[AMRadio] AM Radio

[Bernie Doran]

It is not that simple. if the drive control controls the grid drive to the 
6146s they will drop out of class c and not modulate properly. second if you 
are driving the linear too hard it will not be running as a linear 
regardless of what the ID states.     Load the linear to what ever you think 
is full output, then slowly reduce the drive to it. the output should fall 
immediately and smoothly, if not, it is not in a linear region.  assuming it 
does fall in a smooth fashion, I would continue to reduce the drive until it 
is down about 15 percent from max.  That is your PEP output under 
modulation. now continue to reduce the drive until the output is 1/4 of the 
just determined to be max.     Keep in mind that the tube plate dissipation 
will now be at least twice the carrier output and you must keep them cool at 
that level.   the power supply also may not be able to handle that load 
under long transmissions.     Regarding the transmitter, you may have to 
reduce the screen voltage to keep the drive in the propper range. the 
quickest method would be to build a resistave pad to suck up the  extra 
power prior to getting to the amp.        Again, it is simply not worth the 
effort for less than 6 DB.    now if you must have a big amp. I have a Henry 
5k to sell you, it will do 1 KW carrier on AM and near 5,000 on cw.  I do 
not even use anymore.  Bernie [  ----- Original Message ----- 
From: "Rick Poole" <wa1rkt at arrl.net>
To: <amradio at mailman.qth.net>
Sent: Tuesday, January 24, 2012 2:35 PM
Subject: Re: [AMRadio] AM Radio


> At 01:53 PM 1/24/2012, rbethman wrote:
>
> >>>>>
>>I simply stated "There is no straight out of the box solution" with
>>regard to taking the FULL Apache power output and make the legal limit.
> <<<<<
>
> OK, that makes sense.
>
> So, here comes another rookie question:  The DX-100 has a "Drive"
> control that seems to do a pretty good job of directly controlling
> the transmitter output.  So, I tune and load my big hairy-chested
> Brute linear to 1500 watts carrier, then back off the DX-100's
> "Drive" control without touching anything else until the amp output
> is 375 watts.  Then I watch the scope waveform and adjust the audio
> level for 100 percent modulation.  Right?  Seems too easy.  What am I 
> missing?
>
> Rick WA1RKT
>
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