{Collins} Re: Fwd: Re: 6146B Neutralization technique



I started reading late, and don't know if we're talking about a KWM-2A
or the 32S-series.

I do know that properly neutralizing the -2A is quite a chore.
There are four different circuits that enter into the neutralization of
both the Driver and the Final. Two of these circuits are coupled, through
C121. The two coupled circuits are the Driver Neutralization and what
Collins called the "Feedback Neutralization." It's not actually a
neutralization
circuit but is R.F. Negative Feedback, to make the tuning of the
Driver-Final combination more uniform over frequency.

Because two of the four "neutralization" circuits are coupled, the total
neutralization job must be done in a particular sequence. The Service
Instructions are to perform the adjustments in the order of
Final, Driver, and Feedback.

I haven't dealt with the 32S-series, yet, but will, one day soon, since
I've got a 32S-1 sitting on the roll-around rack with a red tag on it.
I hope it's not as complicated as the -2A  :)

John Painter
W5LQS

----- Original Message -----
From: "Robert & Linda McGraw K4TAX" <RMcGraw@xxxxxxxxxxx>
To: <ronaldron@xxxxxxxxx>; <collins@xxxxxxxxxxxxx>
Sent: Wednesday, July 21, 2004 10:12 PM
Subject: {Collins} Re: Fwd: Re: 6146B Neutralization technique


In just about all the broadcast transmitters that I've handled, the term
"right side of resonance" comes to mind.  This was accomplished by adjusting
the PA network for resonance as indicated by a dip in plate current and then
adjusting for a slight increase in plate current which yielded slightly more
output.  This increase was always accomplished by effectively reducing the
value of C or tuning to the high side of resonance.  Going to the other side
of resonance did not product an increase in output.  This is true on the AM
rig that I run on 160M. (See my call on QRZ.COM for a pix of the little
rig.)  as well as the grounded grid 8877 that is on VHF.

It's been a while since I've dealt with a pair of 6146's, although I have
just acquired a 32S-1 that I'll get on the air in a couple of weeks or so.
I look forward to seeing just how that PA performs.  I'd expect that when
properly neutralized that I will find that bringing the PA slightly out of
resonance will provide slightly more output and better linearity.

Stay tuned.

73
Bob, K4TAX


----- Original Message -----
From: "Ronald Mott" <ronaldron@xxxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Wednesday, July 21, 2004 6:02 PM
Subject: {Collins} Fwd: Re: 6146B Neutralization technique


>
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> From: ronaldron@xxxxxxxxx (Ronald Mott)
> Date: Wed, 21 Jul 2004 06:04:15 -0500
> To: gmcalmo@xxxxxxxxxxxx, collins-bounce@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: {Collins} 6146B Neutralization technique
> Message-ID: <25178-40FE4DAF-2@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> In-Reply-To: Gene McCalmont <gmcalmo@xxxxxxxxxxxx>'s message of Tue, 20
Jul
> 2004 20:31:34 -0500
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>
> Hi GENE                                                    You might
> just try nurtralizing the 6ah6 driver circit per your book as you didnt
> replace output tubes.
> As for the peak power at plate current dip has always been my final test
> for correct neutralization.
>
>
>
>
>
>
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Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
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Sponsored by the Collins Collectors Association http://www.collinsradio.org
Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
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