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Re: [Amps] 4CX1500B

To: "R.Measures" <r@somis.org>, GGLL <nagato@arnet.com.ar>
Subject: Re: [Amps] 4CX1500B
From: "Carcia, Francis A HS" <francis.carcia@hs.utc.com>
Date: Thu, 22 Sep 2005 14:04:45 -0400
List-post: <mailto:amps@contesting.com>
This is the only accurate way to know the real number. 

-----Original Message-----
From: R.Measures [mailto:r@somis.org] 
Sent: Thursday, September 22, 2005 1:23 PM
To: GGLL
Cc: AMPS
Subject: Re: [Amps] 4CX1500B

With 0db attenuation, take the S meter reading at the adjacent 
frequency, tune to the fundamental frequency, add attenuation as needed 
to give the same S-meter reading as before.  The # of db of attenuation 
is how many db down the total IMD is.

On Sep 22, 2005, at 7:38 AM, GGLL wrote:

>       Hello Rich, have my best wishes for you and family to be ok., I
(once 
> again)
> have a question for you, please see below:
>
> R.Measures escribió:
>> On Sep 21, 2005, at 3:28 PM, robert briggs wrote:
>>
>>
>>> I have received several query's about the Super Cathode Drive method
>>> on my 4CX250 B amplifiers.
>>> The amplifier's take around 100 watts of drive power for 600 watts
>>> output.
>>> When the drive input is correctly matched the Grid ("screen" ) 
>>> current
>>> is 1 to 3 Ma with the amplifier loaded.Anode voltage 2500 vdc.
>>> Idle current for a pair of tubes is 25 to 30 Ma.
>>> According to Orr in his note's "QST July 1967 IMD 3rd order would be
>>> -46 db 5th order
>>> 49 db.I have no measuring equipment to confirm this.
>>
>>
>> The main tool needed to measure total IMD is a second SSB receiver --
>> preferably one with a double-filter -- tuned c. 4KHz above or below 
>> the
>> signal being measured.
>
>       Rich, can you briefly describe me how can I do that test?. What am I

> looking
> for at the second receiver?.
>
> Thanks in advance
>
> Best regards
> Guillermo - LU8EYW.
>>
>>
>>> The point I am trying to establish is whether this setup would be
>>> applicable to the 4CX1500B.
>>
>>
>> The 4cx1500B already has low IMD in grid-driven config.
>>
>>
>>> Bob VK3ZL..
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>
>>
>>
>> Richard L. Measures, AG6K, 805.386.3734.  www.somis.org
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org

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