Teardown: defusing Son of MOAB (?)

[wkb]

Right.. hows that for a subject line? Got your attention I suppose 

Thing is, last Friday I spent EUR 5 at a local HAMfest for acquiring a fascinating piece of kit. In the meantime I think I found out where it came from,
but what exactly its function is remains a bit of a mystery. I hope someone on the EEVblog forum can provide more clues..

[wkb]

more pics

[wkb]

more pics

[wkb]

more pics

[wkb]

More pics.

And some analysis.

Obviously this is something that makes heavy use of (most likely high power) RF energy.  Robust pure copper plumbing, 15kV rated capacitors,
a bi-directional coupler of very substantial construction etc.  It is tunable using the glass-fibre reinforced (?) threaded rod.

Feeding the directional's coupler part# into Google brings me to an MRI unit, 1.5T.

But how this Son of MOAB cilinder fits in the grander scheme of things I still do not know.

Any takers?

Wilko

[wkb]

http://unitedrf.com/product-repair/mri-rf-dc/eto-astex-mks/ is where I found the part# of the bi-directional coupler

[xrunner]

Is it a Klingon warp drive pre-initialization exciter?

[Mr.B]

Is it a Klingon warp drive pre-initialization exciter?

I doubt it.
Definitely of Federation origin.
There are no Klingon markings on the PCB.

[PA0PBZ]

Maybe just me, but I find the pics too small to really see what's going on here 

[wkb]

I kinda (...) dislike the forumsofrware for not doing the rescaling/resizing to its own standards after upload.  The full size images it rejects as (way) too big 

OK: very quick and dirty fix/hack: please find the full size pictures here https://wkb.home.xs4all.nl/SonOfMOAB/

[AF6LJ]

Well I know it is not an initiator for a neutron bomb...
They have Brundy connectors....

Beats the hell out of me.......

[Bud]

Rf high voltage connector -> dual directional coupler -> pi network -> L network -> output stage trim capacitor of some sort -> output terminal.

A heck of RF current must be flowing in those caps/coils

Edit: a directional coupler and matching network, this is what i think it is

Edit 2: if you have a VNA you can measure it. Or estimate frequency from coil diameters and cap values

Edit 3: Magnetic loop antenna coupler ?.

Edit 4: Something like this (pic attached)

[wkb]

Neat diagram Bud!

C1 is in series with the coax chassis connector. For the rest it looks plausible.

Caps are 33pF, all 6 of them.  2 banks of 3 in parallel so 100pF roughly.

I'm still guessing something: matcher for MRI coil?

It is definitely adjustable, that is a factory / service tech job, so not during operation.

Wilko

[T3sl4co1l]

MRI would be reasonable, as they need pulsed RF excitation.

Coupling I would think would be to an inductive "antenna".  It's not obvious if the output L and C match would do (but sure, why not?).

Tim

[URFMAN]

Hello Everyone,

The item that is pictured is an tune cavity for a 53-S23A-64 RF amplifier. This runs at 64 Mhz at 25KW. Nice find.

Eugene Telles
UNITEDRF.com