Spectrum Analyzer vs TIny SA

[@wd8dsb]

Hi FEPLabs, there was really no difference when you turned the harmonic check off compared with it being on when using the TinySA. What happened is that when you reduced the frequency range the location on the screen where the 2nd harmonic is located moved to the vary far right side of the display. The second harmonic of 146.52 MHz is 293.04 MHz and since you changed the upper frequency to be 300 MHz versus 350 MHz the second harmonic location moved to the very far right side of the display right below the vertical axis labels (right below the -80 axis label). You will also note that at 8:24 in your video you had reduced the frequency range and the RBW was at 112 KHz and the 2nd harmonic is very obvious but then at 8:31 in your video the RBW changed to 621 KHz which raised your noise floor which made the 2nd harmonic much less obvious. A smaller RBW setting will lower the noise floor and provide a better signal to noise ratio regarding the signal of interest versus the noise floor. Looks like the TinySA did a fantastic job, and it was working just like it should. Just FYI, Don

[@HOAHamRadio]

Some day I gotta learn this sciency stuff and the fancy gadgets. It all seems second nature to you in the way you explain it. Thanks.

[@ErikKaashoek]

Curious why you where using 5dBm/division on theRigol???. Now it was not possible to see the 2nd harmonic with 10kHz RBW so not visible if the 2nd marker was positioned correctly. Why is the output power of the transmitter differ with the RBW? Was 10KHz too narrow to catch all the power of the FM modulated output?

[@FEPLabsRadio]

All I was looking for were harmonics less than -40db down from the primary signal.

[@DonzLockz]

thanks Jim, I'll be a scope expert in no time! :)

[@FEPLabsRadio]

Then you can show me some stuff - I am never 100% sure of what I'm doing at times.

[@DonzLockz]

​@@FEPLabsRadio haha, I'll never catch up. 😆

[@TheSmokinApe]

Nice work Bubba 👍

[@FEPLabsRadio]

Thanks 👍

[@frack4oil16]

Howdy. Can you share the make/model for the attenuator/dummy load? Thanks!

[@FEPLabsRadio]

Howdy! I got that off of ebay, it's a Celwave DL-200. I got mine from Martin RF Supply - www.ebay.com/str/martinrfsupply

[@frack4oil16]

@@FEPLabsRadio oh so many thanks for getting back to me so quickly!

[@barrykery1175]

Interesting to watch. But you should have shown third order harmonics. Always check for odd order harmonics, not even. Barry

[@FEPLabsRadio]

Thing is, if the second harmonic is in the basement, as was the case, anything beyond that will be pretty much non-existent.

[@wd8dsb]

@@FEPLabsRadio Hi FEPLabs, depending on the circuit it's not uncommon for the odd harmonics to be much stronger than the even harmonics (push-pull amplifier as an example), and that's why Barry Kery recommended that you also check (display) the 3rd harmonic. As an example I just checked a Baofeng UV-5RB and its 3rd harmonic is 8 dB stronger than its second harmonic. Just FYI, Don

[@germanjohn5626]

second harmonic, not first...first is the fundamental

[@FEPLabsRadio]

Yeah I missed that during editing.

[@UpcomingJedi]

With the Chinese putting out these tiny "instruments" on a chip which seemingly do the same basic thing as this $800-1000 Rigol, why would anyone but Uncle Sam pay up to $52,000 for a 'real' spectrum analyser?

[@DIYJim-wx6hq]

@@UpcomingJedi because Uncle Sam buys them for F-16’s instead of cheap HAM radios.

[@Gw0wvl]

Comparing a Sports car to a horse and cart 🤣 .... You can't expect the Tiny SA to perform as a lab SA , It's just not in the same league , It's ok for basic work , To give an indication of what's going on , But it's not going to give the same results as a 10K SA , Any one who doesn't know this is living in the land of Fairytales .

[@FEPLabsRadio]

Sure. And not everyone is going to spend the money on a spectrum analyzer. A Chevy and a Maserati are worlds apart, still do the same thing.

[@HowToHam_Tom]

Jeem- I went into this video not expecting them to be the same. Nor did I think that was what you were going to try and do. I also went into this with zero knowledge of the tinySA at all other than having heard of it anecdotally. THANK YOU for being so brave as to post this video out for the feeble minded souls such as us to learn from. I hope none of the brainerds out there got dumbed down by it. ;) Now, off to search for an affiliate link…

[@germanjohn5626]

Lol comparing a Maserati to a matchbox car.

[@FEPLabsRadio]

Right!

[@const_8]

Do you seriously believe that the Rigol DS 815 is a Maserati? With its phase noise close to that of the Tiny SA? Both analyzers are toys, however Tini SA is much cheaper and also more compact - this is useful when it makes no sense to carry a normal analyzer with you.

[@wd8dsb]

Hi German John, the "matchbox car" probably did just as well as the "Maserati" in this video (actually better), but impossible to tell as there was some confusion in the settings of the TinySA and where the 2nd harmonic was actually located as the location moved on the TinySA screen because the poster of the video changed the frequency range on the TinySA part way through the test. Also the RBW changed during the test which changed the signal to noise ratio due to the change in the noise floor which confused the poster. Therefore with the proper settings the TinySA probably was doing a fantastic job, and probably did as well as the Rigol except his settings on the Rigol did not even allow us to see what was happening where the 2nd harmonic would be located as his vertical scale on the Rigol was inadequate to see the noise floor (or the approximate -87 dBm 2nd harmonic signal per the TinySA) and his markers on the Rigol do not appear to be actually set for the correct frequencies so the marker value displayed for the 2nd harmonic was probably just a display of the noise floor and not the signal strength of the actual 2nd harmonic signal. Really impossible to see how well the TinySA did compared with the Rigol in this video but based on my experience they both would likely produce similar results when properly configured (actually the TinySA did better because its auto ranging vertical axis allowed us to see the 2nd harmonic signal which we had no chance of seeing on the Rigol due to its vertical axis setting not being correct). Just FYI, Don

[@RichardsWorld]

The best SA is the one that you bring with you.