HBTE Group Topics

Erik, Thank you for the post. I also have a couple of the AD831 modules and want to try them for the SA project. How exactly are you connecting the LO to AD831's? If putting a LPF on the signal input

I assume that's an ADF4351. Jerry

Mixers tend to mix everything available, not just the stuff you expect. And with some mixers at least, the unwanted (and wanted) products can get reflected back in to make another set of permutations.

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: > with just 18ma of current draw on Rx, it can't do a good job of > looking at weak signals in the presence of strong signals. doesn't quite hit the mark. The si4432

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

> Now I'm using 110MHz as second IF and 10.7MHz as 3rd IF (for the resolution filters) Should work fine, cheaper too. But the PX1002 is drop in with no tuning required. > I did this for my own build

On Thu, Jan 10, 2019 at 12:07 PM, Jerry Gaffke wrote: Something like PX1002 SAW filters at 86.85mhz might be a better choice than 10.7mhz for a second IF, avoid image trouble.Now I'm using 110MHz as

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 to

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 your

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?

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