I designed spectrum analyzers for Hewlett Packard as my first job out of collage in 1971. The group I worked in is now called Keysight. They were very expensive but I see you can buy one now for a few hundred dollars and get a spectrum analyzer that works to 22GHz. Wow. I worked on the log amplifier that had a dynamic range of 100dB. Loved this video. I think that this cheap analyzer is mixing the input down to DC but the filter is actually a bandpass with a bandwidth of about 250 KHz and a center frequency of about 200 KHz. Thus when you input a signal you see both the + and - image products of the mixer output spaced 400 KHz apart. The display occupies that plus the bandwidth of the filter so they call it 1 MHz. When the LO is tuned to the frequency of the input signal the output is DC and the filter blocks it so you see what looks like a notch in the output.
Yeah that's very plausible. Thank you! That both side bands are visible seemed obvious. But how is this avoided in the design of professional instrumentation?
@@LutzSchafer It gets very complicated as there are way more things to worry about than just the issue with this cheap spectrum analyzer. But for the question asked I will give a short reply. If you want to analyze .1 to 2.5 GHz, mix the input up to 3.6 GHz. Then the LO goes from 3.7 to 6.1GHz and the difference signal is 3.6 and the sum is 3.8 to 8.6 and can easily be filtered out. Then use another mixer to get the signal down to 300 MHz and another to get to 21MHz where I built the Log amp. These frequencies need to be carefully selected so that harmonics of the LO do not put spurious signals in band so they are picked more carefully that what I did in the above example. Hope this helps.
Let's wait for Andreas' answer ... (but) If you go back you'll find re. "🤠" that he is/used to be a steampunk afficionado... (zurich maker faire 2017) 73 de 🚲
Best "organized" Vid in RUclips! Please never give up your style of "summarization". -seems yet another piece of equipment where I have to know the result before I can measure it... let me check the improvements ;)
@@AndreasSpiess - Yes, definitely on of the best organized tec chanel's over YT. And there are no wrong miss leading or confusing procedures. It's Swiss prescision content!!!
Thank you for wonderful explanation! I got exact image of this spectrum analyzer (LTDZ_35-4400M). I had interest in notch characteristics for CW (Continuous Wave) that 145.55MHz in your video. I checked the circuit diagram and I understood the mechanism of that. Following 2 things are the points of the notch: - The same idea of DCR (Direct Conversion Receiver) - The characteristics of RBW (Resolution Band-Width) filter About the DCR, when we apply the same frequency signal for RF (measurement signal) and LO (Local Oscillator) of the mixer (IAM81008), the mixer output become DC signal. And amplitude of the DC signal depend on the phase difference between RF and LO. However, RBW filter has DC block capacitors, so DC voltage doesn't reach to Logamp (AD8307) input pin. These DC block capacitors are the major reason of the notch characteristics. About the RBW filter, I simulated RBW filter (including DC block capacitors) that using LTspice. It had f0= 200kHz +/- 100kHz of bandpass filter characteristics. When we apply CW to the RF input, Logamp input will appear twin peaks of signal because RBW filter has bandpass characteristics. I think your demonstration of 145.55MHz CW agree to my estimation. Because I seen the frequency difference between peak to peak is 400kHz (=200kHz*2) in your video. I got additional idea from these consideration. It is TG (Tracking Generator) offset frequency. In DCR idea, if LO and TG sweep with the same frequency, mixer output will be DC voltage. In this spectrum analyzer, we cannot see frequency spectrum because DC block capacitor blocks DC voltage. So in this spectrum analyzer, TG (become RF signal) and LO frequency should have offset value such as 200kHz.
Amazing explanation! I was trying to figure out what was causing the notch. This design was used to simplify the mixing stage, using just one, in contrast to "conventional", or "real" spectrum analyzers that uses two or more mixing stages, right?
Let me say thank you for this video Andreas. I had this same device from banggood sitting on my desk and couldn't get it to work, i will be going back to it now that i have a better understanding of it..thank again.
I appreciates how you do the comparison in a very in-depth details. I works as a RF engineer and always find myself lacking in many area. This information is very useful to me on how normal practices are done based on different people and their background. Thanks man!
I used my R&S FSEA20 analyzers almost every day for a seven year period. I got pretty used to these high performance machines that had a noise floor of about -160 dBM at zero span. Made my job easy. These days those analyzers can be had for about 1500 bucks in good working order.
You are right. I see a lot of people buying these old instruments. They are a very good choice if you have enough space and maybe also some knowledge to use/repair them. For you, as a long-time user, this is a perfect fit and not comparable with such a cheap device...
Perfect timing. I just ordered two BF-F8HP radios last week and started studying for my technician license. This week I learned about antennas, SWR meters, and the NanoVNA. So much new information introduced to me in such a short time I feel like I am in college again. Thanks for making this video to supplement what I am already trying to learn.
Thx for the walkthru, well done and I love how you link and make due diligence on these products and link to the relevant parts, that a possible owner can benefit from.(golden) many other channels can learn from the "viewer perspective-awareness" you seem to suit your videos with. well done Andreas. +1 Don't have this Spectrum analyzer but were looking into it as an entry tool to just get familiar with this kind of class apparatus. at around 30 bucks delivered for this unit (no shell), alternatives are not hanging on the threes in this sub 100 bucks environment.
In my small lab I have an anti static workstation. Earthing, wrist strap points etc. Grounding for me, my equipment and soldering station. The sight of the purring cat is cute. Except all I could think of was "THE STATIC!".
I made a receiver with tracking ADF synth and nextion display some years ago. To have a flat power signal, I had to add an amplifier and a step attenuator (controlled by µC). It has to be calibrated ! Now I have +/- 1dB precision. (compared to my keysight at work)
wow this is so cool. I am starting to check out how to build a SDR radio telescope and one video used a cheap spectrum analyzer test the 21cm astronomy hydrogen line. This is a all new learning curve on making a homemade radio telescope using SDR software. 😎 thanks a lot.
Thank you for quality information. I'm using sdr + white noise Zener + spektrum software to align homemade vhf filters. Regarding my application my setup performs similar to NWT. At the end nothing can replace a good sigilent anritsu Hp spectrum analizer. Thanks again !!!
