Outfitting a lab for 6GHz work? - Page 1
Forum section: electronics / testgear

author: Ideal
author_rank: Newbie
timestamp: April 02, 2016, 12:02:37 am
content: Hi everyone,I'm at that point in my life where I feel the urge to drop some money on better equipment (budget is a flexible 15k). I've been doing RF consulting on the side and have hit that threshold where I really should purchase equipment rated for my 6+GHz (mostly Wi-Fi) work.For my budget, looking for solid 6GHz equipment has been difficult. It's basically been choose one: a great SA or a nice HP VNA, which is why I thought I would see if anyone had any suggestions! I'd especially like to hear from anyone who does 6GHz development in their personal lab and what your setup looks like/recommendations.Appreciate the help!

author: nctnico
author_rank: Super Contributor
timestamp: April 02, 2016, 10:03:53 am
content: I think good cables with low loss at high frequencies could set you back a couple of hundred. Even on Ebay a 1 meter cable with Huber+Suhner RG223 coax from China will set you back $30 to $40. Currently my equipment doesn't go over 3GHz and the RG223 is OK for that purpose.Did you look at the equipment from Signal hound? IIRC they have a tracking generator / spectrum analyser combo which goes to 12 GHz. This is a software defined radio solution which uses a PC to do all the hard work. From what I have read it isn't fast but it works well. I'd look into it if I where you.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: April 02, 2016, 10:25:57 am
content: Quote from: Ideal on April 02, 2016, 12:02:37 amWhat exactly do you want to do? "RF Consulting" isn't exactly a precise description, and WiFi stuff can cover a lot of different tasks. A bit more information would help here.As to money, $15k probably won't get you very far for decent 6Ghz lab equipment if its new, so I guess that leaves you with 2nd hand gear. Just to give you some idea what you can get: I currently have three Spectrum Analyzers of which two, a 7Ghz Rohde & Schwarz FSP7 and a 13.2Ghz Anritsu MS8609A, go above 6Ghz (the third one is an Agilent E4406A VSA although it only goes to 4GHz, but then they're dirt cheap). I also have three RF generators (1x Afilent E4433B 4Ghz and 2x Anritsu MG3700A, one 3GHz and one 6GHz unit). All devices have in common that they can often be found for somewhat little money.I don't have a VNA, which would be nice, but a decent one that covers a wider frequency range goes still for serious money, plus so far I haven't found a situation where I couldn't do without.In terms of SA, the real bargain was the Anritsu MS8609A, which I got for less than $1500, which isn't bad considering that it's an only four years old lab-grade analyzer in pristine condition. There's also an 8.5GHz variant (MS8608A) which usually goes for slightly less money, and aside from the lower bandwidth is identical to the MS8609A. Both models are essentially Anritsu MS3683A/MS2687A lab-grade spectrum analyzers with a slightly different software stack which were sold as 'Transmitter Testers'.Besides the high bandwidth, these SAs have a few other advantages, like a RBW that goes up to 20MHz which is really helpful for wideband signals like WiFi (most newer mid-range SAs go to 10MHz, and many older SAs only go to 1MHz). In addition, it's a Vector Signal Analyzer similar to the Agilent E4406A but without the RBW/span limits (there are software options for GSM/HSDPA/HSUPA and WiFi). There's also a digital RBW option which goes down to 10Hz, a narrow RBW option which goes to 1Hz, an option for a lower noise floor and a precision frequency reference option. The UI looks a bit dated but these SAs are very easy to operate, and are quite fast. The RF performance is pretty good, even better than my R&S FSP7 (which already isn't a bad performer). It's all lab-grade kit.However, specific instrument suggestions aside, as said above it pretty much comes down to what exactly you want to do. You might well be able to live with software tools only, or some other alternatives. Without knowing what exactly your intentions are ("consulting" is a big field) then it's difficult to make useful recommendations.

author: Howardlong
author_rank: Super Contributor
timestamp: April 02, 2016, 10:39:45 am
content: What kind of things is the OP doing? "WiFi work" is a bit vague. If you're using precertified modules with integrated antennas or antenna connectors then I could see the equipment being little more than trophy pieces.Equally, if you are designing and fabricating antennas then you might want an anechoic chamber.Could the OP be a bit more specific on what kind of consulting they are doing?

