[HBR] HB Receiver

[N2EY at aol.com]

In a message dated 8/4/06 9:22:32 PM Eastern Daylight Time, bjtatum at ev1.net 
writes:


> I plan to set the tuning cap back away from 
> panel and make a homemade round tuning dial that will mount on the 3 gang 
> tuning capacitor and to place this dial behind a window on front panel. 

This will work really well. Mount the capacitor on a metal plate, and space 
the plate behind the front panel with some spacers. Put some pilot lights where 
they can illuminate the dial and you can have a really slick looking setup.

The geared mechanism is better than almost anything you can buy.

Just 
> 
> a thought -- this would save on buying an expensive dial mechanism and allow 
> 
> me to use the tuning capacitor as originally done { dial and geared down 
> mechanism}. I imagine I will need to leave only a couple of plates on the 
> tuning cap.

Please don't pull plates!


 Later I will go out in shop and measure capacitance at 3.5 MC 
> 
> then measure it at 4.1 MC on the 3 gang capacitor, this should tell me 
> approx. how much capacitance change I will need to tune the 600 KC range.
> 

The caps in a 3-6 Mc. ARC-5 are 142 uuf per section.  Assuming about 32 pf of 
padding and strays, the RF and mixer coils are 16 uH. 

So for a tuning range of 3.5 to 4.1 Mc, the capacitance should be about 130 
pf at the 3.5 end and about 90 pf at the 4.1 end. That's a capacitance change 
of about 40 pf overall - just about what you get from a BC-455 capacitor.

73 de Jim, N2EY