Hello DK7FC,
Thursday, October 29, 2015
I have breadboarded the motor drive circuit and tested it with 2 one
and a half volt cells centre tapped and 1k pot to simulate the phase
change input. The drive motor works fine, and lowering the voltage to
say 7V it moves the variometer REALLY slowly. I am now about to build the
phase meter part of the antenna circuit. Do I need to isolate the
phase meter ground with say a 470pF parallelled with a 0.1uF to true ground?
Thanks.
> Hi Chris,
> Am 29.10.2015 21:26, schrieb Chris Wilson:
>> [...] albeit my loading coil needs manual
>> tweaking to move to the right part of the band. Not sure of the best
>> way to remote tune it, it would be nice to have the ability to move
>> about the band without running outside in the dark. I may start a
>> thread about what alternatives there are, thanks again Erwin
>>
> I'm using a motor driven variometer which uses the phase meter circuit
> of the M0BMU LF tuning meter. It is working well on LF, where my antenna
> resonance is so sharp that i have to re-tune when doing QSY by 7 Hz.
> See:
> https://dl.dropboxusercontent.com/u/19882028/LF/LFtunemeter.pdf
> https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC%20Automatic_variometer_tuner%20.jpg
> https://dl.dropboxusercontent.com/u/19882028/LF/automatic_variometer_board.jpg
> https://dl.dropboxusercontent.com/u/19882028/LF/LF_variometer_drive_engine_arrangement.jpg
> https://dl.dropboxusercontent.com/u/19882028/LF/phase_meter.jpg
> 2011 was a nice LF year for me!! :-)
> 73, Stefan
--
Best regards,
Chris 2E0ILY mailto:[email protected]
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