On 5/23/2016 6:52 PM, wrote:
rickman wrote:
On 5/23/2016 6:05 PM, David Ryeburn wrote:

I've kind of liked end-fed wires as antennas ever since, though now I'm
well aware of their limitations, and, with a pacemaker inside me, I no
longer dare use one. Balanced lines and center-fed doublets are a
nuisance when you go backpacking, but I do want to be able to hike back
out to the car afterwards.

What is wrong with pacemakers that they can't make one that functions
around radios and microwaves?

Lack of space for installing the faraday cage.

Pacemakers DO function around radios and microwaves.

http://www.heart.org/HEARTORG/Condit...13_Article.jsp

Lol! Devices that have to work should be designed to work properly in
the very low level fields that occur in every day life. It's not really
hard. There are any number of engineers who can do that.

Here's the list from your reference. Notice that even MP3 players with
earbuds are a risk!



Devices with risk

Anti-theft systems (also called electronic article surveillance or EAS):
Interactions with EAS systems are unlikely to cause clinically
significant symptoms in most patients. However, the American Heart
Association recommends that you:

Be aware that EAS systems may be hidden or camouflaged in entrances
and exits in many businesses.
Don't stay near the EAS system longer than is necessary.
Don't lean against the system.

Metal detectors for security: Interactions with metal detectors are
unlikely to cause clinically significant symptoms in most patients.
However, the American Heart Association recommends that you:

Don't stay near the metal detector longer than is necessary.
Don't lean against the system.
If scanning with a hand-held metal detector is necessary, tell the
security personnel that you have a pacemaker. Ask them not to hold the
metal detector near the device any longer than is absolutely necessary.
Or ask for an alternative form of personal search.

Cell phones: Currently, phones available in the United States (less than
3 watts) don't appear to damage pulse generators or affect how the
pacemaker works.

Technology is rapidly changing as the Federal Communications
Commission (FCC) makes new frequencies available.
Newer cellphones using these new frequencies might make pacemakers
less reliable.
A group of cellphone companies is studying that possibility.
Bluetooth® headsets do not appear to interfere with pacemakers.

MP3 player headphones: Most contain a magnetic substance and research
has documented that placing the headphones too close to the pacemaker
caused interference.

Keep your headphones at least 1.2 inches (3 cm) away from your
pacemaker.
Never rest your head on the chest of a person with pacemaker while
you're wearing headphones.
Both the earbud and clip-on types of headphones can cause interference.
Do not place headphones in a breast pocket or drape them over your
chest.

Extracorporeal shock-wave lithotripsy (ESWL): a noninvasive treatment
that uses hydraulic shocks to dissolve kidney stones.

This procedure may be done safely in most pacemaker patients, with
some reprogramming of the pacing.
You'll need careful follow-up after the procedure and for several
months to be sure your pacemaker is working properly.
ESWL should be avoided in patients with certain kinds of pacemakers
implanted in the abdomen.
Discuss your specific case with your doctor before and after the
treatment.

Magnetic resonance imaging (MRI): a noninvasive diagnostic tool that
uses a powerful magnet to produce images of internal organs and functions.

Metal objects are attracted to the magnet and are normally not
allowed near MRI machines.
The magnet can interrupt the pacing and inhibit the output of
pacemakers.
If MRI must be done, the pacemaker output in some models can be
reprogrammed.
Discuss with your doctor the possible risks and benefits before you
undergo MRI scanning.

Power-generating equipment, arc welding equipment and powerful magnets:
Such as found in some medical devices, heavy equipment or motors can
inhibit pulse generators.

If you work closely with or near such equipment, be aware of the
risk that your pacemakers may not work properly in those conditions.
Follow your healthcare provider's instructions about being around
such equipment.

Radiofrequency ablation (RFA): A medical procedure that uses radio waves
to manage a wide variety of arrhythmias.

RFA is usually performed before the pacemaker is implanted.
Studies have shown that most permanent pacemakers aren't adversely
affected by radio frequencies during catheter ablation.
However, if RFA is performed with a pacemaker, a variety of changes
in your pacemaker are possible during and after the treatment.
Your doctor should carefully evaluate your pacing system after the
procedure.

Short-wave or microwave diathermy: A medical procedure that uses
high-frequency, high-intensity signals for physical therapy. These may
bypass your pacemaker's noise protection and interfere with or
permanently damage the pulse generator.

Therapeutic radiation (such as for cancer treatment): May damage the
pacemaker's circuits.

The degree of damage is unpredictable and may vary with different
systems.
The risk is significant and builds up as the radiation dose increases.
The American Heart Association recommends that the pacemaker be
shielded as much as possible and moved if it lies directly in the
radiation field.
If you depend on your pacemaker for normal heart pacing, your
electrocardiogram (ECG) should be monitored during the treatment, and
your pulse generator should be tested often after and between radiation
sessions.

Transcutaneous electrical nerve stimulation (TENS): A medical device
used to relieve acute or chronic pain with electrodes placed on the skin
and connected to a pulse generator.

Most studies have shown that TENS rarely inhibits bipolar pacing.
It may sometimes briefly inhibit unipolar pacing. This can be
treated by reprogramming the pulse generator

--

Rick C