[RFI] Cree LED Bulbs?

Tue Mar 12 06:47:16 EDT 2013

Everyone hates to be a jerk, but are these part 15 devices?  At some point
that may need to be invoked....

73,
Joe kk0sd

-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of Dale
Sent: Monday, March 11, 2013 11:41 PM
To: Mike Ryan; rfi at contesting.com
Subject: Re: [RFI] Cree LED Bulbs?

Mike,

I ran into a keyboard problem and accidentally sent my prior posting before
it was complete.

To finish ...

Yes, I think you have a problem and one way to get going on fixing it is to
go visit the K9YC web site, as has been posted here many times.  If you are
lucky, judicious application of ferrite chokes and/or beads onto the low
volatge lines of EACH lamp head might bring the problem under control.  My
guess is that the interconnect wiring is playing "antenna" for most of that
hash from the switchers.  You will most likely need to treat each cable from
each head, so I hope your neighbor is cooperative.  

Good luck and continue to keep us posted.

73, Dale
WA9ENA  

-----Original Message-----
>From: Mike Ryan <mryan001 at tampabay.rr.com>
>Sent: Mar 11, 2013 11:27 PM
>To: rfi at contesting.com
>Subject: Re: [RFI] Cree LED Bulbs?
>
>The box that these lights come in from Lowes says they are LED lights.  I 
>bought one today and I am sending it to a friend to take a look at along 
>with a power supply.  He wants to look it over to see what can be done. But

>for now it appears that I am scr...d, blued, and tatooed.
>-M
>
>-----Original Message----- 
>From: Dale
>Sent: Tuesday, March 12, 2013 12:21 AM
>To: ka5s at earthlink.net ; rfi at contesting.com
>Subject: Re: [RFI] Cree LED Bulbs?
>
>Cortland, Mike, Kurt, and All,
>
>If you go back to my post of a few days ago, it sounds as if I may have 
>scored a direct hit (by dumb accident) on this system; after careful
reading 
>of Mike's information, it does sound like the manufacturer is using a 
>simple, iron core transformer to go from 120 VAC to 12 VAC. That's the good

>news.
>
>Now, one thing I have not seen Mike comment on is if the devices inside 
>those lamp heads are bulbs or LEDs. If they are LEDs, I can tell you that 
>there are several manufacturers out there making specialized ICs that serve

>as the constant current controllers for LEDs. If they are bulbs, then I 
>agree with Kurt's comments about bulbs not caring if they get AC or DC. 
>Either way, the picture I am getting is that we have a low voltage, 
>relatively high current wired distribution system that goes from the 
>step-down transformer to the individual lamp heads. The problem may well 
>then be what's inside those heads, particularly if the lighting devices are

>LEDs.
>
>
>Since cost is always THE driver these days (sad, but true), I can tell you 
>that I have been shocked by the number of app notes I have seen from the
LED 
>constant current guys about circuits to use their chips and in which there 
>is little or even NO suppression of switching noise on the input side of
the 
>device. Some of these chips are meant to run on low voltage AC input, and 
>then the constant current controller is a specialized switcher that outputs

>DC to the LEDs. So, the bad news is that my "guess" about each lamp head 
>containing a small switcher might be correct. If it is, wow - what a mess!
>
>
>
>-----Original Message-----
>>From: Cortland Richmond <ka5s at earthlink.net>
>>Sent: Mar 11, 2013 9:21 PM
>>To: rfi at contesting.com
>>Subject: Re: [RFI] Cree LED Bulbs?
>>
>>On 3/11/2013 2125, Cortland Richmond wrote:
>>> On 3/11/2013 1952, Mike Ryan wrote:
>>>> The landscaping lights turn out to be 12 volt AC powered and not 12
>>>> volt DC powered.  All the suggestions about a car battery and/or an
>>>> Astron or other linear power supply now go out the window.  -M
>>>>
>>>
>>> But the converter is still very likely a switch-type converter;
>>> modern-day efficiency rules often rule out transformers on account of
>>> core losses.
>>>
>>>
>>> Cortland Richmond
>>> KA5S
>>> _______________________________________________
>>> RFI mailing list
>>> RFI at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
>>>
>>
>>And even if it does use a linear 12VAC transformer, the LED's themselves
>>require a constant current source -- and probably incorporate switching
>>regulators at each fixture. Have you contacted the system maker?
>>
>>
>>Cortland
>>KA5S
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>
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