[Heathkit] SB-401/HW 101 Final Questions

[jeremy-ca]

----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at verizon.net>
To: <Heathkit at mailman.qth.net>
Sent: Friday, May 23, 2008 4:06 PM
Subject: Re: [Heathkit] SB-401/HW 101 Final Questions


>
> Neutralization works much better if you use Heathkit's "Other"
> method which was published in a service bulletin: i.e., remove
> plate and screen voltages from the final amp tubes, connect an
> oscilloscope or HF VTVM (HP-401C) to the antenna jack, and
> adjust for minimum output.


Another option is to use a seperate receiver as a selective voltmeter. Just 
be sure the screen voltage is removed first! Use the minimum drive to give a 
midscale S meter reading with the AVC shut off.
That was often the only way I could completely neutralize some rigs, 
especially Drake's, and I do it currently with the TS-830.



> Replacing the 4 diodes in the balanced modulator with hot-carrier
> diodes will often make a big difference too.

The 1N5711 is an excellent Schottky/hot carrier diode for this application. 
They also reduce distortion when used in place of general purpose germanium 
or silicon diodes used in product detectors.

Carl
KM1H


>
> Ken Gordon W7EKB
>