours. Having no idea how long this flight would last we decided to use the stronger yet heavier battery, which wound up being far larger than necessary for the three hour flight. In the future we'll use a smaller battery and save some weight.
The remaining components were the wire for the vertical 20m dipole (we used the mil-spec Teflon-coated silver wire that was donated by a Club member), some Kevlar cord for strain relief, a soda straw and some Kapton tape. We taped the transmitter and the battery to the soda straw along with the antenna wire for strain relief on the solder joints to the transmitter and ran the Kevlar cord lengthwise through the straw to connect to the balloon. The antenna was wound around a wooden 1x2 with the Kevlar cord protruding from the soda straw for safekeeping during assembly. The Kevlar cord and one end of the dipole antenna are attached to the balloon with the Kaptan tape while the other end of the dipole hangs free below the transmitter.
Filling the balloon with the proper amount of helium is somewhat challenging. The goal is to add enough helium to lift the weight of the payload plus an additional amount based on other experimenters’ recommendations that we established at 8 grams. Since the weight of the payload (radio, battery, antenna, and other components) was 52 grams we decided to inflate the balloon to have 60 grams of lift. This is done by connecting a 100 gram weight to the bottom of the balloon, placing the weight on the gram scale, and inflating the balloon until the scale shows 40 grams. This is easier said than done.
The balloon needed to be filled through the soda straw which was pressed up against the inflater on the helium tank that itself needed to be bent to release the helium. This worked pretty well, but Doug inadvertently over-inflated the balloon passed the lift point that we had identified. Since we were concerned about the balloon clearing the trees at launch we decided to leave the extra helium in the balloon. After inflation we taped the top of the Kevlar cord and the antenna to the balloon with the Kapton tape and were almost ready to go.
At that point we went outside and got ready for final testing and launch. Doug had brought a fishing pole with a long length of monofilament line that he looped over a knot in the Kevlar line, keeping one end of the monofilament on the fishing reel and holding the other end in his hand. That allowed him to play out the line and see how the balloon responded to the wind, but also to reel it back in. That approach proved very helpful in precisely launching the balloon at a point when the winds were favorable. Doug unspooled the monofilament to allow the balloon to rise enough to extend the top half of the antenna for transmitter testing while Angela Metzger KE2DRJ held the bottom of the payload to keep it from moving around too much in the wind.
Checking The Radio
Before launching the balloon we needed to make sure the radio was transmitting properly. The radio puts out a WSPR signal on 20 meters (14.0971 MHz), so Mike tuned in that signal on the Flex radio in the HF room and verified that it was transmitting properly. In fact our WSPR transmissions, with half of the 20 meter dipole on the ground, were still picked up worldwide! Such is a testament to the robustness of WSPR.
The Launch!
At that point we were ready to go. A moderate-sized crowd of Club members and kids had gathered over by the Clubhouse to watch the launch. Unfortunately the wind had picked up slightly at that point and was swinging in different directions, so we held onto the balloon until it was favorable to the north, which was our furthest distance from the trees. At that point Doug asked the critical question “Clear to launch?” and in my best Gene Krantz imitation I shouted “Launch approved!”. Doug released the monofilament line and the balloon soared almost vertically and slightly to the north. We watched for several minutes until it disappeared into the clouds and then headed into the Clubhouse to track the telemetry.
Tracking The Balloon
Inside the Clubhouse, Mike was already tracking the balloon on several websites that could show various aspects of its progress. The WSPRnet site shows stations that have received WSPR transmissions from the balloon transmitter, so we could tell that the transmitter was being heard by many stations hundreds of miles away. That site didn't tell us where the balloon was so we primarily use the SondeHub website, which receives data from WSPRnet and was populated by a program that Mike wrote that transferred that data to SondeHub. We also use the Traquito site that showed graphical telemetry information. WSPR updates occurred about every 10 minutes, with an initial identification packet being followed by the telemetry packet, so we waited eagerly for those 10 minute updates.
At first the balloon headed north almost directly towards Philadelphia International Airport but quickly turned northeast on a path that had followed through most of its journey. It slowly ascended reaching 10,000 feet after about 1/2 hour, meeting our first success criterion. As it rose we continue to monitor the temperature, concerned that if it dropped below freezing the battery would cease to function. Although the temperature dropped to the mid 40s it remained above freezing so battery function was never a concern.
