[Heath] Fixing Heath Tube transmitters with an HP-410B VTVM

[Wilson]

Good grief.
If u have the peak voltage you have the RMS more accurately than all those 
conversions!ARRL is your friend: 
http://www.n9xh.org/license/pcara_general_upgrade_lesson_07.pdf
WL

-----Original Message----- 
From: Kenneth G. Gordon
Sent: Wednesday, January 15, 2014 11:37 AM
To: Robert Myers
Cc: heath at puck.nether.net
Subject: Re: [Heath] Fixing Heath Tube transmitters with an HP-410B VTVM

On 15 Jan 2014 at 4:12, Robert Myers wrote:

> Is there an easy way to do the calibration on the higher RF scales of
> 30V, 100V, and 300V RMS?  I don't have a test instrument to generate
> these values at such a high level.

Actually, I think you do: I assume you do have a 50 ohm dummy load, and a
transmitter?

First, measure the true resistance of your dummy load to as close accuracy
as you can. This will be your "R".

Then using a calibrated oscilloscope, accurately measure the peak-to-peak
voltage of your RF wave (which hopefully is a sine wave) into your dummy
load at various output powers.

Then use the formula PtoP=2*pi*RMS to find your RMS voltage. (I think my
memory is accurate about this forumla)

Lastly, use P=E^2/R to correct those RMS RF voltages at those various
powers.

This should give you those voltages you seek within a decent precentage of
accuracy.

Ken W7EKB
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