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Electric power “black box” detects crashes for government users

Ali Cheung — Wed, 01 Feb 2012 18:38:15 +0000

When a mountain-top radar system crashes then re-starts as though nothing happened, it’s dangerous. It can be really tough to figure out if the crash was caused by a software bug, loose cable, bubble in the cooling water or power glitch.

A new tiny recorder called the PQube solves this problem by capturing complete information about every power disturbance. The tough PQube functions like the black box in an airplane, recording the reason for every crash. Government technicians and engineers use PQubes to increase the reliability of airport systems, data centers, sophisticated medical electronics and building automation systems.

Using miniaturized technology, the PQube power monitor is about the size of a large digital camera and costs about the same as a high-end digital camera. The unit replaces older portable instruments the size of a suitcase and cost as much as a small car.

Currently deployed by the FAA, U.S. Navy, NASA, Intel, and hundreds of other organizations, the PQube automatically write reports to pop-in, pop-out digital camera memory cards. If an Ethernet port is available, the PQubes will even automatically email photographs of every power disturbance to their user. No software is required – everything is built into the PQube. They even functions as an ultra-accurate ultra-high-resolution energy meter, with a built-in web server.

A new partnership between Technical Communities, a contract, marketing and sales company focused on the public sector, and Power Standards Lab (PSL), the maker of the PQube monitors, gives government buyers greater access and lower pricing in multiple distribution channels, including www.gsaadvantage.com, www.gsamart.com, and www.testmart.com. PSL products will be offered to eligible organizations under General Services Administration (GSA) Multiple Award Schedules (MAS) managed by Technical Communities using Schedule #GS24F0066M.

“Our new partnership with Technical Communities will make it even easier for government buyers to take full advantage of PQube power monitors,” said Alex McEachern, President of Power Standards Lab. “And we’re proud that all of our instruments, including the PQube, are designed and made here in the USA.”

“Technical Communities is excited to offer the federal government power quality and energy monitoring instrumentation from PSL,” said Peter Ostrow, President and CEO of Technical Communities. “With Technical Communities’ expertise in the federal market, we could help PSL achieve greater reach into government purchasing organizations.”

iOS spectrum analyzer lights up with WiFi

Travis Wheeler — Tue, 31 Jan 2012 21:47:07 +0000

Oscium, the company that developed an iOS oscilloscope, has added a spectrum analyzer/power meter for WiFi frequencies. The WiPry isn’t a general-purpose spectrum analyzer because it’s frequency range is limited to the wifi band: 2.4 GHz to 2.495 GHz. It’s available as a spectrum analyzer only ($99.97), an RF power meter ($149.97), or a combination of both ($199.97), which was the unit I tried. See a video of the WiPry in action.

The WiPry’s primary purpose is to help you troubleshoot interference on your wireless network from interference. It lets you see the signals on each of the 13 Wifi channels. I tested the WiPry at home, where my computer detected 11 wireless networks-and that’s with my closest neighbor’s wireless router turned off because the house is vacant during renovations.

Like its oscilloscope cousin, the WiPry attaches to its host directly through its I/O connector. While that’s convenient, it feels kind of weak and could break unless you take care of the system. I’d rather have an extension cable. But wait, Apple’s extension cable won’t work because it extends the power only.

As a spectrum analyzer, the WiPry will show you the activity in the WiFi band. It offers two displays, a “real wave” and a waterfall. The real wave is just what you’d expect, peaks appear whenever a wireless devices transmits (Figure 1). But, those peak some in short bursts and are difficult to capture. Fortunately, the WiPry has a persistance feature that holds the peaks for a few seconds. The waterfall display lets you see the density of the signals as they scroll across the screen. But, the points are difficult to see in the default colors, but yo ucan change them to improve visibility (Figure 2). My home wireless router uses channel 6 and that’s apparent from the waterfall display.

The WiPry screen lets you highlight any of the 13 wifi channels. Simply tap the “+” sign in the screen’s upper left corner. That lets you see the bandwidth of each channel and how the channels overlap (Figure 3). You can also highlight any of the WiFi channels by touching any of the channel buttons (Figure 4) and then touch outside the highlighted channel to see another channel. The video demonstration lets you see that in action.