The balloon continued to move northeast at about 45 mph and rising slowly until it reached almost 23,000 feet several miles east of Medford NJ. It then began to slowly descend at about the same rate that it had risen. Having far exceeded our initial goal of reaching 10,000 feet we recalibrated that goal to hope that the balloon would reach international waters before finally hitting the ocean, which we were pleased to see occurring on the balloon’s final transmission.
When about 7 minutes passed with no WSPR updates we declared the mission over, but also successful. The intrepid Clubhouse team that had been hanging around for about 3 hours finally relaxed.
What Happened To The Balloon?
If we were SpaceX we would have had multiple sources of telemetry they could have identified the exact causes of the ultimate failure of the balloon. In particular, knowing the internal pressure of the balloon would tell us why it had descended, but here's our best guess. Since the balloon was vented at the bottom with the soda straw to allow pressure to escape and avoid bursting we're guessing that too much gas escaped at 22,000 feet. Without sufficient gas to continue to maintain altitude the balloon slowly descended over about 1/2 hour period. We don't believe that the balloon burst because the descent would have been faster. And noting that we had initially over inflated the balloon the excess internal pressure of the balloon occurred at a lower altitude than if we had properly inflated it.
What’s Next?
If we're correct in our assumptions there's another logical test to try, which is sealing the bottom of the balloon and seeing how high it will go before it bursts. We're going to try that sometime over the week of July 29th and may have some additional information at that point. Regardless of that outcome we plan to launch the SBS balloon on August 3rd and with the goal of achieving a successful circumnavigation of the earth.
By Jon Pearce, WB2MNF
We finally flew our first BCAR (Balloon Carrying Amateur Radio)! Here’s how that happened.
Background
As most readers know, we were approached several months ago to develop a STEM (Science, Technology, Engineering, Mathematics) program for the Woodruff Middle School in Cumberland County. After discussions with the staff we proposed a project involving launching high-altitude balloons carrying Amateur Radio as a core topic from which many others could be derived. Once committed to that concept, though, the Club team determined that we needed to launch one or more balloons in advance of the beginning of the school project to develop the skills and experience needed for successful launches. We acquired many of the items needed, built a team, set up an active Discord discussion group and did lots of research. Now we were ready for the first launch.
First Flight Objective
Although our overall objective is to build a balloon that will circumnavigate the earth we decided to take an incremental approach by setting more modest goals along the way that would allow us to use less costly materials. By substituting Mylar® party balloons for the more durable super-pressure balloons and using batteries instead of solar panels we saved significant cost, but also knew that there was no chance for a long duration flight. A shorter flight would still allow us to test many of the balloons and radio preparation steps, check out the telemetry and have some initial success. After some discussion we set a modest goal of declaring success if we could monitor the balloon up to an altitude of 10,000 feet.
Approach
The SBS balloons that we obtained for the actual launches are quite durable but also quite costly, so Doug Dersch KD2VQA picked up a few 36 inch Mylar® balloons for a few dollars that we decided to try. When completely filled with helium these balloons generated almost 150 grams of lift, so since our payload was slightly more than 50 grams we attempted to partially fill the balloon to create this much lift and no more.
Partially inflating the balloon would allow some expansion as the balloon reached thinner air, but we also tried another approach to lessen the chance of the balloon bursting as the pressure in the balloon exceeded that of the ambient air surrounding it. In the inflation port of the balloon we inserted a soda straw holding a small piece of a cotton mop found in the Clubhouse. We reasoned that this would allow some gas to escape from the balloon and thus would lessen its chance the bursting. (In actuality that approach may have hastened its demise, as described later.)
Several months ago we purchased two balloon tracking units from ZachTek (https://www.zachtek.com), which were described in previous CrossTalk articles. While we still expect to use these for actual flights, we also identified a lower cost alternative that utilizes a Raspberry Pi Pico combined with an add-on board containing a GPS receiver, power converter and 20 meter transmitter that together cost about $11. Mike Thompson KG4JYA figured out how to configure these devices by selecting a “channel” that defines the transmit frequency, timing, and several parameters in a spoofed call sign that allow specific identification of the WSPR packets since these devices send data that doesn’t conform to the WSPR protocol.
