[Amps] Fwd: Deep Brain Stimulation for Parkinson's treatment and RF in the ham shack

[Roger (K8RI)]

On 8/5/2014 11:42 PM, John Farber wrote:
>
>
> Sent from my Verizon Wireless 4G LTE Smartphone
>
> <div>-------- Original message --------</div><div>From: John Farber <kg6i at comcast.net> </div><div>Date:08/04/2014  12:29 AM  (GMT-08:00) </div><div>To: amps at contesting.com </div><div>Subject: Deep Brain Stimulation for Parkinson's treatment and RF in the ham shack </div><div>
> </div>
>
> -------- Original message --------
> From: John Farber
> Date:08/04/2014 12:29 AM (GMT-08:00)
> To: amps at contesting.com
> Subject: Deep Brain Stimulation for Parkinson's treatment and RF in the ham shack
>
> 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 (fmri ?) to facilitate the placement of two small shielded leads which terminate in tiny gold electrodes. The area of the brain in which the electrodes will be  placed is named, in my case, the substantia nigra, the meaning of which I take to be roughly "important dark area". When i fIrst learned of this impressive new surgical procedure which is designed to offer a bit of hope to the many people suffering from the insidious neurological disease named for the physician who first described it, Parkinson's dIsease,  I was very interested. That was because Parkinson's is not much fun. It's usually described by three three.following scary words: progressive, chronic and incurable. In sim
>   pler words.it is a disease which only gets worse, goes on and on and it has no cure. It affects a person's ability to walk, stand, reach and hold things, talk, swallow, control their facial muscles and stabilizing muscles requIred to smile or even sit up.it also causes deep depression and/or dementia In about 60 % of sufferers. The famous actor and TV star, Michael J. Fox established and funded through ongoing very generous donations, many millions of dollars, the Michael J. Fox Foundation which is dedicated to finding a cure for Parkinson's. Mr. Fox by his own admission has been very lucky
>
>   It's located  lies way down at the base of the brain near the interface of the old  er "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 collar bone where they connect to a sealed battery powered microprocessor-based pulse 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 s
>   ynchronize the more randomised 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 serindipidous 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 there has been 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 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. If you would like to perform the demonstration you should 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 electr
>   onics/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 on 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 just  have to wait this out. Amps advertised as being "instant-on" 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.The practical effect noticed is the ac em field interacting with the steady-state permanent magnetic field produced by the hand-held supermagnet results in a very strong vibration felt in the hand holding the supermagnet.
> So I'm interested in both potential problems caused by the DBS system being affected by rf pickup from legal limit hf or 6 m
>   
> r tedday to day.
>
>
>
> e
>
>
>
>
>
>
>
>
>
>
> I
>
>
>
>
>
>
>
>
>
>
>
> .
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> nces

The question this raises for me is, are you measuring the flux out st 
the magnet, ir is it the flux from the super magnet interfering with the 
transformer.  From my magnetics classes, oh so long ago, I'd expect the 
field from the hand held magnet to extend much farther than the closed 
loop in the transformer.  I would expect the magnetic field from the 
hand held, "open frame" magnet

A much simpler and more sensitive measurement would be a simple magnetic 
compass, or a loop of wire connected to an oscilloscope, similar to a 
dip meter.  In this case you are measuring the voltage induced in the 
wire coil.

I would expect the magnetic field from the transformer to drop off 
rapidly.  I'm not sure how you'd get a calibrated reading.

73

Roger (K8RI)


>
>
>
>
>
> Sent from my Verizon Wireless 4G LTE Smartphone
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>



---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com