Digital instruments are great at capturing screens for reports. While you can do that by pressing the front button while holding the on/of button, you can also do that with the WiPry software. Just touch the settings icon and the screenshot button to capture the screen. I prefer using the WiPry’s screen capture to the iPad buttons. The WiPry app produced a landscape image, which was easier to read than the portrait image that the iPad produced. You even use the WiPry app to send a e-mail containing the screen. That’s useful when you don’t have a USB cable or access to your computer.

As a power meter, the WiPry can capture bursts of received signals and display them as peak-to-peak, RMS, duty cycle, min, max, and several other measurements. Power bursts appeared randomly and were difficult to capture at first. When they did appear, they would fade in a few seconds, making cursor measurements rather difficult. Touching and holding the pause/play button sets the WiPry for single-shot capture. Then, the image held.

Full article by Martin Rowe, Test & Measurement World

Smart devices create opportunities for test vendors

Travis Wheeler — Fri, 20 Jan 2012 18:06:11 +0000

The rapid changes that are taking place in the wireless communications industry are driving growth in the wireless test equipment market. With the growing number of wireless subscribers, smartphones, wireless data services, mobile banking, and social-networking applications, there is a need for increased functionality in test and measurement tools.

The wireless test equipment market consists of signal generators, spectrum analyzers, network analyzers, and telecom and datacom test equipment. The global wireless test equipment market generated revenues of $3.1 billion in 2011 and is expected to exceed $5.8 billion in 2017 with a CAGR (compound annual growth rate) of 11.0% from 2011 to 2017. Numerous factors are contributing to the growth.

As LTE technology moves toward deployment, it brings new challenges, including higher data rates. The volume of mobile data traffic is increasing as a result of several factors: high-speed networks; an increased penetration of next-generation mobile phones (especially smartphones) and connected devices (laptops, netbooks, notebooks, and tablets); and higher-bandwidth-consuming applications and services.

In 2009, the penetration rate of active 3G (and 3.5G) users in North America was 12%, and it is expected to exceed 35% in 2015. Consequently, the demand for 3G-compatible test equipment is expected to increase. Likewise, the demand for QoS (quality of service) and QoE (quality of experience) analysis is increasing as growing mobile data usage creates more traffic on the network.

Smart devices are changing the mix of traffic from mostly voice to integrated voice, video, and data, thus creating a demand for products that can test a network’s performance and capacity along with how well it handles the integrated transmissions. Another issue that is a driver in the market is the need to support mobility across different technologies, from LTE to 3G, and back to 2G.

The rise of location-based services will also drive growth in the test market. A number of enabling technologies come into play for these services, such as WiFi and different satellite technologies beyond the original assisted GPS.

While the telecommunications industry is excited about data rates of 150 Mbps, LTE-Advanced promises 1 Gbps and 100-MHz bandwidth. The increases in data rates and bandwidth will drive more demand for wireless test equipment for mobile devices and base stations. T&MW

Full article by Olga Yashkova, T&M World

Technical Communities Receives “Exceptional” Rating for GSA Schedule 66 Management

Ali Cheung — Thu, 19 Jan 2012 19:27:37 +0000

Technical Communities, Inc., the company technical organizations who sell to the government rely for proven contracting, marketing and sales solutions, received a top “Exceptional” rating from U.S. General Services Administration (GSA) for administrative performance against Federal Supply Code (FSC) 66, Scientific Equipment and Services contract GS-24F-0066M.

The rating on the GSA Administrative Report Card is based on the requirement and performance of the contractor in contract compliance, record accuracy, lowest pricing options, and timely delivery.

“Technical Communities is proud to receive an exceptional rating for our service performance in the scientific and test equipment GSA Schedule,” said Peter Ostrow, President and CEO of Technical Communities, Inc. “This rating is a strong proof of our commitment and hard work in optimizing the GSA buying experience for government users, military personnel and federal contractors.”

Technical Communities markets and sells FSC 66 test, measurement, laboratory and scientific equipment under the TestMart and LaboratoryEquipmentMart ecommerce sites and brands. The company regularly sells to more than 1,400+ U.S. government, military and prime federal contractor buying organizations. Technical Communities has a record number of partnerships with 120+ technical companies. In addition to service offerings, the company holds and manages multiple federal, state and local government contracts.

Technical Communities Breaks Sales Records for 2011

Ali Cheung — Tue, 10 Jan 2012 23:33:49 +0000

Technical Communities, Inc., the company technical organizations who sell to the government rely for proven contracting, marketing and sales solutions, broke its all-time annual sales record in 2011.

