138M-4.4G sweep simple spectrum analyzer generator - Page 1
Forum section: electronics / rf-microwave

author: ebclr
author_rank: Super Contributor
timestamp: August 04, 2016, 10:11:09 pm
content: Anybody can recommend this one , for low budge

author: Bicurico
author_rank: Super Contributor
timestamp: August 20, 2016, 08:05:28 pm
content: Hello,I wrote a new software for the SMA Spectrum Analyzer 138MHz-4.4GHz. More details on my blog:http://vma-satellite.blogspot.pt/The pictures you show are from the NWT4000. This is a different device than the one your subject title mentions!NWT500 -> Original device. This uses the german software that is shipped with all clones.NWT4000 -> Modded device with extendend frequency range.SMA Spectrum Analyzer 138MHz-4.4GHz -> Lowcost copy of the NWT4000, featuring only one ADF4350. This means that the a signal can EITHER be read or output, but not simultaneously! Hence this device is no good for antenna tuning!SMA Spectrum Analyzer 38MHz-4.4GHz -> Lowcost copy of the NWT4000, featuring only one ADF4351. The only difference is the ADF4351 instead of the ADF4350 and subsequently the price.While the NWT devices are good for antenna tuning, which was the original intent of these devices, the SMA ones are nice as spectrum analyzers.However, the original software was not exactly built for this purpose. Sure enough, a spectrum mode exists (sweep), but it lacks many features common in a spectrum analyzer.This is why I developed my own program. It is what it is, made by myself for my own education and fun, but I think it is actually quite good and lets one play with a spectrum analyzer that costs around 50 Euro!I do own professional equipment (mostly field meters for TV, CATV and SAT), but for an amateur the SMA Spectrum Analyzer is a great toy.Careful with the input signal, though: I killed the mixer within 3 days, because I forgot about the 14/18V of the LNB power... A DC blocker is mandatory for SAT applications and recommended for CATV (due to possible power for active elements in the distribution network). Connecting plain reception antennas should be OK without a DC blocker.Replacing the M810 mixer is not difficult, but best done with a heat gun soldering station. The IC's can be bought cheaplit at Alixexpress.Hope this helps regarding this device.Regards

author: Kalvin
author_rank: Super Contributor
timestamp: August 21, 2016, 05:08:31 pm
content: Bicurico,What do you think about using a "35M-4.4GHz PLL RF Signal Source Frequency ADF4351 Development board" as a tracking generator with the "SMA Spectrum Analyzer 138MHz-4.4GHz"? Basically, with a decent VSWR bridge the system could be used as a poorman's spectrum analyzer. One part of the software will perform the RX sweeping and the other part will control signal generator frequency and other parameters.

author: Emo
author_rank: Regular Contributor
timestamp: August 21, 2016, 06:26:28 pm
content: Hi,Enclosed is image of the above mentioned clone of the NWT4000 board. Bicurio was so kind to let me test drive his software on this board.His software is awesome especially compared to the original SW with smart coordination between this unit and TV-dongles, handy preset buttons and an neat layout.It is easy to setup and use and is definitely a tool I will take with me on the road, also taking up low resources on the host system.Eric

author: Ivan7enych
author_rank: Regular Contributor
timestamp: August 22, 2016, 09:30:32 am
content: Quote from: ebclr on August 04, 2016, 10:11:09 pmHere is my review (in russian)http://forum.rcdesign.ru/blogs/188754/blog20793.htmlIn short words - it works well as a scalar analyzer with ~80dB range. It allows to measure filters, tune antennas (with directional coupler).As a spectrum analyzer it's almost useless, see last picture in review. There's only one RBW 1MHz wide, shifted low by 250KHz.I see more interesting new device NWT6000 -http://www.ebay.com/itm/121997719933?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITBut there's no actual review.

author: Bicurico
author_rank: Super Contributor
timestamp: August 22, 2016, 10:58:15 am
content: @Ivan7enych: You tested the NWT4000, while the 138M-4.4G sweep simple spectrum analyzer is indeed a cut-down version with only one ADF4350. This IC is used alternatively for input/output, meaning it cannot read its own output back in! This makes it useless for antenna tuning, reflectometer measurements, etc., unless you buy a separate noise source.As a spectrum analyzer, it is usable for certain applications. I come from the TV world and for measurements in TV, CATV or SAT bands, it is a usfull device, considering it's price.Do you want to test my software? If so, go to my blog for the download link and send me an e-mail with the system code. I will send you the activation code for free.Regards

author: Ivan7enych
author_rank: Regular Contributor
timestamp: August 22, 2016, 12:09:50 pm
content: Quote from: Bicurico on August 22, 2016, 10:58:15 amThank you!I'll send you an emal.