We decided to use a battery instead of solar cells for this launch, partly to save cost and partly because we haven’t yet decided how to fasten solar cells to this radio. An additional benefit to using batteries is that they provide a constant source of power for the radio telemetry units, meaning that we would get a telemetry update every 10 minutes. Solar cells only provide power in direct sunlight, so we might miss getting telemetry in the early stages of the launch if the balloon passed through a cloud and solar cells weren’t brightly lit. We used a 2200 mAh LiPo battery to power the radio after doing some testing with that 1100 mAh battery and finding that the smaller battery would power the radio for about 24 hours. Having no idea how long this flight would last we decided to use the stronger yet heavier battery, which wound up being far larger than necessary for the three hour flight. In the future we'll use a smaller battery and save some weight.
The remaining components were the wire for the vertical 20m dipole (we used the mil-spec Teflon-coated silver wire that was donated by a Club member), some Kevlar cord for strain relief, a soda straw and some Kapton tape. We taped the transmitter and the battery to the soda straw along with the antenna wire for strain relief on the solder joints to the transmitter and ran the Kevlar cord lengthwise through the straw to connect to the balloon. The antenna was wound around a wooden 1x2 with the Kevlar cord protruding from the soda straw for safekeeping during assembly. The Kevlar cord and one end of the dipole antenna are attached to the balloon with the Kaptan tape while the other end of the dipole hangs free below the transmitter.
Filling the balloon with the proper amount of helium is somewhat challenging. The goal is to add enough helium to lift the weight of the payload plus an additional amount based on other experimenters’ recommendations that we established at 8 grams. Since the weight of the payload (radio, battery, antenna, and other components) was 52 grams we decided to inflate the balloon to have 60 grams of lift. This is done by connecting a 100 gram weight to the bottom of the balloon, placing the weight on the gram scale, and inflating the balloon until the scale shows 40 grams. This is easier said than done.
The balloon needed to be filled through the soda straw which was pressed up against the inflater on the helium tank that itself needed to be bent to release the helium. This worked pretty well, but Doug inadvertently over-inflated the balloon passed the lift point that we had identified. Since we were concerned about the balloon clearing the trees at launch we decided to leave the extra helium in the balloon. After inflation we taped the top of the Kevlar cord and the antenna to the balloon with the Kapton tape and were almost ready to go.
At that point we went outside and got ready for final testing and launch. Doug had brought a fishing pole with a long length of monofilament line that he looped over a knot in the Kevlar line, keeping one end of the monofilament on the fishing reel and holding the other end in his hand. That allowed him to play out the line and see how the balloon responded to the wind, but also to reel it back in. That approach proved very helpful in precisely launching the balloon at a point when the winds were favorable. Doug unspooled the monofilament to allow the balloon to rise enough to extend the top half of the antenna for transmitter testing while Angela Metzger KE2DRJ held the bottom of the payload to keep it from moving around too much in the wind.
Checking The Radio
Before launching the balloon we needed to make sure the radio was transmitting properly. The radio puts out a WSPR signal on 20 meters (14.0971 MHz), so Mike tuned in that signal on the Flex radio in the HF room and verified that it was transmitting properly. In fact our WSPR transmissions, with half of the 20 meter dipole on the ground, were still picked up worldwide! Such is a testament to the robustness of WSPR.
The Launch!
At that point we were ready to go. A moderate-sized crowd of Club members and kids had gathered over by the Clubhouse to watch the launch. Unfortunately the wind had picked up slightly at that point and was swinging in different directions, so we held onto the balloon until it was favorable to the north, which was our furthest distance from the trees. At that point Doug asked the critical question “Clear to launch?” and in my best Gene Krantz imitation I shouted “Launch approved!”. Doug released the monofilament line and the balloon soared almost vertically and slightly to the north. We watched for several minutes until it disappeared into the clouds and then headed into the Clubhouse to track the telemetry.
Tracking The Balloon
Inside the Clubhouse, Mike was already tracking the balloon on several websites that could show various aspects of its progress. The WSPRnet site shows stations that have received WSPR transmissions from the balloon transmitter, so we could tell that the transmitter was being heard by many stations hundreds of miles away. That site didn't tell us where the balloon was so we primarily use the SondeHub website, which receives data from WSPRnet and was populated by a program that Mike wrote that transferred that data to SondeHub. We also use the Traquito site that showed graphical telemetry information. WSPR updates occurred about every 10 minutes, with an initial identification packet being followed by the telemetry packet, so we waited eagerly for those 10 minute updates.
At first the balloon headed north almost directly towards Philadelphia International Airport but quickly turned northeast on a path that had followed through most of its journey. It slowly ascended reaching 10,000 feet after about 1/2 hour, meeting our first success criterion. As it rose we continue to monitor the temperature, concerned that if it dropped below freezing the battery would cease to function. Although the temperature dropped to the mid 40s it remained above freezing so battery function was never a concern.
