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From: N1BUG <paul@n1bug.com>
Message-ID: <136d419d-1de6-e4d8-303a-d7962ff9dc44@n1bug.com>
Date: Thu, 22 Feb 2018 07:38:45 -0500
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Subject: Re: LF: 2200m plan for tonight
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Hi Stefan,

I have seen that M0BMU circuit before, as part of a larger document 
from which I built my scopematch.

I would like to see your circuit for steering the motor. This will 
give me something to work on for the next round of changes to my 
system. I'm learning a lot and someday I could get everything 
working smoothly. Maybe... :-)

73,
Paul


On 02/21/2018 04:38 PM, DK7FC wrote:
> Hello Paul,
> 
> See the circuit of the M0BMU tuning meter. In attachment.
> This device is useful for itselfe. Over the years i built 3 of them :-)
> You will always see if your antenna has a capacitive or an inductive
> component, i.e. if you need more L or less L. This is MUCH better than
> an SWR meter, at least on LF!
> 
> With the phase meter part, you can steer the circuit that steers the
> motor. I can give you the circuit if you like.
> 
> I finally need an alternative to Dropbox which became obsolete a year
> ago. It was very comfortable to share files, i.e. generate and paste a
> link into an email. I can upload any file to the uni server.... I know,
> there alternatives on the Raspi but my time is limited too :-)
> 
> 73, Stefan
> 
> Am 21.02.2018 22:26, schrieb N1BUG:
>> Hi Stefan,
>>
>>> You need an automatic variometer. A phase meter that steers a motor
>>> which turns a variometer coil inside your main coil.
>>> On LF i had a very high Q system and has to use such an application. It
>>> worked perfectly over years.
>>
>> That is a very interesting idea. I wouldn't have any idea how to build
>> something like that, but it would be useful. If not that, at least I
>> need to devise some kind of high SWR shutdown for the amplifier. I
>> lost one FET already and it will surely happen again.
>>
>> I need to make a few small changes to the coil and variometer. It just
>> has enough tuning range for dry conditions. When there is rain or ice
>> I cannot tune far enough with it. I think I chose the wrong gear motor
>> to turn it also. It works fine but the tuning rate is very slow. I
>> should use a motor with more RPM. :-)
>>
>> 73,
>> Paul