CMC TEST - CHOKES

ALL of the chokes shown on this page were used in the test.

  • RF chokes C1, C2, C3, & C4 were used in various tests
  • Both power supply chokes were used in all test involving the transmitter

C1 - W2DU / MAXWELL

 

C1 - W2DU / MAXWELL 

 

  • 20x CST 9.5/5.1/15 - 3S4,     beginning permeability: 1700
  • 40 cm RG-142
  • Weight:  150 gr.

 

NOTE:  This is not exactly a Maxwell.  The original Maxwell used smaller coax, smaller ferrite beads, and about 5x as many beads.  However in the meantime it seems common to call all chokes using beads over coax a Maxwell choke.

C2 - RADIOWORKS T4

 

C2 - RadioWorks T4

 

Technical Specs "UNKNOWN"

 

The RadioWorks does not publish

any specs for this device.

It is BIG, HEAVY, and EXPENSIVE.

  • Weight: 428 gr.

 

The RadioWorks does not describe the technology used inside this dog bone. I assume it is a Maxwell, but I can't say for sure.

 

We shall see if it is any good...

 

C3 - 1:1 GUANELLA

 

C3 - 1:1 GUANELLA  (Coaxial)

 

  • 1.2m RG-316 Teflon Coax
  • 1x TX36/23/15-4A11 Toroid (-43)
  • 16 turns
  • Cross-wound (Reisert)
  • Weight: 110 gr.

 

C4 - GM3SEK MID-BANDS CHOKE

 

C4 - GM3SEK MID-BANDS CHOKE


 

This choke is built according to GM3SEK's plan for a mid-range choke.

It compliments the Low-Band and High-Band chokes.

 

The advantage of this type of choke is, it achieves a very high impedance to common mode current with just 3 low cost ferrite cores, yet it can still handle high power.

 

The disadvantage is, its performance is frequency dependent.

For this reason you need three different, but similar chokes in order to cover the entire hf range.

 

This choke is excellent for 60m, 40m, and 30m.

It is also usable on 80m and 20m in most cases.

 

On 40m, this choke's impedance reaches nearly 5K Ohms.

(See specs in the Picture Gallery below.)

It is perfect for testing the 40m dipoles and for some of the tests on the 40m OCFD's.

 

 

THE CORES:

 

Fair-Rite part number 2643167851

 

 

 

 

More pictures:

C5 - GM3SEK HIGH-BANDS CHOKE

C5 - GM3SEK HIGH-BANDS CHOKE

 

I have not yet built the one on the left, nor the one on the lower right.

 

OTHER CHOKES

Mains (AC) Choke

 

The Mains (AC) Choke is built acording to the recommendations of GM3SEK, as per his Mid-Bands Choke.

 

There are 4 turns passing through the 3 oval ferrite cores and 3 turns between them.

 

The 13.8v D.C. Choke is also built along the recommendatons of GM3SEK's Mid-Bands Choke.

 

There are 4 turns passing through the 3 oval ferrite cores and 3 turns between them.