Thanks! I was looking at such a very device just the other day to analyse my antenna design. It's really cool that you showed another device @9m30s that is probably more what I was looking for. Thank you for your good quality videos.
You could say that the Mixer is a Multiplier. If you remember your trigonometry: sin(a)* sin(b) = (cos(a − b) − cos(a + b))/2 This is why the sum and difference of frequencies appear. In practice the Mixer is not perfect and there are nonlinearities that generates also harmonics so you get N*a + M*b (with N and M integers). But the other frequencies and usually much attenuated with a good Mixer.
@@AndreasSpiess I understand that just putting a trigonometry formula in a video can scare people 😆 I'm not a RF guy at all but I find that part of electronics quite stimulating. I just wanted to add some extra for the curious ones that asked themselves "how does a mixer work?"...
Good video. I had a look at this cheap device a few weeks back, my mouse cursor hovered over the 'buy now' button. After watching this review i decided NOT to buy it, save up more money for a proper one. This video saved me $55 and disapointement. Thank you Andreas !!
Great videos :) Love the artificial hand...lol You have a great sense of humor along with great tech knowledge... Thanks for making it so much fun to watch.
Excellent video, as usual, thanks very much, Andreas. That German "Tiefpaßfilter" should be at least 24 years old as it is written "Tiefpassfilter" since 1996. Now I know what a spelling reform is good for.
The solution of removing the display and just add an USB control makes instruments cheaper and, more importantly, smaller. I've made several USB instruments under the same principle. Actually, the video caught my attention because of this. Anyway, loved the video and also subscribed. Thanks for sharing!
Thanks for the video! I found it really informative. I probably would have wanted one of these had I seen them for sale, but as I mostly would use it to measure harmonics from transceivers they are kinda useless. I think for cheap harmonics measurements an SDR dongle and attenuator is the way to go. I already have a Nano VNA for checking filters and antennas.
If I understand everything correctly then this spectrum analyzer uses an low IF frequency of ~few hundred kHz, most spectrum analyzers use high IF that is higher than maximum frequency they can measure. Because of that it is going to see signals that are centered at LO +/- few hundred kHz and that's why there are 2 peaks when you measure signal of that handheld. That's very bad because some signals, like signal from that handheld will appear to occupy twice the bandwidth and have a weird notch in the middle as seen on the video.
Thank you for this excellent review! I have a spare Agilent 6ghz directional coupler and plan to get this for a friend who needs to measure SWR for his home-built 3.5ghz 5G-antenna. It lacks speed and resolution as a spectrum analyzer, but I hope it works fine for plotting S11 curve.
Thanks for the video Andreas. My radio club bought a Rigol Spectrum analyser a few months ago and I wanted something similar for my little work bench and having found this on ebay thought it was a good little project ( I bought the naked board). I've only yesterday finished putting it into a case with N connectors and will be keen to try the new software. Love the cat on keyboard :-) Keep up the vid's, It's good to see a ham doing such a diverse range of topics.
Thanks Andreas a good informative video. I just purchased a unit off AliExpress not the same one you have here but its labled 35-4400MHz with a IN and OUT port and USB port. I hope it will work well for monitoring a wideband Digital DVB-S2/T ATV transmission at 1255 MHz...love your puscat I have a long hair pus too...Cheers Clint - VK3CSJ...
Thank you Guy with a swiss accent. I visited Luzerne for 1 day. At night. It was okay. :) I want a spectrum analyzer. I don't have a use for it right off the top of my head but I would find a reason. Not swiss mentality but hey... this is internet.
Thanks for the great video! After this video I bought this analyzer! I am a developer for electronic devices and I think this device helps me. Lg Szivatz.at from Austria
You saved me $50. I might have bought this for fun. Also from the comments I learned that the Germans have abandoned the old version of "ss" which I learned back in the 1970-s. The "sharp s" which it was called here. (Where is it on my keybord?)
Always looking forward to hearing from you! I’m not into RF much myself (except when having to filter harmonics, hee hee), but your videos are always didactically well prepared so it’s pure joy watching them and there’s always something to learn. And of course I dig cat-lovers, having had my own lab cat for ever so many years. :-) Anyways, thanks for being there, doing all this and even teaching an old fart new tricks from time to time!
in summary: the price difference has its weight, then it depends on the use you want to make of it. $ 3,000 is a great investment for a hobby, so the $ 50 device might be enough, once you compare it to some more advanced device ( hoping you can do it) you have a "touchstone" for your purposes. If, on the other hand, you have to study the behavior of various equipment rigorously, perhaps for work, then you must think of a quality product such as Siglent or of equal quality. Tnx for yours intersting videos Andreas and i'll see you next time!
I most probably will not do a SA comparison on this channel. There are other channels focused on this topic. I just wanted to give some advice to people hoping they can save 2850$ to go to this cheap device ;-) And they should know a little on what they have to look if they buy another one.
@ Andreas Spiess: I completely agree with you: I was also a radio amateur, and I never had a spectrum analyzer .. in reality I was more of a CB than a real radio amateur (even if I had acquired a license and license: my name was Ik4DZF but some time has passed ... 20-25 years !!) and when I built the jpole for 144 MHz I went by attempts trying to respect the project's measurements ... it worked , at least to get on 144MHz repeaters :-)
I do not know a lot of bode diagrams. But the device has a built-in tracking generator. Mind the minimal frequency if you would like to use it for audio.
Very good info..I subscribed and plan to watch more vids. I have added some external filters and a 30db wide band LNA on the input of mine. It has made the spectrum analyzer more useable. It’s still not great, but much better. I also did clean up the Power supply and did the mods going around on the net. I added a variable attenuator on the in and TG out along with the ext Amps. I packed it a nice shielded cabinet its not as good as a real network analyzer, but it is actually useful now. I actually made a selectable multi filter selection for different band widths. The stock internal filtering was pretty bad. I may try to do some more improvements? We will see? Too many pokers in the fire. Great channel. I enjoyed watching.
Andreas Spiess . Thank you sir. I will try to put together all my info on the mods i made. Its pretty much chicken scratch now, but i will try to compile it i to something intelligible. I will be watching and i will let the channel know when i have good information to share. Thank you for the warm welcome.
This is not ham channel. It focusses on the ISM usage of RF because only a very few of my viewers are HAMs. Maybe I can motivate a few ISM guys go get licensed...
