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CHA HYBRID - MINI / MICRO 

Page 5 

 

antenna to the receiving antenna when they are within the radio line-of-sight.  Typically, this distance is 8 to 14 
miles  for  field  stations.    Surface  waves  follow  the  curvature  of  the  Earth  beyond  the  radio  horizon. 
They  are  usable,  during  the  day  and  under  optimal 
conditions, up to around 90 miles, see table (1).  Low 
power,  horizontal  antenna  polarization,  rugged  or 
urban  terrain,  dense  foliage,  or  dry  soil  conditions 
can  reduce  the  range  very  significantly.  The  U.S. 
Army found that in the dense jungles of Vietnam, the 
range  for  ground  waves  was  sometimes  less  than 
one mile.   

Frequency  Distance  Frequency  Distance 

2 MHz 

88 miles 

14 MHz 

33 miles 

4 MHz 

62 miles 

18MHz 

29 miles 

7 MHz 

47 miles 

24 MHz 

25 miles 

10 MHz 

39 miles 

30 MHz 

23 miles 

 

Table 1. Maximum Surface Wave Range by Frequency. 

Sky waves are the primary method of HF radio wave propagation.  HF radio waves on a frequency below the critical 
frequency (found by an ionosonde) are reflected off one of the layers of the ionosphere and 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), and Optimal Working Frequency (OWF).  The 
MUF is the frequency for which successful communications between two points is predicted on 50% of the days of 
in a month.  The LUF is the frequency below which successful communications are  lost due to ionospheric loses.  
The OWF, which is somewhere between the LUF and around 80% of the MUF, is the  range of frequencies which 
can be used for reliable communication.  If the LUF is above the MUF, HF sky wave propagation is unlikely to occur.  

The  HF  part  of  the  Radio  Frequency  (RF)  spectrum  is  usually  filled  with  communications  activity  and  an 
experienced operator can often determine where the MUF is, and with less certainty, the LUF by listening to where 
activity  ends.    The  operator  can  then  pick  a  frequency  in  the  OWF  and  attempt  to  establish  contact.      Another 
method  is  using  HF  propagation  prediction  software,  such  as  the 

Voice  of  America  Coverage  Analysis  Program 

(VOACAP)

, which is available at no cost to download or use online at 

www.voacap.com

.  The operator enters the 

location  of  the  two  stations  and  the  program  show  a  wheel  with  the  predicted  percentage  of  success  based  on 
frequency and time.  ALE, which is the standard for interoperable HF communications, is an automated method of 
finding a frequency in the OWF and establishing and maintaining a communications link. 

 Even under optimal conditions, there is a gap between where ground waves end (around 40 to 90 miles) and the 
sky wave returns to Earth on the first hop (around 300 miles). NVIS propagation can be used to fill this gap.  The 
frequency selected must be below the critical frequency, so NVIS is can normally only be used on frequencies from 
around 2 to 10 MHz.  Frequencies of 2 

 4 MHz are typical at night and 4 

 8 MHz during the day.   

 

Parts of the Antenna 

The CHA HYBRID - MINI / MICRO is comprised of the following components, see plate (1):

  

 

a.

 

Hybrid Base (Mini or Micro)

 

The Hybrid Base, see plate (1), provides a mounting base and impedance matching for the CHA HYBRID - MINI 
/ MICRO antenna system.  

b.

 

Antenna Wire

  

The Antenna Wire, see plate (2), is a 60 foot length of black insulated wire.   

Содержание CHA HYBRID MICRO

Страница 1: ...Hybrid Portable HF Antenna CHA HYBRID MINI MICRO Operator s Manual California USA WWW CHAMELEONANTENNA COM VERSATILE DEPENDABLE STEALTH BUILT TO LAST ...

Страница 2: ...CHA HYBRID MINI MICRO Page 2 ...

Страница 3: ...ole 16 Recovery Procedure 17 Troubleshooting 18 Specifications 18 Accessories 23 Chameleon AntennaTM Products 24 References 26 Be aware of overhead power lines when you are deploying the CHA HYBRID MINI MICRO antenna system You could be electrocuted if the antenna gets near or contacts overhead power lines All information on this product and the product itself is the property of and is proprietary...

