RoadTest: Tektronix RSA306 USB Spectrum Analyzer
Author: kas.lewis
Creation date:
Evaluation Type: Independent Products
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: null
What were the biggest problems encountered?: Getting enough information to properly be able to use the preset test settings in the software, this is still a work in progress.
Detailed Review:
This Review is NOT Complete But Due to Time Restrictions My Outline is Being Posted and WILL Be Updated as Progress is Made
Firstly I would like to say thank you to Element14 and Tektronix for this amazing opportunity to both review the RSA306 as well as to learn more about the latest a gratest in Spectrum Analyzer technology. In this review I will attempt to show some real world uses for such as the ability to track down “interference signals”, do protocol analysis, signal strength measurements , look at BER and attenuation/interference by objects in line of sight (LOS) or near by. To perform these tests I will be using some of the many RF modules and kits I have laying around.
I will not review the laptop that accompanied this road test, mainly due to a discussion I had with Tektronix in which it was explicitly stated that the laptop was only provided to complete the road test and not technically part of the road test. That being said any positives or obvious negatives that occur because of the laptop will be mentioned.
Unboxing
The unboxing of this road test was quite disappointing. Unlike previous products I have reviewed, this product did not appear to be untouched. This was noted mainly due to the missing documentation. After some communication with Tektronix I was assured everything was new and something must have happened between the designation of the unit by Tektronix and me receiving the unit from Element14. I was promptly shipped the documentation that was missing from the box as well as a second USB key.
The box the unit came is rather small and contains the standard hard foam packaging that such equipment is usually shipped with. I’m not sure if the unit should have been in plastic or not but it would have been nice if the unit was wrapped to protect the rubber from being pulled by the foam. In the box that I received was a 1 meter long L-COM USB 3.0 cable as well as a single USB key that contained a copy of SignalVu-PC, demo signals as well as lots of other documentation .The documentation that was missing was the certificate of calibration, Tektronix RSA306 USB Spectrum Analyzer - Simple Demos, Packing list, RSA306 Safety and the Installation Manual. I was also interesting to note that for the Sudden Impact Challenge I was given sheet outlining the rules of a road test (which it isn’t, its a challange) but for this road test there was no outline of rules provided.
Tektronix for the my troubles was kind enough to ship me a duck antenna as well as a full demo license for the SignalVu-PC that expires in 300+ days.
First Impressions
Before connecting the unit or even wondering what the unit was capable of, I wanted to get a physical feel of this unit. The RSA306 is touted as a rugged go anywhere unit (Mil-Std 28800 Class 2 environmental, shock and vibration specifications for use in harsh conditions). The first thing I noticed was the rubber on the RSA306 didn't feel right. While I may have a good sense of touch as I do a lot of delicate work I was informed by Tektronix that I was indeed correct. The rubber on the RSA306, for the first production run, was glued to the housing and was therefore loose and bubbly in some areas. I have also been told by Tektronix, but unable to verify this independently, there is now a new procedure where the rubber is instead stretched over the unit causing a much more snug and contoured fit with no loose or bubbly feeling. I would also note that while Tektronix mentions the size as a large book that could be carried in your back pocket (see their promotional videos for more info) there is no realistic way to carry the RSA306 in a back pocket unless you are Paul Bunyan. Another aspect that stood out in my mind was that the N-type connector (that is generally covered in the field ,as its has an antenna connected to it) has a rubber cover for to keep out any dust or dirt but unfortunately there are no covers for the two SMA connectors (trigger input and 10 MHz input clock signal). While some people will say this is a spectrum analyzer and it should be treated carefully, this is a field unit and should be fully protected as such. Another is issue that has come to my attention is the USB 3.0 connection. While the connector may work well for lab situations in the field this connector tends to get bumped and pulled causing the integrity of the connector to become compromised. I believe Tektronix is working to integrate a more robust USB 3.0 connector such as those with used in harsh environments such as factory floors or in military field applications.
Basis of my Testing
As the RSA306 is meant to be used as a portable and accurate interference locator I am very intrested in its over the air capabilities. It is a lot easier to plug a unit directly into a SA and look at the signal and debug a system in this setup, when doing over the air measurements there are other considerations that need to be taken into account. It is this second method I am predominantly interested in. The modules/signals I have chosen to look at are:
Device | Protocol | Frequency | Modulation |
WiFi (Coffeeshop) | 802.11 n | 2.4 GHz | |
CC2530 | Zigbee | 2.4 GHz | BPSK |
Cell Phone | WCDMA | 1700 MHz/2100 MHz | |
CC3100 | 802.11 | 2.4 GHz | |
eRIC (LPRS) | 868 MHz 915 MHz | FSK/MSK | |
Hands Free | Bluetooth | 2.4 GHz |
as well as attempting to replicate some of the tests done with the Agilent N9322C inorder to get some idea of how the two stack up.