The balloon continued to move northeast at about 45 mph and rising slowly until it reached almost 23,000 feet several miles east of Medford NJ. It then began to slowly descend at about the same rate that it had risen. Having far exceeded our initial goal of reaching 10,000 feet we recalibrated that goal to hope that the balloon would reach international waters before finally hitting the ocean, which we were pleased to see occurring on the balloon’s final transmission.
When about 7 minutes passed with no WSPR updates we declared the mission over, but also successful. The intrepid Clubhouse team that had been hanging around for about 3 hours finally relaxed.
What Happened To The Balloon?
If we were SpaceX we would have had multiple sources of telemetry they could have identified the exact causes of the ultimate failure of the balloon. In particular, knowing the internal pressure of the balloon would tell us why it had descended, but here's our best guess. Since the balloon was vented at the bottom with the soda straw to allow pressure to escape and avoid bursting we're guessing that too much gas escaped at 22,000 feet. Without sufficient gas to continue to maintain altitude the balloon slowly descended over about 1/2 hour period. We don't believe that the balloon burst because the descent would have been faster. And noting that we had initially over inflated the balloon the excess internal pressure of the balloon occurred at a lower altitude than if we had properly inflated it.
What’s Next?
If we're correct in our assumptions there's another logical test to try, which is sealing the bottom of the balloon and seeing how high it will go before it bursts. We're going to try that sometime over the week of July 29th and may have some additional information at that point. Regardless of that outcome we plan to launch the SBS balloon on August 3rd and with the goal of achieving a successful circumnavigation of the earth.
TEST Balloon Launch Planned For
Saturday, July 20, 2024 @ 1100 Hours
The long-awaited tank of pure helium (not that 80% party balloon gas) has arrived at the Clubhouse so we can finally begin actual tests of the radio-carrying balloons. Working with the Woodruff Middle School we will have the materials for enough balloons for many flights over the next year, most of which we hope will circumnavigate the globe and give us an opportunity to test various balloon and radio configurations and see how they perform.
Saturday's test will not be one of those configurations; instead it will be using low-cost balloon, radio and other materials that will hopefully allow us to view the first few hours of its flight. Instead of the $175 SBS balloon that's expected to survive over long periods of time in the upper atmosphere we'll be using a large $5 party balloon that we expect will burst at some point as it reaches thinner air. Instead of the $45 ZachTech Radio with multiple solar cells we'll be using an $11 Taquito WSPR transmitter built from a Raspberry Pi Pico with an add-on board containing the GPS and transmitter module. We'll also be using a battery instead of solar cells, again to save on cost.
The battery should last for about 18 hours, allowing the balloon to move eastward over the Atlantic; however we don't expect it to reach Europe or Africa before it runs down. We should be able to track the transmitter using WSPRnet and several other online sources, and also possibly live RF WSPR transmissions on 20 meters, monitoring its location and battery voltage until its eventual demise. There are many potential points of failure including the balloon itself, storms, battery failure and some mechanical or electrical failure of the radio that we may be able to assess from this flight. If all goes well we hope to launch the "flight" version of the balloon on Saturday August 3, weather and other factors permitting.
The "test" version of the transmitter is currently on the air sitting on a table at the Clubhouse with a W2MMD callsign and is connected to a hamstick on the Skunkworks tower. It can be viewed on the WSPRnet, https://www.wsprnet.org/drupal/wsprnet/spots website as well at the Sondehub, https://amateur.sondehub.org/#!mt=Mapnik&mz=8&qm=12h&mc=39.73254,-75.20966&f=W2MMD/3 site that's specifically designed for balloon tracking. Those are the primary sites that we'll be monitoring during this balloon's short flight and for the "flight" version of the balloons thereafter. It's currently running on a battery for battery life testing so it may not be on the air at various points as the battery runs down. We'll be swapping out the battery tomorrow afternoon so it should be back on the air at some point thereafter.
Our plan on Saturday is to connect the transmitter, battery and antenna to the balloon and tether it to be sure that it's transmitting properly. Once we assess the wind direction and make a final launch decision based on wind speed (less than 10 mph) we'll release the tether and hopefully watch it ascend into the air moving eastward. We plan for that to happen around 11 AM although unforeseen issues may change that time. Once launched we'll be aggressively monitoring for the next 18 hours or until the battery finally runs down (these types of balloons are never recovered). This process will take over the main table of the Clubhouse so other Clubhouse activities that morning will need to relocate until we get the balloon system assembled.
