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DG8SAQ VNWA Operational Test on an 8 Inch Budget Windows 8.1 Tablet Jan Verduyn SDR-Kits – www.SDR-Kits.net Introduction: Following recent reports by users on the VNWA Reflector on the possible use of the DG8SAQ Vector Network Analyzer with a small Tablets with the Windows 8.1 Bing Operating System, we at SDR-Kits decided to purchase one of these budget Tablet to gain some experience ourselves. The report below describes our experiences. We also made a short Video of our test and posted this on You Tube: Disclaimer: We only tested the VNWA on one Manufacturer’s Tablet as described below. Other Windows 8.1 Bing Tablets may not support the VNWA. The tablet in question is sold in the UK under the name of Bush Windows Windows MyTablet Windows 8.1 Bing which was offered at special price of GBP 79.00 (approx. 100 Euros) during February 2015. We decided on this particular model as there was a quite a positive review in one the UK Monthly Computer Publications Review in PCPRO:
A brief specification of this tablet is:
Processor RAM Operating system Screen size Screen resolution Connectivity Front camera Rear camera Storage Memory card slot Wi-Fi Bluetooth Size (WDH) Weight
1.33GHz Intel Atom Quad Core Z3735G 1GB Windows 8.1 with Bing 32-bit 8in 1,280 x 800 IPS 1 Micro USB socket and Micro HDMI cable 0.3MP 2MP 32GB eMMC built-in microSD single-band 802.11n 4 207 x 9 x 124mm 336g
Since our test a competing LYNX 8 inch W 8.1 Bing Tablet is also available in the UK. This tablet was also reviewed in PCPRO here:
Connecting the Bush MyTablet to the VNWA: To connect the DG8SAQ VNWA requires a Micro USB On the Go “OTG” cable. It is advisable to buy the OTG cable, and an optionally a tablet vase and a screen stylus. These items can be readily purchased on Ebay. If you would like to use a mouse with the tablet then an OTG cable with Micro USB connector to twin USB A Receptor Port OTG Cable is needed. Note that the majority of tablet cases for 8 inch Tablets may not fit the Bush MyTablet. Measuring 20.7cm x 12.9cm) this tablet is more compact than older Tablets with an 8 inch screen. The battery charger also has a micro-usb connector, hence when operating the VNWA the tablet battery cannot be charged. Plug-in the standard VNWA USB Cable supplied with the VNWA into OTG USB Cable. Follow the Manufacturer’s tablet instruction to set up Windows 8.1 Bing OS on the tablet. A Microsoft email address is required to get the tablet operational. If you do not have a MS Email address, then this can be newly created. Set-up instructions for VNWA Application for Windows 8.1 are in the “VNWA Getting Started booklet” and you start by downloading the VNWA executable. Installation of the VNWA application was very quick under Windows 8.1, taking less than 15 seconds. The Amateur Radio Certificate and the LibUSB driver installed without any problems. VNWA Installation and Operation
1. The Intel Quad processor is certainly powerful enough to run the VNWA application. Typical
processor loading running the standard SDR-Kits commissioning test between 0.1MHz to 1300 MHz with a 1 pixel trace width is only 10 – 11% as shown below.
2. When selecting 2 pixel trace width the processor loading increased to about 33-36%. But the display is easier on the eye. I wonder if Intel know about this? This issue is also happening on all other Laptops running Windows XP, W7 and W 8.1 using the Intel Graphics driver.