Getting started
To get up and running with the unit I first thought, I've used spectrum analyzers before this shouldn't be too complicated. I quickly learned that there are basic uses (filter response, attenuation measurements etc.) and then there are advanced uses. Thankfully the SignalVu-PC comes with a decent number of examples to get you started. There are nine demo signals starting with simple carrier waves, through short burst frequency hopping radar bursts to the newer 802.11 ac. All of these demos walk you through the interface and gives you a good basic idea of how to use SignalVu-PC.
The first thing looked at after completing the demos was to try and see any WiFi signals. While it was easy to see the burst in both the DPX and spectrogram views there was no success in any of the decoding, getting network specs or even getting a meaningful constellation diagram as was demonstrated in the 802.11 ac demo. After trying a few more things there was still no progress so it was decided to try the eRIC modules I was awarded in a previous road test. Again with this module it was easy to do things like signal strength measurements side peak measurements but nothing more. Knowing that the eRIC modules use FSK to modulate their signals I was hoping to be able to do more than just the basics.
I decided to go back to Tektronix for some help. They were kind enough to spend an hour on the phone with me in a conference call where I could see their screen and they could really help me out. It appears the one main point missing from the demo as well as in other information provided is the need for the trigger to be used or for the testing to be done with a direct connection and not over the air. Once the trigger was set accordingly I was quickly able to get started first with the CC2530DK that I have left over from a previous project. I started with this unit due to its simplicity and availability at the time. As I am still working on getting a better grasp of the RSA306 I will update this blog as I move further into the review.
Use Cases
CC2530DK
The CC2530DK is a Zigbee module offered by Texas Instruments. The kit includes two SmartRF05 Evaluation Boards that allow for easy Packet Error Rate (PER) testing as well as two CC2530EM. Once powered up is is as simple matter to choose the channel to operate on, the number of packets to send and the transmit rate. Using the SmartRF Studio other options can be selected such as data to transmit, transmit power, modulated/unmodulated signal as well as measuring the RSSI for receive packets and viewing any data received.
Seeing as SignalVu-PC has the capability to properly measure the metrics for BPSK (used by Zigbee, 802.15.4) I thought this would be good place to start with my testing.
First test was to simply see if the reported output power and frequency was in the ballpark reported by both the transmit power and channel setting as well as the measured RSSI value. TAKE MEASUREMENTS OF POWER AND ADD SCREENSHOTS OF SIGNALVU-PC TO SHOW RESULTS
eRIC Module
The eRIC modules appears to use a proprietary protocol to transmit data using FSK/MSK modulations schemes. Included with the eRIC Dev Kit is a software interface that allows for data transmission, power level, frequency/channel and over the air data rate selection. In a previous road test in which I reviewed this product I had mention that while I was able to run the provided test I was unable to verify any of the numbers without a spectrum analyzer so I decided to review some of those questions so as to verify some of the provided specs.
Two of the options provided in the easyRadio Companion software is the ability to turn on and off the high and low side band using the spectrogram or the DPX views there was nothing to be seen with these two options selected. However when using the constellation diagram……….
CC3100
The CC3100 is another module I have worked with both through a road test review as well as for a side project of mine. The CC3100 is a WiFi SoC from Texas Instruments. Since the CC3100 works with SmartRF Studio this was going to be another interesting experiment to see how well the RSA306 performed under controlled WiFi conditions before going to a completely “open” WiFi connection. I was also interested in the performance as I had had some issues with the CC3000 (the predecessor to the CC3100) connecting to my home WiFi and was therefore wondering if the CC3100 could give me some insight as to what may be going on with regards to the signals in my house as the WiFi router is not that far from where the computer/CC3100 is/was resting.Initially with test I wasn't able to get anywhere and the initial conference call with Tektronix only helped me get FSK and BPSK signals to be resolved correctly by the RSA306 but did not help at all with WiFi signals.
Bluetooth 802.15.1
Another application specific package that can be added on to SignalVu-PC is the Bluetooth package which gives you the ability to check and verify that Bluetooth units are working as they should and within speck. To test this functionality a bluetooth hands free speaker was paired with a phone and the the data transmitted throughout the duration of a call was monitored. This was done more to see what SignalVu-PC was capable of as there was no real application here. Opening the preset standard setting for bluetooth brings up six windows that allow you to see things such as frequency deviation versus time, center frequency offset and drift, the eye diagram as well as the spectrum and an overall summary of the protocol performance (channel power, payload length, frequency offset and drift, etc.)
WCDMA
The last signal that I wanted to look at was from my local cell phone provider. After having connection issues since they started expanding their network even though my phone kept reporting full signal strength I decided there must be more to the issue then just signal strength. The main issue I had been having was the sound during a call would sound garbled even when the phone was reporting a seemingly full or almost full signal strength. To me this could be due to one of two things, either there was a “timing error” in which the start of one packet would be confused with another (think of it as shifting bits in a message) which didn't seem very likely with all the checks and balances in place to prevent this or, the constellation was becoming distorted, so even though the signal was strong the message received was not always the correct one. To test this out I needed to decode the cell providers protocol and then determine how well there constellation was aligned.
Summery
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