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Re: [Amps] Deep Brain Stimulation for Parkinson's treatment and RF in th

To: John Farber <>, "" <>
Subject: Re: [Amps] Deep Brain Stimulation for Parkinson's treatment and RF in the ham shack
From: Kimberly Elmore <>
Reply-to: Kimberly Elmore <>
Date: Mon, 4 Aug 2014 09:30:29 -0700
List-post: <">>
My son Type I diabetes April 2004. By August 2004, he was recommended for an 
insulin pump. We fund the Medtronic had the best features, but before we went 
down that road, I called Medtronic and asked to speak to engineering.  

Their engineers are very aware of RFI/EMI and were in the process of planning a 
trip to the EMI laboratory maintained here at the University of Oklahoma for 
testing of the their latest products. They had originally planned to test their 
newest designs for compatibility for something like 100-3000 MHz, but they 
started asking me questions about of antennas, power levels, frequencies, 
modes, etc., and based on my query extended their protocol to 500 kHz to 3000 
MHz.  At least the insulin pump passed all compatibility tests. I regularly run 
1500 W on 160 m through 10 m and my son's pump (which uses a 406 MHz data link) 
has never been affected in the least. It was the first time I'd ever spoken to 
anyone in any engineering department that knew about ham radio but was not 
themselves a ham.

However, it was affected when he inadvertently entered a room containing a 1.5 
T MRI imager. The exposure to such a strong magnetic field affected the pump to 
such an extent that it had to be replaced, though it was done under a trade-in 

Call Medtronic and ask to speak to engineering. When you get that far, ask to 
speak to someone in the EMI department -- they will connect you with people 
that can answer all your questions and, if they can't will find out. 

Kim N5OP

On Monday, August 4, 2014 2:29 AM, John Farber <> wrote:

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 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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