Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
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NF and Gain Measurement using SA & Noise Source - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
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but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: NF and Gain Measurement using SA & Noise
Unread postPosted: Sun Jul 11, 2004 5:38 pm
help me to Measure LNA NF & Gain using Spectrum Analyzer & Noise
Unread postPosted: Tue Jul 13, 2004 12:51 pm
Joined: Sun Aug 03, 2003 2:02 pm
Location: Erie, PA
Agilent has an application
note for that here:
Spectrum Analyzer Measurements and Noise
Application Note 1303
- Kirt Blattenberger :smt024
Post subject: Using Noise generator for
Unread postPosted: Tue Dec 14, 2004 9:30 pm
Sorry the Agilent app note referenced in the other reply will not
help you .
see instead /5952-3706E.pdf.
You need to set your
spec. an. to work as a RF power meter.
1. Set IF bandwidth high
as you dare.
2. Set Video filter as low as you have time to wait
3. Set to 1 dB/ div or if youre lucky use a maker at the
centre of your noise.
4. You will need a low noise preamp if the
gain of your device or system (DUT) is gain is less than about 20dB.
5. Check for this - the noise level should drop by at least 10dB when
you disconnect or power down your DUT.
6. If not use minicircuits
or other gain block amplifier to get result 5.
super low noise not
required about 4dB is OK.
7. Connect noise generator to DUT. switch
on, your spec an noise should jump at least 3dB.
8. Apply Y factor
formula to calculate result from generator ENR, ambient temp (ussually
assumed), and change in spec. an. dB reading noise generator off to
on. Y is this dB reading converted to a straight power ratio
factor method formulas are on the net see /5952-3706E.pdf