[BC] Scope for Mod Monitor...

[Bill Croghan]

	The day I met Dane Erickson 25+ years ago, he was still working for
the FCC and started out handing me a polaroid of an oscilloscope showing my
station over modulating.  Heck of a note to end my first week there.  He
showed me how they modulated an FM generator, watching for the nulls on a
spectrum analyzer that showed the proper modulation index for the defined
100% modulation and observing the demodulated signal on an o-scpe.  They
then calibrated the vertical on the O-scope to that point, and started
watching the stations modulation.  The over modulation was obvious.  I
learned a lot that day!  I still use that system to check my own modulation
monitors.

Bill

Bill Croghan CPBE WB?KSW
Chief Engineer, 
KOMP/KXPT/KENO/KBAD
Lotus Broadcasting
Las Vegas, NV
Email to loteng (at) lvradio.com
Phone 702-315-3030
Fax      702-876-6685





-----Original Message-----
From: broadcast-bounces at radiolists.net
[mailto:broadcast-bounces at radiolists.net] On Behalf Of Jerry Mathis
Sent: Wednesday, July 19, 2006 11:28 AM
To: Broadcasters' Mailing List
Subject: Re: [BC] Scope for Mod Monitor...

On 7/19/06, Robert Meuser <Robertm at broadcast.net> wrote:
>
>
> The FCC measure ALL modulation with a scope. This includes FM. Jeff W
> and Willie have both offered valid ways to set positive mod using a
> scope although negative peaks are all that really matters..
>
> R
>
>

I, and I bet others, would be interested to learn how you check FM
modulation with an oscilloscope.
-- 
JM
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