[BC] BC] Some Input Needed Re: CBS 400, Mosely TFL-280

[Robert Meuser]

Scott:

 the Volumax did have an asymmetry control. It was a switch and as I recall the max you 
could get out of the unit was 300% positive. If my memory is faulty there I know it was 
way over 125%. Later models may have had just a 100% and a 125% position. I would trace 
the bias lines to the encapsulated clipper module. The control should be easily found.

As for supermod, etc. You sort of have things backwards. Before the late 70s, there was 
no rule pertaining to supermod. The only rule was not to exceed 100% negative mod, there 
was no positive limit. People had homebrew positive clippers on air back well into at 
least the 60s. Problem was not too many TXs could do much positive. I worked at one 
station that was running 500 W with a 20V-3 cut back. We did some positives. The problem 
came when the BC-5 HA hit the market in a stealthy way. This was essentially one box with 
a 5 KW RF section and another box with a full 10 KW modulator. The few stations that put 
these on the air were in large markets and raised havoc with the 50K stations there. This 
was a time when there were still a lot of plate mod TXs running as mains. Once the arms 
race started heating up with new 317Cs and MW 50s going into service, the FCC was 
pressured into establish a cap. They REDUCED the limit from none to 125%..

R



On 10 May 2005 at 12:16, Scott Bailey wrote:

> Robert,
>    Of all the CBS Volumemax boxes if ever seen, I don?t remember any asymmetrical controls
>    on that 
> Box.  Bear in mind, those boxes were built before the early 80?s term ?Super Modulation?
> came about.  This is were the Commission made it legal for AM?s to do 125% positive
> modulation.  You may want to use a Inovonics 222 to increase your positives.  I?ve got one
> of those boxes on the shelf, and it has a positive peak pot on it and it will give you up
> to 130% asymmetrical modulation.
> 
> Good Luck!
> 
> Scott Bailey
> WMRO-AM
> Gallatin, TN
> 
> > I know the CBS volumemax is a Wideband AM AGC. Does anybody know if it 
> > will do asymetrical limiting? I want to hook it up between my Ranger 
> > and Stock mike and possibly a Turner Plus III in the future. Will this 
> > work? I want to Beef up my AM Audio and Especially my SSB Audio. Also 
> > how would i set this up? I know most HAM/CB Stuff is 600 ohm, but i am 
> > not sure if they are balanced or unbalanced so how would i hook the audio thru the
> > processor.
> > 
> > Any help would be appreciated. I'm just looking to do something worth 
> > while with these.
> > 
> > Also what exactly is the Mosely TFL-280?
> > 
> > Thank You,
> > 
> > -----------------------------------------------
> > Rev. Robert P. Chrysafis
> > Universal Life Ministries (ULC)
> > http://www.ulc.org
> > -----------------------------------------------
> > http://www.part15.us
> > http://www.freecycle.org
> > -----------------------------------------------
> 
> 
> 
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