Shively Labs 6814, Instruction Manual

Page 1: ...Circularly Polarized FM Broadcast Antenna Model 6814 Instruction Manual Installation Operation Maintenance ...

Page 2: ...ts Our technical staff has a wealth of experience in the broadcast industry and is standing by to serve you in any way This manual is intended to give you a good basic understanding of your antenna its proper and safe installation startup and operation and trouble shooting and maintenance information to keep it working satisfactorily for years to come Please have everyone involved with the antenna...

Page 3: ...this manual in its entirety before beginning installation of your antenna Failure to follow the installation and operation instructions in this manual could lead to failure of your equipment and might even void your warranty ...

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Page 5: ... the feedline sections 9 Figure 7 Feedline flange detail 9 Installing the transformer 10 Figure 8 Transformer installation top view 10 Chapter 3 De Icer Installation if applicable 11 Precautions 11 De icer system description 11 Dual setting thermostat 11 Electric power 11 Figure 9 De Icer electrical schematic diagram 12 Table 2 De Icer specifications 13 De icer installation 13 Installing the de ic...

Page 6: ...Labs de icer control system 22 Chapter 5 Maintenance 23 Precautions 23 Maintenance log 23 Physical inspection 23 De icer check 24 Paint 24 Radiator removal for repair 24 Return policy 24 Troubleshooting 24 Internal arcing 24 Broad spectrum RF noise 24 High VSWR at startup or during operation 25 Erratic VSWR during impedance trimming 25 Change in coverage 26 Pressure loss or excessive gas usage 26 ...

Page 7: ... or otherwise Take pains to keep the antenna components dry You will need to purge mois ture from the interior of the antenna components before applying trans mitter power and purging will be much more time consuming if the components get wet Unpacking a Find Box 1 it is marked Open This Box First It contains the transformer and two copies of the installation drawing The parts list on one sheet of...

Page 8: ...ower and review the installation drawings before the full rigging crew arrives If design problems are found contact Shively Labs immediately Pay particu lar attention to Frequency of the antenna Fit of the mounts to the tower members Freedom from interference by gussets leg flanges guys and their attachment points tower face members obstruction lights and other components Compatibility of transmis...

Page 9: ...rather than U bolts and don t overtighten b Lay a feedline section horizontally supported off the ground with its baymount flange pointing upward Secure the feedline section at the brass end using clamps to prevent its turning with the weight of the radiator Figure 1 Baymount detail CAUTION All contact surfaces and openings to the interior of the components are protected from contamination and fro...

Page 10: ...n accordance with the installation drawing If you don t the antenna may not perform as expected g Remove the matching radiator assembly from its protective plastic bag CAUTION Be sure the radiator s inner conductor fits cleanly over the baymount s inner conductor connector If any of the fingers of the connector are forced outside the radiator s inner conductor a split bullet this will cause arcing...

Page 11: ...tom narrow mating flange and drain holes radome halves NOTE The feedline comes with a 20 inch long extension in place see Figure 2 This extension in effect moves the feedline joints outside the radome and thus allows you to mount the radome on the ground You should treat the feedline with its extension as a single unit c Remove the closure plate bolts where the mount will slip under the closure pl...

Page 12: ...rting its mount into its closure plate i Bolt the radome halves loosely to the mount with the mount bolts 3 8 with lock washers and flat washers Figure 4 Radome installation j Fasten the two radome halves together with the 1 4 flange hardware starting at the feedline side and working around both sides to the outer edge Tighten the flange hardware NOTE You may have to squeeze the radome flanges tog...

Page 13: ...tallation to installation to accomodate various tower and mounting pole requirements Figure 6 shows several common con figurations Your feedline mounts may be one of the common designs shown if they are not they will be shown in detail on your installation drawing Before you begin installation study the mounts the mounting tower leg s or pole and your installation drawing carefully establishing wh...

Page 14: ... or where tower obstructions exist See your installation drawing for your mount configuration and special requirements if any CAUTION If you don t get good electrical contact between the mounts and the tower the antenna may not perform as designed and may produce stray signals that will interfere with other services on the tower ...

Page 15: ... include bullet guides see Figure 7 to help prevent split bullets Be sure the bullet guides are in place before assembly a Install the feedline sections transformer and other components carefully in accordance with your installation drawing and the illustrations in this chapter b Secure the feedline to the mount saddles using the clamps provided generally two clamps on a 6 long saddle and 4 clamps...

Page 16: ...antenna systems is the adjustable impedance matching transformer provided with the antenna It allows the installer to compensate for changes in the input impedance caused by the installation tower conduit ladder etc Figure 8 Transformer installation top view NOTE The transformer may be oriented in whichever direction you wish see Figure 8 Make it easy for yourself to reach for adjustment at startu...

Page 17: ...Electrical specifications Table 2 on page 13 Bay junction box Figure 10 on page 14 Thermostat readings Table 3 on page 15 Your system may also include specially ordered items such as a ground mounted main control box a power cable extending up the tower or a tower mounted dual setting thermostat Dual setting thermostat CAUTION Remember that conditions may be favorable for icing on the tower even i...