author: Bicurico
author_rank: Super Contributor
timestamp: April 23, 2019, 08:17:49 am
content: Hi,There is a major update of my software:https://vma-satellite.blogspot.com/2019/04/quick-preview-gone-are-notches-of.htmlThis new version removes the annoying notches!Regards,Vitor

author: ElectronicCat
author_rank: Regular Contributor
timestamp: April 25, 2019, 07:47:09 pm
content: I've seen lots of conflicting information on these devices, are there any with better than 100kHz resolution bandwidth? Also is there Linux software available? Any sources other than eBay?

author: Bicurico
author_rank: Super Contributor
timestamp: April 25, 2019, 10:39:51 pm
content: These SMA/NWT/D6 devices can be bought on eBay, AliExpress and Amazon.They have limitations in terms of bandwidth and should not be considered for less than around 50kHz bandwidth signals (in my opinion).The alternative would be using cheap SDR like the RTL2830U based dongles, HackRF One, ADALM Pluto, etc.These, however, have the inconvinience of not allowing swept spectrum analysis over bigger frequency ranges: they only work with FFT on the supported sample rate (2M for RTL2830U, up to 54M in case of ADALM Pluto, but that is limited by USB2.0, so efectively 16M).Of course they allow demodulation of the signals, which is not possible with SMA/NWT/D6 devices.Take a look at my blog and my Youtube channel (https://www.youtube.com/user/dazed1970/videos). It should allow you to better understand what is to be expected from these devices.Note that I am not affiliated with the development or sale of these devices - I just wrote a software that allows them to be used like a spectrum analyzer, according to my needs and ideas.Regards,Vitor

author: DurandA
author_rank: Newbie
timestamp: June 03, 2019, 01:33:39 pm
content: I just stumbled upon this:https://www.banggood.com/Geekcreit-Spectrum-Analyzer-USB-LTDZ_35-4400M_Spectrum-Signal-Source-with-Tracking-Source-Module-RF-Frequency-Domain-Analysis-Tool-p-1450129.htmlIf I understand correctly, it is software compatible with the NWT500. From the picture, it seems to have two ADF4351 so it may be possible to use input and output simultaneously. If this is true, it would a pretty decent bang for the buck and suitable for antenna tuning.Does anyone have more info about this device?@Bicurico, do you think it will be compatible with your software?

author: Bicurico
author_rank: Super Contributor
timestamp: June 03, 2019, 01:52:10 pm
content: Hello,This specific board/version is currently NOT compatible with my software!Without owning such a board it will be hard to figure out why it is not working.The same happend with the "D6" board, which is sold at AliExpress. In this case I fixed the issue, but had to purchase a board to figure out what was the problem.Regards,Vitor

author: DurandA
author_rank: Newbie
timestamp: June 03, 2019, 02:45:29 pm
content: @Bicurico thank you for the clarification.Is there any cheap clone that is decent at antenna testing/tuning in your experience?

author: Bicurico
author_rank: Super Contributor
timestamp: June 03, 2019, 04:42:51 pm
content: The SMA/NWT devices are in my opinion still the best choice at the moment.They offer:- Metal case- Best signal/noise ratioThe D6 model is cheap and hast a 3 times faster spectrum sweep. However it has about 10dB higher noise floor, which is not good. There are some hacks/mods to it, which I have not tried myself. These will improve sensitivy and lower the noise floor, but measurements will then be off by about 10dB.The device you mention: I have no idea. I just know from one user that it does not work with my software, locking it up.You might be interested in a HackRF, for which you can use this software:https://github.com/pavsa/hackrf-spectrum-analyzerThis will work up to 6GHz with excellent refresh rate - quite spectacular, actually. But the software has little to no measurements, at least compared to what my software offers.Going up in price, you might be able to purchase a second hand HP 859x starting at 500-600 Euro in working condition. Bear in mind that this can be difficult to repair. I have three broken PSU's, which I gave up on and two 8594E which are otherwise working, if I had the PSU running...Further up, you could consider a new Siglent SSA3021X at 1200-1400 Euro.Regards,VitorRegards,Vitor

author: OwO
author_rank: Super Contributor
timestamp: June 04, 2019, 04:11:30 am
content: Quote from: DurandA on June 03, 2019, 02:45:29 pmA spectrum analyzer is not what you want for antenna tuning. Use the right tool for the job.

