Date: Fri, 24 Sep 2010 07:34:41 -0500
From: donroden@hiwaay.net
Subject: Re: [Amps] Pulse tuning
The fallacy of the whole "pulse tuning" theory is that most amateurs
are looking at an analog meter ( averaging ) when they should be
looking at an oscilloscope
( peak-reading ) and tuning for the most linear peaks. You can force
an analog meter higher while the peaks WILL NOT increase .... only
flatten out as they hit the emission ceiling. This is a form of RF
compression similar to low level speech compression, and it could be
argued that soft tubes or a soft power supply
will produce a higher average-to-peak ratio than a new tube or a stiff supply.
## excellent point. I hated using my Coaxial Dynamics pep meter, simply
cause it has a super long.....'hang' time. A scope works better. The best yet,
is using the Array Solutions wattmeter's. Just tune for a peak on the auto
ranging bargraph. Once peaked, I then look at the numerical display, which
has several hang times to pick from [use the fastest].. then you can literally
tweak the last watt out of it. The bargraph is plenty good enough, and way
better
than the scope. On any scope, you are only looking at the top 1/2 of the
scope,
so the resolution is not that great. Scopes are not linear, they are V squared
/ 50 ohms.
So, I ask this ............
In the SSB mode, do receivers respond to peak or to average power ?
## The S-meter in a SSB RX responds to PEAK power. Your ear, however
responds to the AVERAGE power of the recovered audio. Having said that, the
AGC in
the RX wil probably trigger off the peaks, so the guy who is loudest on the
S-meter, will
control the rx's agc.
Jim VE7RF
Don WA4NPL
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|