Page 18: ...OTE A liquid tight conduit con nector 3 8 conduit size by 1 2 hub size for the harness entry to the tower junction box is packed loose with the de icer harness NOTE Shively recommends the use of shielded braided polyethylene covered wire or rubber sheathed flexi ble metal conduit or rigid conduit and weather tight fittings at all junctions ...

Page 19: ...g tie wraps secure the entire length of the de icer harness to the RF feedline at about 24 60 cm intervals Run the ten foot de icer pigtail along a feedline mount to the tower junction box and secure it to the mount and the tower Table 2 De Icer specifications High Band 98 0 108 0 MHz Low Band 88 0 97 9 MHz Heater Leg Resistance Heater Leg T1 or T2 Current Draw amps Heater Leg Resistance Heater Le...

Page 20: ...at measure the resistance across the thermostat circuit and from it to ground to ensure that there are no short circuits Thermostat readings should be as shown in Table 3 on page 15 b Mount the thermostat near the antenna and connect the thermostat leads to points S1 and S2 in the control box as shown in the schematic diagram Figure 9 on page 12 CAUTION Shively Labs s de icer control box Model 940...

Page 21: ...rcuit Resistance infinite ohms open circuit Leg to Ground Any Defective thermo stat or shorted leads OK Leg to Leg Above about 38 F 3 3 C Defective thermo stat or shorted leads OK Between about 10 and about 38 F 6 7 to 3 3 C OK Defective thermo stat or broken leads Below about 10 F 6 7 C Defective thermo stat or shorted leads OK ...

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Page 23: ...sure and the temperature c Wait twenty four hours then read the pressure and the temperature again and use the pressure correction formula at left to obtain a corrected pressure for comparison d If the system loses pressure at an unacceptably high rate re pressurize it leaving the gas supply on A rule of thumb is that the final pressure should not be less than half the initial pressure after twent...

Page 24: ...ermine how wet the system is and thus how much purging will be required If a system of rigid line carefully protected from weather and assembled in dry weather is average a system exposed to moisture during storage or installation will be relatively wet New semi flex transmission line delivered pressurized with dry gas will be relatively dry used semi flex will be extremely wet CAUTION If all mois...

Page 25: ...he system as shown in Figure 11 Raise the gas pressure to 12 or 13 psig 83 90 kPa CAUTION You must blow dry gas through the system not just maintain a pressure The gas volume accomplishes the purge e If the relief valve has opened the nitrogen cylinder will slowly drain or the compressor dehydrator will not shut down Leave the system pressurized After completion of the purge reduce the supply pres...

Page 26: ... It will move stiffly because of O ring friction c Read the VSWR If the reading went down move the control rod again in the same direction If the VSWR went up move the same rod in the opposite direction d Keep adjusting the same rod until no further improvement is seen Adjust the second rod in the same manner If you get lost return both rods to the factory setting Table 5 and start over e Return t...

Page 27: ...is applied Many riggers can sweep your system after installation or recommend a con tractor to perform it Alternatively Shively Labs makes available instructions for system sweep on our Web site www shively com Checkout Before beginning checkout of the antenna system be sure the following items have been done The antenna system has been installed in accordance with this manual and the installation...

Page 28: ...the system If icing conditions are expected the heaters should be turned on in advance as a preventive measure It is much easier to prevent ice formation than to remove a heavy coating Shively Labs de icer control system If you have the Shively Labs de icer control box and dual setting thermostat you have the choice of manual or automatic operation There are three switch settings AUTOMATIC OFF and...

Page 29: ...the interior of the system Be sure the O ring is properly seated in its groove and not pinched between the flange contact surfaces Maintenance log Shively recommends that you keep a maintenance log in it record perfor mance parameters such as readings of VSWR and de icer current draw Such a log can be invaluable in spotting and identifying problems Sample maintenance log on page 27 shows a suggest...

Page 30: ...tact Shively Labs before attempting this pro cess Return policy When returning any material to the factory be sure to call your salesman and obtain an returned material authorization RMA number first Use this num ber in all correspondence This number helps us to track your returned item It will expedite repair or replacement and prevent loss of your material Troubleshooting Cantact Shively Labs if...

Page 31: ...t extends back from the end seal The length angle and straightness of the feed strap are critical to the radiator s perfor mance Components of other services that have entered the RF field later installations or broken components Physical damage to the transmission line feedline or radiators This may be from ice lightning tower work or any other source Paint applied to the radiators possibly durin...

Page 32: ...bjective factors or faults of the receiving equipment Before doing more than checking the VSWR be sure that an actual coverage change has occurred Pressure loss or excessive gas usage Failure to hold pressure may be caused by the following O ring missing or poorly installed in transmission line feedline or baymount flange Leaky end seal see Figure 2 on page 4 Loose connecting hardware between line...

Page 33: ...ample maintenance log DATE DE ICER CURRENT or resistance VSWR GAS PRESS OBSERVATIONS Visual Inspection of Antenna Obstruction Lighting Hardware Checked Tower Repairs Accomplished etc BLACK b neut NEUT red bl RED r neut ...

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