[BC] 492x -494x and 300 Hz RBW...

[Burt I. Weiner]

Keep in mind that 73.44 only requires 300 Hz RBW for measurements 
with 11.5 kHz of the carrier.  Beyond that you can use 1 kHz 
RBW.  When I was using my 494AP for NRSC measurements I used 100 Hz 
RBW for the close in measurements, which will accomplish the intent 
of 73.44.  I made a statement in my reports in the methodology 
section about using these RBWs.

One of the things you want to be careful of is that many of the older 
analyzers did not have the low noise floor necessary to easily allow 
you to go out to 1 Kilometer and be able to see 80 dB below the 
carrier (assuming the man made noise would allow it with any 
instrument!), especially on lower power stations.

Burt

At 02:34 PM 10/9/2007, you wrote:
>From: Mike Holderfield <mikeholderfield at gmail.com>
>Subject: Re: [BC] Tektronix 494x Spectrum Analyzers...
>To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
>Message-ID: <470B9161.9020704 at gmail.com>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>Good to know on the 492. I was thinking about option 03
>giving 300 Hz but was obviously confused.
>
>One that has not been mentioned that is often seen on ebay is
>the IFR A-7550. It will do 300Hz RBW and I have used one for
>AM NRSC before. And can be found with a tracking gen and AM/FM
>demod.
>
>
>
>Burt I. Weiner wrote:
> > None of the 492/494 series, including the 494AP that I have will do 300
> > Hz RBW.  They have 10 Hz, 100 Hz, 1 kHz, 10 kHz and 1 MHz RBW.
> >
> > The 2712 will do 300 Hz RBW and is a fairly decent unit.  The 2710 will
> > do 300 Hz RBW but is basically a cable TV unit.  I would advise staying
> > away from the 2710.
> >
> > Burt

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at earthlink.net
K6OQK