Dr Ronald Stiffler SEC technology

[gyulasun]

Hi Nick,
In my reply  above  I also clearly noticed that Dr Stiffler said a no for the 27 MHz frequency.

I think that he very likely uses the 13.4-13.6 MHz range when he retunes his signal generator because the self resonance frequency of his air coil changes whenever the capacitive load on it also changes by any reason like due to the LEDs or when he uses an additional diode etc. 

I do not think that this narrow frequency range is strictly a must to observe because the CREE LED board needs such specific frequency where it behaves like he shows and it would not give as much brightness at say 11.9 MHz (random example) frequency. 

If someone has a signal generator i.e. a stabil frequency source, with the 20-25 Vpp output level, then a frequency sweep could be done on a similar LED board like the SMD CREE within say the 12-15 MHz range and then gradually widening the test range to see how the LEDs brightness behaves.  I do not rule out that his LED board may not work as good as it is seen in that narrow range when the frequency is changed to other frequencies that are say 1-2 MHz below or above that, of course. 
One could speculate that the CREE board has a specific size, arrangement that give a strange excitation for the LEDs only in that narrow range but I would be surprised if that would be the case. 

Notice that to do such frequency sweeps, one needs to have a variable inductance air core coil, known as a roller inductor so that the self resonant frequency of the coil could be matched to the changing generator frequency. See such roller inductor randomly chosen here for instance: http://www.freewebs.com/antreas555/MIKRO%20ROLLER%201.JPG 

An alternative solution to substitute this relatively expensive roller coil is to make several taps on a single layer solenoid coil of the needed size and place the connections always as the frequency dictates it.
 
I do believe though that his chosen narrow frequency range covers the 13.56 MHz industrial (also very narrow) band where one can use a limited power transmitter without license, quasi all over the world, this can surely be one explanation.    This may even explain the no for the 27 MHz frequency too...  no need for causing unwanted interference.
So crystals can be purchased for 13.56 MHz, that is what I mainly mean here.

Gyula

[NickZ]

   Gyula:
   You are full of great ideas and information. And it may all add up.
   The industrial band, so no guys in white trucks... these little oscillator probably wouldn't reach out the door.

   I've just pulled out a couple of those types of crystal oscillators from old crt monitor, or Tv. The value is not readable.   Can they be tested, or are most of the ones that come on Tvs  13.5MHz, or so? They get rusted easily, and values can't be read.
    I think that we need to pin down the exact type and model of led bulb, at least that it has to have that metal backing.
    Looking on the internet for Cree 13w led bulbs for home use, gives me no results. There are some 13w ones for cars headlight or running light. Doc said they were 60w equivalent, I believe.  I find no such bulbs. There are 40, 60, 100w equivalent, but, no 13w leds that are 60w equivalent. So, I don't know which bulb he uses. But, I think that the main thing is, that it needs to have the metal backing, or it may not have the capacitive gain in output, to make up for all the losses.
And therefore, low efficiency, as far as seeing anything like OU.
   

[Slider2732]

Some fun replies
The 27MHz is only because I don't have others.
There is a PC card *somewhere* that has a bunch of the 4 legged on it, I just can't find it. It's circa 1993 and was kept specifically for those crystals. Happens all the time, throw stuff anywhere and it can be found, put something safe and it disappears !!!
There are many laptop and Pentium III/4 boards though and i'll look on those. Just recently I threw out loads of PII's, for no other reason than thinking I had enough crap around here 
   
Will try the tank idea, it makes sense.

A very kind subscriber on Youtube has sent funds to buy an AD9850 that runs at up to 50MHz. Am also going to order a 1602 screen and perhaps other items to complete it. It means that the frequencies above, below and exacting to 13.6Mhz can be tried !

[NickZ]

   Sweet!!! I hope that you get it soon.

[Slider2732]

me too !

Just had a look at the crystal and it's a COMCLOK CT31AH
Am not finding info on it, but some quick tests with grounding and Vcc'ing have shown that the in series LED on Vcc brightens when an L3 is connected from the output to it. A 0.1uF cap, similarly connected as a tank, seems to make the scope read either 9MHz or 15MHz, flickering between the two. Am sure the loading is the thing because of the noted changes of waveform too.
Will try the 1K etc ideas of Gyula's from the previous page.