Measuring FM Deviation using the MIN/MAX Method (030b)

In this video I will be showing you how to measure FM Deviation using what I call the "MIN/MAX" Method.

This provides the *peak-to-peak* deviation. If you are interested in the *peak* deviation, then divide by 2.

To do this you will need a Spectrum Analyzer.

Yes, I *did* notice that the MIN hold envelope for this radio is a bit funky. Normally they will be very similar to the MAX Hold trace, just narrower. I don't know what is up with that....yet.

Time Markers for Your Convenience
----------------------------
00:05 Introductory Comments
01:01 What do we need to do this?
01:38 CAUTIONS
02:01 Spectrum Analyzer Settings
02:52 Test Setup-the Tour
03:33 Making the Measurement
07:12 The Special Case of the CTCSS Tone
09:47 Final Comments and Toodle-Oots
-----------------------------

[htify]

Excellent video! Thanks for sharing your knowledge.

[DucatiMTS]

Very clear instructions. Thanks so much Ralph. 73 de GI8WFA

[radioaficiona]

An excellent work. I learn a lot when I watch your videos. Thanks . GBY🙏

[ScottsRadios]

Wouldn't you divide the end number by 2?
When testing a monoband 10 m FM transmitter with your method. I'm coming out with approximately 6.125 kilohertz deviation.
I think realistically the number should to be divided by 2.
I don't think my transmitter is designed to produce 6.125 kHz of FM deviation on 10 meter.

[Atreju]

Great video!
Short question, why are you measuring the first deviation at -40db and then the CTCSS deviation at -30db? Is there a reason why you choose this levels?

[WalterBrollo]

Your video is very interesting. I don't understand why you recommend using a 100 or 10 Hz RBW but in the video you use a 3 KHz RBW. Did I see wrong? Thank you :)

[xenia]

Terminology is the difficult part of testing and understanding. Peak to peak vs. peak seems to get unmentioned in most FM discussions including those from ARRL.