[Milsurplus] To be 90 or not to be...

[Brenda Gentry]

The regulated 90 volts is for the detector. The RAK and RAL are some of 
the best regenerative receivers ever made, and have the smoothest 
control over regeneration. A  steady voltage is vital to stable 
regeneration control. I have had the receivers over the years, and 
didn't always regulate the 90 volts. For typical use, it doesn't matter 
much. However, for serious DX, the regulation helps get a regeneration 
setting just on the verge of oscillation where sensitivity is maximum.

     B.Gentry, KA2IVY


On 9/2/25 12:17 PM, Charlie L. wrote:
> Since the RAK/RAL has come up, what is the deal with the 90 volts?  I 
> built a supply for my RAK which I acquired first and put in a  
> regulator circuit using a 90 volt reg. tube that I just happened to 
> have, it glows orange, but the radio worked just fine with or without 
> the 90.  My other supply for the RAL is the correct supply for it and 
> got that from Brian KN4R. The only problems so far after a decade or 
> more has been replacing the 1uf caps and other large bypass caps, 
> tubes I have found plenty of.  That one stacked cap under the chassis 
> might be a concern, but if need be, could be subbed with individual 
> bypasses if it ever fails.  The RAK gets its most use during the 
> winter when I am looking for NDB's, using it or a Mackay 128XX, the 
> RAL gets used throughout the year.
>
> Charlie in NC.
>
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