On Fri, 12 Feb 1999 13:41:18 +0000 "Jim Thomson" <firstname.lastname@example.org>
>Carsten,Rich,Carl. Re the RI-40.
So who is the manufacturer Jim?
I had thought it might be more junk from Aneheim.
The main problem with this roller
>is that shaft only protudes out one end. Unfortunately,it's out the
>wrong end! Tapered pitch should be at back with shorting strap at
>Thats how it was done on old RI-50 coil.The RI-50 didn't have the
>tapered pitch. Thr ri-40 is identical frame,but with tapered
>pitch,inductance has dropped from 50uh down to 40uh(overkill for
Forgive my missing something here....who is RI ??
>The "10 amp contacts" consists of FOUR 10 amp gold contacts,(2 per
>side) that pinch the ribbon.The ribbon does not move.The gold
>are on heavy silver plated bar that spirals around the ribbon. There
>a 3/4" square silver plated shaft running down the center of the
>coil,complete with more heavy contacts that ride on all 4 sides.4
>fingers grab the disc at both ends. All these contact surfaces are
>bigger than those found on any radio corp switch.
That is VERY impressive.
After playing with
>several rollers over 25years,I'd say this one from sson is the best
>designed,trbl free one of the lot. The biggest problem with the edge
>wound rollers from Multronics and Henry radio is their "pickup
>It rides on the edge of the edge wound roller,like a small pulley.
>SSON ones,with the 4 x gold contacts, pinch BOTH SIDES of the ribbon
>tightly.Although the price sucks,it's the best built/designed one to
Have you priced a Multronics recently ? Actually $245 is not bad for a
3000-5000W dissipation class tube..
The entire ribbon is covered in green RF conductive grease. I
>doubt anyone will run 2.5 amps with a 3CX-3000A7. More like 1.5 amps
>6000=5500w out. With a Q of 9-10, 15 amps of circulating current
>results. I doubt Carsten is planning RTTY.
Amen, Rich runs his numbers as they suit his argument, not reality.
I wound some 3/8" tubing
>mine,stuck on end of ri-50,and at right angles,for high bands. Simply
>crank roller to zero inductance,and use the tubing for 10-15m. The
>of the ri40/ri50 is made from 3/4" x 1 1/2" solid Micarta (HV
>fibreglass). They have been selling that roller for a long time.I
>it would pass the test of time,but that remains to be seen in my
Many tnx for the very credible info Jim.
73 Carl KM1H
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