Steven Mark´s associate Jack Durban comes forward with more info !

[chadj2]

@Yucca,

I haven't actually run my setup yet but from what I have studied on this subject I would suspect 2 things that could be varying your frequency. First, the air in you spark gap is heating up as the spark fires. This would effect the voltage at which the air breaks down. As I have seen some Tesla coil people running fans through their spark gaps to ensure they fire properly. Also, I am sure that your ceramic capacitors are type 2 or 3 ceramic material which vary quite a bit in their capacitance as they heat up. Type 3 varies more than type 2 check the datasheet to be sure. But these are just guesses. By the way thanks for posting that video.

Chad

[onthecuttingedge2005]

Nice Video Yucca.

I would love to see someone build an EM reflective room and in that room place just one active tesla coil in the middle, around the active tesla coil place a hundred inductive tesla coils that only react to the one active coil so that all other secondaries are inducted to convert the EM field to electrical voltage output. sort of a Tesla coil recycling room.

it would be expensive but it would be the neatest experiment I would ever see and anybody else for that matter.

That would be sweet!
Jerry

[BEP]

@BEP,

Once again thank you for your observations. You have definately convinced me to look again into more thorough shielding. I will leave you alone about your EMP device in the future. I am just a little puzzled as to how you are sure you are not transmitting radio frequency energy. I would assume that you pulse has a rise time pulse period and a fall time which would fall at some frequency. I mean even microwave crowd dispersal cannons have a radio frequency range that they operate at. As far as I understood there wasnt a lot of difference between EMP and HERF(high energy radio frequency). But once again thanks for your time.

Chad

You are welcome.

At best, HERF is a demonstration of the very last part of an EMP. After the relaxation of an EMP, there are very wide band damped oscillations. A typical EMP is a single pulse. Hence the letter 'P' in EMP 

The damage is done during the bubble expansion. Not so much by the expanding magnetic bubble but the charges that fill the void during the expansion - and then the reverse action during relaxation.

If an EMP like action is related to a TPU then I don't think the damped oscillations are needed or wanted. I can imagine the sudden expansion, relaxation and magnetic disconnection/reconnection causing actions at the molecular level.

For me, the rate and sequence of these appear to be the question.
-----

You mentioned looking into better shielding. This is always good but this means you didn't understand my statements about shielding from an EMP 

As far as I know, there are only two components to shielding from a real EMP - mass and distance.

[Yucca]

hi chad,

the air in you spark gap is heating up as the spark fires. This would effect the voltage at which the air breaks down. As I have seen some Tesla coil people running fans through their spark gaps to ensure they fire properly

I can have the ceiling fan on and leave the circuit unpowered for 1 minute and also fan the gap with a sheet of paper, it still starts up at the higher power mode. Only after leaving for an hour will it revert to low power startup mode.

Also, I am sure that your ceramic capacitors are type 2 or 3 ceramic material which vary quite a bit in their capacitance as they heat up. Type 3 varies more than type 2 check the datasheet to be sure. But these are just guesses. By the way thanks for posting that video.

Chad

all output components seem cool to the touch, but maybe thet are heating internally? thanks for giving it some thought, I´ll experiment with this some more.

edit:
my bad... I think its the cap on the HV module sparkgap, it does get quite warm when running, so this is probably the reason. I missed it because I was only considering the components on the aircoil board and the HV input spark gap seemed to run the same by ear, but as the cap gets warm it must change. Thanks for helping me see that.

[xee2]

@ yucca

Could any of you guys with HV/RF experience explain this:

http://www.youtube.com/watch?v=2BFca2xGpaA

I think your coil core is heating up. As iron gets hotter it has less magnetic strength and thus reduces the inductance of the coil. Lower inductance increases frequency.