3. VNWA driver and application Installation was a doddle – taking less than 10 – 15 seconds. Faster than a Acer 1810 Netbook with a dual core Atom processor when it was new in 2010 when I had only a few applications installed. 4. With VNWA 3E window covering about 75% of the screen and screen brilliance also set to 75% I obtained about 2.5 hours operating time. The VNWA was sweeping from 0.1 MHz to 1300 MHz continuously, displaying the SDR-Kits standard final Commissioning Test with a 2 pixel trace width. Of course longer battery life will be obtained with non-continuous operation. During operationg the VNWA3E draws between 250mA to 340mA current from the USB Port. Note that the VNWA3 (VNWA Expansion Board Not fitted) draws between 320mA to 400mA current from the USB Port and this will result in between 1.5 – 2 hrs battery life. (see Appendix 1 below)
5. The VNWA application seems quite robust, I have not had a lockup or other issue apart from running out of battery power. Operator Convenience: 6. If you have previous experience with small tablets or have reasonable good eyesight and dexterity with your fingers, operating the VNWA application from 8 inch tablet is possible. Generally I could access most of the functions with my fingers but you may prefer to have a screen stylus for better control. One of the functions which caused some irritation was trying to Store Calibration results to File... This function is just above „Invalidate Calibration“ button, which is easily pressed by mistake! This issue will be fixed in a future VNWA Release. To improve operatability I suggest to pin the VNWA application and Keyboard to the Taskbar and also have the taskbar permanently visible on the bottom line of the display as shown below. In addition, Batterylife/Screen brightness Icon should be already available by default on the taskbar.
7. The standard Screen Resolution of the tablet is 1280x800, shown here, however you may prefer to reduce the screen resolution to 1024 x 768 pixels (see 8.) for better readability and control of buttons.
8. Preferred 1024 x 768 pixels Resolution Screenshot displayed below:
9. Finally a practical Band Pass and Return loss Measurement of a 434 MHz Helical Filter taken with the tablet.
10. Conclusion: The Bush 8 Inch MyTablet with 1.33GHz Intel Atom Quad Core Z3735G with Microsoft Windows 8.1 Bing Operating System was found capable of running the VNWA Application. The VNWA3E (fitted Expansion board) is preferred for use with the Tablet for the reason that significant less current drawn from the Tablet USB port compared to the VNWA3. • • •
User Operability depends very much on previous tablet experience and also on having fairly good eyesight. More Senior VNWA users may want to buy a 10” tablet, which should be eaiser on the eyes and also easier to control. It is recommended to set-up a particular VNWA measurement in advance when taking a tablet outside for measurements in the field. The VNWA will store a number of Instrument setups which can then be readily loaded, saving time in the field.
Update 26.4.2015: Tom Baier DG8SAQ, the VNWA designer reported successful VNWA operation on a HP Stream 7 inch Windows 8.1 Tablet. He found that increasing the Windows font size to 200% he could fairly well controle the menus using his fingers. Appendix 1: The following Internal USB Voltage were measured on the VNWA 3E (max current draw 325-340 mA) Start of test: Battery indication 98% VNWA USB Voltage 4.89V little variation during a sweep.. after 30 mins: Battery indication 80% VNWA USB Voltage 4.71V to 4.89V during sweep after 60 mins: Battery indication 63% VNWA USB Voltage 4.61 to 4.81V during sweep after 90 mins: Battery indication 39% VNWA USB Voltage 4.09 – 4.78V during sweep after 120 mins: Battery indication 9% VNWA USB Voltage varying from 3.98V to 4.36V
The VNWA was still displaying good results at this stage! After 120 minutes operation the following internal voltages were measured on the VNWA3E: USBCodec 3.72V no variation, 3.3V Regulator: 3.3V No variation, 6.2V from Switching Regulator: 6.2V no variation during sweep. DDS Voltage Regulators input 2.52V no significant variation – DDS Voltages all 1.79V or 1.80V steady.
References: [1] DG8SAQ VNWA: http://www.sdr-kits.net/ [2] SDR-Kits Tablet Demonstration You Tube Video: http://youtu.be/OFyicGYEpTs [3] DG8SAQ Yahoo Reflector: https://groups.yahoo.com/neo/groups/VNWA/info [4] HP Stream 7 Windows 8.1 Tablet review: http://www.zdnet.com/article/hp-stream-7-windows-81-tablet-for-79/
