I Cut the Ferrite Successfully!


John H. Bryant <bjohnorcas@...>
 

I finally got time to try cutting a small ferrite bar on my diamond-bladed tile saw.  I'd been cautioned to use plenty of water so as not to damage the annealing. I did.  It cut VERY easily and cleanly. I could tell no rise in temperature by touch, immediately after making the cut. It worked like a charm.  Thanks to everyone who made suggestions last week.

Someone asked why would you want to cut a ferrite bar??? Well, one reason might be if you were making a large bundled bar antenna where the final bundle is several bars in cross section (usually 3 or 7) and several bars long.  One way to help the lines of magnetism not see the end (butt) joints between individual bars is to stagger the ends at least one bar diameter... two is probably better. If you stagger the ends of the individual bars, you end up with a ragged end at the front and back of the bundle.... so, you might want to cut things off flush, for magnetic as well as aesthetic reasons. 

Another reason...mine in this case... is jamming a large high-grade IF filter in a little bitty radio... the E100. Since I intend to DX with either a larger ferrite bar or with a normal outside antenna, the stock bar is only needed as the core of an inductive coil arrangement for the outside antenna. It could also be used to pick up local stations when no outside antenna is attached. Neither of those functions require the size bar that comes in the E100 and I desperately need the space for the IF filter, so, I just cut an inch off'n mine and I'm happy as a clam.  Cutting the 3.3 inch bar to 2.3 inches did not change the inductance of the coil much, so sliding the bar a little farther to the center corrects the alignment. Losing 1/3 of the bar length should reduce sensitivity and nulling capability somewhat, but in this application, that is plenty OK.

If you've read this far and don't own a tile saw, you'll be happy to know that Lowe's stores have them to cut customers tile and I'll bet that Home Depot does, too. Likely catching the staff at a quiet time and crossing their palm with a bit of silver could get your bar cut very nicely.

Thanks again for the suggestions!

John B.
Orcas Island, WA, USA
Rcvrs: WiNRADiO 313e, Eton e1, Ultralights
Antennas: Two 70' x 100' Conti Super Loops, West and Northwest

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