[Test-Equipment] LF Ailtech 7514 and noise sorce

[Chris Trask]

>
> > Ed,
> >     What frequency range?  For HF I use a General Radio 1383 noise
> > generator, an HP-141T spectrum analyzer, a homebrew 30dB amplifier, and
a
> > 3dB pad.  Works well as long as you're measuring a NF of 3dB or higher.
> >
> >   I have an Ailtech 75 PANFI and an Ailtech 136 precision receiver, but
no
> > low frequency noise source to go with them.
> >
>
> 10 MHz to 10.5 GHz will work for me
> WA3BZT
>

Ed,
    Well, that helps define what you need to do NF testing, and that
frequency range is not going to help you much in terms of economizing.  You
can use the Ailtech 75 (as well as later models) if it has the internal
mixer option, or with an external mixer.  That will require a fairly quiet
signal generator for the LO.  Plus, you'll need two of the Ailtech/Eaton
noise sources to cover that bandwidth.  You can get the Ailtech 75 fairly
cheaply, but that generator and the two noise sources are going to cost you
a bit of $$.

    The NF test set that I described earlier is fairly inexpensive, but it's
only useable to 20MHz unless I want to add a mixer and LO to the noise
generator, then I can do 40MHz bandwidths at any centre frequency provided I
calibrate the then converted noise source so that I have the correct noise
power density for the calculations.

Chris

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