[amsat-bb] RFI/EMI-quiet LED 48 inch T8 tube lights (to replace fluorescents)

[David J. Schmocker]

Everyone:
Some of us have fluorescent tube-lights in our homes or garages and 
desire to replace them with energy-efficient LED bulbs. However as 
weak-signal enthusiasts, many LED bulbs are electrically noisy.

So I set out to identify and test LED bulbs that are both energy 
efficient and EMI/RFI quiet (starting at 50.2 MHz because I do 
moon-bounce work there).

This need for electrical quiet applies also to 2m and 70cm and other 
satellite bands too.


50.2 MHz test findings:

Test site (KJ9I QTH): N5654 County Road F  Sullivan, WI 53178

Test location: basement of residence (location of these lights)

Test date: May 2020

Test result: no change in WSJT v10 Rx level with all basement lights on 
or off (0dB relative signal level both before and after lights 
illuminated).


Fluorescent light replacement (formerly electronic ballasts) converted 
to direct-wire, single-end fed LED bulbs.

*Hyperikon SKU: 841000631* (XYL requirement was soft-white, so 3000 
degrees K was selected).  18w bulbs.

In May 2020, I installed 14 bulbs (seven dual light fixtures) removing 
the old ballasts and fluorescent tube lights.   I trimmed all unused 
wires to minimum physical length and removed excess wire from fixtures 
that had been attached to electronic ballasts.

The fixtures in which these were installed are typical tin metal legacy 
fluorescent fixtures.

Note:  Hyperikon Non-Shunted Tombstones (end mounts) were replaced on 
only the energized end of each installed LED bulb. The opposite 
(non-energized) end retained the original tombstone with wires trimmed 
off as short as possible.


There is no change in my WSJT v10 (nor WSJT-X) signal level with lights 
all on or off.    When Rx level is set to 0dB, it holds at this level.

Test Antenna is 1 x LFA-HZE-10 (2-inch homebrew round boom design) up 88 
feet Above Ground Level with HA8ET 50MHz LNA fed into SSB Electronic 
LT6S transverter (1dB NF) then to JRC JST-245DX 28Mhz transceiver.


Today I received good news that another ham (Frank W3LPL) also installed 
Hyperikon LED bulbs at his QTH and he also reported 6m RFI-quiet.

I hope this data is useful.   73,

Dave KJ9I


The disclaimer: I have no financial nor any other connection with 
Hyperikon beyond being a satisfied customer of the above bulbs.