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Forums | Crystal Radio Think Tank ** Advanced Forum | Z-Match Post Reply Send Topic To a Friend
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John Bruce McCreathPosted - 19 September 2012 7:48  Show Profile  Email Poster  Edit Message  
A few weeks ago I set out to try adapting the popular Z-Match circuit, used by hams for 80 to 10 metres, into an antenna matcher for the AM broadcast band. After a few snafus, I came up with the right component values and have an AMU that really does the job.

Do a Google search for Z-Match to get the basic circuit and then substitute the following component values. For C1, the input varicap, I used a 3 gang cap which varies from 75 to 775 pF. with all 3 sections paralleled. For C2, the tank cap, I used a 4 gang varicap with two of the sections paralleled for both the full coil and centre tap connections. Each pair varies from 50 to 1120 pF. The tank coil is 60 turns, centre tapped, and is wound in the figure 8 manner on a T200-2 toroid. The link coil is 9 turns wound over the "cold" end of the main winding.

73, J.B., VE3EAR

Steve McDonaldPosted - 16 October 2012 18:46  Show Profile  Email Poster  Edit Message  
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Steve McDonaldPosted - 16 October 2012 18:47  Show Profile  Email Poster  Edit Message  
Hi J.B. ...Can you describe what antenna you are using with the tuner and how you are coupling into your detector...sounds interesting.

Steve / VE7SL

Steve McDonaldPosted - 16 October 2012 18:55  Show Profile  Email Poster  Edit Message  
OK...found your info on the other forum JB...any chance for a schematic sometime?

Steve

John Bruce McCreathPosted - 17 October 2012 22:39  Show Profile  Email Poster  Edit Message  
Hi Steve,

I'll draw up a schematic and post it in a few days. In the meantime, just Google single coil Z-Match and you'll get a slew of schematics. I simply made a few minor changes in the basic hookup.

73, J.B., VE3EAR

Into radios since 1959.

John Bruce McCreathPosted - 18 October 2012 7:35  Show Profile  Email Poster  Edit Message  
Hi Steve,

I'll draw up a schematic and post it in a few days. In the meantime, just Google single coil Z-Match and you'll get a slew of schematics. I simply made a few minor changes in the basic hookup.

73, J.B., VE3EAR

Into radios since 1959.

Steve McDonaldPosted - 18 October 2012 20:43  Show Profile  Email Poster  Edit Message  
Thanks JB....are you activley crystal radio DXing these days?

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