So if you're interested come on out to the Clubhouse on Saturday, July 20th, and see how everything works out. Hopefully you'll view the beginning of some really interesting experimentation over the next year or so.
73 de Jon WB2MNF
Saturday's test will not be one of those configurations; instead it will be using low-cost balloon, radio and other materials that will hopefully allow us to view the first few hours of its flight. Instead of the $175 SBS balloon that's expected to survive over long periods of time in the upper atmosphere we'll be using a large $5 party balloon that we expect will burst at some point as it reaches thinner air. Instead of the $45 ZachTech Radio with multiple solar cells we'll be using an $11 Taquito WSPR transmitter built from a Raspberry Pi Pico with an add-on board containing the GPS and transmitter module. We'll also be using a battery instead of solar cells, again to save on cost.
The battery should last for about 18 hours, allowing the balloon to move eastward over the Atlantic; however we don't expect it to reach Europe or Africa before it runs down. We should be able to track the transmitter using WSPRnet and several other online sources, and also possibly live RF WSPR transmissions on 20 meters, monitoring its location and battery voltage until its eventual demise. There are many potential points of failure including the balloon itself, storms, battery failure and some mechanical or electrical failure of the radio that we may be able to assess from this flight. If all goes well we hope to launch the "flight" version of the balloon on Saturday August 3, weather and other factors permitting.
The "test" version of the transmitter is currently on the air sitting on a table at the Clubhouse with a W2MMD callsign and is connected to a hamstick on the Skunkworks tower. It can be viewed on the WSPRnet, https://www.wsprnet.org/drupal/wsprnet/spots website as well at the Sondehub, https://amateur.sondehub.org/#!mt=Mapnik&mz=8&qm=12h&mc=39.73254,-75.20966&f=W2MMD/3 site that's specifically designed for balloon tracking. Those are the primary sites that we'll be monitoring during this balloon's short flight and for the "flight" version of the balloons thereafter. It's currently running on a battery for battery life testing so it may not be on the air at various points as the battery runs down. We'll be swapping out the battery tomorrow afternoon so it should be back on the air at some point thereafter.
Our plan on Saturday is to connect the transmitter, battery and antenna to the balloon and tether it to be sure that it's transmitting properly. Once we assess the wind direction and make a final launch decision based on wind speed (less than 10 mph) we'll release the tether and hopefully watch it ascend into the air moving eastward. We plan for that to happen around 11 AM although unforeseen issues may change that time. Once launched we'll be aggressively monitoring for the next 18 hours or until the battery finally runs down (these types of balloons are never recovered). This process will take over the main table of the Clubhouse so other Clubhouse activities that morning will need to relocate until we get the balloon system assembled.
So if you're interested come on out to the Clubhouse on Saturday, July 20th, and see how everything works out. Hopefully you'll view the beginning of some really interesting experimentation over the next year or so.
73 de Jon WB2MNF
No set date for our balloon launches yet!
Editor's Note : "The balloon launch has been postponed because a potential opportunity has arisen to have the lifting gas and related supplies donated to the Foundation and the school, and we need time to explore that option. Because of Field Day and other June activities the launch won't take place until late July. This will also give us more time for testing and configuration."
"For anyone interested in tracking the balloons already floating around the world check out the link below. In particular, the W8BI-12 balloon was launched at the Dayton Hamvention and has travelled east and was last tracked off the coast of Japan. It's carrying an APRS tracker that will only report when within range of APRS internet gateways, which are not numerous in many parts of the world. Our balloons will carry a WSPR tracker on 20 meters which should give us many more reports and allow more consistent tracking.
We'll use software to link those WSPR reports to https://amateur.sondehub.org and aprs.fi. The Monday night TechNet session on June 10 will cover the various balloon tracking options, both by radio and internet."
73 de Jon WB2MNF - May 29, 2024
"For anyone interested in tracking the balloons already floating around the world check out the link below. In particular, the W8BI-12 balloon was launched at the Dayton Hamvention and has travelled east and was last tracked off the coast of Japan. It's carrying an APRS tracker that will only report when within range of APRS internet gateways, which are not numerous in many parts of the world. Our balloons will carry a WSPR tracker on 20 meters which should give us many more reports and allow more consistent tracking.