All Technical Communities’ revenue categories achieved record results, including test, laboratory, medical, information technology and direct marketing. This is the eighth of the past nine years where the company showed year over year sales growth.

The privately held company also now has a record number of partnerships with 120+ technical companies. In addition to service offerings, the company holds and manages multiple federal, state and local government contracts. It is owner and operator of industry leading online marketplaces that focus on the U.S. government agencies, military organizations and prime federal contractors. They include ecommerce sites gsamart.com and testmart.com and the govcontractsmagazine.com government-focused content network.

“We are very excited to announce these results for 2011. It was Technical Communities’ focus on our partners’ needs, expertise in reaching government customers and successful management of multiple GSA Schedules that helped us achieve record sales and partnerships,” said Peter Ostrow, Technical Communities, Inc. President and CEO.

Technical Communities continues to add partners, product lines and services that solve problems and focuses on government customers. The company regularly sells to more than 1,400+ U.S. government, military and prime federal contractor buying organizations and has reach into the 1+ million prospects in its proprietary database.

For the fourth year in a row, Technical Communities was named to Inc. Magazine’s list of the fastest growing private companies in America.

Test and Measurement: On a growth spree

Travis Wheeler — Fri, 30 Dec 2011 17:11:52 +0000

In today’s world of communications, technologies are evolving at a much faster pace, consumers are becoming demanding and there is a strong need for reducing the time-to-market. Along with the quick evolution of technologies, the need of the hour is co-existence of these technologies with better functionality, where test and measurement (T&M) companies play a very crucial role in this dynamic scenario. T&M assures the efficacy of a technology and it vividly defines a roadmap of technologies with an emphasis on the future readiness. After discovering/inventing a technology in any and every segment it is equally important to evaluate its performance before its deployment. As the telecommunications sector ascends the impressive growth curve alongside the emergence of umpteen technologies, T&M is gaining more and more prominence. There is a tremendous demand for conformance and interoperability testing between hands.

Growing Manifold

T&M is growing manifold to date because of the constantly rising subscriber base, higher penetration of technology particularly wireless technologies-LTE, WiMax, BWA, need for QoS, and emphasis on the local manufacturing. Speaking about the T&M dynamics, Shankar Krishnamurthy, country manager, Empirix India and Sri Lanka/Maldives, says, “From a technical perspective, T&M solutions must evolve to support new network protocols and service delivery methods within a single architecture. Operators who can effectively troubleshoot issues can tightly control costs. Those that can assure a great customer experience will build loyalty.” From a business perspective, operators need greater insight into customer behaviors and application usage to make smarter decisions on infrastructure investments, pricing models, marketing campaigns, and revenue generation programs. M Mombasawala, general manager, applications, Agilent Technologies says, “T&M is imperative in providing validation in all areas of telecom, be it R&D activities from companies like Qualcomm or service provider provisioning from Ericsson or consumption from operators.”

Wireless Technologies

Introduction of third generation technologies, proposed launch of fourth generation technologies like LTE, WiMax, broadband wireless access service; and, with the next-generation technologies, telecom T&M is likely to witness strong demand in the coming years. Large scale deployments of communication technologies need large-scale emulation. In India, we predominantly have 2G networks and 3G networks are overlaid on 2G network and ensuring interoperability and inter-working of this network is of paramount importance. The ability to seamlessly hand over between cells while minimizing the interruption to data throughput needs to be tested and assured as does the ability to hand over between different radio access technologies while maintaining the data connection.
T&M plays a crucial role in 3G services, in all aspects of 3G handset and field testing, including core/access network testing. T&M opportunities are increased with the beginning of 3G BTS manufacturing by network equipment manufacturers and 3G handset manufacturing. 3G handset testing and mobile application testing would fall into the testing menu of the SPs. Radio frequency measurements for spectrum clearance, coverage, and interference are a must do to ensure better 3G services. “The adoption of 3G and BWA offer tremendous opportunity. As they add new technologies, operators must include a plan for assuring them. However forward-thinking operators are taking a more strategic approach. Rather than simply installing a new probe to analyze the latest 3G protocol, these operators are choosing a holistic end-to-end T&M solution with predictive capabilities that preempt issues from impacting customers. This assures a better customer experience with significantly reducing the overall cost of troubleshooting and maintaining the network as a whole,” points out Shankar Krishnamurthy, country manager, Empirix India, Sri Lanka/Maldives.

