[Icom] pwr IC746

[Sheldon Daitch]

And as Clete would probably add, when measuring base currents for
AM broadcast stations, with in-line ammeters,  it must be done without
modulation, although Delta RF ammeter sampling coils seem to have
a lot less response to modulation than the usual in-line meters.

Also, a VU meter and a typical voltmeter will read the same on
a steady state sine wave.  It is under dynamic audio that there
will be differences between the readings, specifically as Clete
points out, due to the ballistic characteristics of the VU meter.

From the audio monitoring standpoint, there are peak reading
meters, and there could be as much as 20 dB difference between
a VU meter and PPM on the same audio channel.  The
typical spread is not usually that much, but I did observe
an audio feed that had a high pulse noise that would
drive the PPM much higher than the VU meter reading.
The pulse was simply too short for the VU meter to respond
with any degree of accuracy.

73
Sheldon
WA4MZZ/SV7

Cletus W Whitaker wrote:

> de WB2CPN South Central Pennsylvania   2002.11.17
>
> Adam,
> I've worked where the antenna current at the base of the towers was measured
> regularly.  Of course, the Impedance/Admittance there was established and verified
> on a regular basis.  The other thought you may want to cover is the comparsion of
> VU meters to DB and other meters, and the reason for the ballastic characteristics of
> the VU meters.  I suppose ICOM's meters now don't have the fast attack and slow
> release that we are accustomed to...          73   Clete
>
> ----
> Your Moderator: Dick Flanagan W6OLD, icom-owner@mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.315 MHz
> Icom FAQ: http://www.qsl.net/icom/