We'll use software to link those WSPR reports to https://amateur.sondehub.org and aprs.fi. The Monday night TechNet session on June 10 will cover the various balloon tracking options, both by radio and internet."
73 de Jon WB2MNF - May 29, 2024
Editor’s Note : “The balloon team had targeted this Saturday June 1st to launch the WSPR balloon but we're still in the process of sourcing the hydrogen lift gas and it's unlikely that we'll have everything together by Saturday. We'll announce when we're ready to launch it - hopefully by June 8th.”
73 de Jon WB2MNF - May 28, 2024
73 de Jon WB2MNF - May 28, 2024
The GCARC’s Ballooning Adventure Begins On Saturday, June 1, 2024!
By Jon Pearce, WB2MNF
By Jon Pearce, WB2MNF
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As if our Club didn't already have a full plate of activities, we'll be launching a balloon on June 1st that we hope will circumnavigate the earth sending back WSPR messages on 20 meters! Here's how that will work.
Several months ago the Club was contacted by Club member Joseph Lee N2BNJ, who's also a school board member of the Upper Deerfield Township Schools. Joe was asking if the Club would be interested in developing a STEM program possibly featuring Amateur Radio for students in the Woodruff Middle School. Since supporting Amateur Radio education is an important goal of every group, we immediately jumped on board and started discussions as to the type of activities that might be interesting to students at that level. After evaluating several options, launching and following a circumnavigating balloon carrying an Amateur Radio transmitter was determined to be the best option. |
Figure 1 : SBS-13 Balloon
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This will demonstrate ham radio and provide a multitude of educational opportunities for kids in many related scientific areas.
These activities will begin in the fall, but it was obvious to our team that our first balloon launch couldn't be the large public event that would occur with the school, and that we had to assure ourselves that we had the skills and materials needed to create a successful launch. So a group of Club members started researching websites, watching videos, and slowly building a knowledge base on balloon launching, focusing on learning the best practices of other groups who have had successful ballooning activities.
The Balloon
After evaluating a number of products we selected the SBS-13 balloon (Figure 1) made by Scientific Balloon Solutions (https://www.scientificballoonsolutions.com). This balloon is used by several successful groups and appears to be the current choice of successful Amateur Radio balloonists. The balloon gets partially filled with hydrogen or helium (we're using hydrogen because of its lower cost and greater lift characteristics) until the lift generated by the balloon is approximately 7 grams greater than the weight of the payload. This is measured by attaching the balloon to a weight on a gram scale and slowly inflating the balloon until it lifts the weight by the necessary amount. The bottom of the balloon is then heat sealed, connected to the payload, and launched.
The Payload
The payload of circumnavigating balloons includes a transmitter, solar cells, and one or more antennas. Virtually all circumnavigating balloons utilize the WSPR protocol on HF frequencies because of its ability to be decoded at low signal levels over long distances. In addition, some groups have also included an APRS transmitter for greater location definition over populated areas, but we chose not to do this on our first launch because of the significantly increased cost of those units.
These activities will begin in the fall, but it was obvious to our team that our first balloon launch couldn't be the large public event that would occur with the school, and that we had to assure ourselves that we had the skills and materials needed to create a successful launch. So a group of Club members started researching websites, watching videos, and slowly building a knowledge base on balloon launching, focusing on learning the best practices of other groups who have had successful ballooning activities.
The Balloon
After evaluating a number of products we selected the SBS-13 balloon (Figure 1) made by Scientific Balloon Solutions (https://www.scientificballoonsolutions.com). This balloon is used by several successful groups and appears to be the current choice of successful Amateur Radio balloonists. The balloon gets partially filled with hydrogen or helium (we're using hydrogen because of its lower cost and greater lift characteristics) until the lift generated by the balloon is approximately 7 grams greater than the weight of the payload. This is measured by attaching the balloon to a weight on a gram scale and slowly inflating the balloon until it lifts the weight by the necessary amount. The bottom of the balloon is then heat sealed, connected to the payload, and launched.
The Payload
The payload of circumnavigating balloons includes a transmitter, solar cells, and one or more antennas. Virtually all circumnavigating balloons utilize the WSPR protocol on HF frequencies because of its ability to be decoded at low signal levels over long distances. In addition, some groups have also included an APRS transmitter for greater location definition over populated areas, but we chose not to do this on our first launch because of the significantly increased cost of those units.
