[AMRadio] 7285Kc tomorrow/Saturday


Mark K3MSB mark.k3msb at gmail.com
Sun Jan 8 21:19:06 EST 2006


On 1/8/06, Brett gazdzinski <Brett.gazdzinski at mci.com> wrote:

> I am not some kind of 40 meter Nazi, but I like when people tell me
> something has gone
> wacko

I didn't take your posting as being offensive.  I too like to be told
if there's something wrong with my signal.   As I said, I wish you had
broken into the QSO or called me afterwards; I would've been glad to
fiddle with my audio to see what your scope showed.   I've always been
told that my audio is fine, so I've always assumed that the modulation
level was OK.

> Is that how you set the modulation level, by the modulator plate current?
>

Yes.  I've tried a scope now and then (I have an old 60 Mhz B&K), but
truthfully I've never been able to really see when the modulation
level is 100% or other.  I know what ideal waveforms look like (with
test inputs),  but I have a hard time with a typical speech waveform. 
 I guess if I'm really at 20% that would be fairly easy to discern. 
When I used the scope before I was trying to figure out how to tell if
I was say at 70%, 80%, 90% etc,  and never felt I could do it
accurately.

I did acquire a Harris AM 80 Modulation monitor a few months ago.  
This week I'm going to build a "pick-off" box and see what the AM-80
shows, and also try the scope.   "Pick-off" is my own term;  it's
simply a metal box with 3 SO-239 connectors;  two for in and out, and
the third to the monitoring device.  The third is connected to a wire
parallel to the wire connecting the other two which couples the
signal.

I'd like to be able to see what my speech waveform looks like for
various modulation levels.  Having both devices will let me do that.

73 Mark K3MSB



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