Hi Andreas, some time ago I bought one of this chip device. I compared features wit a R&S in office lab: agree with your conclusion ... About SW, I tried to be in touch with the original designer but ( I can 100% understand why ) I did not receive an answer. Any way, googling and spent some time reading forum, I found Python driver and commands list ... ... but all is sleeping since "The job is not worth it"
@@AndreasSpiess i love your videos. Thank you so much for producing these. You are an absolute legend. Im looking to build a tinygs soon when my parts arrive. You have inspired me to look into other lora systems as well. Keep up the great work.
Andreas, thank you for your outstanding work! Please, will you PLEASE update your Links at the bottom? Sadly a number of them no longer connect. Thank you again!
About as expected for $50. But I would just go buy used SA off ebay. You can get some really incredible ones for very cheap. Devices which used to cost $150,000 can be purchased for only ~$500. Lesson learned: expensive high end lab test equipment doesn't retain any value and depreciates worse than even the worst automobile.
I recently purchased a miniSA spectrum analyzer. I am Sure you’ve seen it. It is not all that different than the miniVNA. I would love to see you analysis of it and show too it’s usefulness and it’s weaknesses.
Please do a video on SDRs and clever configurable (elegant design and possibly cheap using HEMTs/GaN) front ends. I was hoping for a bit more of a deep dive into that sort of thing when I was notified of this video.
@@AndreasSpiess $50? I'm confused as to the number you came up with as well as the significance-- I just would like to see an exploration of HEMTs before they're commonplace. Also, GaN transistors aren't very expensive now and they are underrepresented in enthusiasts' communities, so I thought you'd have an opportunity to deep dive where no man had before. It's ripe for clever approaches.
@@AndreasSpiess GaN transistors are cheap and extremely capable (maybe you were thinking of SiC?)-- for instance: www.digikey.com/products/en?WT.z_cid=sp_917_buynow&keywords=917-1153-1-ND
I thought your comment was about a device using this new technology ;-) I am no specialist in this and I also think it would be too special for this channel. Maybe others will cover it.
I am sorry watching this video so late - have to be on a HAM-Fest at 9:30 here in Berlin today and bought 2 things to play with .... may be you should mention the cat-content at the end by your overview in the beginning - so viewers stay till the end.
I hope you liked the HAM fest! And maybe found a few interesting things. Concerning the cat: I think it should remain a "surprise" for the guys who stick to the end...
Nice SA overview; i did think that you might add that one often uses a noise source, instead of a tracking generator, since it removes a couple of 'dependencies', but, that's a bit picky... i see that you mentioned the noise source right at the end! Sad, how often some inventive person's work becomes just one more source of a chinese company's income :-( When I was in Helsinki, i visited a showroom of "Finnish Design", showing off the truly-great breadth and quality of art, artisanship, and inventiveness of the people of this country of only 5.5 million people (a shameless plug for them! ), and, what do I see? A small group of mainland chinese (i recognised the mandarin language) , walking around, taking photographs of items... not just a 'snapshot', either, but pictures from every possible angle. Obviously, not just a 'tourist photo', they intended to go home, make a copy, and sell a few million. So, even when it's not 'visible', we may find the nice work of some German, Swiss, Canadian, Finn, at the heart of some chinese gear that is so inexpensive that we canpt avoid buying it...or, can we? Still, it would be a nice surprise for some German, or Swiss, ham person, to receive a few Euros/CHF in his bank or paypal, or 5€ in the post :-) !! itps just a thought....
I remember the 1980s where the Japanese did the same with our products. Nothing new. Switzerland still exists because we are very innovative. The same will happen again and again, I think. This is how the world moves. We were the leading country in textiles 100 years age... As you mention we can send these people a few Euros if we want. Like my patreons do it with this channel, for example.
Buyer beware. If you only need a *cheap* spectrum analyzer, get yourself a used RSP1 or RSP2 for about 100 € or even less and the spectrum analyzer software from sdrplay. Pretty accurate and much more sensitive than this crap here, although it is not as fast as a real spectrum analyzer. Andreas, well done this video!
I think that the 'notch' is not RBW-related issue, but due to the LO 'step', since it appears that the design does not actually 'sweep', but uses discrete step sizes, or?
It's because when the frequency of the LO is exactly the same as the input frequency the output of the mixer is DC and the logarithmic amplifier does not amplify DC or very low frequency, also because of capacitor C29 which blocks any DC into the amplifier anyway. As the LO moves slightly above or below the input frequency then the frequency of the output from the mixer is again high enough to pass through C29 and for the AD8307 to amplify it. Apart from the notch this design has another flaw, that of 'reflections'. If for instance you were to look at an SSB signal it would appear as a double sideband one with suppressed carrier. In 'real' spectrum analysers they do not convert to DC but instead to an intermediate frequency of a few MHz and then measure the amplitude of that. That also eliminates the reflection problem.
@@listerdave1240 Thank you for explaining this phenomenon. This "notch" didn't make much sense given the theoretical principle of operation. BTW, isn't C18 also a problem?
@@listerdave1240 The AD8307 can handle up to 500MHz. An IF around 450MHz would stay well within the specs of the 8307 and make it easier to design the image rejection filter.
@@listerdave1240 This makes alot of sense. Why couldn't they just down convert to a constant IF like in any good old superheterodyne receiver? Then using a narrow band amp with filters would also filter out the odd integer multiples due to the square waveform of the LO. Yeah I realize this 50 bucks spend wasn't worth it's bang ...
Merci fürs Zeigen, das Teil ist somit für mich im Grunde unbrauchbar, schade. Perfekt wäre gewesen, wenn sie noch kurz gezeigt hätten, wie man eine Filterkurve mit dem Nanovna erstellt, aber ich suche das jetzt einfach mal im Netz. VG
@@AndreasSpiess ich habe das gerade mal probiert, aber mein 868mhz circuit filter ergibt eine sehr fragwürdige ch1 Log Kurve...jetzt trau ich dem Filter nicht mehr. Übrigens Gratulation zu den >200k Views von letzter Woche.
