[HBR] HB Receiver

[Byron Tatum]

OK Jim-
    I won't pull any plates on my tuning caps. Thank you for the technical 
information. I look forward to getting some shop time on this project.
----- Original Message ----- 
From: <N2EY at aol.com>
To: <hbr at mailman.qth.net>
Sent: Friday, August 04, 2006 9:54 PM
Subject: Re: [HBR] HB Receiver


> 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
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