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[AMPS] Peak reading vs True peak

To: <amps@contesting.com>
Subject: [AMPS] Peak reading vs True peak
From: jono@enteract.com (Jon Ogden)
Date: Wed, 23 Jun 99 09:39:29 -0500
>In tuning high power amps, a CW signal will drive the watt meter to a
>given level while reading the PO on the average watts scale of the meter
>(Autek WM-1).

Peak and average power for a CW signal is identical.

>Then switch the watt meter to "peak", and modulating with a SSB note,
>the peak level is not much higher. The amp has 3, 3CX800A's, and should
>carry max PO. Is it?
>

A lot depends here.  First of all how good is your peak reading meter?  
How fast is it?  SSB voice peaks are pretty short.  My Daiwa has a peak 
hold function and using that, my peak power is the same as on CW.  Also, 
how strong are you modulating?  Is your mic gain set correctly?

>Also, I have noticed some watt meters advertising TRUE peak power
>readings, like the new Amertron AWM-30. Is there a difference between
>peak power and True peak power?

Sounds like MFJ-style advertising.  Peak power is peak power, IMHO.

> Am I reading the real SSB power, and is
>there a needle delay on the upswing of the plate meter and the peak
>power meters?

Sure there's a needle delay.  That's why you really can't see peak power 
on a normal meter.  The movement is too slow to catch the peak.  I think 
a peak meter will typically have some sort of detector and dampening 
circuit in it that will allow detection of the peak and will remember it 
after the peak is passed.

Bottom line is if you are modulating correctly, your SSB peak and CW peak 
powers should be the same.

73,

Jon
KE9NA




--------------------------------------------------------------------------
The Second Amendment is NOT about duck hunting!


Jon Ogden

jono@enteract.com
www.qsl.net/ke9na

"A life lived in fear is a life half lived."


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