On ‘Interference’

So I’m operating at my parents QTH at the moment, and after a Discone related incident that prevented my mother from unlocking her car (Discones are very wide band & have a wide aperture , and her FOB is 433MHz, so 70cm repeater use was problematic), she has always been ‘interested’ in HAM caused QRM.

Naturally, when she saw my 20M 1/4 vertical (aka a large antenna), her mind conjured up all sorts of images of pissed off neighbours with pitchforks. This wasn’t helped by my bragging about how strong the finals were in my new FT-101E.

Of course, the question came up: Are you causing interference?

I thought about explaining how I had checked to make sure I wasn’t overdriving the PA section, how 7MHz is quite different to 477MHz etc, but the truth of the matter is that a) it would mean nothing to her and b) even a perfect station can overload poorly designed consumer appliances.

There was only one thing to say: “Well Mum, I don’t know, but no one has knocked on the door!!” For obvious reasons, this answer didn’t quite satisfy, but I reiterated that I had a license, was operating correctly and efficiently, and that it was beyond my legal rights (not to mention obligations), to go into all her neighbour’s homes and inspect there equipment!

Lastly, I spoke a little louder to her to demonstrate the effect of a 3dB power increase, and she was satisfied with my explanation that such an increase in power would be next to meaningless if she was listening to my voice 10m away!

And there you go… The AF QRM surrounding HF QRM is generally more interfering… 😉

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