[Test-Equipment] LF Ailtech 7514 and noise sorce

[J Forster]

Most of the SS noise sources are already padded internally with something in the range
of 10 to 20 dB.. Also, padding a source with a ca 15 dB ENR doesn't make measurements
exactly easy. Most of the PANFIs I've seen want an ENR in the range of 14 to 16 dB.

Personally, I would stay away from gas tube noise sources.

Best,
-John



Brooke Clarke wrote:

> Hi John:
>
> Yes, and in addition the VSWR comes into play.  It's good to pad down the noise
> source with a 10 (or better 20) dB pad both to lower any spikes and also set
> the VSWR.
>
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.precisionclock.com
> http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam
>
> J Forster wrote:
> > If you are planning to use the noise source with solid state devices (very
> > likely) you need to be really careful of spikes from gas tubes which can blow
> > input stages.
> >
> > Also, calibration of the ENR of a noise source without a known good standard is
> > distinctly non-trivial. I basically assume a SS noise source is either good and
> > essentially in calibration, or very sick, so test them by comparing an unknown
> > source to several others. If they all correspond well, IMO they are likely all
> > OK. In fact, all of the AILs I have seen are good. I've never seen a bad one and
> > have bought all mine surplus.
> >
> > Best,
> > -John
> >
> >
> >
> > Brooke Clarke wrote:
> >
> >
> >>Hi Chris:
> >>
> >>The 5722 tube was designed to generate noise from DC through 500 Mhz, see:
> >>http://www.prc68.com/I/NSLB.shtml
> >>
> >>The other way is to use a zener or better a noise diode.
> >>
> >>The advantage of the 5722 is the noise is a function of the plate current.
> >>
> >>Have Fun,
> >>
> >>Brooke Clarke