CMC TEST - BALUNS

B0 - ZERO BALUN

 

ZERO BALUN

 

  • Simple Dipole Center Insulator
  • No BALUN at all.
  • SO-239 

 

 

 

B1 - 1:1 GUANELLA

B1 - 1:1 GUANELLA, Rear View

 

1:1 GUANELLA, 50 OHMS

 

  • Core: Wuerth 7427015 
    • 40mm diameter
    • Nickel-Zink (4W620)
    • Permeability 620
    • Similar to -43
  • Teflon insulated wire, AWG-20
  • V2A Hardware
  • SO-239 (Gold-Plated Center Connection)

 

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B2 - 1:1 GUANELLA, COAXIAL BALUN

 

B2 - 1:1 GUANELLA, COAXIAL BALUN

 

 

This is a Spiderbeam 1:1 Guanella (Reisert) Balun, as used in the Spiderbeam Yagi antennas.

 

The main reason for choosing this balun is, I already have one built.

  • Core: T-240-61
  • Diameter: 2.4 in.
  • Permeability:  160
  • Coax: RG-142 (Teflon Insulated)
  • V2A Hardware
  • SO-239

This is normally used on 20 thru 10m where its impedance is greater than 1000 Ohms, but it still has an impedance of about 500 Ohms on 40m.  If I build another one before the tests begin, I will add a few more turns of coax.

 

(The two connections on the top will not be used.)

 

B3 - 4:1 GUANELLA / DUAL-CORE

SIMILAR BALUN - EXCEPT the real balun will have parallel wires (bifilar) instead of twisted pair.

 

B3 - 4:1 GUANELLA / DUAL CORE

 

This is my "Standard BALUN" for OCFD antennas.

 

  • Core: 2x  TX36/23/15-4A11 (like "-43"), 36mm
  • Teflon insulated wire, AWG-22
  • SO-239, (Gold-Plated Center Connection)

 

NOTE:  The picture is "similar" to this balun.  This balun will have parallel wires, rather than twisted pair.  I haven't built it yet, therefore the substitute picture.

 

B4 - 4:1 GUANELLA / DUAL-CORE TP

This is my previous standard balun. I used twisted pair to simplify construction.

 

B4 - 4:1 GUANELLA / DUAL CORE TP

 

This is identical to B3, except this one uses Twisted Pair wires.  The reason for using twisted pair is simple; I can buy the wire in twisted pair and don't have to tape the wires together.  Theoretically this is not as good as when the wires are taped in parallel.  But how much worse is it really?  Is it worth the extra effort to use parallel wire?

 

All else is identical to B3.

 

 

B5 - 4:1 GUANELLA / SINGLE-CORE

Similar picture (place holder until a new balun is built). Will have an SO-239 and look like B1 (above).

 

B5 - 4:1 GUANELLA / SINGLE-CORE

 

Theoretically this balun will not work.  It will not produce equal current in each antenna half.  Yet it is being sold in this configuration by many commercial balun companies.  How much worse is it really?  

 

The main justification for this design is size, weight, and cost.  

 

  • Core: TX36/23/15-4A11 (like -43)
  • Teflon insulated wire (twisted pair)

 

The physical shape may differ but the balun core and wiring will be the same as pictured.

 

B6 - 4:1 Guanella / Dual-Core

 

B6 - 4:1 GUANELLA / DUAL - CORE

 

This balun uses two cores, with each transmission line having its own dedicated core.  This assures equal current will be forced into each leg of the antenna.

 

The cores used in this balun are a little smaller than the core used in B5 above.

  • Core:  CST 29/19/7.5-4A11
  • Permeability: 850 (similar to -43)
  • Abt. 3mm separation between cores
  • Teflon insulated wire (twisted pair)
  • No coax connector (direct connect)

B7 - 4:1 Guanella / Dual-Core

 

B7 - 4:1 Guanella / Dual Core

 

Internally, this balun is identical to B6 (above).  

 

I had a local company build it into one of their enclosures for me. It looks good, functions great, but it is too heavy.  

 

The two toroids together weigh just 42 gr. including the wire.  The enclosure and SO-239 weigh 227 gr., bringing the total weight to 269 gr.  A nice balun, but

MUCH TOO HEAVY  

for using with lightweight fiberglass poles.

B8 - 4:1 Guanella / Dual-Core

 

B8 - 4:1 Guanella / Dual Core

 

Internally identical to B6 & B7 (above).

 

  • Core:  CST 29/19/7.5-4S2
  • Permeability: 850 (similar to -43)
  • Abt. 3mm separation between cores
  • Teflon insulated wire (twisted pair)
  • No coax connector (direct connect)
  • Enclosure: Polycarbonate
  • Weight:  165 gr.

B9 - 4:1 Guanella / Dual-Core

 

B9 - 4:1 Guanella / Dual Core

 

Internally identical to B6 & B7 (above).

 

  • Core:  CST 29/19/7.5-4S2
  • Permeability: 850 (similar to -43)
  • Teflon insulated wire (twisted pair)
  • No coax connector (direct connect)
  • Enclosure: Plastic
  • Weight:  80 gr.

 

More baluns may be added.

 

In addition, I will use some of the chokes as balun substitutes.