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Chameleon Antenna CHA F-LOOP, Operator'S Manual, Page: 12 / 15

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Chameleon Antenna CHA F-LOOP Operator'S Manual Download Page 12

CHA F-LOOP 

Page 12 

 

Loop Operation 

The CHA F-LOOP is very easy to use.  Perform the following steps whenever you change frequency.

 

1.

 

The  CHA  F-LOOP  is  bidirectional  favoring 
the  sides,  see  plate  (7).    If  possible,  point 
one side toward the target signal and rotate 
the antenna for maximum signal strength. 

2.

 

Set  the  Band  Switch  (i)  to  the  desired 
frequency range. 

3.

 

Adjust  the  Tuning  Knob  (h)  for  maximum 
receive  signal  strength.    Turn  the  Tuning 
Knob  counterclockwise  to  decrease  the 
resonant  frequency.    You  will  know  when 
you  are  close  to  resonant  frequency 
because you will start hearing signals and a 
marked  increase  in  receiver  background 
noise.  

 

 

         Plate 6. CHA F-Loop Antenna Tuning. 

The Tuning Knob uses a 6:1 reduction drive 
which  allows  for  fine  adjustment  and  will 
rotate  approximately  2¾  revolutions  from 
lowest  to  highest  frequency.    Do  not 

attempt  to  force  the  Tuning  Knob  past  the 
stops.   

4.

 

Ensure your transmitter is set for no more 
than 5 Watts during tuning.  

 

Plate 7. CHA F-LOOP Antenna Directivity. 

5.

 

Transmit  a  carrier  and  gradually  turn  the 
Tuning  Knob  counterclockwise  and  then 
clockwise, around the highest receive signal 
point  found  in  step  3,  to  obtain  the  lowest 
SWR.    An  SWR  of  1.5:1  or  less  is 
satisfactory.    Your  hand  may  slightly 
influence  the  resonance  of  the  loop  while 
turning the Tuning Knob.  This is completely 
normal and you may have to “touch up” the 
adjustment  slightly.    The  bandwidth  of  the 
loop  at  60  meters  is  only  15  KHz,  so  once 
you  are  close  to  resonance,  make  only  the 
slightest of Tuning Knob adjustments. 

6.

 

Increase transmitter power to no more than 
15 Watts, see specifications. 

 
Troubleshooting 

1.

 

Ensure the loop is away from metal surfaces.  Sometimes simply reorienting, relocating, or elevating the loop 
around two to four feet higher will reduce the SWR.  

2.

 

Ensure Takedown Hardline Connections (e) and Radiator Loop Connections (f) are securely tightened. 

3.

 

Inspect Takedown Hardline Sections for damage.  Replace if damaged.  

4.

 

Inspect Flexible Radiator Loop (b) for damage.  Replace of damaged. 

5.

 

Ensure the Coaxial Cable Connection (g) is securely tightened. 

6.

 

Inspect Coaxial Cable assembly for cuts in insulation or exposed shielding.  Replace if damaged. 

Summary of Contents for CHA F-LOOP

Page 1: ...HF Faraday Loop Antenna CHA F LOOP Operator s Manual California USA WWW CHAMELEONANTENNA COM VERSATILE DEPENDABLE STEALTH BUILT TO LAST ...

Page 2: ...tect you Stay away from all power lines WARNING Never operate this antenna where people could be subjected to high levels of RF exposure especially above 10 watts or above 14 MHz Never use this antenna near RF sensitive medical devices such as pacemakers WARNING A tuned loop can exhibit several hundred Volts and concentrated electromagnetic radiation when operating at QRP power levels 5 10 W At hi...

Page 3: ...MHz to 29 7 MHz 60 10 meter ham bands The magnetic loop is different than typical antennas because it emphasizes the magnetic part of the radio wave H field rather than the electric part E field of the radio wave It also has a high Q resonance of around 15 KHz on 60 meters providing immunity from interference outside the bandpass The CHA F LOOP Antenna was designed with weight portability versatil...

Page 4: ...nd back to Earth between 300 and 2 500 miles depending upon the frequency and ionospheric conditions HF radio waves can then be reflected from the Earth to the ionosphere again during multihop propagation for longer range communication The most important thing for the operator to understand about HF radio wave propagation is the concept of Maximum Usable Frequency MUF Lowest Usable Frequency LUF a...

