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Handheld Users Group

Handheld Users Group

Delivering leading solutions for today's field and maintenance challenges

 
Interference hunter


With over 20 years leading the way in handheld testing Anritsu has a well earned reputation for superior measurements in not so superior conditions. learn more about the very latest handheld testing technology.

Click the article below to learn more...

   

The Need for Accurate Power Measurements

When a BTS (Base Transceiver Station) is installed, output power is measured and verified. System designers walk a delicate tightrope when determining the proper output power. High levels equal better coverage area but more interference. If the power output is below a minimum limit, coverage is reduced, possibly leading to dropped calls and dissatisfied customers.
Needless to say, the accuracy of the power measurement is very important and can have a significant impact on performance and end user experience. If a base station operating at 900 MHz has an Effective Radiated Power (ERP) of +46 dBm and the receiver needs -55 dBm, the user needs to be 2,976 meters away from the transmitter to reduce the power to these levels if only the path loss is taken into consideration. A 1.5 dB error in the power measurement would give you an ERP of +47.5 dBm and the corresponding distance to achieve the same received power is now 3,537 meters, or 18.8% greater. In other words, because the power is, at best, inversely proportional to the square of the distance, small errors in power can result in large coverage errors.
 
MS2712E
Anritsu’s Site Master™, Cell Master™, BTS Master™, Spectrum Master™, and VNA Master™ handheld analyzers provide a wide range of modes and options for making accurate power measurements in field. One of the more popular is the High Accuracy Power Meter option.
The High Accuracy Power Meter, in conjunction with the PSN50 sensor, provides accurate measurements from 50 MHz to 6 GHz. True RMS measurements from -30 to +20 dBm are possible, making the test solution ideal for both CW and digitally modulated signals, including WiMAX, GSM, EDGE, GPRS, CDMA, EV-DO, WCDMA, and HSDPA. Field users now have a practical power meter solution for base station testing that delivers bench top accuracy in the field. Among all the power solutions available, the High Accuracy Power Meter provides the most accurate measurements.
Understanding measurement configuration is important for accurate tests. Base stations typically output 20 W (43 dBm). Placing a 30 dB attenuator between the power sensor and the DUT lowers the power level to 13 dBm. The upper measurement range of the sensor is +20 dBm and placing an attenuator between the sensor and the DUT prevents the sensor from getting damaged. It also ensures that measurements are made in the linear range. The standard offset feature can be used to measure the S21 of the attenuator accurately, as well.
 

Questions and Answers

Question: Are CDMA measurements supported in the BTS Master?

Answer: Yes, CDMA measurements are supported in the BTS Master, as well as the Cell Master and Spectrum Master. These platforms also support EVDO, GSM/EDGE, and WCDMA/HSDPA measurements. Additionally, WiMAX and LTE measurements can be made with the BTS Master and Spectrum Master analyzers.

Question: How do I use a sliding load?

Answer: First, check and adjust the width of the pin depth gauge, if necessary. Next, set the pin depth of the sliding load to -0.0002 to insure that the shoulders of the male and female connectors are sufficiently spaced. After the pin gap is set, the sliding load must be mated to the test port of the VNA when prompted during calibration. Always position the slider as close to the test port as possible when making the connection. Gently tap the shaft of the sliding load if the center conductor is obviously misaligned. When visually centered, carefully mate the sliding load to the test port connector. When prompted, insert the fixed load.

Question: What is the difference between an OSL calibration and FlexCal™?

Answer:With the OSL calibration, you have to calibrate each time you change the frequency range. With the FlexCal, you can change the frequency range and you don’t have to perform another calibration. FlexCal is great for troubleshooting purposes. The accuracy can be affected if your span is really narrow, so for optimum accuracy, it is recommended to use the OSL calibration.

Question: After completing a sweep in return loss with a short connected to the other end, my customer requested I include an insertion loss sweep. How do I convert this return loss sweep to an insertion loss sweep?

Answer: Handheld Software tools solves this dilemma. Set marker one to peak and the second marker to valley. Add the two values together and divide by four. For more detail, see page 3 of the “Insertion Loss Measurement Methods” application note, 11410-00276 (http://www. us.anritsu.com/downloads/files/11410-00276.pdf).

 

Test Tip

Our FlexCal broadband calibration feature offers a simple and convenient way to troubleshoot and identify faulty antenna system components because it eliminates the need for multiple instrument calibrations and calibration setups. Field technicians can now perform a broadband calibration and change the frequency range after calibration without having to recalibrate the instrument.
 

First Comprehensive LTE Base Station Measurement Suite Unveiled

 
MT8221B
 
mt2720t

Anritsu Company’s continued involvement in the development of LTE has led to the introduction of the first comprehensive LTE base station measurement suite. Designed for use with the MS272xB Spectrum Master, and MT8222A and MT8221B BTS Master handheld analyzers, these optional measurement capabilities allow field engineers and technicians to conduct tests necessary for the proper deployment, installation, and operation of LTE networks.
The LTE RF measurement option allows users to accurately and quickly analyze the spectrum for interference and spectral compliance, as well as conduct occupied bandwidth and Adjacent Channel Leakage Ratio (ACLR) tests. With the LTE modulation quality measurement option, Error Vector Magnitude (EVM), frequency error, and Control Channel power tests can be conducted. Over-the-Air (OTA) measurements with the third option are used to determine interference from co-channel transmitters, help troubleshoot problems with coverage area, and verify coverage of self-organizing networks.
The LTE measurement suite supports the MS272xB Spectrum Masters, which are the most advanced ultra-portable spectrum analyzers on the market. With sensitivity of ≤–163 dBm Displayed Average Noise Level Typical @ 1 GHz, the MS272xB series can measure very low-level signals, a critical feature as the RF spectrum becomes more congested. The handheld spectrum analyzers also feature a wide dynamic range to measure very small signals, even in the presence of much larger signals.
The BTS Master MT8221B has been designed to support both 4G standards and installed 2G/3G networks. Its platform provides a 20 MHz demodulation capability, as well as a 30 MHz Zero-Span IF Output for external demodulation of virtually any wideband signal.
LTE measurements are the most recent test capability added to the Spectrum Master and BTS Master platforms. The instruments can also be configured to measure WCDMA/HSDPA, GSM/ GPRS/EDGE, CDMA, EVDO, TD-SCDMA, and Fixed and Mobile WiMAX signals.

 
 

BTS Master Helps Senior Consultant Maintain Problem-Solving Reputation

   
Darrell Ferguson had established a reputation as the problem solver during his 12-year career with AT&T. So, when he started his own company, 3D Telecom, early this year, he knew he had do whatever necessary to maintain his high standing. That’s why he turned to Anritsu Company.
“In my previous job, all the problems that couldn’t be fixed wound up on my desk. Then, when I went out on my own, I realized I was given only the tough jobs; the ones that couldn’t be solved by anyone in-house. Immediately, I realized I needed the right tools because using equipment that would let me down was not an option. That’s why I selected the Anritsu BTS Master,” said Ferguson.
Ferguson was familiar with Anritsu from his days at AT&T. He had used the Spectrum Master and Site Master analyzers to help locate interference and faults at cell sites. The analyzers had set themselves apart from the competition because of their size and performance, according to Ferguson. “I have to say that it’s tough to beat the Anritsu instruments. To get comparable performance, you have to go with a much larger instrument. If you use an instrument of similar size, you’re not going to get the same accuracy,” he said.
Ferguson has found the MT8222A especially useful when measuring fiber distributed antenna systems in W-CDMA/HSDPA base stations. According to Ferguson, the MT8222A is the only way to accurately measure signal power, a critical factor. “If you lower the signal power to a safe region you can reduce data throughput but if too much power is used, the RF input connected to the fiber can become damaged. The BTS Master ensures that the power level is accurate.”
That’s not the only way Ferguson uses the BTS Master. The analyzer has also been very helpful in hunting for interference.
“Recently, a carrier had a group of seven cell sites in Berkeley, California, that was being hit by strong interfering signals on an intermittent basis. I attached a Yagi antenna to the BTS Master and over the course of two nights I was able to find the source of the interference. It was a repeater that was four miles away from the towers. I don’t know how many other handheld instruments could have found that kind of source in that amount of time,” said Ferguson.
Such a success story has helped Ferguson grow his new business. It’s also how he has been able to maintain his reputation as a problem solver for wireless carriers.


 
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