[R-390] Need a RF slug for a R-390A

[ANTHONY CASORSO]

It was one of the goals of the R-390a (cost reduction) to reduce cost. It is written up in the engineering report. I quote:

 

"

Finally, all RF coils were designed to use this same type of
ferrite core. In addition to their higher permeability, these cores also have
a higher Q, helping to overcome the loss of image response resulting from the
elimination of one RF stage. The VIF coils have also been redesigned for use
of a common core. This core differs from that used in RF coils however because
this application called for a lower permeability, higher Q core.

"

 

And elsewhere in that document:

 

"

Later work
showed that similar results could be obtained using the larger coil diameter
with a ferrite core to replace the powdered iron slug. All the RF coils have
since been redesigned to use the same ferrite core. These new coils also have
a higher Q than those in the current R-390. The variable IF coils have also
been redesigned to use a common core. This core however differs from that used
in RF coils, because a lower permeability higher Q core was needed.

"

 

This document is available on the www.r-390a.net site under "references".

 

Tony


 
> From: Flowertime01 at wmconnect.com
> Date: Thu, 9 Apr 2009 11:43:31 -0400
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] Need a RF slug for a R-390A
> 
> Fellows,
> 
> I think you are right on the R390/A slugs.
> There are only two kinds. RF and IF.
> 
> We could look in the 35P manual and see how many different part numbers 
> their are.
> 
> Roger AI4NI
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