@@AndreasSpiess hb9axa hat mir ein Foto geschickt von seiner Analyse seines baugleichen cbp-840c Filters mit einem alten grünen Ozi und der Verlauf sieht schon ziemlich ähnlich aus...aber über 900mhz weicht es dann tatsächlich stärker ab. Bald soll ja V2.0 kommen des Nanovna und bis 3.4ghz gehen, da freu ich mich schon drauf.
I am French. Can you confirm that the voice-over of this video is in English? I have a big doubt because I understood everything without problem! I have rarely seen a video of this quality on RUclips, both technically and in terms of video editing and sound recording ... and with so much humor!
This is a very nice comment! Thank you. French nearly "killed" my career when I was young because of the bad grades. I only learned it when I worked in Cameroon... But since then I forgot most of it. Good that we can communicate in English.
Would be nice to see you show this with an SDR, it eliminates some of the issues shown here (probably adds new different issues). You can use Spektrum made by Pavels on GitHub, I've helped on the development so if you have any question you can shoot me an email !
I designed spectrum analyzers for Hewlett Packard as my first job out of collage in 1971. The group I worked in is now called Keysight. They were very expensive but I see you can buy one now for a few hundred dollars and get a spectrum analyzer that works to 22GHz. Wow. I worked on the log amplifier that had a dynamic range of 100dB.
Loved this video. I think that this cheap analyzer is mixing the input down to DC but the filter is actually a bandpass with a bandwidth of about 250 KHz and a center frequency of about 200 KHz. Thus when you input a signal you see both the + and - image products of the mixer output spaced 400 KHz apart. The display occupies that plus the bandwidth of the filter so they call it 1 MHz. When the LO is tuned to the frequency of the input signal the output is DC and the filter blocks it so you see what looks like a notch in the output.
This is when somebody understood the math behind the view... congrat!
Yeah that's very plausible. Thank you! That both side bands are visible seemed obvious. But how is this avoided in the design of professional instrumentation?
@@LutzSchafer It gets very complicated as there are way more things to worry about than just the issue with this cheap spectrum analyzer. But for the question asked I will give a short reply. If you want to analyze .1 to 2.5 GHz, mix the input up to 3.6 GHz. Then the LO goes from 3.7 to 6.1GHz and the difference signal is 3.6 and the sum is 3.8 to 8.6 and can easily be filtered out. Then use another mixer to get the signal down to 300 MHz and another to get to 21MHz where I built the Log amp. These frequencies need to be carefully selected so that harmonics of the LO do not put spurious signals in band so they are picked more carefully that what I did in the above example. Hope this helps.
By the way, the HP8566 weighed 100 pounds.
I suggest to watch the Signalpath video. There you see exactly what Allen explains: ruclips.net/video/Fn7uaEVeOPk/видео.html
Wow. I understood how a Spectrum Analyzer is working and what it's for. In some 20 minutes. Thanks!
You are welcome!
@@AndreasSpiess BTW, Andreas (du ?), is the hat simply part of your personal style, or is it a kind of "Tracht"?
Let's wait for Andreas' answer ...
(but) If you go back you'll find re. "🤠" that he is/used to be a steampunk afficionado... (zurich maker faire 2017) 73 de 🚲
@@lohikarhu734 It's an 'ensemble' together with the 'lederhose'. Very common in alpine countries... ;-)
@@reinholdu9909 Steampunk :-)
Lab cat. Very important. More valuable than the cheapie spectrum analayzer. Thank you for an informative video.
And also more expensive ;-)
and sometimes cats can be used as an ESD generator.... although usually when you weren't planning on it. :-)
Best "organized" Vid in RUclips! Please never give up your style of "summarization". -seems yet another piece of equipment where I have to know the result before I can measure it... let me check the improvements ;)
Should improve the dynamic range...
Andreas tnx... btw:YOU (and QO-100 :) are driving me now to finally go for a HAM licence ...keep up the good work "in style" (=your's :)
@@AndreasSpiess - Yes, definitely on of the best organized tec chanel's over YT. And there are no wrong miss leading or confusing procedures. It's Swiss prescision content!!!
Awsome work and chanel. Thank you for your dedicated work. For this present moment the great tool is tinySA Ultra.
Thank you for wonderful explanation!
I got exact image of this spectrum analyzer (LTDZ_35-4400M).
I had interest in notch characteristics for CW (Continuous Wave) that 145.55MHz in your video.
I checked the circuit diagram and I understood the mechanism of that.
Following 2 things are the points of the notch:
- The same idea of DCR (Direct Conversion Receiver)
- The characteristics of RBW (Resolution Band-Width) filter
About the DCR, when we apply the same frequency signal for RF (measurement signal) and LO (Local Oscillator) of the mixer (IAM81008), the mixer output become DC signal. And amplitude of the DC signal depend on the phase difference between RF and LO.
However, RBW filter has DC block capacitors, so DC voltage doesn't reach to Logamp (AD8307) input pin.
These DC block capacitors are the major reason of the notch characteristics.
About the RBW filter, I simulated RBW filter (including DC block capacitors) that using LTspice.
It had f0= 200kHz +/- 100kHz of bandpass filter characteristics.
When we apply CW to the RF input, Logamp input will appear twin peaks of signal because RBW filter has bandpass characteristics.
I think your demonstration of 145.55MHz CW agree to my estimation.
Because I seen the frequency difference between peak to peak is 400kHz (=200kHz*2) in your video.
I got additional idea from these consideration.
It is TG (Tracking Generator) offset frequency.
In DCR idea, if LO and TG sweep with the same frequency, mixer output will be DC voltage.
In this spectrum analyzer, we cannot see frequency spectrum because DC block capacitor blocks DC voltage.
So in this spectrum analyzer, TG (become RF signal) and LO frequency should have offset value such as 200kHz.
Amazing explanation! I was trying to figure out what was causing the notch. This design was used to simplify the mixing stage, using just one, in contrast to "conventional", or "real" spectrum analyzers that uses two or more mixing stages, right?
My cat is a 1KHz detector, he came running, meowing every time you whistled. :D
Mine too! She doesn’t like this video :)
Thank you as my cat whined when he whistled and I did not know why but now do.
Sorry for that, guys!
@@AndreasSpiess It was kinda funny, he never comes running when I whistle, I must be off tune.
