Based on the recommendations from members of the reflector, I ordered
Hyperikon 4Ft and 2Ft LED tubes to replace my fluorescent tubes. I thought
I would pass on my results. My main reasons for replacing the existing
fluorescent tubes are; I get tired of having to replace them every few years
as they go bad, and it's getting harder to find a place for disposal (they
contain a small amount of mercury). The big box stores only accept small
CFL's.
I ordered:
(12) T8 LED Tube Light Bulb 4Ft, Single-End, Clear, 4000K (Daylight), 18W
(4) T8 LED Tube Light Bulb 2Ft, Dual-End, Clear, 4000K (Daylight), 8W
(Note there is free shipping for orders over $100, and also a 10% off
coupon)
I measured the noise generated by the fixtures before and after the change
using two receivers:
HT set to 137MHz / 3 element 137MHz Yagi / 45dB attenuator (this is my
standard power line noise hunting arrangement) positioned at 5Ft from the
fixture.
Flex 6600 with 5 element 10M Yagi, 100Ft away, pointed towards the fixture.
4Ft Tubes (used in kitchen, large closet, and basement work area)
Prior to removing the existing fluorescent tubes and ballasts I confirmed
they did not generate any significant RFI.
I replaced the four 4Ft fluorescent tubes with four LED tubes and removed
the ballasts. The new tubes are fed with AC from one end of the tube.
The noise floor increased about 8dB on 137MHz. I could not see an increase
on 28MHz although my noise floor there is currently about S-2 to the West so
I could not measure below that level (I'm working on a PLN issue to the
west).
I was a little concerned about the noise increase at 137MHz, so I used a
Fair-rite Medium Snap-On 0431164181 (thanks K9YC) and made an intermediate
adapter with the left over black and white wire from the ballast removal. I
used 4 turns through the Snap-on and I spliced that adapter between the AC
line and the grouping of tombstone wires using wire nuts.
The metal center cover for the fixture was then replaced and measurements
taken again.
This time the noise level taken at 5Ft was very low, perhaps 1dB above the
137MHz normal noise floor. The 28MHz noise floor remained low.
Based on this success, I installed a second 8Ft fixture with similar
results.
2Ft Tubes (these short tubes are used in the food pantry and small closets)
Prior to removing the existing fluorescent tube I confirmed it did not
generate any significant RFI on either 28MHz or 137MHz.
I replaced the single 2Ft tube. These tubes require an AC power wire to
each end of the tube.
The noise floor increased about 18dB on 137MHz. I was a little surprised
considering this is a small tube. I could hear the change on 28MHz, but
about 1dB change (but remember my base level is currently higher than
normal).
I made up another adapter using 4 turns of the left over black/white wire
through the Medium Fair-rite Snap-on.
This addition cut the noise level down to from about +18dB to +10dB at
137MHz. An improvement, but not as quiet as the 4Ft tubes.
It's not clear why the 2Ft tubes are noisier than the 4Ft. Perhaps the AC
conversion used in the end of the tube is different because it is being fed
from both ends of the tube.
Fortunately, the 2Ft tubes are only on for short duration since they are
used in small closets and the food pantry.
If your antennas are directly over your house, using the 2Ft tubes might be
an issue. It appears the 4Ft tubes should not be a major issue, especially
with the Snap-on ferrite.
I was also curious if there might be any significant power savings from
changing the 4Ft bulbs since they tend to be on for long periods of time.
Assuming the total of all fixtures (Kitchen, closet, work area) are run
about 10 hrs per day, and the cost of power is $0.14 per KWH, looks like
savings would be about $5 per month, excluding any gains for the A/C unit
not having to remove heat generated by the old tubes and ballasts. Likely
about a 2 year payback for the change-out.
Jeff, W4DD (Atlanta)
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