MFJ Differential-T Tuner -986 Instruction Manual Download Page 1 | Manualshive

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MFJ Differential-T Tuner -986 Instruction Manual Download Page 1

INSTRUCTION MANUAL

CAUTION: Read All Instructions Before Operating Equipment

COPYRIGHT 2013 MFJ ENTERPRISES, INC.

C

VERSION 7A

MFJ ENTERPRISES, INC.

300 Industrial Park Road

Starkville, MS 39759 USA

Tel: 662-323-5869 Fax: 662-323-6551

Requires 9VDC Battery or 12VDC Source for Meter Operation

Model MFJ-986

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Summary of Contents for Differential-T Tuner -986

Page 1: ... Before Operating Equipment COPYRIGHT 2013 MFJ ENTERPRISES INC C VERSION 7A MFJ ENTERPRISES INC 300 Industrial Park Road Starkville MS 39759 USA Tel 662 323 5869 Fax 662 323 6551 Requires 9VDC Battery or 12VDC Source for Meter Operation Model MFJ 986 ...

Page 2: ...al manuals documents positional handbooks or other official publications The copy of this manual provided to the customer will not be updated to reflect current data Customers using this manual should report errors or omissions recommendations for improvements or other comments to MFJ Enterprises 300 Industrial Park Road Starkville MS 39759 Phone 662 323 5869 FAX 662 323 6551 Business hours M F 8 ...

Page 3: ... tuner s matching network in line or direct no matching circuit configurations Understanding Power Ratings There are no standardized power rating systems for tuners The names used i e 3 kW Tuner carry over from the time when amplifiers were rated by peak power input and not the true RF power output For example the one thousand watt Johnson Matchbox was rated to handle a 1000 watt plate modulated A...

Page 4: ...ery powers only the meter electronics It does not power the meter LEDs You must supply external DC to illuminate the SWR meter 2 12 VDC External Power The Meter Lamp power jack is located above the Transmitter connector on the rear panel Apply power from any filtered dc wall adapter MFJ 1312D or equivalent or use your station s 13 8 Vdc supply A cord fitted with a 2 1 mm plug is supplied with the ...

Page 5: ...d by 10 Each picket represents 50 watts below 400 watts and 100 watts from 400 to 2000 watts The reflected power is read on the right hand REFLECTED meter scale This scale indicates 50 watts full scale when the 200W power sensitivity is selected and 500 watts full scale when the 2000W power scale is selected This scale has a picket every watt below 20 watts and every 5 watts above 20 watts This sc...

Page 6: ...t or through the tuner as selected by the ANTENNA SELECTOR switch B Any antenna fed with a single wire should be connnected to the center hole of COAX 1 or COAX 2 C Any balanced feedline open wire twinlead or twin axial lines is connected to the ceramic BALANCED LINE terminals on the back of the unit D Use the GROUND post to ground the tuner to the transceiver amplifier and earth ground E A dummy ...

Page 7: ...ns 5 Starting from the minimum INDUCTOR position highest number turn the INDUCTOR control to add more inductance while applying a slight amount of power less than 25 watts Tune for the lowest reflected power and maximum forward power lowest SWR The lowest reading should occur somewhere above the following recommended inductor positions Tuning Chart Frequency MHz Capacitor Value Inductor counter in...

Page 8: ...maximum power handling capability and efficiency and the least critical tuning adjustments Operating Notes 1 While this tuner is designed to have as large a tuning range as possible there are limits to the tuning range of the capacitor Some antennas may require more or less capacitance than the controls have In these cases the SWR may not be reduced to 1 1 If the SWR is higher than the limits on y...

Page 9: ...hese power levels make sure you are using the least amount of inductance and the greatest capacitance possible that still allows matching the load on the operating frequency If you are still unsuccessful but the tuner does adjust and operate when switched to a dummy load or another antenna please read the ANTENNA HINTS section Grounding Hints To minimize RFI single wire feedlines such as used with...

Page 10: ...emely important to have good RF grounds with long wire or other Marconi style antennas Matching Problems Most matching problems occur when the antenna system presents an extremely high impedance to the tuner When the antenna impedance is much lower than the feedline impedance an odd quarter wavelength feedline converts the low antenna impedance to a very high impedance at the tuner A similar probl...

Page 11: ...42 52 73 83 112 123 or 145 155 ft 32 64 96 128 ft Some slight trimming or adding of feedline may be necessary to accommodate the higher bands WARNING To avoid problems a dipole antenna should be a full half wave on the lowest band On 160 meters an 80 or 40 meter antenna fed the normal way will be extremely reactive with only a few ohms of feedpoint resistance Trying to load an 80 meter halfwave di...

Page 12: ...n the reference meter Adjust the HI FWD trim pot to set the forward power scale to 1000 Watts 6 To set the reflected power interchange the TRANSMITTER and ANTENNA coax cables so that the transmitter is connected to the ANTENNA connector and the dummy load is connected to the TRANSMITTER connector 7 With the 3000 300 Watts button pushed out for the 60 Watt reflected scale Transmit 10 Watts as indic...

Page 13: ...r the MFJ Factory at 601 323 5869 You will be best helped if you have your unit manual and all information on your station handy so you can answer any questions the technicians may ask You can also send questions by mail to MFJ Enterprises INC 300 Industrial Park Road Starkville MS 39759 by FAX to 601 323 6551 through Compuserve at 76206 1763 or by email to 76206 1763 Compuserve com Send a complet...

Page 14: ... the chart below to log values for your station You may want to copy this chart and post it by your tuner Frequency MHz Capacitor Inductor counter indicator 1 8 1 8 2 0 2 0 3 5 3 5 3 5 3 75 3 75 3 75 4 0 4 0 4 0 7 15 7 15 10 1 10 1 14 2 18 1 18 1 21 2 21 2 24 9 28 5 ...

Page 15: ...cover postage and handling 4 This warranty is NOT void for owners who attempt to repair defective units Technical consultation is available by calling 662 323 5869 5 This warranty does not apply to kits sold by or manufactured by MFJ Enterprises Inc 6 Wired and tested PC board products are covered by this warranty provided only the wired and tested PC board product is returned Wired and tested PC ...

Page 16: ...MFJ 986 Manual Version 7A Printed In U S A 300 Industrial Park Road Starkville MS 39759 ...

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