#### ubitx LPF

circular.simetry@...

Hello everybody, i have build a homebrew ubitx and i am working now on the LPF the original uses T30-6 toroids i have available only T37-6 does anybody know how many turns i have to wind?

If you use this calculator, http://toroids.info/T37-6.php to compare the two toroids, it shows the T37-6 to be about one turn more than the T30-6.

Joel
N6ALT

Using the Schem for the uBitx you can convert nano Henry to uH using a converter (found on google) and then using the calculator on this link from Diz at kitsandparts http://toroids.info/T37-6.php the 1st stage for example at KA1 is 400nH=.40uH is 11.5 turns (11 or 12 will work).

Hope this helps.

73
--
David

N8DAH
Kit-Projects.com

Shop is open!

Woody

On 11/1/2019 19:12, circular.simetry@... wrote:
Hello everybody, i have build a homebrew ubitx and i am working now on the LPF the original uses T30-6 toroids i have available only T37-6 does anybody know how many turns i have to wind?

This might help...  Go to   https://toroids.info/
Enter  T30-6 toroid and the number of turns
Get the inductance
Enter T37-6 toroid and the inductance
Get the number of turns.
Caveat - Due to the difference in core sizes, it might not be possible to obtain an exact inductance match.

Woody, KZ4AK
KZ4AK.com
--

MVS Sarma

Even by using T30-6 , we get near by value  not exact value. balance is by adjusting the turn locations  etc and Farhan calls it tweaking.

On Sat, Nov 2, 2019 at 2:44 AM Woody <woody@...> wrote:
On 11/1/2019 19:12, circular.simetry@... wrote:
Hello everybody, i have build a homebrew ubitx and i am working now on the LPF the original uses T30-6 toroids i have available only T37-6 does anybody know how many turns i have to wind?

This might help...  Go to   https://toroids.info/
Enter  T30-6 toroid and the number of turns
Get the inductance
Enter T37-6 toroid and the inductance
Get the number of turns.
Caveat - Due to the difference in core sizes, it might not be possible to obtain an exact inductance match.

Woody, KZ4AK
KZ4AK.com
--

hickmodawg@...

Why not use the online calculators to get an estimate of the number of turns we need, and then use an inexpensive meter to fine-tune the number and arrangement of windings before installing the toroid on the board?  I got a cheap LC100-A meter on EBay that measures inductance and I was a little shocked to see how the inductance values of my toroids changed just from moving the windings closer or farther apart, not just from adding or subtracting winds.  It seems to me, that the size and composition of the toroid, and the spacing of the windings may have an effect on the resulting inductance, not just the number of windings.  I’m really still quite new to this, but, I’m wondering, why not use a meter before installing our toroids onto the board?  Is it because these cheap meters are very inaccurate?
Martin, AJ6CL

Ian Reeve

The spacing between turns,the number of turns,the wire diameter and the type of torrid all have an effect on the inductance. I use one of the "cheap" inductance meter and the readings are very close to a instrument costing nearly £100 so for me the inexpensive   one is good.

From: BITX20@groups.io <BITX20@groups.io> on behalf of hickmodawg@... <hickmodawg@...>
Sent: Saturday, November 2, 2019 8:05:28 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] ubitx LPF #bitx20 #bitx20help #bitx40 #bitx40help #ubitx #ubitx-help

Why not use the online calculators to get an estimate of the number of turns we need, and then use an inexpensive meter to fine-tune the number and arrangement of windings before installing the toroid on the board?  I got a cheap LC100-A meter on EBay that measures inductance and I was a little shocked to see how the inductance values of my toroids changed just from moving the windings closer or farther apart, not just from adding or subtracting winds.  It seems to me, that the size and composition of the toroid, and the spacing of the windings may have an effect on the resulting inductance, not just the number of windings.  I’m really still quite new to this, but, I’m wondering, why not use a meter before installing our toroids onto the board?  Is it because these cheap meters are very inaccurate?
Martin, AJ6CL

DF1EA@...

Hello,

this tool can help http://www.dl0hst.de/dateien/software/minirk13_install.zip

73 de Chris, DF1EA

MVS Sarma

Somehow the new version is not intslling on my 64 bit win 7 laptop .

Incidentally one could hombrew vk3bhr lc meter 2 using pic16f628a.

It works well, i have been using it for a decade now.

Sarma vu3zmv

On Sun, 3 Nov 2019, 2:18 am , <DF1EA@...> wrote:
Hello,

this tool can help http://www.dl0hst.de/dateien/software/minirk13_install.zip

73 de Chris, DF1EA