author: Bicurico
author_rank: Super Contributor
timestamp: June 04, 2019, 07:16:07 am
content: You can use a spectrum analyzer with tracking generator, together with a directional coupler for antenna measurements.I agree, that a vector network analyzer (VNA) is an even better solution, as you can measure the phase of the signal. But this comes at a much higher cost.Simple Google search will explain the difference between a spectrum analyzer and a vector network analyzer.Regards,Vitor

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: June 04, 2019, 08:54:55 am
content: Quote from: Bicurico on June 04, 2019, 07:16:07 amYes, but only if you can keep all the cables very short. Longer cable is worse.The phase information is vital in order to calibrate out your cables. Say you use your spectrum-analyzer setup to measure a over a wide band with a long cable: At certain frequencies you will reflect all the power, at others it will appear like a perfect match, because your long cable + short happens to look like a stub matching network. So be careful when trying to measure using a makeshift scalar analyzer.

author: Bicurico
author_rank: Super Contributor
timestamp: June 04, 2019, 11:24:35 am
content: As I said, I do agree.Just wanted to point out what can be done with each kind of device.For further information:About the devices:https://en.wikipedia.org/wiki/Signal_analyzerhttps://en.wikipedia.org/wiki/Spectrum_analyzerhttps://en.wikipedia.org/wiki/Network_analyzer_(electrical)Antenna measurements with spectrum analyzer:https://rigol.desk.com/customer/en/portal/articles/2270018-how-do-i-measure-vswr-using-a-spectrum-analyzer-http://wireless.ictp.it/handbook/C6.pdfAntenna measurementes with vector network analyzer:https://www.element14.com/community/groups/test-and-measurement/blog/2018/08/19/antenna-measurement-with-the-rs-fpc1500-vector-network-analyzerWhen radio amateurs talk about antenna tuning, they often mean the creation of a Smith Chart:https://en.wikipedia.org/wiki/Smith_chartFor this you need a vector network analyzer, which can be bought cheap from China, with dubious quality:https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=antenna+measurement+vector+analyzerRegards,Vitor

author: erikka
author_rank: Regular Contributor
timestamp: June 06, 2019, 01:03:49 pm
content: Or build a 0.4 till 750MHz VNA for less then 50$ yourselves.https://github.com/erikkaashoek/Tapr-VNA

author: rprr
author_rank: Newbie
timestamp: October 15, 2019, 09:49:56 pm
content: @Bicurico, does your software work with the something like this:https://www.aliexpress.com/item/32908082468.htmlThanks.

author: Bicurico
author_rank: Super Contributor
timestamp: October 19, 2019, 11:09:34 am
content: Yes, but I doubt that this device willnotprovide any TRACKING GENERATOR functionality!Devices like the NWT6000 cost a lot more money and contain two MAX2870:https://www.aliexpress.com/item/4000269559972.htmlRegards,VitorEDIT: Had a double negation...

author: m3vuv
author_rank: Super Contributor
timestamp: October 19, 2019, 11:25:25 am
content: Have a look herehttp://www.foxdelta.com/projects/aaz-0914a.htm ,ive got one,brilliant bit of kit,knocks spots off the mfj crap,on both price and ease of us

author: Bicurico
author_rank: Super Contributor
timestamp: October 19, 2019, 02:51:50 pm
content: @m3vuv:Interesting, but very different kind of device.It supports a frequency range of up to 60MHz.The devices discussed here START at more or less this freqeuncy and go up to 4GHz or even 6GHz.Regards,Vitor

author: Big Duck
author_rank: Newbie
timestamp: October 12, 2021, 11:17:57 pm
content: I can not find the software for this unit. Would someone please help me with making this work? Label says that I need WinNWT4.09 However all I have found is WinNWT5 which does not seem to "see" my unit when I plug it in to my USB port, although my computer "sees" it when I plug it in and "sets up drivers." Win 10HELP PLEASE!!! :-(

author: Bicurico
author_rank: Super Contributor
timestamp: October 13, 2021, 09:42:08 am
content: Take a look at my signature.Go to my blog and then to the download page.I cannot redistribute WinNWT, as it is not freeware and the author decided to withdraw the application.However, the internet archive is your friend:https://web.archive.org/web/20180318113910/http://www.dl4jal.eu/hfm9.htmRegards,Vitor