author: G0HZU
author_rank: Super Contributor
timestamp: April 02, 2016, 01:17:03 pm
content: As Howard says, a lot depends on what you want to do. You might not need much more than a reasonably good Rx/Tx SDR and one of the USB based Mini VNAs to do want you want to do with WiFi?QuoteMy background is purely in RF and I've worked in high end RF labs all my working life. The last 25+ years have been spent doing RF design and consultancy work.So for the stuff I do, the most important thing in the lab is a decent suite of RF simulation tools because a lot of the stuff I do can/should be simulated first on a PC. To back this up with test gear for home use, I try to buy high end test gear rather than anything in the low/mid class ranges. With your (my?) budget this would mean buying fairly old test gear and there are obvious risks with that. But you can buy old/good test gear for very little money these days.Up until I bought my latest VNA (a few months ago) I have never spent more than about £1k on a piece of RF test gear for use here at home although I do have numerous items that cost this much or nearly this much. But my setup here at home has allowed me to do a lot of valid research/dev work over the yearsTest sets are often touted on here as cheap ways to get lots of functionality within one box but I would normally only recommend buying these if you actually need the specialist measurement functions they offer. eg tools for verifying GSM or other comms systems.So if you are doing a lot of WiFi based stuff then you may want to look at test sets that cater for this. Or maybe look atsomething from Ettus Research to see if one of their SDR based Rx/Tx modules can mimic and analyse what you want to do with WiFi.https://www.ettus.com/product/category/DaughterboardsOtherwise, you may end up with a test set box (from Agilent or Marconi or R&S etc) containing a mediocre spectrum analyser, sig gen and power meter. If you are doing other forms of RF design/consultancy work you will soon find the limits of all these tools in the test set and will find yourself buying a better analyser or sig gen or power meter anyway. Once you get used to the performance of the replacement tools you may find that you avoid using the test set altogether.

author: Ideal
author_rank: Newbie
timestamp: April 02, 2016, 06:15:11 pm
content: Thanks everyone for the feedback! Sorry for being vague, didn't want to drone on and on but I guess I missed some important detailsMy side work includes:-Some minor antenna work, but mainly just looking at S11 on the boards I design to make sure it's 50ohm matched. I may be doing more LNA design in which case S12 is important.-There is a possibility I will need characterize delay lines (phase, attenuation, etc), basic VNA stuff.-Mostly building embedded RF systems like microcontrollers + attenuator blocks, radar emulators, RF power detectors, etc. Small consignment type work building custom test equipment for customers.-Have access to anechoic chambers already-Hoping to do some characterization of 802.11ac devices (160MHz BW, yikes...), likely including some MU-MIMO and channel modeling. Probably not entirely feasible given my budget, but would love to be able to use a SA and VNA to analyze channel conditions and co channel interference, would be very useful!Thanks again for everyones suggestions so far!

author: Ideal
author_rank: Newbie
timestamp: April 02, 2016, 06:26:57 pm
content: QuoteLove Ettus, didn't know they made this board though. Thanks for the suggestion!QuoteThank's for the recommendation, I found one on ebay for about the same price. Looks like a great piece of equipment, thanks!QuoteI've looked into their products for more field application work. Definitely cool stuff! I'm still torn on if I want to go full software, getting equipment without a screen definitely saves money but there is something about having it all ready to go at the touch of a button that I don't know if I can give up. A friend also suggested the Tektronix RSA600, it comes with their signalVU software which is pretty awesome (http://www.tek.com/spectrum-analyzer/rsa600-series)

author: dkozel
author_rank: Regular Contributor
timestamp: April 02, 2016, 11:09:40 pm
content: Hi Ideal,I work at Ettus (engineering, not marketing) and would be happy to answer any questions you have about the various motherboards and daughterboards. Schematics are all here:http://files.ettus.com/schematics/and the drivers are open source:https://github.com/EttusResearch/uhd.No sales pitch, just love SDR and always happy to chat about it. Have you used one of the radios before?There are various GNU Radio projects which implement parts of WiFi protocols, but not AC as far as I know.I also personally own a Signal Hound BB-60A spectrum analyzer. For the price (and I got mine used for less), it's a great tool. Being tied to a Windows computer though is definitely a limitation. Most of the time I'm using it I'm doing power level measurements inside a circuit or looking at wide spans of spectrum to monitor general system behavior. The software has been regularly updated and the company is responsive to messages. If I could afford the Tek306 though I'd probably have gone for that. The RSA600 looks interesting as well. I'm so happy about this trend for small test equipment as I move often. The Copper Mountain Tech and Anritsu Shockline VNAs both look really promising, but haven't hit the used market yet.If you haven't see it there are reviews of both the Signal Hound and Tek RSA306 on The Signal Path.

author: stuartk
author_rank: Regular Contributor
timestamp: April 11, 2016, 01:00:49 am
content: Hi Ideal,I have a used 6 Ghz spectrum Analyzer for sale if you are interested.https://www.eevblog.com/forum/buysellwanted/for-sale-rohde-and-schwarz-fsl6-spectrum-analyzer-9-khz-to-6-ghz/Regards,Stuart