T3

General discussion and support for the Peaberry SDR V2.

T3

Postby donde » Sat Mar 07, 2015 4:20 am

Why do all the T3's show an inductance measuremnent and not the other T's? I measured T3 and it showed a bit low, like 1.5 uH instead of 1.7. I pushed the turns of T3 very close together and it barely made 1.7 This test was across the single winding not the bifilar winding. Should I return the winding back to what is was before? Or leave it the way it is now?
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Re: T3

Postby AE9RB » Sat Mar 07, 2015 4:48 am

Not all the transformers are used for inductance.

There's a reason the instructions do not ask you to use an LC meter. You can not trust your LC meter. It is not testing at the target frequency. It is not testing in-circuit. It is not precise enough even if you spent $500 on it. I have made sure you will get a proper filter by using math and verifying with a VNA. Follow the directions. Use even spacing around the entire toroid. Do not listen to anyone telling you to add extra gap at the bottom. Do make sure the number of turns is exactly correct.
73 David AE9RB
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Re: T3

Postby donde » Sat Mar 07, 2015 2:52 pm

Hi David,

So you're saying to ignore the micro henry value on all coils and transformers? And do what said in the previous reply.
Actually the B & K LCR meter I used on the single wire wound coils was pretty close.

73 ... Don
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