[Amps] 4CX1500B

[R.Measures]

Correct. Congrats.

On Sep 22, 2005, at 10:42 AM, m.ford wrote:

>
> Ok, so we are using the same meter for both measurements
> and at the same level of meter deflection. The actual measurement
> is taken from the step attennuator therefore the quality of the S meter
> has no bearing on the measurement unless it is sticking.
>
> Mike k1ern
>
> ----- Original Message ----- From: "R.Measures" <r at somis.org>
> To: "GGLL" <nagato at arnet.com.ar>
> Cc: "AMPS" <amps at contesting.com>
> Sent: Thursday, September 22, 2005 1:23 PM
> 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..
>>>> _______________________________________________
>
>
>

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