@Green Steve: My natural authority over small animals? ;-)
Let me say thank you for this video Andreas. I had this same device from banggood sitting on my desk and couldn't get it to work, i will be going back to it now that i have a better understanding of it..thank again.
I hope it will work for you.
5:48 _natural sine wave generator_ 😄
1570 Hz (by Android apk) ;o)
So it was a bit over the 1k signal...
Freaked my dog out
I appreciates how you do the comparison in a very in-depth details. I works as a RF engineer and always find myself lacking in many area. This information is very useful to me on how normal practices are done based on different people and their background. Thanks man!
Glad it was helpful!
You are incredibly talenful in teaching and explaining things in a way that makes it easy to understand.
Thank you!
I was about to buy one of these 50 dollars spectrum analyzer, but after seeing this video I changed my mine. Thanks Andreas Spiess
You are welcome!
I used my R&S FSEA20 analyzers almost every day for a seven year period. I got pretty used to these high performance machines that had a noise floor of about -160 dBM at zero span. Made my job easy. These days those analyzers can be had for about 1500 bucks in good working order.
You are right. I see a lot of people buying these old instruments. They are a very good choice if you have enough space and maybe also some knowledge to use/repair them. For you, as a long-time user, this is a perfect fit and not comparable with such a cheap device...
Perfect timing. I just ordered two BF-F8HP radios last week and started studying for my technician license. This week I learned about antennas, SWR meters, and the NanoVNA. So much new information introduced to me in such a short time I feel like I am in college again. Thanks for making this video to supplement what I am already trying to learn.
Seems you are on the right track!
Thx for the walkthru, well done and I love how you link and make due diligence on these products and link to the relevant parts, that a possible owner can benefit from.(golden)
many other channels can learn from the "viewer perspective-awareness" you seem to suit your videos with.
well done Andreas. +1
Don't have this Spectrum analyzer but were looking into it as an entry tool to just get familiar with this kind of class apparatus.
at around 30 bucks delivered for this unit (no shell), alternatives are not hanging on the threes in this sub 100 bucks environment.
You are right: For sure it is good as an education device. And knowing this technology is important for many projects
Thank you for yet another very interesting video! The testing, the explanations and the conclusions at the end are all very valuable. Thank you!
You are welcome!
Thank you so much Andreas!! Lovely video. Thanks for your time.
yes, he has very cool videos
You are welcome!
In my small lab I have an anti static workstation. Earthing, wrist strap points etc. Grounding for me, my equipment and soldering station. The sight of the purring cat is cute. Except all I could think of was "THE STATIC!".
She is for sure not helpful to prevent static charges, you are right!
Excellent presentation and explanations Mr. Andreas. Keep sharing your knowledge and we will enhance our world one step at a time!
Thank you for your nice words!
Very usefull tutorial about Spectrum Analyzer .. the natural sinewave generator is a must and cat is paying atention even "sleeping".
Yes, she usually does not sleep. She just "rests"...
I made a receiver with tracking ADF synth and nextion display some years ago. To have a flat power signal, I had to add an amplifier and a step attenuator (controlled by µC). It has to be calibrated ! Now I have +/- 1dB precision. (compared to my keysight at work)
Sounds like a nice project! All possible with today's cheap ICs. And a good instrument for calibration ;-)
Thanks for the video. Very helpful… and your lab assistant napping at the end is great.
Glad it was helpful!
wow this is so cool. I am starting to check out how to build a SDR radio telescope and one video used a cheap spectrum analyzer test the 21cm astronomy hydrogen line.
This is a all new learning curve on making a homemade radio telescope using SDR software. 😎 thanks a lot.
Check the newest link in the description before you buy a TinySA. There is a new version available.
@@AndreasSpiess I checked it out and ordered a: tinySA ULTRA 100k-5.3GHz Hand held tiny Spectrum Analyzer + 4" TFT LCD +Battery. Thank you very much.
Thank you for quality information. I'm using sdr + white noise Zener + spektrum software to align homemade vhf filters. Regarding my application my setup performs similar to NWT. At the end nothing can replace a good sigilent anritsu Hp spectrum analizer. Thanks again !!!
The new cheap VNAs are a handy replacement for antenna design in my opinion. And affordable for most.
Thanks! I was looking at such a very device just the other day to analyse my antenna design. It's really cool that you showed another device @9m30s that is probably more what I was looking for. Thank you for your good quality videos.
You are welcome!
Before Spectrum Analyzers we had Frequency Selective Voltage meters. Aka the most expensive AM Radio's in the world. Cool Video yet again Sir.
This was probably many years ago... But they did the job. And many awesome projects were done in this time.
You could say that the Mixer is a Multiplier.
If you remember your trigonometry: sin(a)* sin(b) =
(cos(a − b) − cos(a + b))/2
This is why the sum and difference of frequencies appear.
In practice the Mixer is not perfect and there are nonlinearities that generates also harmonics so you get N*a + M*b (with N and M integers). But the other frequencies and usually much attenuated with a good Mixer.
And if you want to know how to multiply signals:
ruclips.net/video/7nmmb0pqTU0/видео.html
You are, of course, right. For my videos I usually need more time to "leave things out" than to "put things in"...
@@AndreasSpiess I understand that just putting a trigonometry formula in a video can scare people 😆
I'm not a RF guy at all but I find that part of electronics quite stimulating.
I just wanted to add some extra for the curious ones that asked themselves "how does a mixer work?"...
BTW: Your link points to a very good channel...
Good video. I had a look at this cheap device a few weeks back, my mouse cursor hovered over the 'buy now' button.
After watching this review i decided NOT to buy it, save up more money for a proper one. This video saved me $55 and disapointement. Thank you Andreas !!
You are welcome. Decisions like that are the purpose of this video...
Thanks. Useful pointers here of what to look for in a cheap analyser.
As I like to say, I would RTFM, but there was no FM to R.
Documentation and software is not a strength of Chinese manufacturers, you are right.
I love the little 🖐, pointing out things 😂
:-)
Me too. Where did you buy it?
Great videos :) Love the artificial hand...lol You have a great sense of humor along with great tech knowledge... Thanks for making it so much fun to watch.
Thank you for your nice words!
Tnx for nice explenation! Got it: the FIXED Resolution Band Width!
