New Bipolar Boost TX and Front End

[KingJL]

I will send you some 300 x 200 elliptical versions when I do the new batch. Hoping to finish of the forms over next few weeks and do some test runs and tweak the process.

For your form (eliptical 300x200) what is the circular coil diameter that fits the form/shell? If I know that, I will make my test coil that diameter and just fit it in.

[Mdtoday]

For your form (eliptical 300x200) what is the circular coil diameter that fits the form/shell? If I know that, I will make my test coil that diameter and just fit it in.

Diameter would be 233-236 mm winding center to allow for any shielding, no shielding, you could go out to 242-245 mm winding centre (both allowing for insulated or Litz wire)

[eclipse]

With the latest additions (single board design/no transformers) this project turns out to be very interesting. Keep up the good work.

[KingJL]

... Still need to wind a mono coil for testing. Target parameters for the coil are 10.25" diam, 320 uH, 1.5 ohm...

Went ahead and wound a 10.25 ID" coil... results (coil only, unshielded) are 21 turns, 319.5uH, 1.4ohms, 90pf, 938kHz. I think i'll keep it!

[bklein]

What are you using for wire, capacitance, and freq. measurement technique?
I’d like to duplicate your efforts.

[KingJL]

What are you using for wire, capacitance, and freq. measurement technique?
I?d like to duplicate your efforts.

About a year or so ago, I bagged a bulk sale of 4000' of some military spec wire that had some specs that I found appealing and thought it might be good for coils. Previously, I had made a coil for my VMH3CS that with it. The specs are 24AWG, 12 strand, tinned copper, outer diameter 1.04mm (0.041"). This coil was wound on a 10.25" form, 21 turns, and covered with 0.25" spiral wrap.

Inductance was measured with BM4070 LCR meter, frequency measured with Hantek 2D72. The Hantek 2D72 AWG function was used to excite the coil with a 1kHz 2V P-P square wave, 5% duty cycle though a 10pf capacitor. Used the Hantek 2D72 Scope function w/10x 100MHz probe to measure the frequency of the oscillations. Capacitance was calculated by ElectrDroid using inductance and frequency measurements.

[bklein]

Wow, thanks, I wasn’t aware of those item - I’ll check them out.

[dbanner]

About a year or so ago, I bagged a bulk sale of 4000' of some military spec wire that had some specs that I found appealing and thought it might be good for coils. Previously, I had made a coil for my VMH3CS that with it. The specs are 24AWG, 12 strand, tinned copper, outer diameter 1.04mm (0.041"). This coil was wound on a 10.25" form, 21 turns, and covered with 0.25" spiral wrap.

Inductance was measured with BM4070 LCR meter, frequency measured with Hantek 2D72. The Hantek 2D72 AWG function was used to excite the coil with a 1kHz 2V P-P square wave, 5% duty cycle though a 10pf capacitor. Used the Hantek 2D72 Scope function w/10x 100MHz probe to measure the frequency of the oscillations. Capacitance was calculated by ElectrDroid using inductance and frequency measurements.

KingJl, what is your impression of the DM4070 lcr meter. I wanted to get one of those because it is really good price (cheap-o, good for dropping on the floor without too much regret) for the range of functions, and I like the fact that is has no Auto-ranging, somehow I prefer old selector range switching. The lcd readout digits also look bigger than the average meter, useful feature when the eyes are no longer what they once were, as in my case.


Do you have the model where the LCD screen can swivel at an angle? That's the one I wanted but I can't seem to find that model anymore.

[KingJL]

KingJl, what is your impression of the DM4070 lcr meter. I wanted to get one of those because it is really good price for the range of functions, and I like the fact that is has no Auto-ranging, somehow I prefer old selector range switching. The lcd readout digits also look bigger than the average meter, useful feature when the eyes are no longer what they once were, as in my case.

I got my BM4070 2 years ago and have been quite happy with it. I mainly got it because of the inductance measurement capability. I have cross checked it with more sophisticated measurement techniques and the results that the BM4070 gives has been consistent with those other methods. And I wholeheartedly agree with you about the usefulness of the large LCD readout.

Do you have the model where the LCD screen can swivel at an angle? That's the one I wanted but I can't seem to find that model anymore.

Yes!
https://www.amazon.com/Proster-Multi...8969310&sr=8-1

[dbanner]

Bingo! Thanks JL, good to know the inductance measurements are accurate and reliable. The "tilt-up" screen is ideal for my lab bench (the kitchen table).

Wow, that is fantastic price! I should get a pair of those.

[KingJL]

Bingo! Thanks JL, good to know the inductance measurements are accurate and reliable. The "tilt-up" screen is ideal for my lab bench (the kitchen table).

Wow, that is fantastic price! I should get a pair of those.

If ever the inductance indication ever seems unstable... change the battery... ask me how I know!!! With a good battery the indication is rock stable and accurate.

[dbanner]

If ever the inductance indication ever seems unstable... change the battery... ask me how I know!!! With a good battery the indication is rock stable and accurate.

"ask me how I know"

If I had to wager a guess, it took you down a toroid winding "dark alley", into the twilght zone.

Thanks for your opinion JL. much appreciated.

[6666]

Twice the price here in Oz

[Ferric Toes]

I got my BM4070 2 years ago and have been quite happy with it. I mainly got it because of the inductance measurement capability. I have cross checked it with more sophisticated measurement techniques and the results that the BM4070 gives has been consistent with those other methods. And I wholeheartedly agree with you about the usefulness of the large LCD readout.


Yes!
https://www.amazon.com/Proster-Multi...8969310&sr=8-1

Ordered one today, should have it Friday. Brilliant price GBP20.85 and free delivery.

Eric.

[Qiaozhi]

Ordered one today, should have it Friday. Brilliant price GBP20.85 and free delivery.

Eric.

I've also just ordered one. Scheduled to be here tomorrow (Wednesday) using Prime delivery (Free).
My multimeter leads are in need of replacing anyway, and the LCR meter has some really fiddly connectors, so it would be good to consolidate all measurements in one unit. Since it's been recommended, I cannot miss the opportunity.