Digithin as a starter project
Posted: Tue Jul 14, 2015 6:59 pm
As Steve mentioned in his QRP post, there is real potential with the Digithin / Minituner projects to make a great starter project that we can use to get people on air easily and even push in to local radio clubs as an ideal club project.
For transmit you have the Rpi (everyone has one in cupboard!), plus Evariste’s software and the BATC Digithin kit which could be upgraded to include the 200 Mhz Si570 to produce an output on both 146 and/or 437 MHz. This can be used barefoot, as Steve and Arthur have proven, to work across town and get that first QSO.
Rob M0DTS published the design for the RD06 and RD15 146 MHz PA which is inexpensive and easy to build but will need a PCB layout (including an input filter) that works as it is quite prone to hoot due to the overall gain. Alternatively someone like Minikits may do something suitable.
For Rx we have Minitune USB kit with PCB and Minitioune software which will now run on any PC and to rx 437MHz we have the SUP L band upconverter.
However the missing link is an upconverter for 146MHz. We either need to find a consumer device or a design for a simple upconverter to L band with an F type output powered from the Nim.... Or maybe we can tweak the SUP oscillator down by 200 MHz???
Put these together with standard 2mt beam and pre-amp that people tend to have and you have a system with a total cost between £100 - £150 that produces excellent video and is good enough for people to work across town and get a real taste of ATV. Once they get the bug, the equipment they have, can be used to work better DX on 146MHz (100 KMs under flat band condx) & 437MHz and used as the basis for other bands.
We could do a CQ-TV style system book on how to put it all together, sell the components at cost through the BATC shop and we have something we can push out as a starters kit and try to get some radio clubs to adopt as a club project....
Thoughts / ideas particularly on the missing link of a 146MHz to L band u/converter.
73's
Noel - G8GTZ
For transmit you have the Rpi (everyone has one in cupboard!), plus Evariste’s software and the BATC Digithin kit which could be upgraded to include the 200 Mhz Si570 to produce an output on both 146 and/or 437 MHz. This can be used barefoot, as Steve and Arthur have proven, to work across town and get that first QSO.
Rob M0DTS published the design for the RD06 and RD15 146 MHz PA which is inexpensive and easy to build but will need a PCB layout (including an input filter) that works as it is quite prone to hoot due to the overall gain. Alternatively someone like Minikits may do something suitable.
For Rx we have Minitune USB kit with PCB and Minitioune software which will now run on any PC and to rx 437MHz we have the SUP L band upconverter.
However the missing link is an upconverter for 146MHz. We either need to find a consumer device or a design for a simple upconverter to L band with an F type output powered from the Nim.... Or maybe we can tweak the SUP oscillator down by 200 MHz???
Put these together with standard 2mt beam and pre-amp that people tend to have and you have a system with a total cost between £100 - £150 that produces excellent video and is good enough for people to work across town and get a real taste of ATV. Once they get the bug, the equipment they have, can be used to work better DX on 146MHz (100 KMs under flat band condx) & 437MHz and used as the basis for other bands.
We could do a CQ-TV style system book on how to put it all together, sell the components at cost through the BATC shop and we have something we can push out as a starters kit and try to get some radio clubs to adopt as a club project....
Thoughts / ideas particularly on the missing link of a 146MHz to L band u/converter.
73's
Noel - G8GTZ