Coax and N-type to Probe Pieces

TOF work took up most of this week, but I have been working on the problems:

  1. Better Coax – Thanks to Kevin who sent me a link to the “Air Dielectric Cable” and it can handle much higher power then the LMR-400.  I have been trying to track down a source for it in Canada.  Part of the problem is that the bending radius of LMR-400 is 1″, already pretty stiff, and the Air Dielectric cable is 5″ which might be too stiff.  Actually, now that I think about it some more, it doesn’t matter if the cable was completely solid, as long as it can swing with ease, it would still be easier to move a few centimetres than moving a heavy shelf with all the fans, magnetron, waveguides, circulator and water on it.  Coax it is!  Maybe I can find a freely rotatable waveguide transition piece in amongst all those spare parts at the university, hmm…
  2. Better N-Type connector – this is going to be more difficult and here is what I am trying:
    • I am getting a quote from the Canadian division of Richardson Electronics for another Wavguide to N-type transition.  However, the spec makes clear it can only handle a paltry 0.3 KW which is much too low.  I’m guessing they will want $300 to $600 for it anyway..
    • I also have a call into Gerling Applied Engineering, Inc. who has been helpful in the past.  They also make the transitions and might be able to sell or help me solve the problem.
    • It might be possible to use the dielectric from one of the waveguide-to-n-type transitions at the university to replace the one we burned up.  I’m guessing that whatever that dielectric material is made of, it is much better then the one we had because the waveguide-to-N-type connector at the top of the coax has not burned up yet (hmm, I should check, I never looked there for smoke!) It should also be possible to purchase just the dielectric and replace the one we burned because everything else including the probe looks fine.
    • I am desperate enough that I have emailed Shawyer to ask him what probe-to-N-type transition he used and you have been bcc’d.

Another possible solution is to move the probe which leads to a question – Even from our own simulations, it is apparent that the highest power is going to exist within the coax-to-probe conversion point:

The big red arrows are a bad thing!  Is it possible to locate the probe at a different point and decrease the amount of power it sees?  I will try that test on the simulator when I get back from vacation in July.

Unfortunately, eBay has been all but useless in this endeavor…