phase detector for tuning magnetic loop

[ub5_073_oleg]

Hi,

I'm thinking about building an automatic tuning controller
for my magloop. It could search for a current max, but this
can be a challenging task.

It's probably easier to look for a capacitor position where
the phase between voltage and current  crosses the 0, with
reasonable deadband for stability. This is probably easier
to find than a current max.

What I'm looking for is a working example, since my
experience is not enough to design the whole from scratch.

I found already some commercial devices:
http://wimo.de/magnetische-loop-antennen_d.html
http://q-mac.ru/en/qmac_mx9027.html

Joe K3JLS is working on MLC, too (was
www.k3jls.com/mlc.html, should be put live when Joe's
project is ready)

A nice newsgroup conversation on the same subject:
http://newsgroups.derkeiler.com/Archive/Rec/rec.radio.amateur.antenna/2005-10/msg00268.html

Does anybody here use an automatic, phase detector based
magloop tuner?

73! Oleg DL2IPU


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[Julian, G4ILO]

ub5_073_oleg wrote

Hi,

I'm thinking about building an automatic tuning controller
for my magloop. It could search for a current max, but this
can be a challenging task.

It's probably easier to look for a capacitor position where
the phase between voltage and current  crosses the 0, with
reasonable deadband for stability. This is probably easier
to find than a current max.

What I'm looking for is a working example, since my
experience is not enough to design the whole from scratch.

I found already some commercial devices:
http://wimo.de/magnetische-loop-antennen_d.html
http://q-mac.ru/en/qmac_mx9027.html

Joe K3JLS is working on MLC, too (was
www.k3jls.com/mlc.html, should be put live when Joe's
project is ready)

A nice newsgroup conversation on the same subject:
http://newsgroups.derkeiler.com/Archive/Rec/rec.radio.amateur.antenna/2005-10/msg00268.html

Does anybody here use an automatic, phase detector based
magloop tuner?

73! Oleg DL2IPU

About a year ago I came across a site containing a full description of a PIC based automatic tuner for the MFJ magnetic loop. I think it was a US ham's site. But I didn't bookmark it and I have never been able to find it again. Perhaps someone knows where it is.

[KK7P]

> About a year ago I came across a site containing a full description of a PIC
> based automatic tuner for the MFJ magnetic loop...

< URLhttp://www.hamsdr.com/discussion.aspx?id=3 > is a text description.
  < URL:http://www.hamsdr.com > and go to DOwnloads...Public Downloads
then select "Filter by Folder" and scroll to "Loop Antenna" and you'll
see the files.

73,

Lyle KK7P

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[ub5_073_oleg]

Julian, Lyle,

thanks for your replies!

Hamsdr magloop tuner is 'simply' an advanced memory device,
helping to reproduce a tuning found once quickly again.
(PLease correct me if I misunderstood it)

I'm still trying to find a magloop tuner which does the same
what I do - searching the resonance, no matter if done on
this particular frequency before or not.

73! Oleg DL2IPU


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[ub5_073_oleg]

here is a phase discriminator used in a MIL tuner:
http://www.tpub.com/content/antennaandmasts/TM-11-5821-284-34/TM-11-5821-284-340011.htm

Do you think this is what I was looking for?


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[ub5_073_oleg]

Ian GM3SEK referred me to G4WIM's article in Radio
Communication Nov'1986 "A 1-8 MHz Auto Tuning Verical
Antenna".

It describes a system, based on phase detector, to tune a
motor-driven coil. Magloop's capacitor could be tuned just
as well, I think.


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