I was having some problems with DATV-Express, initially I thought it
was the software and spent a couple of weeks debugging it to no avail.
I was starting to get a bit desperate and doubting my own sanity.
In the end I found there was a dry joint on one or more of the FPGA pins.
I have re-soldered the chip and now it is all working much better. there is
still a minor issue with the Kernel USB drivers where it seems to loose all
knowledge of the capture card and DATV-Express if the program closes badly.
That is a minor issue.
There are two strands to the DATV-Express software, one is the Linux
QT5 program that you all know about. The other is a much simpler program
that only implements DVB-S that will run on a Raspberry PI or other ARM
based board. The second program is aimed at portable operation or use in
repeaters as no heavy PC will be needed to use it. The second program
is also very modular and I hope hackable by others.
I have install a GIT server on my Synology Network Disk Server and I already
have a GIT depository of the smaller ARM based program on it. In the next few
days I will put the QT5 program under GIT management. Eventually these two
repositories will be moved to a public server for people to download and play with.
All this GIT stuff is new to me and I am making many mistakes along the way
but that is the way to learn about things.
We have decided to make one more version of DATV-Express before we go
into production. The analogue tracks from the DAC to the IQ modulator need to
be made as symmetrical as possible to improve unwanted sideband supression
and we need to improve the cooling of the modulator chip as it gets very hot.
This is an issue with the chip itself and not our design. Apart from that a few
resistor values need to be changed to simplify the inventory.
We are still on track to make the first boards available to brave early adopters
around the time of the BATC convention in October. We are not sure how many
boards will be manufactured yet as it will involve a significant cash outlay.
A large batch significantly reduces the per unit cost but is quite risky on the
We thank everyone for their patience as you know this is being done on a not for
profit basis in our spare time and hence the long time scale.