If it powers on briefly then dies it is usually an indicator of an internal short circuit. There is a self-reset able fuse that protects it and turns it off and it usually takes a second or so for it to disconnect the load that is why you see the brief Green Power LED. An internal short usually means a dead Power Amplifier. They are soldered on the board on version 1.20, later in version 2 Hardware they sit in a socket so they can be easily replaced. But this one has to be removed with a hot air station and replaced. Let me know if you want to do that job yourself and I will post a couple of PA circuits to you in a letter. If you do not feel comfortable doing it yourself you can send it back to me for repairs. In that case email me at harry@zachtek.com for instructions. 73 //Harry

No, the side with the silver label should go down. It has a magnet on that side so you can stick to a piece of metal to give it a ground plane, that will increase reception. As long as you get a GPs fix it really doesent matter how you point it. 73 //Harry

Yes, delivery is by USPS (you can even track it on their webpage using the tracking number provided) And yes, a signature is required as it is an insured door-to-door package 73 //Harry

Ther is a bug in the calculation of suffix encoding that makes it not decode properly for some callsigns. So if you are going to use suffix test it on the ground first if your callsing is affected by this bug or not. This might be what is happening in this case. //Harry

1000 thanks Phil !! Super usefull, I will spread the word. Yes I can imagine trying to test the second transmission with out any data would be hard. Aslo the time for the first transmission have to be known, as is is now the user can set it in the schedule so suporting that for you means a setting in your GUI for that and that would probably be to complicated for both you and for the users. A better option would be to simple decide that first transmission is always on say minute 00, 10, 20, 30, 40 or 50 And the sencond is then +2 minutes of this and I would then force this in the software for balloons. The KC9LGS/G seems to be a ZachTek balloon flight that transmitted the first transmission on minute 00 a couple of weeks ago if you want to check out a table that has the correct encoding. But what to do when not both transmission were received, still plot the postion but no altitude data in these cases I guess? This site shows all the known ballon flights http://lu7aa.org/wsprx.asp Click on a call sign to see that specific flight, the tracker type should be of the type "ZachTek1" for flights that send altitude data in two back-to-back packets. Thank you also for the Mobile option, more and more people are using WSPR transmitters as a mobile tracker in cars so this is very usefull, it worked before aswell but with an balloon icon, no problem but this is nicer! 😋 73 //Harry

You need to set up a receiving station so you can self- detect your transmission in the software WSJT-X. Once you are able to decode your own transmissions you can check who else heard you. //Harry

The 4.5V 50mA variant of the Powerfilm solar cells weigh 1.76gram a piece, you need two. So with soldering blobs and thin wires should come in below 5grams for the two, possible 4 grams?

Well, live and learn I guess. I think it be fine at 15.8 grams. The Summer storms that can bring down low altitude ballons will not be here for another few months so you should be good. If you want to get the PowerFilm solar cells from Mouser their ordering number is : 730-MPT4.8-75 They give you free shipping when you reach a certain ammount, dont know what that limit is outside Sweden, here it is around 45$ 73 and good luck with your flight. //Harry

Whaaaat 😀 I have never noticed that, just tried it, there it is... Nice! 🍾😍 I will let everyone know. Actually the altitude is now most often sent as two transmissions - the first is the 300m per dB as you show but the second tx then adds finer resolution were every dB is 20m. Users will add these to get the altitude. This will run in a schedule every 10 minutes so the first tx is always on the same minute e.g minute 02,12,22 etc. But this is good enough for many users I would say. That was a great surprice, your webpage is such a great resource, I should really do a Video on all the features one day but it might have to be severals Videos to cover all the stuff you have put in there. Your the man Phil, thank you!

Nice setup! I never get the Pico to run on the ground unless it's really bright sunny day in the summer. So I am guessing that you dont get enough sunshine on it for it to start or it could just be that you need another cell in series as you hinted. It draws around 60mA at startup then goes down to about 40mA once it gets a GPS lock. It seems that once you are up at altitude it's no problem running it in the winter, the efficieny goes up on the Polymer solar cells with lower temperature and also there is no haze at altitude so that is probably why it works fine at altitude but not on the ground. 73 //Harry

Hi Milan. I dont have any experience with other solar panels other than the ones I use and they give around 5V so aim for that. The encoding dont use timeslots or channels so you dont have to bother with that. Just track it on wspr.rocks using ther balloon option (in this case you will have to do the altitude calculation yourself, see dowcumentation or the software hints how to do it) or you can use http://lu7aa.org/wsprx.asp to track it and it will do the altitude calculations for you. On that site use the preset function to define the tracker as a "zachtech1" and it should work fine. If you have more qustions around balooning I sugest you head over to Pico Balloning on groups.io This is were all the experts on balooning hangs out. https://groups.io/g/picoballoon/topics 73 //Harry

Please note that there is a firmware bug that affects prefix and suffixes. The bug makes the transmission not being decoded so you will not get any spots. This bug only affects some callsigns so you must test this out first. The easiest way of testing it is to run your own instance of wsjt-x and receive you own transmissions. The transmitter dont need to have an antenna attached, If you try it on your bench the reciver should be able to pick it up anyway. Start with regular transmissions without sufix and make sure you can decode your transmissions. then try it with sufix enabled and see if it is still being detected. If it works than I would say use it. If not just use your regular call sign with no prefix. As your locator is being transmitted people will still see your true location so should not be big issue running without prefix. 73 //Harry

Here is the spec for the female connector, its the DC-005-25A version https://datasheet.lcsc.com/lcsc/2108131730_Korean-Hroparts-Elec-DC-005-25A_C136715.pdf

You got some sweet DX there! Besides Reunion Island you got the Neumayer III station as well: https://www.awi.de/en/expedition/stations/neumayer-station-iii.html 73 //Harry

Ther is no way of doing this by using the the desktop transmitter. You ned to know if the Kantronics expect RS-232 levels, 5V TLL or 3.3V TTL so you can find the correct device. When you know that you should be able to find a small GPS board that does this from Aliexpress/Amazon/eBay etc 73 //Harry.

You can download the elictrical Schema here: I sugest taking it from R13 as this will get you the receivere frequency whenever the sidetone is on.

Hi Glenn. I see that you have got some excelent replies from other forum members so this might be redundant but I will answer it anyway for future forum readers. 1. The Desktop models have built in filters that are automatically switched so you don't need any external filter for the Desktop models, just plug in an antenna and start using it. 2. All my tranmitters are SWR tollerant. You can not destroy them with high SWR. I have tested to transmitt using the signal generator in to a shorted output for 20 minutes! (Z=0ohm) I then transmitted in to an open outpout for 20 minutes (Z=infinite) and nothing bad happened. I have tried this multiple times with all my models and they can take this beating just fine. The power amplifier can go bad though. It happens. I dont know how they go bad as it has not happen to me but I suspect from reverse RF or by lightning. If it does go bad you can esily replace it yourself it as it sits in a socket (This is only true for hardware revisions 2.6 or higher, check the sticker at the bottom or in the configuration software) 3. The Desktop models are 100% built and ready to be put on the air. The WSPR-TX XP and XP Plus are built tested and calibrated just like the Dekstop models but they do not come in an aluminium box and they have no low pass filters fitted. You have to do that yourself, see the options in point 1 73 //Harry PS Here is an overview of the different models here https://www.zachtek.com/wspr-tx

Thank you for the great explanation how it all works Phil!

Thats great to hear! Some computers may need to have a driver installed. You find it in my download section.