:-)
Excellent video, as usual, thanks very much, Andreas. That German "Tiefpaßfilter" should be at least 24 years old as it is written "Tiefpassfilter" since 1996. Now I know what a spelling reform is good for.
Interesting. Frequencies still are the same today...
The solution of removing the display and just add an USB control makes instruments cheaper and, more importantly, smaller. I've made several USB instruments under the same principle. Actually, the video caught my attention because of this.
Anyway, loved the video and also subscribed. Thanks for sharing!
Welcome aboard the channel!
Thanks for the video! I found it really informative. I probably would have wanted one of these had I seen them for sale, but as I mostly would use it to measure harmonics from transceivers they are kinda useless. I think for cheap harmonics measurements an SDR dongle and attenuator is the way to go. I already have a Nano VNA for checking filters and antennas.
You are right.
If I understand everything correctly then this spectrum analyzer uses an low IF frequency of ~few hundred kHz, most spectrum analyzers use high IF that is higher than maximum frequency they can measure. Because of that it is going to see signals that are centered at LO +/- few hundred kHz and that's why there are 2 peaks when you measure signal of that handheld. That's very bad because some signals, like signal from that handheld will appear to occupy twice the bandwidth and have a weird notch in the middle as seen on the video.
Exactly! But for 50 dollars an IF above 4GHz including filters is probably still not possible.
Cat found the best spot for a snap :D
This is why I need three monitors. One is no more usable...
Super interesting & my dog jumped from her bed & started barking at your whistle, so we both got something from your video. Thanks for sharing!
:-)) You are welcome!
Very nice video again! You make my day, because I learn several new things and that is a must for me. Thank you Andreas!
I try to add some value to my test videos. Like that I hope it is easier for the viewer to decide if someting is good or bad for his application.
Thank you for this excellent review! I have a spare Agilent 6ghz directional coupler and plan to get this for a friend who needs to measure SWR for his home-built 3.5ghz 5G-antenna. It lacks speed and resolution as a spectrum analyzer, but I hope it works fine for plotting S11 curve.
I like the VNA to measure S11. But a SA should also work.
Thanks a lot Andreas, I will give it a go :)
Thanks for the video Andreas. My radio club bought a Rigol Spectrum analyser a few months ago and I wanted something similar for my little work bench and having found this on ebay thought it was a good little project ( I bought the naked board). I've only yesterday finished putting it into a case with N connectors and will be keen to try the new software. Love the cat on keyboard :-) Keep up the vid's, It's good to see a ham doing such a diverse range of topics.
For HAMs a nanoVNA maybe is a better choice to measure antennas and filters. I hope your SA will do the job.
Thanks Andreas a good informative video. I just purchased a unit off AliExpress not the same one you have here but its labled 35-4400MHz with a IN and OUT port and USB port. I hope it will work well for monitoring a wideband Digital DVB-S2/T ATV transmission at 1255 MHz...love your puscat I have a long hair pus too...Cheers Clint - VK3CSJ...
Usually these devices are not used as receivers. They are more used to measure emissions... 73 de Andreas, HB9BLA
Thank you Guy with a swiss accent. I visited Luzerne for 1 day. At night. It was okay. :) I want a spectrum analyzer. I don't have a use for it right off the top of my head but I would find a reason. Not swiss mentality but hey... this is internet.
I also have bought a few things like that ;-)
Amazing how cheap things can be when the core functionality can be implemented in software.
And excellent chips can be bought from Analog Devices for nothing...
This was a great video. You explained everything so well. Thanks!
You are welcome!
Yes, yes Andreas is a good communicator
Thanks for the great video! After this video I bought this analyzer! I am a developer for electronic devices and I think this device helps me. Lg Szivatz.at from Austria
Glad you like it!
I understood the first and the last couple of minutes. Most important component is a furry oscillator.
"Furry oscillator"! Man, I almost spit my coffee against the screen laughing … have to remember that one! :-) :D
@Malt :-)) You got all you need, I think ;-)
I love that tiny helping hand
:-)
TLDR It works but you get what you paid for. Thorough video again by Andreas!
I still think, we get quite a lot for 50 dollars. Those new AD chips really make it easy to build interesting things...
You saved me $50. I might have bought this for fun. Also from the comments I learned that the Germans have abandoned the old version of "ss" which I learned back in the 1970-s. The "sharp s" which it was called here. (Where is it on my keybord?)
AFAIK it is still on their keaboard. We Swiss never needed it ;-)
Always looking forward to hearing from you! I’m not into RF much myself (except when having to filter harmonics, hee hee), but your videos are always didactically well prepared so it’s pure joy watching them and there’s always something to learn. And of course I dig cat-lovers, having had my own lab cat for ever so many years. :-)
Anyways, thanks for being there, doing all this and even teaching an old fart new tricks from time to time!
I am an old fart, too. And Dishka, too. So we are already three. She, however, seems not to be too interested in learning new tricks...
I also would have enjoyed seeing the cat's purring on an audio spectrum analyzer's display output!
Maybe stuff for another video...
I like the way you reply to each comment. Keep going
Thank you!
I hope that they continue to improve the device.
Let's hope...
in summary:
the price difference has its weight, then it depends on the use you want to make of it.
$ 3,000 is a great investment for a hobby, so the $ 50 device might be enough, once you compare it to some more advanced device ( hoping you can do it) you have a "touchstone" for your purposes.
If, on the other hand, you have to study the behavior of various equipment rigorously, perhaps for work, then you must think of a quality product such as Siglent or of equal quality.
Tnx for yours intersting videos Andreas and i'll see you next time!
I most probably will not do a SA comparison on this channel. There are other channels focused on this topic. I just wanted to give some advice to people hoping they can save 2850$ to go to this cheap device ;-) And they should know a little on what they have to look if they buy another one.
@ Andreas Spiess: I completely agree with you: I was also a radio amateur, and I never had a spectrum analyzer .. in reality I was more of a CB than a real radio amateur (even if I had acquired a license and license: my name was Ik4DZF but some time has passed ... 20-25 years !!) and when I built the jpole for 144 MHz I went by attempts trying to respect the project's measurements ... it worked , at least to get on 144MHz repeaters :-)
That whistling bounced off my walls and really creeped me out.
Very good job Andreas, nice presentation and very useful, tanks you...!
Glad you enjoyed it!
I LOVE the pointer.
