[RFI] Cree LED Bulbs?

[Pete Smith N4ZR]

Scrood indeed, but the good news is that Lowes and Home Depot (if they 
are carrying the same type) may be big enough to be susceptible to 
pressure.  What these systems are doing is contrary to FCC regs, and the 
RFI people at ARRL HQ (Ed Hare, W1RFI, is very knowledgeable) may be 
willing to get involved.  A few years ago, they scored a notable success 
by getting the makes of the Homeplug LAN hardware to notch out the ham 
bands.

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 3/12/2013 12:27 AM, Mike Ryan wrote:
> 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 ships 
> 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 controiller 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
>> _______________________________________________
>> RFI mailing list
>> RFI at contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>
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