Message-ID: <5650BCC4.2010404@posteo.de>
Date: Sat, 21 Nov 2015 19:49:40 +0100
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <1981852865.20151017122027@chriswilson.tv> <1530BFEB-9BC2-4CA2-A7A3-338629A98202@me.com> <308511169.20151029202607@chriswilson.tv> <56328B1F.2080901@posteo.de> <299444874.20151120223657@chriswilson.tv>
In-Reply-To: <299444874.20151120223657@chriswilson.tv>
Subject: Re: LF: Automatic variometer circuit
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Status: O

Hi Chris,

I took a separate floating power supply to build this circuit, a simple 
transformer (10VA), a bridge rectifier, electrolyt capacitors, voltage 
regulators, you know, the traditional stuff :-) You could decouple the 
ground of the phase meter to the coax screen by a large C. But i think 
is is worth to build a separate power supply. I personally prefer to 
spend a few parts more just to avoid eventual EMC problems at high power 
levels, you know...

73, Stefan

Am 20.11.2015 23:36, schrieb Chris Wilson:
> 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
>>      
>
>
>
>
>
>
>
>