On Wed, 15 Oct 2003 19:53:46 -0400, "Tarmo Tammaru"
wrote:

Richard,

I went to a Bob Pease seminar a few years ago, great guy.

You are missing one of the points of the simulation. I am not trying to
market an SWR meter. I simulated it with ideal parts so that the instrument
is not affecting the reading. How are you going to measure an SWR of 65:1
with a real meter?

Hi Tam,

A very good question. The Metrologist wouldn't, there are better
techniques that are more accurate.

I did change the source impedance, and it did not change the SWR within the
limits of what I could resolve. In addition, as I told Slick a couple of
months ago, I used a real meter (Kenwood SW2000) to measure the SWR with two
different source impedances and two different load impedances, and the
source impedance made no difference.

That too is unremarkable. The difference is not resolved at one point
as I have demonstrated.

I don't know that the Harris transmitter is the same as what was described
in Circuit Cellar. The Harris has no modulators and no linear amplifiers;
just a bank of 65 CW power modules that get switched on and off and
synthesize the desired envelope power at something like a 20 KHz rate. Sort
of a D/A converter that runs at a power level of 50 KW.

No, this misses the mark considerably. The lowest bit rate is half
the Fo of the transmit frequency (typically the bit rate is equal to
the Fo). It is accomplished with a ROM lookup table to achieve the
modulation (much like the Circuit Cellar Ink articles by Don Lancaster
but with significant differences too as his discussion was strictly
CW).

73's
Richard Clark, KB7QHC