T.G.M. Communications 121 Devon St., Stratford, Ont., Canada, N5A 2Z8 Tel & Fax (519) Web site

Transcription

1 Model B-24 Compact 2 Element 4 band Yagi 20,15,10 and 6 Meters with tuner Electrical Specifications Mechanical Specifications Forward Gain (Ref. Dipole) 6M 5.0dBd,10M 4.5dBd, Element Length 11 Ft 9 inches 15M 3.2dBd, 20M 2.0 dbd, Boom Length 64 inches. Resonance See Curves Turning Radius 6 Ft 6 inches Power Rating 1500 W P.E.P. Weight 14.5 lbs Front to Back Ratio 6 to 8 dbd Mast (not inc l) up to 2 1/8 inch Input Impedance Single 50 OHM Feedline Wind Loading 1.5 sq ft. Rotor TV Wind Survival 75 MPH Materials 6061-T6 Aluminum G12 Fiberglass coils, Stainless steel hardware, except large mast U bolts T.G.M. Communications 121 Devon St., Stratford, Ont., Canada, N5A 2Z8 Tel & Fax (519) Web site tgmc@sympatico.ca B-24 Manual.doc Page 1 of 1

2 B-24 Parts List Safety Precautions Warning! You can be killed if the antenna, feedline or the equipment used to install the antenna accidentally contacts any utility lines. Never install an antenna near power lines! 1. Be careful while climbing and carrying the antenna. It is heavy enough to cause you to lose your balance if it is handed too casually or if the capacitance spokes are snagged on a gutter, ladder, tree, tree limbs and so forth. 2. Mount the antenna high enough so that it is out of reach. The ends of the capacitance spokes can cause eye injury, serious RF burns or both. 3. Make sure that mast is sturdy enough to support the 19 pounds weight and the wind load of approximately 1.6 square feet. CHOOSING A LOCATION FOR THE ANTENNA The best performance on receiving and transmitting will be obtained by mounting the antenna in a clear location above or away from buildings, towers, feedlines, utility wires and other antennas. While your own ingenuity and Page 2 of 2 B-24 Manual.doc

3 particular circumstances will determine the final mounting method, we will pass along a few ideas for both permanent installation and portable operation. Never mount this antenna in a location that permit unsuspecting people to come in contact with the loading spokes or any other part of the antenna. Never mount this antenna where a mechanical failure might allow the antenna to contact power lines or other utility wires. Always ground the feedline at the point it enters a building to a good earth ground or directly bury the cable in the earth for several feet before it enters the building for lightning protection. The coaxial cable should be totally disconnected from the station during threatening weather conditions for maximum lightning protection. Note: Wear safety glasses whenever working near or on this antenna! Assembly Instructions for B-24 Please read these instruction over before attempting to assemble your antenna. Page two shows the component parts and their description. These components will be referred to by the description in the following instructions. 1. Choose a cleared area to proceed with the assembly such as a garage floor, patio, etc. 2. Remove loading coils and spoke package; set them aside while performing the hardware assembly. The coils are the last step performed in these instructions. 3. Director Element Parts are code with yellow dots. Assemble center element and tighten the hose clamps. All yellow dots should be face up when assembled. B-24 Manual.doc Page 3 of 3

4 4. Driven Element Parts are coded with blue dots. Assemble driven element and insulating dowel with 1 3/4 long bolts and nuts as shown in picture above. This is heavy current point; nuts must be pulled down to ensure a good contact. All blue dots are facing up when finished. 5. Attach driven elements to the insulating board, counter bored holes in the board to provide clearance for the driven element bolt nuts. Secure the driven element to the board with U bolts, nuts and washers. I would put the nuts washers and lugs back on the bolt s that stick through board, but not tightened, till your ready to hook up balun. See above diagram. Page 4 of 4 B-24 Manual.doc

5 6. Attach director element to the insulating board, Secure the director element to the board with U bolts, nuts and washers. See above diagram. 7. Picture of the balun mounted to top of boom, Note this is a different antenna model but mounts the same way. B-24 Manual.doc Page 5 of 5

6 8. Attach driven and director elements to boom as shown, U bolts sit up against the plastic end caps on both ends. Attach mast-mounting plate to boom as shown Page 6 of 6 B-24 Manual.doc