The transmitter (Figures 2 & 3) that we selected is made by ZachTek (https://www.zachtek.com) and comes as a mostly assembled PC board with two super capacitors that need to be soldered onto the circuit board. It's programmed through a serial connection which is then removed before flight. Power is obtained from 2 solar cells mounted at angles on the board to create maximum illumination from sunlight.
The whole device is tiny and virtually weightless - the transmitter itself weighs less than 9 grams and the solar cells weigh about the equivalent of a sheet of paper. Mike Thompson KG4JYA assembled and programmed both of these, and we'll hang them outside of the Clubhouse for testing until the launch date.
The whole device is tiny and virtually weightless - the transmitter itself weighs less than 9 grams and the solar cells weigh about the equivalent of a sheet of paper. Mike Thompson KG4JYA assembled and programmed both of these, and we'll hang them outside of the Clubhouse for testing until the launch date.
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The payload is hung from the balloon from a 17 foot length of fishing line and also a 17 foot length of enameled #36 wire that forms the top half of a vertical 20m dipole. Below the transmitter is another 17 foot length of wire completing the lower half of the dipole. Figure 4 shows this configuration for one of W5KUB's launches although we're not using the APRS transmitter that he is including. Although the transmitter only runs about 20 milliwatts it can still be heard at great distances. Mike set it up at a location in Michigan and was received as far away as Florida, and with the balloons riding at about 45,000 feet the coverage area should be significantly better. Some balloonists have been reporting that they were able to follow their balloons on the radio virtually in real time. |
Figure 4 : W5KUB's Balloon
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Tracking (Reference Figures 5, 6, 7, and 8)
There are several methods of tracking the satellite, some involving actual radio reception while others utilize the worldwide WSPR receiving network with some supplemental work done to get the data onto various websites. Direct reception of WSPR signals is done using the standard WSJT program in WSPR mode (Figure 5), and listening on 14.095.600 MHz, the standard WSPR frequency. WSPR transmissions are two minutes in length, but an additional 2 minutes is needed to send the last two digits of the six digit grid square, so it takes 4 minutes to gather all of the information from one transmission. Hams with decent 20m receiving antennas may be able to track this balloon themselves.
For those without radios and to access the worldwide WSPR receiving network at the https://www.wsprnet.org/drupal/wsprnet/spots website receives and tracks WSPR reception (Figure 7) throughout the world. It displays it in tabular and map formats and also allows database queries. Figure 6 shows Mike testing the transmitter connected to a dummy load while receiving at the Clubhouse HF station.
Finally, the https://sondehub.org website (Figure 8) is specifically designed for balloon tracking, displaying only WSPR signals from balloons.
Next Steps
At the time of this writing we have all of the components assembled other than the lifting gas, which is still in process. We have materials for two complete balloons and will be launching them individually with the second’s schedule predicated on the success of the first. Weather conditions for a launch must be dry with winds less than 10 mph.
If everything works out we’ll attempt to launch on Saturday, June 1, 2024 around noontime.
Check the GCARC e-mail reflector for announcements.
There are several methods of tracking the satellite, some involving actual radio reception while others utilize the worldwide WSPR receiving network with some supplemental work done to get the data onto various websites. Direct reception of WSPR signals is done using the standard WSJT program in WSPR mode (Figure 5), and listening on 14.095.600 MHz, the standard WSPR frequency. WSPR transmissions are two minutes in length, but an additional 2 minutes is needed to send the last two digits of the six digit grid square, so it takes 4 minutes to gather all of the information from one transmission. Hams with decent 20m receiving antennas may be able to track this balloon themselves.
For those without radios and to access the worldwide WSPR receiving network at the https://www.wsprnet.org/drupal/wsprnet/spots website receives and tracks WSPR reception (Figure 7) throughout the world. It displays it in tabular and map formats and also allows database queries. Figure 6 shows Mike testing the transmitter connected to a dummy load while receiving at the Clubhouse HF station.
Finally, the https://sondehub.org website (Figure 8) is specifically designed for balloon tracking, displaying only WSPR signals from balloons.
Next Steps
At the time of this writing we have all of the components assembled other than the lifting gas, which is still in process. We have materials for two complete balloons and will be launching them individually with the second’s schedule predicated on the success of the first. Weather conditions for a launch must be dry with winds less than 10 mph.
If everything works out we’ll attempt to launch on Saturday, June 1, 2024 around noontime.
Check the GCARC e-mail reflector for announcements.