Wednesday, September 30, 2009

External VFO controller for the FT-102


Had been without time so no updates were made on the last days but today I got some free time and on we go with the projects.

I decided to call this project an external vfo controller for the FT-102 since it doesn't mimics all the functions of the original external vfo but it is adaptable to any external vfo in the range 5-5.5Mhz with 130mV (or something like that) output powered by an 8v supply. Mine was an FV-107.

I did lost some time making this simple schematic just because when reading the FT-102 schematic I was seeing the ouput of a simple zener regulator as the imput making no sence to as the FT-102 controls the external vfo, in fact as soon as I placed the din plug on "ext vfo A" of the FT-102 it came to light. When you connect a plug in the external vfo A of the FT-102 he simple disconects the power supply from the internal vfo, ther's a connection so you can power it again. That's is how "control" is done. Ext vfo B it's just used to give indications on the mic buttons and internal reference oscilator case you use an pll.

Another issue that arrived is that the 12v present on the ext vfo plug aren't enough to power an hungry FV-107 with all the lights on ,so I just used the vfo part and not the christmas light's part, after all I just want ot make split's biger than 10Khz given by the internal vfo rit control. I still placed a capacitor to minimize power on current but it wasn't enougth, probably changing to an external power supply would solve this issue but wanted to keep it simple.

I think the "external vfo A" din plug on the FT-102 is not a standard one but you can "convince" a "normal" din to fitt there, assuming it has the same number of pins!

Here the schematic and the equipment working on an action video.






















video



As soon as I found a cheap reduction drive and a nice capacitor will make an vfo smaller than the FV-107 so it can take less space and free it to another project.

By the way, I did this just to see if it was possible since my last QSO was more than an year ago, I gess I prefer to brew and no to chat.

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