7 9. Attach balun wires to the lugs and solder for a long lasting connection. Connection in this order -- washer, wire lug, washer, lock washer and nuts. Repeat on the other connection., Then tape balun and coaxial cable to the boom and mast. 10. THIS COMPLETES THE HARDWARE ASSEMBLY OF YOUR ANTENNA 11. Coil Assembly and Frequency Adjustment for 10,15 and 20 meters. The drawing below shows one driven coil and one director coil. Also shown are the spoke distribution and various rings, which affect operating frequency for 10,15 and 20 meters. 12. Spoke length is measured from the top of the bend to the spoke end. Avoid bending the buss bars, straighten if necessary B-24 Manual.doc Page 7 of 7

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9 Adjustable Tuning Spokes This antenna has adjustable tuning spokes included with it to make tuning easier. By loosening the top 4-40 screws the spoke can be lengthened by up to 1 5/16 of an inch thereby lowering the frequency. If you need to raise the frequency push the spoke back into the adjuster, if the spoke is already all the way in the adjuster you will be required to cut the spoke shorter according to the chart in this manual. A large pair of pliers with the cutter on the side will shear the spoke off squarely, but you could still be required to file the burrs off, so the spoke will fit back into the adjuster. These adjustable tuning spokes can be placed along the buss bar on the same side of all four loading coils to make the easier to reach for adjustment. Note: the coils are mounted in the antenna with the buss bars down. B-24 Manual.doc Page 9 of 9

10 The Model B-24 is factory resonate to the phone band. The antenna as supplied resonates at approximately around 50 KHz of the following frequencies. 20 Meter Band MHz Approx. 15 Meter Band MHz Approx. 10 Meter Band MHz Approx For those who wish to operate higher or lower in frequency, the resonance of individual bands may be increased or decreased by changing the length of one spoke in each driven coil on any or all bands you wish to change. The table below indicates the amount of frequency change in each band in each band by removing or adding length from one spoke from each coil for that particular band. Adjustment of one band has minimal effect on the resonance frequency of the other bands. The values for removal of ½ of spoke length in the table are to be considered typical this is only a guide. The relationship is basically linear e.g., if ½ or ¾ is removed the frequency increases is about one half the value shown in the table and if 1 is removed the frequency increases twice the value shown in the table. Example: You wish to raise the frequency of the 20 meter section by 100 KHz. Choose the adjustable spoke from each 20 meter driven ring, remove 1/2 from the two spokes, return the shortened spokes to the 20 meter driven rings. NOTE: Remember the adjustment is made on one spoke from each driven coil for that band you wish to change. All shortened spokes should have the rounded end left on to prevent corona. Note: Only the driven element is tuned. 13. Spoke Installation Insert the spokes into their respective rings starting at 10 meters and working out, leave one row along the buss bar open for the adjustable or longer fixed length tuning spokes. Make sure the spokes are to the bottom of the ring holes, then tighten the locking screw snugly. 14. Assembly driven coils (blue colored end) to the driven elements and the director coils (yellow colored end) to the director elements. Page 10 of 10 B-24 Manual.doc

11 Proper connection of lug on buss bar to clamp and clamps to end of antenna elements. Very Important Buss bar, clamp and wide slot must face down to drain any moisture B-24 Manual.doc Page 11 of 11

12 Antenna should be checked and adjusted if necessary on the ground. It is recommended to set the antenna up at about six feet above the ground for easy testing. The balun should be installed and if possible coaxial cable you are going to use. The SWR can be measured by using a transmitter and SWR bridge or SWR analyzer. Always tune the antenna from lowest frequency to the highest frequency. It is recommended to resonate 20 to 10 meters approximately 20 KHz below the desired frequency. Note : Six meters is not tunable recommended to use a tuner to lower SWR. Page 12 of 12 B-24 Manual.doc

13 General Notes The general information below is somewhat random in nature and has been included in this special section. 1. Longer spokes are available or new ones can be made from 1/8 diameter Aluminum tig filler welding rod, a hook for safety can be bent with pliers. 2. The model B-24 is intended for mounting with an 1 ¾ to 2 1/8 OD mast.(not included) 3. When operating the B-24, the input power to the final must be limited to 1500 watts P.E.P. During tune-up and when operating in the key down or CW mode, dc input must be limited 600 watts and a 40% duty cycle. 4. Replacement or spare parts are available if required, from your local dealer or from the address below. 5. Recommended balun 50Ohm 1:1 with ferrite core. 6. RFCB-6U 80-6 meters available from T.G.M communications when ordering antenna. T.G.M. Communications 121 Devon St. Stratford ON. CAN. N5A 2Z8 Tel. & Fax tgmc@sympatico.ca B-24 Manual.doc Page 13 of 13

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