I have been avidly following the discussion on rf exposure and the possible
negative consequences on human heart pacemakers. Im scheduled for surgery in a
few months for implantation of two electrodes entering the skull at the top of
the brain and with very precise real -time positional monitoring, the ultimate
placement of two small shielded leads which terminate in snd small gold
electrodes. The area of the brain in which the electrodes are placed in my case
is named the substancia nigra, the meaning of which I take to be important dark
area. It lies way down at the base of the brain near the interface of the older
"animal brain" which controls many autonomic activities and the "new brain"
which incorporates higher thought, math, science, ham radio-sorry I couldn't
resist the opportunity. The salient point to me at least, is the two leads will
traverse nearly the entire distance from the top of my head down
to.approximately the level between my ears, roughly 6 inches in length for each
of the two leads. From the top of the skull the leads are buried
sub-cutaniously (under the skin) down the side of the neck to the area just
beneath the xxx bone where they connect to a sealed battery powered
microprocessor-based controller. The controller sends precisely-timed electric
pulses to the neurons of the section of the brain which is responsible for
initiating and sustaining physical movement such as walking, reaching and
tuning your rig or sending cw. The pulses of current have been found to help
synchronize the more random firing of neurons occurring in the brains of
Parkinson's sufferers. So it can be thought of in gross terms as a sort of
"pacemaker for the brain".
I think you can see why I reckon the current discussion may be serindipidy and
quite relevant to my approaching situation as well. I queried my Neurosurgeon
about all of this and despite his looking me squarely in the eye and displaying
an excellent polished bedside manner as he fielded ham radio-centric very
specific rf-related questions concerning specific frequencies and power levels,
all I was given upon leaving his office, was his promise to seek answers and
get back to me. So far no further word from him. The controller is made by
Medtronics. My attempts to date to gain answers to my questions from Medtronics
have resulted in frustration.
Just as a seat-of-the-pants calculation of most likely frequencies to be wary
of is dependent on the half-wave dipole length of the two wire runs from the
brain implant terminating electrodes all the way down the side of the neck to
the controller. Without the opportunity to measure the leads I have a general
feeling that I probably should avoid high powered transmitters operating in the
roughly 240-230 KHz range. On the subject of avoiding the very powerful ac
magnetic fields produced by popular Linear yt? Amplifiers: I came up with a
very simple but yet very dramatic method to demonstrate the silent, invisible
magnetic flux fields reproduced by the hv transformer typically used in hf
linears.obtain one or more supermagnets typically available for sale for a
couple dollars at any common ham radio, computer or general electronics "geek"
flea market, garage (or as my buddy from New England calls them: tag sales) or
electronics/computer "surplus" stores. To demonstrate the powerfull
ac electromagnetic field produced by a linear amp's hv transformer, simply hold
the supermagnet firmly (I'm serious folks), in one hand and turn in the linear.
For most modern amps using one or more ceramic-metal tubes, there will be a
designed time delay of about 3 minutes before the hv transformer springs to
life so you will most likely have to wait this out. Amps advertised as being
"instant-on" use typically use glass envelope tubes such as the hugely popular
3-500Z units. The amp I built around 1980 which was my attempt to build an hf
amp from the ground up and cover 160- 10 m using a pair of 3-500Z tubes. I
chose to incorporate step start circuitry for both the tube filaments as well
as for the hv. The point being you may find amps using 3-500Z or similar glass
envelope tubes may include a time delay albeit much shorter than 3 minutes. I
used just a few seconds delay for each step start circuit in.my amp.
In any case once the hv power transformer energizes, simply hold the
supermagnet a few feet away from the linear being used for this test. Most
folks to whom I've shown this demonstration have been amazed both by the power
of the radiated magnetic field as well as the consideral distance at which the
field can be strongly felt. In my shack setup my Alpha 99 hf linear sits
roughly 3 ft away from the left side of my body. Upon testing with the magnet
it was clear I've been unknowingly bathing my body in powerful 120 Hz (the
output of a 60 Hz power line frequency doubled by the full-wave bridge
rectifier circuit in the amp's power supply) electromagnetic fields. I know
there have been many studies on the effects of exposure to high levels of
commercial power line frequencies over the years, with no clear consensus over
the highly debated topic. I do remember reading of one study done by NASA in
the late 1950s or early 11-960s which clearly showed that long term exposure to
em fields significantly different from those generated by the human body were
positively shone to cause the physiological effects similar to those caused by
stress. When these effects became apparent, NASA decided to end the testing.
So I'm quite concerned about not only strong near field rf-related exposure
effects on a DBS system but also the effects of exposure to the day-1
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