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Toroid size for scratch build Bitx40

 

Hello,?
I was hoping someone could help me with choosing the correct toroid for a scratch built bitx40.
The circuit description on hfsignals below.

The inductors used on the board as follows:

  • L1, L2, L3?: 6uh, 40 turns on T30-6 core
  • L4?: Only needed the analog VFO, 9uh, 50 turns on T30-6 core
  • L5?: just a jumper on the standard bitx40, you will have to an inductor of a few uh to pull the BFO down for upper-sideband
  • L6, L7?: 1.1 uh, 17 turns on T30-6 core
  • L8?: 10 turns on FT37-43
  • T1,T2,T4,T5,T6,T7?: 10 turns trifilar on FT 37-43 core

  • I could not find FT37-43 so i ordered the FT37-61
  • these cores look way smaller than any build i have seen.
  • Thanks in advance for any advice.?
  • JR
 

I was going to say you try Diz at , but I see he doesn't have them?either...

--
Paul Mateer, AA9GG
Elan Engineering Corp.
 

I take that back, he does have them...
?


On Thu, Feb 8, 2024 at 10:00?PM AA9GG via <paul.aa9gg=[email protected]> wrote:
I was going to say you try Diz at , but I see he doesn't have them?either...

--
Paul Mateer, AA9GG
Elan Engineering Corp.




--
Paul Mateer, AA9GG
Elan Engineering Corp.
 

Hello,

With this mini tore calculator software you can calculate the number of spins.?
It seems that there is a difference in frequency range between FT 37-43 and FT37-61
cdt
 

Thanks for the help.

JR
 

I didn't notice the frequency difference between the ft37-43 and the ft37-61 thanks for the heads up.
John R
 










Can be in these characteristics?
an expert in toroid will answer?
Can these transformer strands be replaced by something else?
example:??

cdt
 

The FT37-61 toroid has a much lower permittivity than FT37-43, translating into a far lower inductance. I'd guess 5 to 10 times less inductance. It might work, but why go through the trouble? FT37-43 are pretty common. In fact, you can get 10 via Amazon for less than $7.

I would not use the FT37-6. It has low permittivity, and I believe higher losses at RF.

On Thu, Feb 8, 2024 at 5:27?PM <johnrichmond461@...> wrote:
Hello,?
I was hoping someone could help me with choosing the correct toroid for a scratch built bitx40.
The circuit description on hfsignals below.

The inductors used on the board as follows:

  • L1, L2, L3?: 6uh, 40 turns on T30-6 core
  • L4?: Only needed the analog VFO, 9uh, 50 turns on T30-6 core
  • L5?: just a jumper on the standard bitx40, you will have to an inductor of a few uh to pull the BFO down for upper-sideband
  • L6, L7?: 1.1 uh, 17 turns on T30-6 core
  • L8?: 10 turns on FT37-43
  • T1,T2,T4,T5,T6,T7?: 10 turns trifilar on FT 37-43 core

  • I could not find FT37-43 so i ordered the FT37-61
  • these cores look way smaller than any build i have seen.
  • Thanks in advance for any advice.?
  • JR
 

BTW, the 37 in FT37-43 means its size is 0.37 inch, and 43 is the material mix of the toroid. So yes, they are very small. If you have fat fingers, the FT50-43 is a bit bigger. Use about one turn less for the same inductance.


On Mon, Feb 26, 2024 at 1:35?PM Dan Damon via <dan.g.damon=[email protected]> wrote:
The FT37-61 toroid has a much lower permittivity than FT37-43, translating into a far lower inductance. I'd guess 5 to 10 times less inductance. It might work, but why go through the trouble? FT37-43 are pretty common. In fact, you can get 10 via Amazon for less than $7.

I would not use the FT37-6. It has low permittivity, and I believe higher losses at RF.

On Thu, Feb 8, 2024 at 5:27?PM <johnrichmond461@...> wrote:
Hello,?
I was hoping someone could help me with choosing the correct toroid for a scratch built bitx40.
The circuit description on hfsignals below.

The inductors used on the board as follows:

  • L1, L2, L3?: 6uh, 40 turns on T30-6 core
  • L4?: Only needed the analog VFO, 9uh, 50 turns on T30-6 core
  • L5?: just a jumper on the standard bitx40, you will have to an inductor of a few uh to pull the BFO down for upper-sideband
  • L6, L7?: 1.1 uh, 17 turns on T30-6 core
  • L8?: 10 turns on FT37-43
  • T1,T2,T4,T5,T6,T7?: 10 turns trifilar on FT 37-43 core

  • I could not find FT37-43 so i ordered the FT37-61
  • these cores look way smaller than any build i have seen.
  • Thanks in advance for any advice.?
  • JR
 

25 pieces for $7.00 from DIZ...

?


--
Paul Mateer, AA9GG
Elan Engineering Corp.
 

Pricing page...

?


On Mon, Feb 26, 2024 at 11:27?PM AA9GG via <paul.aa9gg=[email protected]> wrote:
25 pieces for $7.00 from DIZ...

?


--
Paul Mateer, AA9GG
Elan Engineering Corp.




--
Paul Mateer, AA9GG
Elan Engineering Corp.

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