A comprehensive test of radio frequency, protocol and system level elements such as base stations, cell sites, handsets and network infrastructure in a 4G network is a major requirement for its operational efficiency. M Mombasawala, general manager, applications, Agilent Technologies mentions, “A transition to 4G/ LTE greatly increases the complexity of the task of monitoring and troubleshooting mobile data services. Service providers need to develop, deploy and manage the technology in a way that ensures a high QoS while minimizing capex and opex. The latest generation of T&M equipments help to evaluate and deploy equipment that meets specifications and quality standards, verifies new services, and accelerates problem resolution cycle time.” Carriers that get T&M would have many loyal customers on their network for long term. Both fixed and mobile WiMax, a 4G technology, have a very complex requirement in terms of characterization. Conducting a basic RF transmitter measurement on WiMax requires high performance test equipment with advanced measurement functionality. Hence ensuring operational readiness of 4G networks is essential not only during the initial launch of technology but also as network and services grow and mature.

Apart from technologies, there is a dire need to test applications as well. The mobile applications will have to be tested for robustness under bad RF conditions, so as to provide a great end user experience. Besides, enterprise offerings such as cloud computing and virtualizations is also driving T&M. Referring to the T&M requirements Shankar Krishnamurthy says, “End-to-end visibility, regardless of network protocol or service delivery method, is the most important requirement for T&M today. If an operator cannot see the entire communication from start to finish, they cannot understand customer experience, Quality of Service or application performance. If an operator cannot see their entire operations, they cannot assure interoperability, cost-effectively troubleshoot issues or effectively integrate new technologies to optimize the network.”

Increasing Subscriber Numbers

The functionality of T&M tools have been accelerated due to the increasing number of wireless subscribers, increasing number of mobile devices particularly smartphones, a transition from voice to data services including mobile banking, mobile social networking applications, etc.

Service providers ought to ensure better quality of service and experience hence the need to testing has increased. In order to meet the customer expectations, SPs should ensure high quality of network performance thus channel coding, BER, latency, and throughput rates under varying conditions including fading and mobility must be tested.

Full article by Malini N, Voice & Data

How a standard defines a voltage or current pulse greatly influences wave shape

Travis Wheeler — Sat, 17 Dec 2011 18:02:39 +0000

Electronic products must pass some level of immunity tests when subjected to conducted or radiated energy. Some of those tests include subjecting the equipment under test to electrical impulses–short duration single events using defined voltage and current waveforms. Engineers also use impulse tests to verify electrical spacings on PCBs and to periodically check motor-insulation.

Several international standards define impulse waveforms, but only at certain points in how a voltage or current will rise and fall. The waveform shape, peak voltage, impedance, and application of the pulse varies among standards. The test pulse you use depends on the standard you apply because standards define impulses differently.

Waveform Definition

The IEC (International Electrotechnical Commission) has at least two standards that define impulse tests and their waveforms. Use IEC 60060-1, “High Voltage Test Techniques” when testing insulation systems and use IEC 61000-4-5, “Testing and Measurement Techniques – Surge Immunity Test,” for switching and lightning-transient tests. Many standards that define testing of specific products reference either of these two standards because these two standards.

In some end-use Standards, both the insulation system of the DUT (device under test) and the ability of the device to withstand lightning and switching transients are important. The requirements of IEC 60060-1 and IEC 61000-4-5 are different, so the authors of the end-use standard must decide which standard to reference. A relevant example is IEC 61730-2, the Standard for photovoltaic (PV) panels, which references IEC 60060-1 as its impulse standard definition, which is applicable to insulation systems. In the PV standard, the authors note that the test is “To verify the capability of the solid insulation of the module to withstand over-voltages of atmospheric origin. It also covers over-voltages due to switching of low-voltage equipment.” While this scope would be closer to that of IEC 61000-4-5, the authors elected to conduct the test under the requirements of an insulation impulse test, which they deemed a better definition of their test program.

Full article by Jeff Lind, Test & Measurement World

Technical Communities and Primex Wireless Sign Government Services Partnership

Ali Cheung — Tue, 06 Dec 2011 18:02:55 +0000

Technical Communities, Inc., the company technical organizations who sell to the government rely on for proven go-to-market solutions to grow sales, lower costs and reduce risks, today announced a new government services partnership agreement with Primex Wireless, the leading provider of solutions to automate and maintain facility compliance.