:-)
Great Sir! I guess it will be a good instrument to design antenna
As I mentioned. For antenna tuning, a VNA is a much better tool
wonderful explanation on a Spectrum analyzer. Thanks ✨✌😊
You are welcome!
Relearned the term "tracking generator" from school, but these days you might as well get an SDR in that price range.
As I mentioned, the SDRs are not exactly the same. If you want one with transmit you are in a higher proce range.
Thanks Andreas
You are welcome!
Perhaps it is mentioned, but I didn't got it. Can this analyzer work as a tracking generator, e.g. for bode plotting?
I do not know a lot of bode diagrams. But the device has a built-in tracking generator. Mind the minimal frequency if you would like to use it for audio.
Even though I' have a degree in EE I have never worked in rf or high frequency areas. I find these videos interesting but intimidating.
RF is not the simplest topic ;-)
I think there's a reason a lot of RF Engineers are older. Because it takes quite a long time to learn RF !! 😉
Very good info..I subscribed and plan to watch more vids. I have added some external filters and a 30db wide band LNA on the input of mine. It has made the spectrum analyzer more useable. It’s still not great, but much better. I also did clean up the Power supply and did the mods going around on the net. I added a variable attenuator on the in and TG out along with the ext Amps. I packed it a nice shielded cabinet its not as good as a real network analyzer, but it is actually useful now. I actually made a selectable multi filter selection for different band widths. The stock internal filtering was pretty bad. I may try to do some more improvements? We will see? Too many pokers in the fire. Great channel. I enjoyed watching.
Welcome aboard the channel! You invested quite some effort¨. Maybe you document it for others to follow?
Andreas Spiess . Thank you sir. I will try to put together all my info on the mods i made. Its pretty much chicken scratch now, but i will try to compile it i to something intelligible. I will be watching and i will let the channel know when i have good information to share. Thank you for the warm welcome.
Excellent explanations. Thank you
You are welcome!
Thank you for another great video. I wish to see more episodes related to RF signals and ham radio. Vy 73!
This is not ham channel. It focusses on the ISM usage of RF because only a very few of my viewers are HAMs. Maybe I can motivate a few ISM guys go get licensed...
Hi Andreas, some time ago I bought one of this chip device. I compared features wit a R&S in office lab: agree with your conclusion ...
About SW, I tried to be in touch with the original designer but ( I can 100% understand why ) I did not receive an answer. Any way, googling and spent some time reading forum, I found Python driver and commands list ...
... but all is sleeping since "The job is not worth it"
I tried to reach the author too with no success. The software could be so much more improved.
I ❤ the Mini Me FINGER. Just saying. Good show (you can take my word for it)
🇺🇸
Thank you!
The cat was really impressed
:-))
Natural signal generator =whistle... love it
Simple and cheap ;-)
@@AndreasSpiess i love your videos. Thank you so much for producing these. You are an absolute legend. Im looking to build a tinygs soon when my parts arrive. You have inspired me to look into other lora systems as well. Keep up the great work.
Fantastic video! Thank you!
Glad you liked it!
Thank you, That was one of my questions I posted some videos ago!
:-)
Excellent educational presentation, bromigo!
Thank you!
Andreas, thank you for your outstanding work! Please, will you PLEASE update your Links at the bottom? Sadly a number of them no longer connect. Thank you again!
With 400 videos I cannot update all links :-( But I updated the link to the TinySA
About as expected for $50. But I would just go buy used SA off ebay. You can get some really incredible ones for very cheap. Devices which used to cost $150,000 can be purchased for only ~$500. Lesson learned: expensive high end lab test equipment doesn't retain any value and depreciates worse than even the worst automobile.
You are rright. Especially spectrum analyzers. The Siglent is also only 3000 Euros for 3.2GHz. Costed also a fortune a few years back ;-)
I recently purchased a miniSA spectrum analyzer. I am
Sure you’ve seen it. It is not all that different than the miniVNA. I would love to see you analysis of it and show too it’s usefulness and it’s weaknesses.
You find a few very good videos on RUclips. It seems to be much better than the one here...
Please do a video on SDRs and clever configurable (elegant design and possibly cheap using HEMTs/GaN) front ends. I was hoping for a bit more of a deep dive into that sort of thing when I was notified of this video.
For 50$? GaN? Maybe in a few years...
@@AndreasSpiess $50? I'm confused as to the number you came up with as well as the significance-- I just would like to see an exploration of HEMTs before they're commonplace. Also, GaN transistors aren't very expensive now and they are underrepresented in enthusiasts' communities, so I thought you'd have an opportunity to deep dive where no man had before. It's ripe for clever approaches.
@@AndreasSpiess GaN transistors are cheap and extremely capable (maybe you were thinking of SiC?)-- for instance: www.digikey.com/products/en?WT.z_cid=sp_917_buynow&keywords=917-1153-1-ND
I thought your comment was about a device using this new technology ;-) I am no specialist in this and I also think it would be too special for this channel. Maybe others will cover it.
I defenately liked this one ! Excellent and well described !
Thank you!
I am sorry watching this video so late - have to be on a HAM-Fest at 9:30 here in Berlin today and bought 2 things to play with .... may be you should mention the cat-content at the end by your overview in the beginning - so viewers stay till the end.
I hope you liked the HAM fest! And maybe found a few interesting things. Concerning the cat: I think it should remain a "surprise" for the guys who stick to the end...
Nice SA overview; i did think that you might add that one often uses a noise source, instead of a tracking generator, since it removes a couple of 'dependencies', but, that's a bit picky... i see that you mentioned the noise source right at the end!
Sad, how often some inventive person's work becomes just one more source of a chinese company's income :-( When I was in Helsinki, i visited a showroom of "Finnish Design", showing off the truly-great breadth and quality of art, artisanship, and inventiveness of the people of this country of only 5.5 million people (a shameless plug for them! ), and, what do I see? A small group of mainland chinese (i recognised the mandarin language) , walking around, taking photographs of items... not just a 'snapshot', either, but pictures from every possible angle. Obviously, not just a 'tourist photo', they intended to go home, make a copy, and sell a few million.
