[RFI] [Magic Band EME] site test of LED 4 foot T8 tube lights

donovanf at erols.com donovanf at erols.com
Sat Jul 18 13:21:39 EDT 2020

Hi Dave, 

I replaced 30 florescent lamps in my shack and workshop: 


The RFI silence is deafening! 

Thanks for your very valuable tip. 


----- Original Message -----

From: "David J. Schmocker" <kj9idave at charter.net> 
To: donovanf at starpower.net 
Sent: Saturday, June 13, 2020 1:40:57 AM 
Subject: Re: [Magic Band EME] site test of LED 4 foot T8 tube lights 

hi Frank: 
You're most welcome. You may want to just buy 4 bulbs first, install then test those to ensure you see same quiet result in your QTH (because some hams told me the lights I bought were highly noisy). 

One other thing about the lights I chose is you can (if you look up at the bulbs) see the individual LEDs within the long glass tube. This doesn't bother me, but my XYL did comment about it (I chose the clear lenses so as not to block any light output). 

Here's what I purchased (factory-direct / internet from the Hyperikon website): 

bulbs: https://www.hyperikon.com/led-lighting/t8-led-tube-light-bulb-4ft-single-end-powered-ballast-bypass-clear/ SKU: 841000631 clear lens 3000 deg K and select whatever quantity you need. 

Then I ordered the tombstones from same company (standard non-shunted tombstones) but I did this by asking Hyperikon customer service for the standard non shunting tombstones (they figured out the P/N). Although I asked them to ship them with the bulbs, the tombstones arrived in a separate shipping container. It worked fine. 

I like the soft (yellowish) color just as my wife does. However the higher color temperatures throw slightly more lumens of light. I don't regret our choice now as the existing fixtures with fluorescents replaced throw probably 50% more light than we had from those old worn down fluorescents. 

I hope your results are as good as mine Frank. 

Let me know if I can help you with any more details. 

73/ 161, 
Dave KJ9I 

On 6/11/20 11:14 PM, donovanf at starpower.net wrote: 

Hi Dave, 

Thanks for your very informative email. My old electronic ballasts 
raise my 6 meter noise floor by 6 dB when I beam west towards 
my house. Would you have chosen something other than 3000K 
now that you've installed it (wifely objections aside...) 

Please provide a URL for the exact RFI free LED lights you're 
using, or enough detail so I can purchase exactly the same product. 

Did you purchase on the internet or in a brick and mortar store? 

Did you purchase the tubes separate from the tombstones, or were 
they packaged together? 


----- Original Message -----

From: "David J. Schmocker" <kj9idave at charter.net> 
To: magiceme at googlegroups.com 
Sent: Tuesday, June 9, 2020 5:05:52 PM 
Subject: [Magic Band EME] site test of LED 4 foot T8 tube lights 

Prior requests to this list found some helpful guidance but inconclusive recommendation on which LED lights would be RFI/EMI quiet when used at a 50MHz EME site. 

This email is to report my 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 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. 

I see no change in my WSJT v10 or WSJT-X signal level with these lights all on or off. When Rx level is set to 0dB, it stays this way. 

Antenna is 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. 

Prior to this purchase, I sought data/input from others' experience. The recommendations I received varied wildly (from RF quiet to RFI terrible). 

I first tried four bulbs and after finding no change in Rx noise level, I added the rest (still no change in Rx noise level). 

Short of testing them in a shielded EMI test center (Hyperikon could not supply such testing data), I opted to test them myself at home. 

I hope this data is useful. 73, 

Dave KJ9I 

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