Under the agreement, Technical Communities will have exclusive rights to offer Primex Wireless facility monitoring solutions on GSA’s Federal Acquisition Service Worldwide Schedules. The Synchronous Network System (SNS^TM) is a single platform with web-based software that gives facility managers unprecedented capabilities for time synchronization, wireless sensor monitoring, automated emergency light testing, automatic email alerting, and accurate event logging. SNS is one of the first wireless platforms on the market that helps facility managers improve efficiency in clock synchronization, school bell systems, and environmental sensor monitoring by using their existing Wi-Fi networks. Primex Wireless’ solutions maximize the benefits of an organization’s existing IT infrastructure and reduce the need for any additional IT capital expenditures.

“Technical Communities provides proven go-to-market solutions for Primex Wireless to sell into the government market,” said Paul Shekoski, CEO of Primex Family of Companies. “This partnership will enable Primex Wireless to more effectively serve the government market with our SNS compliance management and time synchronization solutions.”

“Technical Communities is excited to offer the federal government cost-effective facility monitoring solutions from Primex Wireless,” said Peter Ostrow, President and CEO of Technical Communities. “We have a total commitment to create the most effective public sector buying and selling opportunities for industry-leading organizations such as Primex Wireless.”

Primex Wireless products will be offered to eligible entities under General Services Administration (GSA) Multiple Award Schedules (MAS) managed by Technical Communities, which will provide Primex Wireless with sales support, demand generation, marketing and reporting services. Primex Wireless products are available for purchase through the GSA’s e-commerce web site, www.gsaadvantage.gov, and the company’s own online marketplaces, www.gsamart.com and www.testmart.com.

New rules allow small business “set asides” under GSA schedules

Linda Rodden — Tue, 29 Nov 2011 21:49:14 +0000

The FAR Council issued an interim rule Nov. 2 establishing a set aside option for orders placed under GSA Schedules and other IDIQs. In the past, the FAR Guidance on ordering from small businesses under GSA Schedule ordering procedures was simply that agencies may consider socio-economic status when identifying contractors for consideration or competition for award. They could also credit for their small business goals. GSA would from time to time set aside some Special Item Numbers for small businesses, too.

The new changes make clear that contracting officers can set aside task or delivery orders or Blanket Purchase Agreements (BPAs) for small businesses under the GSA Multiple Award Schedules or on blanket purchase agreements, and on any other multiple-award contracts.The revisions add a new section in the FAR. It authorizes agencies to set aside one or more contracts for small business on a multiple-award contract, including any of the socio-economic programs, such as the service-disabled, veteran-owned small business program.

Although the revisions cover more than just GSA Schedules, the changes may have a larger impact on the GSA Schedules ordering procedures. Specifically, FAR 8.405-5 has now been modified to state that ordering activities may, at their discretion:

(i) Set aside orders for any of the small business concerns identified in 19.000(a)(3); and

(ii) Set aside BPAs for any of the small business concerns identified in 19.000(a)(3).

As before, orders placed against schedule contracts may be credited toward the ordering activity’s small business goals. For purposes of reporting an order placed with a small business schedule contractor, an ordering agency may only take credit if the awardee meets a size standard that corresponds to the work performed. Ordering activities should rely on the small business representations made by schedule contractors at the contract level.

The FAR also directs that ordering activities may consider socio-economic status when identifying contractor(s) for consideration or competition for award of an order or BPA. At a minimum, ordering activities should consider, if available, at least one small business, veteran-owned small business, service disabled veteran-owned small business, HUBZone small business, women-owned small business, or small disadvantaged business schedule contractor(s). GSA Advantage! and Schedules e-Library at http://www.gsa.gov/fss contain information on the small business representations of Schedule contractors.

Contracting Officers now have an easier way to reach their small business goals. Although the revised FAR 8.405-5 specifically states that the preference programs of FAR Part 19 are not mandatory, contracting officers could look to the guidance in FAR Part 19.502 and use the “rule of two” found in 19.502-2 or look to the simplified acquisition total set aside rules found in FAR 13.003.

