On Mar 19, 2005, at 6:44 AM, GGLL wrote:
> Hello Rich, may I ask a question?; you state below that running
> less ALC (rig + amplifier system) produces more PEP output, my doubt
> is, when there's some ALC action, that's because all is running at
> full PEP capabilities and you begin to overdrive, so why running less
> ALC would produce more PEP?. I heard also in the past a comment that
> some ALC would produce a somewhat useful compression effect.
> Many thanks in advance and our best regards for you and your family.
Guillermo -- I am posting this to AMPS because it's something that
might be of general interest.
- Amplifiers typically use unregulated anode supplies. Thus, the more
average power one drives them with, the more anode-I is drawn, the more
the anode-V decreases, and the less anode-voltage the tube sees. Less
anode-V means less PEP.
- When I hear someone using way too much ALC, it's a good bet that
his/her amplifier has a serious deficiency.
- cheerz
>
> Guillermo - LU8EYW.
>
> R.Measures escribió:
>> On Mar 18, 2005, at 6:40 PM, VK3HE Craig wrote:
>>> If you concerned about IMD use the 4cx1500B. At low screen
>>> potentials it
>>> has a good figure of -43 db below one of 2 tones. Nothing would
>>> prevent you
>>> using the full screen potential with output power and IMD figures
>>> being
>>> similar to the 4cx1000A. The radios IMD will always be greater than
>>> the
>>> tubes IMD, unless you using something like the FT1K5 in classA.
>>> These days
>>> ALC design faults are more responsible for bad IMD than the below
>>> average
>>> IMD numbers of the radio.
>> Amen, Craig -- ALC design faults can be countered by using the lowest
>> level of ALC that is detectable. This, however, is considered an
>> anathema on the 11m band. In actual practice, using a typical
>> post-xcvr amplifier, running less ALC produces more PEP to the
>> antenna than is the case with running maximum ALC.
>>> Craig
>>> VK3HE
>>>
>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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