[TowerTalk] Fwd: 4:1 balun questions KT-34XA

[Steve Hunt]

I'd be very interested to hear how you managed to achieve that, and how 
you measured it. I've never measured any air-cored coax choke that 
achieved 500 Ohms (or more) over a 33:1 frequency range; less than 6:1 
is more usual.

The results for air-cored chokes I've measured are shown at the bottom 
of this table:
http://www.karinya.net/g3txq/chokes/
As you can see,  the choke with just 25 turns of RG58 on a 4.25" 
diameter form had dropped below 500 Ohms by 21MHz - so I've no idea how 
you could maintain >500 Ohms out to 60MHz with 40 turns.

I'm also puzzled how you managed to get 40 turns of RG58 in a 6" winding 
length?

Steve G3TXQ





On 29/10/2014 22:41, Hans Hammarquist via TowerTalk wrote:
> Myself, I am using a air wound coil, 40 turns of RG58 on a 4 1/2" D, 6" L cylinder as the choke. No, it is not hanging in free air but is well supported. End up to work well from 1.8 to 60 MHz. Has a Z=500 Ohm at 1.8 MHz and 60 MHz.
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> Best 73 de,
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> Hans - N2JFS
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