Only time will tell if the new rules result in larger share of orders being placed with small businesses. There are many questions regarding implementation of these new rules, particularly around the status of large businesses in teaming agreements with small businesses and the non-manufacturer rule implementation. The effective date of the new rule is November 2, 2011. Public comments on the interim rule are due by January 3, 2012.

Things to Do Now:

If you are a small business make sure your agencies are aware of the new rule and your company’s status.

Subscribe to GovContracts to receive notices of opportunities (http://search.govcontractsmagazine.com/contracts/fbosearch.cfm)

Ensure all who wish to purchase under the GSA Schedule contract are eligible to do so.

To expand the government’s ability to access your products you can get your items on a GSA Schedule contract.

Locate partners now such as Technical Communities who aresmall businesses.

Make sure they have full access to the products or services that are in demand for those government markets.

Gigahertz RF measurements can be accurate

Travis Wheeler — Sat, 19 Nov 2011 18:18:11 +0000

Extremely high frequency, which can be defined as the frequencies between 30 and 300GHz, remained relatively undeveloped for many years, except for somewhat esoteric applications such as radio astronomy and remote atmospheric sensing.

That is because this frequency range is highly susceptible to atmospheric attenuation – when resonance of the oxygen molecule attenuates the signal, or when rain absorbs the signal, reducing signal strength.

But with spectrum scarcity in the sub-10GHz band, applications for millimetre-wave systems are found in consumer and non-consumer communications, security, imaging and radar. In particular, with increasing demand for multi-gigabit-per-second communication created by the likes of high-definition (HD) and 3D video, it was soon recognised that the 7GHz of unlicensed bandwidth available around 60GHz was a big opportunity.

So, for several years, the extremely high frequency region has become an area of intense development, with several applications actually being able to capitalise on its signal attenuation characteristics.

Wireless HD

Among the many short-range communications standards that have appeared in the 60GHz frequency range is WirelessHD, a media standard for video in the home that effectively untethers the TV from other home video and audio devices.

Conceived as an in-room, point-to-point, non-line-of-sight standard that uses the band between 57GHz and 64GHz, it is capable of transmitting HD video images and the first products have a limited range of up to10 metres, pleasing copyright owners.

The increased signal attenuation at high frequencies is due to the very small wavelengths generated.

So WirelessHD antennas use various beamforming techniques to concentrate power in the direction of the receiver and bounce signals off nearby objects, using both direct and reflected signals to achieve a stronger, more stable signal.

As you move into higher frequencies and the wavelength size decreases, so the physical structure of devices also comes down in size. This can increase cost dramatically because of the machine costs related to making smaller components. The tolerances involved become much greater too.

Instrumentation can also prove more expensive at higher frequencies, because the frequencies and modulation bandwidth are outside the range of most standard test equipment. One reason for the cost increase is economies of scale.

SiGe and CMOS transistors that can run fast enough for circuits in the millimetre-wave region are a relatively recent arrival, so the growth in millimetre-wave applications has created a correspondingly recent demand for millimetre-wave instrumentation for device specification verification.

Costs can be trimmed by using a down converter module to convert the 60GHz signal to lower frequencies that can be analysed on standard equipment. But there is a risk when using a downconverter or harmonic mixer that the mixing produces multiple image frequencies unsuitable for spurious measurements.

Waveguide flange

Users of harmonic mixers would also need to take account of the waveguide flange, requiring a further conversion to 1.85mm coax to interface with the DUT.

Any additional hardware will also add measurement uncertainty into the signal observed. So it is advisable to use millimetre-wave test equipment that allows measurements to be performed directly on the signal.

When calculating uncertainty in RF measurements stemming from voltage-standing-wave-ratio mismatch, it is important to recognise that uncertainties increase as the frequency rises. So although many spectrum analysers have good power measurement capabilities, a dedicated RF power meter provides better accuracy and impedance matching – critical at higher frequencies.

Precise calibration

It has been said that a vector network analyser (VNA) is only as useful as its measurement accuracy. So to get the best out of a high-frequency VNA, precise calibration is vital. Sources of error come from less than perfect input impedance at the RF receiver and/or output impedance by the RF source, as well as wear and tear to cables and connectors.

Things are further complicated when measurements cannot be made easily at the coaxial connectors, for instance on wafer devices. Calibration won’t fix every error, but you can minimise them by choosing a VNA with good raw system performance and unique calibration techniques.

Full article by Jamie Lunn, ElectronicsWeekly