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MFJ-1623 Instruction Manual 

Window/Balcony  Mount Antenna 

 

4

Note:

 

These controls interact.  Go back and forth between these adjustments as required until 

maximum RF current is obtained. 

4)  The transmitter power may now be increased up to a maximum of 200 watts.  Make sure you 

reduce the RF SENSITIVITY control as necessary to keep from pinning the RF Current meter. 

Note:

  The MFJ-1623 will reduce the SWR of most antenna systems to below 1.5:1.  Maximum RF 

current also corresponds to minimum SWR.  This can be verified with an external SWR meter if 
desired. 

In Case of Difficulty 

 
If this tuner 

fails to tune, 

please double check all connections and follow the tuning procedure again. 

 
The power rating of this tuner is 200 watts on 30-10 meters.  If this tuner

 arcs

 at the rated power 

levels, please double-check all connections and follow the tuning procedure again.   
 
If you are still unsuccessful, please read the following ANTENNA HINTS text. 
 

Grounding Hints 

 
To minimize RFI, antennas should be kept away from other wiring as much as possible.  Also, the 
antenna should be adequately insulated to prevent arcing or accidental contact if placed near other 
objects. 
 
For safety, it is always best to use both dc and RF grounds.  A DC ground may not be practical in 
some portable locations, however. 
 
It is always important to have a good RF ground, provided by the counterpoise, when using any whip or 
long-wire antenna.  This is because the MFJ-1623 tuner needs something to "push" against in order to 
force current into the antenna.  If a good RF ground is not available, RF will usually find its way back 
into the power line (RFI), transmitter audio circuits (RF feedback), or the operator (RF burns). 
 
Water pipes provide good dc and ac safety grounds, but they are often inadequate for RF grounding 
because they are long single conductors.  RF grounds require large "spread out" surfaces with direct 
multiple connections to the equipment ground point.  Water pipes, heating ducts, or multiple ground 
rods may work (especially if they are all connected together with jumper wires), but the best RF 
grounds are radial systems or multi-wire counterpoises. 

Содержание 1623

Страница 1: ...uning controls and only one tuning solution for given impedance match The MFJ 1623 has rear panel connectors for coaxial input and a Hi Z Lo Z switch for reversing the L network An internal input isolating current balun provides isolation of DC and RF grounds for optimum tuning of the RF counterpoise An RF Current Meter indicates the summed antenna and counterpoise antenna currents making tuning p...

Страница 2: ...ch the mounting bracket in position by placing the bracket over or around the surface of the support NOTE THE ANTENNA SHOULD BE ORIENTED AWAY FROM WINDOWS AND OTHER OBJECTS THAT ARE WITHIN CLOSE RANGE IF POSSIBLE 4 Tighten the screws on the rear of the base plate against the surface of the support The screws should be tightened in equal increments to keep the force on the spacer plate proportioned...

Страница 3: ...he tuner This should be done with a dummy load Tuning Procedure WARNING Never transmit while changing the INDUCTOR SELECTOR 1 First tune for maximum receiver noise as follows While listening to your desired receive frequency adjust the ANTENNA control for maximum receiver noise Adjust the MATCHING control for maximum receiver noise Adjust the COUNTERPOISE control for maximum receiver noise Note If...

Страница 4: ...imize RFI antennas should be kept away from other wiring as much as possible Also the antenna should be adequately insulated to prevent arcing or accidental contact if placed near other objects For safety it is always best to use both dc and RF grounds A DC ground may not be practical in some portable locations however It is always important to have a good RF ground provided by the counterpoise wh...

Страница 5: ...ch is properly set Installation of a Suitable Counterpoise Artificial Ground The MFJ 1623 includes a counterpoise set of wires that will work well from 80 10 meters It is important to keep the last few feet of the counterpoise wires as far as possible two feet minimum from each other and other near by conductors You can also build your own counterpoise system if you desire A RF counterpoise system...

Страница 6: ...mizing RF Current described in the tuning procedure WARNING This unit does NOT provide a dc or ac safety ground through the COUNTERPOISE terminal A separate wire from the station ground bus to an electrical or earth ground must be used TVI and RFI Hints It is possible for RF to flow down power cables into the house wiring This may cause TVI Stereo VCR or other RFI problems As a precaution a ferrit...

Страница 7: ...MFJ 1623 Instruction Manual Window Balcony Mount Antenna 7 Schematic ...

Страница 8: ...ake a copy of this page and place it near the tuner Insert your own values for each frequency according to your station Freq MHz Counterpoise Matching Antenna Hi Lo Z switch Extra cap switch 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 ...

Страница 9: ...MFJ 1623 Instruction Manual Window Balcony Mount Antenna 9 ...

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