So far, AL7CR and I have launched 3 flights using the ZachTek PICO transmitter. Our first two were successful (for beginners) with the first one ending up somewhere near Hudson's Bay Canada and the second one went all the way to the IRAN/AFGHANISTAN border before we lost contact. We had anticipated that these two flights would be lucky to make it to the state line! Our third flight contained some major changes which we are still considering. We used two Chinese clear party balloons attached tail to head using our heat sealing roller machine. Until this time we had only used a single balloon per flight. Also, I split the free lift between the two balloons which was probably the wrong thing to do. We lowered the solar panels about another 10 degrees thinking that Fall would not provide the same amount of sunlight and that a lower angle would capture more solar power. We thought we needed some more altitude in order to avoid WX problems and that 2 balloons would provide that. The launch of the the flight was quite nerve racking in that, although it was perfectly still, the balloons did not want to rise and had a difficult time clearing the trees on a ridge to the north of the launch site. Our other flights were up and away gaining altitude quickly. Secondly, the balloon went north from our place and drifted for about 40 miles until it turned and came south again and finally went east. It crossed Texas and we lost contact with it near the Louisiana border. Again we think weather was a factor since we were only at 26,000' or so. So, we are now planning our 4th flight. Dean, AL7CR, assembles the hardware at his shop in Oregon and ships the transmitter and antenna to me here in NM. We think NM is a favorable launch site since we are at 7,000' elevation here. I figure out the free lift tests and basic testing of the transmitter. They have always worked very well. Then we decide on a launch day and if the weather cooperates we let it go. We have always only used 20 meters for WSPR transmissions. We are making some changes to the antenna system that will hopefully cut our payload weight by 6 grams or so. We are using much lighter weight antenna wire and fishing line than on the previous flights. This change will give us the additional 5,000' feet or so, we think. The lighter wire requires some serious thought about stress on the mounting points and the soldered attachment to the PCB. Dean has a stress free design in mind which we will incorporate this time. He is an aeronautical engineer and comes up with some interesting ideas. Currently, we plan to wait until after January 15, 2021 to have a more favorable sun angle. You have to think of everything in this hobby but that is what makes it interesting.