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eHam Forums => RFI / EMI => Topic started by: HFCRUSR on April 09, 2018, 06:21:23 PM



Title: Question About Street Lights
Post by: HFCRUSR on April 09, 2018, 06:21:23 PM
I just got a letter from PG&E stating they're going to replace our old sodium vapor streetlights with new LED lights. I'm asking you guys here what does that mean for RFI? I suspect that I'm getting RFI already from some of these sodium lights as I get certain buzzing at nightfall. I'm hoping teh new LED ones emit less overall. Anyone know about this stuff? Thanks.


Title: RE: Question About Street Lights
Post by: WB4SPT on April 09, 2018, 07:28:08 PM
See if they will get you the head to test.   I was given, once upon a time, a LED cobra head street light.  It contained a 24V dc output switching power supply.  about 3 or 4 Amps worth.   I don't recall if it was a RFI issue, it was too bright for me to keep on in my small back yard.   ;D


Title: RE: Question About Street Lights
Post by: NK7Z on April 10, 2018, 06:47:33 AM
I was involved in our City's testing of new LED streetlights, with regards to RFI.  All that the city had for testing were fine here.  No issues of any kind.  Of course they were new.


Title: RE: Question About Street Lights
Post by: HFCRUSR on April 10, 2018, 11:33:18 AM
Thanks for the replies! I guess I can look forward to at least some of the RFI in HF to go away maybe. I have 4 of those sodium lights right near me.


Title: RE: Question About Street Lights
Post by: AE5GT on April 10, 2018, 07:36:06 PM
LED lighting uses a switch mode supply in most cases .  The short answer is ...it depends. I used LED track lighting in the shack , the amount of noise was highly dependent on the manufacturer, all were bad ...some much worse than others . I went back to low watt halogens ...problem solved. Lighting is much better too. Cheap LEDs have poor spectral distribution , loads of light but you cant see anything.


Title: RE: Question About Street Lights
Post by: HFCRUSR on April 10, 2018, 08:14:55 PM
LED lighting uses a switch mode supply in most cases .  The short answer is ...it depends. I used LED track lighting in the shack , the amount of noise was highly dependent on the manufacturer, all were bad ...some much worse than others . I went back to low watt halogens ...problem solved. Lighting is much better too. Cheap LEDs have poor spectral distribution , loads of light but you cant see anything.
We'll see how she goes-don't tell me there'll be a crapload of switching PSs all over here :P Here at my shack it's all good old incandescent bulbs (can I say that?) but all throughout this building they have those curlys plugged into every socket they got. The PG&E letter claims  that the new LED lighting will of course use less power but will provide much better light for drivers and pedestrians alike! Yaay.


Title: RE: Question About Street Lights
Post by: K8BYP on April 19, 2018, 10:31:35 AM
LEDs dont make RF, the power supplies do.

Anything that an LED makes should be at microwave (?) frequencies.

PS I bought a commercial LED panel light and divorced the PS, placing the PS on the floor and panel on the ceiling. The wiring between the two radiate RFI!

I shoulda known better..its not severe, but...


Title: RE: Question About Street Lights
Post by: IW5CI on May 24, 2018, 08:08:40 AM
Unfortunately i have bad news. 10 days ago in my street, the sodium light where replaced by new led lights this is the result:

https://youtu.be/u2pTZdTDo1o

i have contacted the light company and they will investigate about the cause of the noise (from 14mhz to 50mhz)


Title: RE: Question About Street Lights
Post by: NK7Z on May 24, 2018, 10:01:25 AM
Time to bust out the loop and see where it is coming from...


Title: RE: Question About Street Lights
Post by: HFCRUSR on May 24, 2018, 10:08:49 AM
IW5CI thanks for your video. Boy that's pretty bad noise. It sounds like a noise that maybe could be almost eliminated by the NB. Is it? Or is it just too strong for that? I couldn't see any NB settings on your display.


Title: RE: Question About Street Lights
Post by: N4UE on May 24, 2018, 03:17:08 PM
I watched the video and have one comment.
I've moved a lot in my professional career, and some locations had severe power line noise.
If the LED lights were the root cause of your problem, wouldn't the noise be constant?

It 'looks' like typical loose hardware/insulator arcing to me. It typically comes and goes randomly, just like your video.
Perhaps the installation produced the problem?

In any case, if you have a good RFI Investigator (as I do) he/she should be able to pinpoint the source easily.

Good luck....

ron
N4UE


Title: RE: Question About Street Lights
Post by: IW5CI on May 25, 2018, 02:23:10 AM
The noise blanker completely eliminate the noise, but we know that there is a price to pay for that.... some distortion on strong signals and a worse intermodulation performance.
Fortunately i have fresh good news.
Yesterday the light company called me. The team engineer is an ham operator. I sent him the video and his supposition is in line with N4UE , he suppose that one of the fuse holder in a light pole has intermittent contacts.
Next week they turn off the single light pole until they find which one cause the noise.
I hope this will solve the problem.
I will inform you about the solution of the cause.


Title: RE: Question About Street Lights
Post by: IW5CI on May 30, 2018, 12:53:51 AM
After some in the field analisys with my ft-817 , i managed to find the source of the noise. It was an old sodium light in the street that was not working anymore. The electric company immediately powered off the light pole and now the problem is solved.
Now the radio spectrum is very clean and i can say that LED lights are not a problem for Ham radio if are choosen of good quality (no chinese lamps and power supply).


Title: RE: Question About Street Lights
Post by: ZENKI on June 01, 2018, 03:24:56 AM
Thats the secret to having quiet  LED lights "not chinese junk" that have fraudulent standards marked on them and dont meet any recognized international standards. But our politicians allow the importers to sell this stuff in our markets while prosecuting local companies!

One bad LED light and your HF career is over in ham radio. Especially the LED floodlight type lights.

After some in the field analisys with my ft-817 , i managed to find the source of the noise. It was an old sodium light in the street that was not working anymore. The electric company immediately powered off the light pole and now the problem is solved.
Now the radio spectrum is very clean and i can say that LED lights are not a problem for Ham radio if are choosen of good quality (no chinese lamps and power supply).


Title: RE: Question About Street Lights
Post by: NK7Z on June 01, 2018, 05:19:04 AM
Now that yoru RFI is ended, take a spectrogram of your now clean RFI environment, and save it.  See:

https://www.nk7z.net/sdr-rfi-survey-p1/

for how to do this.  Once done, you have a standard by which you can compare your RFI environment over time.  I take one for each band every few months.  It has paid off in deciding what is RFI, vs what is not.