[Top] [All Lists]

[AMPS] Re: RI-40 roller coil

To: <>
Subject: [AMPS] Re: RI-40 roller coil
From: (
Date: Fri, 12 Feb 1999 20:11:16 -0500

On Fri, 12 Feb 1999 13:41:18 +0000 "Jim Thomson" <>
>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 
>Cul......Jim VE7RQ

Many tnx for the very credible info Jim.

73  Carl  KM1H

You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at
or call Juno at (800) 654-JUNO [654-5866]

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>
  • [AMPS] Re: RI-40 roller coil, <=