CB transmitter test

I just finished installing a new CB antenna on my Jeep and thought it would be prudent to test for any interference with my pacer before I drive around some of those wild roads.

The antenna is installed on the left rear corner of the Jeep about 4' from my pacemaker location when I'm sitting in the drivers seat. The top of the Jeep is fiber glass so does not provide any shielding.

So I ran several tests where I used a small pulse oximeter that shows my heart beat waveform to look for even small variations in pacing. Each test involved transmitting on several channels, whistling in the mike, and moving around a bit while watching the oximeter pulse. I tested at the following locations:
1. Drivers seat.
2. Standing outside the Jeep by the driver side door.
3. And finally about a foot from the antenna.

None of the test produced any change in pulse. Since I am nearly 100% paced in my ventricles there would have been a very noticeable change in my pulse if there was any problem The last time I had the Medtronics rep interrupt pacing my HR dropped to under 40.

So bottom line I can say that a 5 watt transmitter in the 27MHz band with the antenna only a foot or two from the pacemaker doesn't produce any effect.

Another interesting thing is that while I was getting ready for the the test, but had no power to the CB, experienced a couple of PVC's. If I wasn't aware of their nature and was apprehensive I could easily thought the transmitter was causing my feelings. I got quite a laugh out of it.

best,

frank

6 Comments

Radiation

by biker72 - 2010-10-24 07:10:17

It would be interesting to see what the actual field strength of the signal was. Five watts from an omni antenna running at maybe 50-60% effieiency is probably a lot less than a local tv or radio station putting out mega-watts.

Put a 1kw linear amp on that radio and we may have something....:-)

True

by ElectricFrank - 2010-10-24 09:10:39

I agree. Of course most of us don't get anywhere this near a commercial radio/TV station.

And of course no one would run a KW linear on a CB rig. That's illegal Heh Heh Heh.

This is the reason I test each new possible source of interference I encounter. The variables of frequency, power, modulation, attenuation of each individuals skin, etc can make a difference.

cheers,

frank

Mt Bigelow

by ElectricFrank - 2010-10-25 01:10:00

Nope. I didn't get south of Mesa. Spent most of the time in the area just north of Flagstaff.

Back in the 80-90's when I lived in Tucson I used to explore around Mt Lemmon though.

frank

Bigelow INterference

by ElectricFrank - 2010-10-25 03:10:43

You were pretty close to multiple powerful transmitters. One of these time when I visit my daughter in Tucson, I'll have to run up the highway with my trusty pulse oximeter on to see what happens.

CB v. cell phone

by ccmoore - 2010-10-30 03:10:12

Interesting, you were testing a 5 watt CB system without interference, I don't see what all the caution is about partial watt cell phones unless it might be frequency range.

later,
Charlie

I agree

by ElectricFrank - 2010-10-30 04:10:58

I've actually been around even higher than that. A while back I was standing next to cars in the parking lot after a Ham Club meeting talking to friends. One of the folks got out of the car I was standing behind and mentioned that he had just made a distant contact. He was running 100 watts. I didn't have my pulse meter with me, but I sure didn't feel it.

Actually a pacemaker being all metal provides an excellent shield from outside interference. The only way anything could enter is through the leads. With the large difference heart signals and RF interference it would be easy to filter the lead connections.

frank

You know you're wired when...

Your pacemaker receives radio frequencies.

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