Страница 4: ...e RACES Salvation Army Team Emergency Radio Network SATERN First Responders and especially for Emergency Preparedness It is also the antenna for hams that enjoy camping and hiking or those living in apartments and condominiums or developments with homeowners associations deed restrictions or CCRs Covenants Conditions Restrictions The CHA HYBRID MINI MICRO is configurable to facilitate Near Vertica...

Страница 5: ...ost due to ionospheric loses The OWF which is somewhere between the LUF and around 80 of the MUF is the range of frequencies which can be used for reliable communication If the LUF is above the MUF HF sky wave propagation is unlikely to occur The HF part of the Radio Frequency RF spectrum is usually filled with communications activity and an experienced operator can often determine where the MUF i...

Страница 6: ...p An Isolation loop is permanently attached to the Wire Connector f end the CHA HYBRID MINI Antenna Wire b and both ends of the CHA HYBRID MICRO Antenna Wire d Carabiner The Carabiner is a removable pear shaped stainless steel hooks with a spring loaded gate Plate 2 Antenna Wire e Insulator ...

Страница 7: ...na Shackle assembly see plate 3 consists of a shackle bolt and nut It is attached to the top of the Hybrid Base a Antenna Configurations Using the supplied components the CHA HYBRID MINI MICRO can be deployed into a number of configurations Seven configurations some configurations require optional components that are sold separately see table 2 are Configuration Ground Short Medium Long Directiona...

Страница 8: ... requires two supports that will enable the ends of the antenna to be raised to a height of 10 12 feet and 60 feet apart A counterpoise wire with a length of 50 to 55 feet is recommended If a counterpoise wire is not used the coaxial cable must be 25 to 100 feet in length as the shield of the coaxial cable provides the counterpoise Use the following procedure to install the Horizontal NVIS configu...

Страница 9: ...milar knot tie another long length of Paracord to the Insulator e or Isolation Loop c at the end of the Antenna Wire 12 Using a throw weight or some other method loop the Paracord over the other support 13 Raise the end of the Antenna Wire to a height of 10 to 12 feet such that the Antenna Wire is not quite taut and secure it to the support using a Round Turn and two Half Hitches Extend the Counte...

Страница 10: ... the CHA Coaxial Cable assembly to the UHF Socket g on the Hybrid Base Raise the Antenna 8 Using a Bowline or similar knot tie a long length 50 feet or more of Paracord to the Insulator e or Isolation Loop at the end of the Antenna Wire 9 Using a throw weight or some other method loop the Paracord over the support 10 Raise the end of the Antenna Wire to the desired height and secure it to the supp...

Страница 11: ...I CHOKE and coaxial cable or the Integrated RF Choke end of the CHA Coaxial Cable assembly to the UHF Socket g on the Hybrid Base Raise the Antenna 8 Using a Bowline or similar knot tie the end of a short length around 4 feet of Paracord to the Carabiner 9 Drive a Stake into the ground near the location closest to the radio set and tie the Paracord from the Hybrid Base to the Stake using two Half ...

Страница 12: ...ICRO Manpack Vertical configuration Best ground wave communication occurs when the radio set is located in a clear area and the whip antenna is vertical Refer to plates 1 and 3 for the following steps 2 If attached remove the Antenna Shackle k from the Hybrid Base a by loosening the nut on the Antenna Shackle and then unscrewing the Antenna Shackle from the Antenna Connector h Store in secure plac...

Страница 13: ...f ground mounted One to four counterpoise wires 25 feet in length should be used You may also use the supplied 60 foot antenna wire as the counterpoise All of these counterpoise options can be quickly deployed and will provide good performance The antenna may also be attached to a standard 3 8 mobile mount on a stationary vehicle No radials are required when mounted on a vehicle An antenna tuner o...

Страница 14: ...tion is fully seated onto section below until the whip is fully extended 10 Connect the CHA MIL WHIP to the CHA MIL EXT by carefully screwing the 3 8 base stud into the top section until finger tight Extend the Counterpoise 11 Extend the counterpoise wire along the ground in any convenient direction The end of the counterpoise wire can be secured to the ground with a tent stake 12 Perform operatio...

