SHIELDING INTEGRITY

Presented by Gary ArmentroutMidwest Regional Sales ManagerComSonics, Inc.Industry Leader In Signal Leakage DetectionHey! Lets Keep the Noise Down

Test Your Leakage IQEvery cable system leaks! T/F Is it ever possible for a system not to leak? Y/NWhere in a cable system does 90% of all leakage occur?75% of all service calls are signal leakage related. T/FA tight system today doesnt mean a ____ _______ tomorrow.Can a leak permanently fix itself? Y/N

Problem Areas100%90%80%70%60%50%40%30%20 %10%0%Active DeviceSetup ProblemPassive DevicesConnectionsBad CableDrop/Customer71%10%9%5%4%1%

Rainy days during a thunder storm are not recommended for leakage maintenance. Water attenuates levels and its probably not a good idea to hold up a dipole in a thunderstorm. T/FA leak of 100 V/m is measured at 100 ft. What will the reading be if you move to 200ft? 50ft?

Test Your Leakage IQ - cont.

The D i s t a n c e FactorHalving the distance from the leak source doubles the V/m level.

80 ft 20 V/m40 ft40 V/m80 V/m160 V/m20 ft10 ft

Dipole Antenna Effects90 rotation of a dipole significantly reduces the level.

80 ft 40 ft 100 V/m< 200 V/m

Dont stop now, were on a roll A good leakage program in the forward direction minimizes problems in the return path. T/FDo financially affluent customers steal cable?If you find a leak around noon time, go to lunch. By the time you get back, the leak will have fixed itself. T/FOnly female squirrels that are pregnant chew and ingest coaxial cable. T/F

Hungry Squirrel

Result

Result

Electrical Damage (Arcing)

Electrical Damage (Arcing)

Electrical Damage (Arcing)

What is a leak?75 ohm cableDielectricHistoryHBOA&EESPNFOX

Characteristic Impedance75 ohm cableHistoryHBOA&EESPNFOX100% of the forward energy is reflected back inside the cable.Dielectric

75 ohm cableDielectric Characteristic ImpedanceStanding Waves

Leakage Problem AreasDrop fittingsAnimal chewageSignal theftPoor constructionCustomer self-installsInstallers with improper training and insufficient test equipment.

Ponder these thoughtsThe drop cable is the first piece of trunk cable in the return path.In todays world, where is most system revenue generated forward or return path?In the return path, every subscriber drop funnels its contents, good or bad, back to the node. It takes only one subscriber to disrupt the entire return operation within the node or an entire series of nodes. ( plant architecture)

Return Path Funneling EffectTo Node

Return Path Funneling EffectTo Node

The Bad Guys of RFI

Detecting IngressFind the leakfix the ingress.Use an SLM to check return path frequencies Drawbackif noise source isnt present, SLM has nothing to see.OrGenerate your own noise source

To houseCATVGround Block27.947 MHz at 5W Illuminates the houseTransmits to vehicle at ~430 MHzTechnician removes the CATV input at the ground block. The Qualifier is then attached as shown. Pressing the button will send a signal to the transceiver located in the service vehicle. This transceiver will then transmit a sub band frequency at 5 watts, illuminating the house. Results will be read on the meter.Drop Cable from Tap (removed)

Finding LeakageHand Held Devices

Finding LeakageAutomated DevicesVehicle mountedUse GPS to note locationsLeakage data loaded to computer to track, edit, generate work orders, etc.

Questions???

If you would like a copy of this leakage presentation, I would be glad to send it to you.All you have to do is send an e-mail to the following address and I will reply back to you with the presentation attached.garya@comsonics.com

An interesting phenomenon...

20dB Directional TapPaper clipLocking Terminator

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