So, even when it's not 'visible', we may find the nice work of some German, Swiss, Canadian, Finn, at the heart of some chinese gear that is so inexpensive that we canpt avoid buying it...or, can we? Still, it would be a nice surprise for some German, or Swiss, ham person, to receive a few Euros/CHF in his bank or paypal, or 5€ in the post :-) !! itps just a thought....
I remember the 1980s where the Japanese did the same with our products. Nothing new. Switzerland still exists because we are very innovative. The same will happen again and again, I think. This is how the world moves. We were the leading country in textiles 100 years age...
As you mention we can send these people a few Euros if we want. Like my patreons do it with this channel, for example.
very interesting !
:-)
Buyer beware. If you only need a *cheap* spectrum analyzer, get yourself a used RSP1 or RSP2 for about 100 € or even less and the spectrum analyzer software from sdrplay. Pretty accurate and much more sensitive than this crap here, although it is not as fast as a real spectrum analyzer. Andreas, well done this video!
I agree.
If in doubt, add cat. It never fails to improve a video.
You are right, of course ;-)
I think that the 'notch' is not RBW-related issue, but due to the LO 'step', since it appears that the design does not actually 'sweep', but uses discrete step sizes, or?
It's because when the frequency of the LO is exactly the same as the input frequency the output of the mixer is DC and the logarithmic amplifier does not amplify DC or very low frequency, also because of capacitor C29 which blocks any DC into the amplifier anyway. As the LO moves slightly above or below the input frequency then the frequency of the output from the mixer is again high enough to pass through C29 and for the AD8307 to amplify it. Apart from the notch this design has another flaw, that of 'reflections'. If for instance you were to look at an SSB signal it would appear as a double sideband one with suppressed carrier.
In 'real' spectrum analysers they do not convert to DC but instead to an intermediate frequency of a few MHz and then measure the amplitude of that. That also eliminates the reflection problem.
@@listerdave1240 Thank you for explaining this phenomenon.
This "notch" didn't make much sense given the theoretical principle of operation.
BTW, isn't C18 also a problem?
@@listerdave1240 The AD8307 can handle up to 500MHz. An IF around 450MHz would stay well within the specs of the 8307 and make it easier to design the image rejection filter.
@@listerdave1240 This makes alot of sense. Why couldn't they just down convert to a constant IF like in any good old superheterodyne receiver? Then using a narrow band amp with filters would also filter out the odd integer multiples due to the square waveform of the LO. Yeah I realize this 50 bucks spend wasn't worth it's bang ...
Grüezi! I enjoyed the video from beginning to end. I still use my Tektronix 2711 and I will not buy the one from Banggood.
Probably not a bad decision ;-)
You need additional white noise generator, or use a happy cat instead. ( What Andreas demonstrated with Mishka at the end of the video )
Not exactly whie noise what she produces...
@@AndreasSpiess Perhaps better suited as a tracking generator for birdies detection.
LOL, the Swiss guy is driving my Germany wife crazy with his whistle.
I hope not ;-)
Merci fürs Zeigen, das Teil ist somit für mich im Grunde unbrauchbar, schade. Perfekt wäre gewesen, wenn sie noch kurz gezeigt hätten, wie man eine Filterkurve mit dem Nanovna erstellt, aber ich suche das jetzt einfach mal im Netz. VG
Genau gleich. Der hat auch einen "TG" und einen Analyzer
@@AndreasSpiess ich habe das gerade mal probiert, aber mein 868mhz circuit filter ergibt eine sehr fragwürdige ch1 Log Kurve...jetzt trau ich dem Filter nicht mehr. Übrigens Gratulation zu den >200k Views von letzter Woche.
Schau mal die Specs für den nanoVNA Bis 300 ok, danach nicht mehr so gut. Und ab 900 MHz nix mehr. Vielleicht traust du dem nanoVNA auch nicht?
@@AndreasSpiess hb9axa hat mir ein Foto geschickt von seiner Analyse seines baugleichen cbp-840c Filters mit einem alten grünen Ozi und der Verlauf sieht schon ziemlich ähnlich aus...aber über 900mhz weicht es dann tatsächlich stärker ab. Bald soll ja V2.0 kommen des Nanovna und bis 3.4ghz gehen, da freu ich mich schon drauf.
Mal sehen wie das Pricing wird. Ich werde ihn dann mit meinem B1201SA und dem MiniVNA vergleichen.
Please a video about using SDR as Spectrum analyser :)
Maybe later...
@@AndreasSpiess Yes please
I am French. Can you confirm that the voice-over of this video is in English? I have a big doubt because I understood everything without problem!
I have rarely seen a video of this quality on RUclips, both technically and in terms of video editing and sound recording ... and with so much humor!
This is a very nice comment! Thank you. French nearly "killed" my career when I was young because of the bad grades. I only learned it when I worked in Cameroon... But since then I forgot most of it. Good that we can communicate in English.
Keep watching Andreas and prepare to learn a lot!
@@AndreasSpiess Oh mon dieux c'est incroyable
Thanks! I was considering buying one but my LimeSDR is much better, I'll stick with that
You a re for sure not bad witrh a LimeSDR ;-)
Wonderful video! Useful & neat!
Thank you!
YOU ARE AMAZING ! thanks for good content
You are welcome!
Маленькая рука-указатель - супер! :)
Thank you!
Probably my favorite video among all your great quality tutorials! But what does the VBW indication on your Siglent screen correspond to?
The explanation is here: www.siglenteu.com/application-note/spectrum-analyzer-basics-bandwidth/
Would be nice to see you show this with an SDR, it eliminates some of the issues shown here (probably adds new different issues).
You can use Spektrum made by Pavels on GitHub, I've helped on the development so if you have any question you can shoot me an email !
Spectrum analyzers do not measure phase as tthe VNAs do. So they are slightly different. I prefer VNAs for Antenna work.
Great video, dude. Love the cat.
Glad you enjoyed it
Nice item
🙂
Yes!
Great channel and great content!
But every time I see this hand pointer I feel terrible may it is kind of phobia I don't know what this feeling!
Maybe you ask your doctor? It is harmless ;-)
@@AndreasSpiess may could I ask you to do not use this hand pointer please?
Only for next video I will really appreciate it. Thanks 😊
NWT4000 DOES NOT RECOGNIZE THE LTDZ 35MHZ 4400MHZ SPECTRUM ANALYZER?