Страница 15: ...pecial configuration designed to provide good NVIS propagation on lower frequencies It is predominately omnidirectional and also provides medium range sky wave propagation on frequencies above 10 MHz You can mount it on a stationary vehicle which has a tilt able 3 8 mobile antenna mount not supplied or any fixed support on which you can clamp the CHA JAW MOUNT and will enable the antenna to be rai...

Страница 16: ...he middle section 8 Connect the CHA MIL EXT to the Hybrid Base by carefully screwing it into the Antenna Connection until finger tight 9 Extend the CHA MIL WHIP by unfolding the sections of the whip starting with the section above the bottom section and ensure each section is fully seated onto section below until the whip is fully extended 10 Connect the CHA MIL WHIP to the CHA MIL EXT by carefull...

Страница 17: ...ated onto section below until the whip is fully extended 9 Connect the CHA MIL WHIP to the CHA MIL EXT by carefully screwing it into the top section until finger tight Extend the Counterpoise 10 Extend the CHA MIL EXT by unfolding the middle section of the extension fully seating it onto the bottom section then unfolding the top section and fully seating onto the middle section 11 Connect the CHA ...

Страница 18: ... the radio set to the antenna tuner or coupler 7 If still not operational replace Coaxial Cable assembly Most problems with antenna systems are caused by the coaxial cables and connectors 8 Connect a Multi Meter to the Antenna Wire to check continuity Replace assemblies that do not pass a continuity check 9 If still not operational replace Hybrid Base a Specifications Frequency all configurations ...

Страница 19: ...psed o CHA MIL WHIP with CHA MIL EXT 17 ft 4 in extended 29 in collapsed Weight o CHA HYBRID MINI 1 5 lbs o CHA HYBRID MICRO 1 lbs o CHA MIL WHIP 1 lbs o CHA MIL WHIP with CHA MIL EXT 2 lbs Personnel Requirements and Setup Time one operator less than 15 minutes antenna wire less than 5 minutes whip Figure 9 SWR by Frequency Graph ...

Страница 20: ...CHA HYBRID MINI MICRO Page 20 Figure 10 Manpack Vertical Far Field Plots 7 MHz left 14 MHz right Figure 11 Portable Vertical Far Field Plots 7 MHz left 14 MHz right ...

Страница 21: ...CHA HYBRID MINI MICRO Page 21 Figure 12 Tilted NVIS Far Field Plots 3 7 MHz left 7 MHz right Figure 13 MIL WHIP EXT Dipole Far Field Plots 7 MHz left 14 MHz right ...

Страница 22: ...CHA HYBRID MINI MICRO Page 22 Figure 14 Horizontal NVIS Far Field Plots 3 7 MHz left 7 MHz right Figure 15 Sloping Wire Far Field Plots 7 MHz left 14 MHz right ...

Страница 23: ...s a must have accessory for use with the HYBRID series antenna bases It is highly portable and enables easy ground mounting of the HYBRID series antennas Tripod This heavy duty antenna tripod can hold equipment up to 15 4 lbs Compact and light weight weighing 5 5 lbs this 10 ft tripod will give you years of service Made of Cold Worked Carbon with special design locking system and double braced leg...

Страница 24: ...less steel flat washer o One 3 8 stainless steel split washer Wide range antenna tuner or coupler Required for most configurations Flashlight Multi tool Throwing weight and string Mallet SWR Power Meter Multi Meter Small canvas or nylon bag to store antenna components Chameleon AntennaTM Products The following products are available for purchase at Chameleon AntennaTM Go to http chameleonantenna c...

Страница 25: ... portable or man pack radios requiring compact but rugged antenna systems Its design has been borrowed from similar antennas utilized by many armies all over the world The CHA MIL is very hardy sturdy and portable being collapsible Un mounted the entire antenna length is less than 29 The 5 aluminum sections are hold together by a piece of 1 8th inch US GI MIL SPEC shock cord The CHA MIL Whip and a...

Страница 26: ...e HF communication where rapid deployment and simplicity of operation is essential but compactness is primordial The antenna will operate at all frequencies in the 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 HYBRID MINI MICRO The C...

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