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----- Original Message -----
From: Luis Cupido
To: TekScopes@...
Sent: Thursday, February 01, 2007 11:21 AM
Subject: Re: [TekScopes] Birdies on a 492....what's normal?


Chris,

With what signal at the input ?

Luis C.
ct1dmk.

----- Original Message -----
From: "Chris Johnson" <strangequark65@...>
To: <TekScopes@...>
Sent: Thursday, February 01, 2007 4:55 PM
Subject: [TekScopes] Birdies on a 492....what's normal?

> I've got a 492 that I haven't had for very long and I'm still
> exploring the possibilities with it. It has options 1,2, and 3.
>
>
> It's a very clean performer and seems to meet its sensitivity specs
> and is reasonably close to calibrated.
>
>
> I do notice a few birdies in it, and while I don't expect any spetrum
> analyzer to be entirely free of birdies, I'd just like to know if the
> ones I'm seeing in this unit are about normal.
>
>
> Of course it has some noise below 100 MHz. I see a spur at about 34
> MHz that's about 20 dB above the noise floor with the video filter set
> to narrow.
>
> At 41 MHz, there's another spur that's about 15 dB above the noise floor.
>
> At 50 MHz, +25 dB.
>
> At 69 MHz, +8 dB.
>
> At 75 MHz, +12.
>
> At 85 MHz, +19
>
> At 93 MHz, +20.
>
> At 99 MHz, +18.
>
> At 100 MHz, +19.
>
> There's a big one at 300 MHz, +25.
>
> At 350 MHz, +20.
>
> At 400 MHz, +10.
>
> At 500 MHz, +10.
>
> Below 100 MHz, there are smaller spurs between the larger ones,
> typically less than 10 dB above the noise floor.
>
> Above 500 MHz, it's very clean.
>
> The apparent magnitude of the spurs does vary somewhat according to
> the span and resolution in use.
>
> All figures reported are in minimum noise mode with the ref level and
> attenuation adjusted to as to yield the largest apparent magnitude
> of the spurs.
>
>
> So is this about right for a 492 or is it more in need of calibration
> (or even repair) than I thought?
>
>
> CJ
>
>
>
>
>
> Yahoo! Groups Links
>
>
>