Page 5: ...ffective antenna for both local and long distance DX communication While not specifically designed for NVIS during field testing of the CHA F LOOP both DX and NVIS contacts were made on the 30 meter ham band within minutes of each other Parts of the Antenna The CHA F LOOP is comprised of the following components see plates 2 and 4 Plate 2 Standard CHA F LOOP Antenna a Tuning Unit The Tuning Unit a...

Page 6: ...on g Coaxial Cable Connection The Coaxial Cable Connection is a UHF socket located on the rear of the Tuning Unit a and is used to connect the Coaxial Cable k to the radio It is not used in the High Efficiency CHA F LOOP Antenna configuration h Tuning Knob The Tuning Knob is located on the front of the Tuning Unit a and is used to adjust the resonant frequency of the loop The relative position of ...

Page 7: ...iator Loop b p High Efficiency Radiator Loop Connections The connections for the optional High Efficiency Radiator Loop b see plate 5 are brackets located on the rear edge of the Tuning Unit a They are not used in the Standard CHA F LOOP configuration q High Efficiency Radiator Loop Joints The High Efficiency Radiator Loop Joints see plate 5 are used to connect together the three sections of the O...

Page 8: ...nna The location can be indoors or in an outdoors area protected from the weather The location must facilitate accessibility by the operator to the Tuning Knob h The operator needs to be able to adjust the Tuning Knob while listening to the receiver activating the transmitter and observing the SWR meter If used indoors the location should also be reasonably away from switching power supplies Inter...

Page 9: ... in an outdoors area protected from the weather The location must facilitate accessibility by the operator to the Tuning Knob h The operator needs to be able to adjust the Tuning Knob while listening to the receiver activating the transmitter and observing the SWR meter If used indoors the location should also be reasonably away from switching power supplies Internet routers and other sources of e...

Page 10: ...n e on the top of the Tuning Unit 8 Place the CHA F LOOP on a table top or attach the Aluminum Base Plate m to a tripod or other antenna mount 9 Connect the Coaxial Cable Assembly l to the Coaxial Cable Connection g on the back of the Tuning Capacitor Box 10 Perform an operational test see procedure below 11 This completes installation of the Optional CHA F LOOP High Efficiency loop configuration ...

Page 11: ...on f 2 Connect the free end of the Flexible Radiator Loop to the Loop Extension Barrel Connector t 3 Connect one end of the Flexible Radiator Loop Extension s to the open Flexible Radiator Loop Connection from step 1 4 Form the Flexible Radiator Loop Extension into a loop like the Flexible Radiator Loop 5 Attach the top of the Flexible Radiator Loop Extension to the Faraday Loop c using a Faraday ...

Page 12: ...nna Directivity 5 Transmit a carrier and gradually turn the Tuning Knob counterclockwise and then clockwise around the highest receive signal point found in step 3 to obtain the lowest SWR An SWR of 1 5 1 or less is satisfactory Your hand may slightly influence the resonance of the loop while turning the Tuning Knob This is completely normal and you may have to touch up the adjustment slightly The...

Page 13: ...r coupler with this antenna Accessories The following accessories are available for purchase from Chameleon Antenna TM Please contact us at support chameleonantenna com for current prices and availability High Efficiency Radiator Loop A high efficiency 1 collapsible aluminum tubing radiator loop which increases efficiency an average of 142 over the standard flexible radiator loop is available as a...

Page 14: ...n a minimum of time and space CHA V2L Mobile Antenna The CHA V2L is a rugged multiband HF antenna designed for smaller vehicles CHA VHF UHF Magnetic Mount Mobile Antenna The CHA VHF UHF is a simple but great dual band antenna for 2M and 70CM CHA Hybrid Mini Portable HF Antenna Base The CHA HYBRID MINI Base is the portable version of the regular HYBRID The unit can be differentiated by the color of...

Page 15: ...he 1 8 54 MHz band without any adjustment with most modern external antenna tuners No masts or guying are required CHA TD Tactical Dipole The CHA TD Tactical Dipole Antenna has been designed as an add on for the CHA F LOOP The CHA TD is a HF broadband antenna specially designed for portable HF communication where rapid deployment and simplicity of operation is essential The antenna will operate at...

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