![]() Step 1 is that the GPS has to show positions are time, and, PPS data which we need for the NTP server. GPSD is a daemon, a process running in the background doing all the work for you, such as making the GPS information available on a port on the system. I used gpio 19 for this purpose (earlier I wrote 29 and this was pin 26 which is a software defined gpio pin while 19 is a hardware PWM pin, there is no difference for the RPi) Setting up your gpsd server The GPS hat comes from dragino, it also does LORA (the white stick) which I’m probably not going to use, the only hardware modification is a (blue) patch wire between the output of the GPS chip and a free gpio port on the Raspberry Pi. We need time with some accuracy, so a GPS (more accurately GNSS) hat on a Raspberry Pi that controls a local NTP server and a travel router should be able to do the job.įigure 1: Upper right is the GPS status window, below that is an existing NTP window, and on the left is a (pulse per second) PPS output windowįigure 2: The Raspberry Pi with the Dragino LORA/GPS hat. ![]() Last update: 3 17:46 (Fixed a few typos).įor digital modes on a field day you have to assume the worst, no internet, no local Ethernet, and therefore no time information. Can it be done easier? Probably yes but this is what I ended up with for mobile WSJT-x. Two projects and came together for this article. I replaced this switch a few years ago when CAT6 gigabit lan was installed, for field LANs we can still use it, 100 MBps is fast enough.įor packet routing you could carry the router you have at home into the field, chances are that your wife and children don’t like you too much when you return home, so, either build your own router (I gave up), or find a mobile WiFi router, also called a travel router or a MiFi device, the one below is really good enough to do the job. I used the MFJ-1234:įT8 and in particular FT4 require time synchronization, you can do this by hand if there is no internet (one of our requirements) but why can’t it be done by GNSS? So this is a task for a second RPi with a GPS hat which needs a GPS antenna currently mounted on a can of chewing gum on the window sill.Įverything that you carry with you in the field has to talk to one another, for this we have an unused netgear switch (if could also go via local wifi). The RPi that controls the FT-857 is also running the WSJT-x software, two radio dependent cables are required, an audio cable and a cat cable. The radio that I use was designed 16 years ago (I found an introduction article in QST in 2004 mentioning that the reviewer got it in 2003) the FT857 is still sold today while we know that there are more modern transceivers with SDR technology, DSP and more of that: ![]() ![]() Access to the RPi’s is what you do with VNC, this is free software that runs everywhere, Ubuntu, Windows, Mac OS or even your tablet.Ī Raspberry Pi (3B+) is fast enough to run FT4, the figure below is the evidence, it shows a FT4 session with the latest version WSJT-x 2.1.0 GA: Also this is wrong, we are not depending on Microsoft Windows, instead we only use Raspberry Pi’s for controlling the radio and timekeeping. The second misunderstanding is that you have to carry a windows laptop in the field to be able to do this easily. Some people think that WSJT-x is not about hamradio, because it is internet related while hamradio is supposed to be independent radio for amateur use on designated frequencies. This article will show that they are wrong, you don’t need the internet, we just need GNSS (thus GPS and the rest) which is always there and free to receive. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |