SOP RF Noise Monitoring, Qualification for Potential Interrogation Sites

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	Standard Operating Procedure
Subject:	SOP RF Noise Monitoring, Qualification for Potential Interrogation Sites
Author:	Scott Livingston
Approved by:	Don Warf

Contents 1 Objective 2 Scope 3 Definitions 4 Responsibilities 4.1 PSMFC's Role 4.2 Requesting Agencies Role 5 (Long Term Monitoring)Equipment Requirements 6 (Short Term Monitoring)Equipment Requirements 6.1 Step 1(Equipment Set Up) 7 Procedure(Long Term Monitoring) 7.1 Step 1(Equipment Set Up) 7.2 Step 2(Tune Transceiver) 7.3 Step 3(Configure Monitoring Software) 7.4 Step 4(Configure Transceivers Internal Diagnostic Reporting Tools) 7.5 Step 5(Evaluation of Collected Data) 7.6 Step 6(Pass_Fail Criteria and Considerations) 7.7 Step 7.(Mitigating In-Band Interference) 7.8 Step 8.(Short Term Monitoring Evaluation) 8 References

Objective

To provide information regarding the standard deployment of an RF monitoring station. This evaluation will aid in the qualification of a potential interrogation site.

Scope

The scope of this document is to ensure that the deployment and utilization of the RF spectrum analysis yields consistent and repeatable results. This document will also describe in detail the duration of each test,the equipment used during the evaluation,test parametric and how the test should be conducted,along with the presentation of the results.

Definitions

• Long Term Monitoring: An RF survey that is conducted over a period of time lasting a minimum of 30 day's or more. This type of monitoring survey utilizes an unmanned fixture and is located in the vicinity of the proposed PIT-tag detection installation. This type of survey continuously logs data 24 hrs a day at a particular sample rate in order to detect potential interference not observed or that may not be detected by the "Short term" survey.

• Short Term Monitoring: An RF survey that does not last more than 8 hrs in duration. This type of monitoring survey utilizes a spectrum analyzer along with a loop antenna and requires a technician to operate and monitor the equipment for the duration of the survey. This type of survey usually detects persistent and obvious RF interference and is a good tool for tracking down the source of the interference.

• Mitigating In-Band Interference: A method in which interference is reduced and or eliminated by means of grounding or shielding offending devices broadcasting emissions that are In-Band of the transceivers receiver circuit.

Responsibilities

PSMFC's Role

1. In General, the Kennewick Operation and Maintenance personnel will be responsible for providing accurate information gathered during the RF evaluation.
2. Disseminate information gathered.
3. Present the information in a meaningful way.
4. Make recommendations to the requesting agency as to the suitability of the location based on data collected during the survey.

Requesting Agencies Role

1. Provide AC power to the general location of the site survey.
2. If possible or practical, provide telephone communications or a LAN drop to the Long Term survey site. This will facilitate the management of the system and make data retrieval more practical and efficient.
3. Exercise surrounding equipment while technicians monitor instrumentation for in-band interference.

(Long Term Monitoring)Equipment Requirements

• Listening Post Base Station (Truck Box) consisting of:

1. FS-1001A transceiver.
2. Laptop computer configured with interrogation software Minimon Ver. 1.4.5 or above.
3. AC power conditioner.
4. 3ft by 3ft PVC unshielded style antenna mounted to wooden support fixture.
5. 12 inch shielded pipe monitor.
6. Antenna cable, Minimum of 20 ft in length.

(Short Term Monitoring)Equipment Requirements

1. Spectrum Analyzer. Mfg:Agilent,Model E4402B,Frequency Range:100Hz-10Ghz
2. Active Loop Antenna. Emco,Frequency Range:1Khz-30Mhz

Step 1(Equipment Set Up)

1. Place the monitoring equipment as close to the potential interrogation site as possible.
2. Set start frequency at 1Khz.
3. Set the center frequency at 500Khz.
4. Set stop frequency at 1Mhz.
5. Set vertical bandwidth to:10Khz(default)
6. Set resolution bandwidth to 10Khz(default)
7. Set sweep frequency to 20.37 ms.

This frequency band will cover up to the 7th harmonic of 134.2 Khz.

1. Adjust the attenuation (in db's)of the spectrum analyzer as needed in order to achieve the best resolution.
2. Turn on the "Max Hold" function. This will log peak signals within the swept frequency range that are randomly collected. This option is extremely helpful when tracking random events.

The below screen shot is an example of the what one would see in a quite environment.

Procedure(Long Term Monitoring)

Step 1(Equipment Set Up)

1. Determine the exact location of the proposed installation's is usually done as a walk through with all interested parties. The group then agrees on a primary and alternate location for the system.
2. Locate the nearest AC power source. The requesting agency should provide an AC power source in the general location of the survey.
3. Orient the PVC unshielded antenna in the zero axis position relative to the water flow of the system being evaluated.
4. The antenna is rested on a wooden cradle and should be well fastened to any adjacent or available structure with the use of ropes or any other means other than a material that will interfere with the performance of the antenna.
5. Attach antenna to the transceiver interface connector on the truck box located at the opposite end of the power plug.
6. Apply power to the truck box AC outlet.

Step 2(Tune Transceiver)

Refer to this link for tuning instructions: SOP FS1001A Tuning

Step 3(Configure Monitoring Software)

1. Set the number of data files created per day to 2
2. Set the 3-digit site code to something appropriate. Example: Little Goose,Site code_GOX
3. If communications to system is available,install or invoke the PcAnywhere application for remote access into the monitoring station.

Step 4(Configure Transceivers Internal Diagnostic Reporting Tools)

1. Set the transceivers noise report delay interval to:5 minutes
2. Set the transceivers status reports delay interval to:60 minutes
3. Set the transceivers coil ID to match the device ID given in Minimon.

Step 5(Evaluation of Collected Data)

1. The information contained in each data file will be sorted and compiled in an Excel spreadsheet. The results will be presented in graph form with the following parameters vs time.

• Average Noise Levels
• Peak Noise Levels
• FDXB Noise Levels
• Transceivers Internal Temperature.(Not shown in example below.)

Step 6(Pass_Fail Criteria and Considerations)

When reviewing the data collected from a listening station, it is important to remember that the initial evaluation is performed with a unshielded antenna. Emissions that are initial cause for concern maybe omitted if the antenna has an effective RF shield.

The site would be deemed to PASS the evaluation under the following situation.

1. Average noise level steady and hovering around 0 to 19 percent through out a 24 hr time frame.
2. Average noise levels have slight bumps in the graph, not to exceed 10 percent above the noise floor. Example: Average noise floor at 5 percent,bumps in the graph could go as high as 15 percent and deemed acceptable.
3. Peak noise levels are generally higher and more sustained than average levels. Sustained peak noise levels that are 30 percent above of the average noise floor for less than 5 minutes are deemed to be acceptable.
4. FDXB noise levels are also generally higher and more sustained than the average noise levels, FDXB noise levels that 40 percent above the average noise floor are deemed to be acceptable. Periodic spikes above the 40 percent noise floor that last less than 5 minutes in duration are deemed to be acceptable.

The site would be deemed to FAIL the evaluation under the following situation.

1. Average noise level steady and hovering above 20 percent through out a 24 hr time frame.
2. Average noise levels have slight bumps in the graph exceed 20 percent of the noise floor for more than 5 minutes.
3. Peak noise levels are generally higher and more sustained than average levels. Sustained peak noise levels that are 30 percent above of the average noise floor for more than 5 minutes should warrant further investigation
4. FDXB noise levels are also generally higher and more sustained than the average noise levels, FDXB noise levels that are 40 percent above the average noise floor should warrant further investigation. Periodic spikes above the 40 percent noise floor also warrant further investigation.

Step 7.(Mitigating In-Band Interference)

1. Set up the listening station and tune the system with an effective, shielded antenna, Preferably with a 12 inch or larger pipe antenna.
2. Re-run the Long-Term test again and re-evaluate the noise data. If the noise levels are in line and meet the criteria for PASSING, then the survey is considered to be over and no other evaluation or mitigation is needed.

If the antenna shield is not effective in reducing In-Band noise then proceed with the following:

1. Set up the Spectrum analyzer and active loop antenna at the same location where the long term listening station was.Refer to Short Term Monitoring,Step 1(Equipment Set Up)
2. The objective here is to try and identify the frequency at which the offending device operates. Once this is known, its easier to locate these nuisance devices and mitigate the interference. Coordination with on-site maintenance personnel will be required.
3. Ask the maintenance personnel to bump start different devices in the general area while monitoring the spec. an.
4. Once the offending emissions are defined and the device located, perform effective means to reduce the offending frequencies.

Step 8.(Short Term Monitoring Evaluation)

1. Set up the Spectrum analyzer and active loop antenna at the same location where the long term listening station was.Short Term Monitoring,Step 1(Equipment Set Up) for details.
2. The objective here is to try and identify the frequency at which the offending device operates. Once this is known, its easier to locate these nuisance devices and mitigate the interference. Coordination with on-site maintenance personnel will be required.
3. Ask the maintenance personnel to bump start different devices in the general area while monitoring the spec. an.
4. Set position of active loop antenna in the zero axis position relative to the water flow in transport pipe being evaluated.Monitor instrumentation for 1 hr.
5. Set position of active loop antenna in the 90 degree off axis position relative to the water flow in transport pipe being evaluated.Monitor instrumentation for 1 hr.

During any of the tests being performed, when events of interest are noticed, take screen shots of the event for future analysis and archiving.

1. Once the offending emissions are defined and the device located, perform effective means to reduce the offending frequencies.

References

SOP FS1001A Tuning
Short Term Monitoring,Step 1(Equipment Set Up)