magnetic fields and phase noise

[alan alan]

Hi All,

Reading the magnetic field and phase noise saga makes me think of
earth loops. If moving to another power socket- as in moving to
another room cures it.
How about using mains isolation transformers so only connection
K2-linear really is the coaxial feeder. Or battery power K2.

Just a thought.

Alan

(actually G0HIQ but my e-mail provider wont let me have it!)


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Subject: [Elecraft] magnetic fields and phase noise?
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Interesting Earl, the non exhaustive tests I've done indicate that it

is not
due to magnetic fields.  But if indeed that is the case, there must
be
a
relatively easy, if perhaps not elegant, way of significantly
improving
this.


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[Ron D'Eau Claire-2]

Alan, G0HIQ, wrote:
Reading the magnetic field and phase noise saga makes me think of earth
loops. If moving to another power socket- as in moving to another room cures
it. How about using mains isolation transformers so only connection
K2-linear really is the coaxial feeder. Or battery power K2.

-----------------

Good points! Has everyone chasing he noise problems at least isolated the
house mains from the rig for RF with a ferrite choke?

Since the K2 uses an external power supply, I use chokes on the 13 vdc
supply lead where it leaves the K2. I don't have your problem to contend
with, so I can't say what difference it might make.

On HF, I currently use a balanced antenna fed with open wire line through a
balanced ATU, so rig grounding isn't a big concern, but on general principle
I like to isolate my rigs for RF to avoid unwanted noise getting in and to
avoid unwanted RF "grounds" from occurring in the house wiring.

Ron AC7AC



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[VR2BrettGraham]

Is the K2's susceptibility to magnetic fields doing more than just
modulating the bits inside that are susceptible?

I do two radio contesting.  I transmit into the driver for one band on
my tribander whilst listening simultaneously to the driver for another
band of the same antenna.  I am CQing at full power on one band &
hoping to hear on the other as well as I could if I was not transmitting
at the same time.  Not quite like VHF contesting in EU, but perhaps
close - certainly more trying for SO2R than for multi-multis at HF.

Some bandpass filtering is necessary to do this, but I really can't tell
that the K2 is worse when it is sitting in the field generated by the 12
volt power supplies that are maybe 20 cm away that powers the small
solid-state amp the K2 my drives.

If anything, I hear more wideband noise about the place when
listening to my TS-950S with the K2, instead of the other way
around.  It reminded me of what we first saw in the 80s at W7RM -
some radios were simply noisier than others.

Plenty of cheap & heavy steel in that 950.  No steel in an Omni-VI
that I once used & its cabinet is all aluminum.  It also didn't bat
an eyelid when those 12 volt supplies were on.

The K2 balks at the power supplies just being on - not from power
supplies supplying amplifier that is key down.

Does somebody have the proper test equipment to look at this?
I was keen to have a go until the 8590-series got poo-poohed
a few days back.

73, VR2BrettGraham

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