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Life is full of learning opportunities and I'd like to share one I had today. I'm trying to measure the signal quality of a SI5351 based signal generator set to 12MHz and using a 30dB attenuator at

That thing I threw out there: doesn't quite hit the mark. The si4432 just can't handle very large signals, but that's what attenuators are for. Dynamic range could be quite large, determined in part

An FCC document with actual measurements. http://dtsheet.com/doc/1380487/si4432-rf-performance-and-fcc-compliance-test Seems that for an adjacent signal 1MHz away the rejection is at least 50dB

I'd looked at the SiLabs ISM band data transceivers pretty hard before, hadn't dawned on me that they could be useful as a UHF spectrum analyzer. Very cool. Datasheet says works from 240-930 mhz, has

I read somewhere about using a si4432 as log detector with 120dB range directly at 400mHz or higher with buildin sw defined resolution filter 6khz to 600khz. This way? you only need one mixer, once

Should work fine, cheaper too.? But the PX1002 is drop in with no tuning required. Have you put up a description of that thing? Sounds right. They fully characterize their parts, and something

Now I'm using 110MHz as second IF and 10.7MHz as 3rd IF (for the resolution filters) I did this for my own build VNA that can run in SA mode with switchable DSP resolution filters Doing the same

These SAW filters for the 915mhz ISM band are quite cheap at $2, under $1 in quantity, 40dB down at 15mhz out: ?

Thanks for taking the time to explain further Erik. So sharp filters and mixers with good isolation is the key then, good to know. Please keep us posted on your progress. And if I get around to

1: Between IF1 and IF2 so: 2510.7MHz -> 110.7MHz -> 10.7MHz 2: Got rid of leakage of LO's (bumps in first part of spectrum of first post) and got rid of mirrors. The IF1 filter is actually 100MHz

Erik, ? can you please elaborate the following: 1. The 3rd IF@110MHz, was put after IF2@...? Or in between IF1 and IF2? 2. How and why did that affect performance? (Trying to learn here so links

I added a third IF at 110MHz.?Now performance is acceptable. Two examples: Wide scan:?200MHz output of a SI5351 through 50dB attenuator to see the harmonics. The actual maximum scan frequency is

This morning it occurred to me -- an MMIC on micro-stripline will basically amplify ANYTHING from DC to daylight, so I googled on "MMIC noise source." It led me to a site which showed a HB noise gen

You can also use the base/emitter junction of a random transistor in place of the zener for the noise generator portion Jim

Jim, I do not have much more than what I posted.? As to a design for UHF, I am not the best to answer that.? You guess looks reasonable to me but that is like asking Ronald McDonald to check over

Doug, Do you have a sample circuit for a noise generator that goes an octave or two higher? Would you be willing to speculate on stripline / SMD construction techniques to go up to or past 1 GHz? My

I want to test filters and once again Santa stiffed me on all the fancy test gear I wanted.? It could be my fault as my chimney leads to the boiler.? Anyway, I have an rtl-sdr and an upconverter so

Some pictures: The complete analyzer: Signal left to right: Input low-pass filter (green), mixer (blue module), IF1 filter (big black brick) ,mixer (blue module), IF2 amplifier (green module), IF2

For the PC I started from scratch using .net libraries. I like the Specan SW as its pure C but that also implies it is too much effort to add functionality? The arduino SW can easily be made to work

The arduino SW is a rewrite/combination of various SW's It can be used as a standalone tool controlled over the serial interface The ADF4351 library is a rewrite of something I found but spur