[RFI] The ARRL Contest Update for April 1, 2020

AA5CT jwin95 at yahoo.com
Wed Apr 1 14:22:25 EDT 2020

One may, if interested, check the OFCOM website link I posted earlier and 
note that picture posted is indeed an incandescent bulb.

I still have questions related to how the device produced EMI in the 119 MHz
range as indicated on the spectrum analyzer display as can be seen on the
same page.

There may have been un-intentional contact between elements within the bulb
AS this "old timey" bulb used a string (versus a coiled element) of (presumed)
Tungsten suspended from multiple 'hangers' or supports inside the bulb. Note
the hangers top and bottom share common placement within glass top and 
bottom respectively. The bulb in the pix has a 'stamp' on the base of 240V,
assuming AC operation, the peak voltage on a circuit of that nature reaches
approx 340 V pk.

The question of whether a vacuum or an inert gas (as is used nowadays) 
filled the bulb envelope also remains unanswered.

de AA5CT Jim


On Wednesday, April 1, 2020, 1:06:30 PM GMT-5, Michael Germino <ad6aa at sbcglobal.net> wrote: 

"Vintage" A modern bulb made to look vintage or "steampunk" may not have been  Incandescent. Probably a "steampunk led bulb".
Mike73, AD6AA 

Sent from AT&T Yahoo Mail on Android 

  On Wed, Apr 1, 2020 at 3:44 AM, Rob Atkinson<ranchorobbo at gmail.com> wrote:  Sadly, the qrznow article covered everything except what is really
interesting:  the mode by which the seemingly incandescent "vintage"
bulbs radiated RFI.


Vintage light bulbs were the ultimate cause of interference to
aircraft communications in the Glasgow, Scotland airport area, but
finding it made an interesting story on QRZnow.com. Four bulbs were
all it took to be a real problem.
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