PROJECT ETI566

[ZuMi77]

Dear Baterista,
Have you got a pdf article on Gemini3 explaining the circuit diagram and the working principle like the one on project 566?

[Baterista]

Hello ZuMi77, I don't have anything about Gemini3.

[kt315]

just a sch of TX part exist.

[ZuMi77]

Dear Baterista,
I have got all the pot cores and their accessories of ETI 566 project. However, there was one thing missing (the threaded insert) that tiny small piece in which the adjuster goes in and out to adjust the inductance. The items cost me a lot. I cannot order the "threaded insert"; that would cost a lot. It's not the price of the threaded insert itself; it's about customs fees and shipment fees. Any ideas on something I can use in place of the missing item?

[Baterista]

Hello ZuMi77, you can do the assembly without the adjuster, so if necessary you can replace the receiver's capacitor C6 with one with a slightly smaller value (220pf for example) or a little larger (300pf for example), which is directly related the frequency together with L2, or a variable capacitor can be used in place of C6, which has a capacitance between 300pf and 100pf.

[ZuMi77]

Dear Baterista,
Thank you for the reply. That's a great idea. It didn't come into my mind. We change the capacitance instead of changing the inductance to control frequency.

[Jafar]

Thanks Dave J. and WM6, as the pot was used a core brand Thornton produced in my country (Brazil), with the following specifications:
- L1 (Tx) NP23/17 - 4900 IP6; ungapped (ue1560)
- L1 (Rx) NP23/17 - 4900 IP6; ungapped (ue1560)
- L2 (Rx) NP23/17 - IP6 400; (ue127)


The original materials are of the type Philips 3H1 (obsolete), and should be replaced by 3H3.
- L1 (Tx) P18/11 pot core Philips, 3H1 - 3400 ungapped (ue1620)
- L1 (Rx) P18/11 pot core Philips, 3H1 - 3400 ungapped (ue1620)
- L2 (Rx) P18/11 pot core Philips, 3H1 - 315. (ue149).
There are other brands, looking for the "ue" similar.

[Jafar]

Thanks Dave J. and WM6, as the pot was used a core brand Thornton produced in my country (Brazil), with the following specifications:
- L1 (Tx) NP23/17 - 4900 IP6; ungapped (ue1560)
- L1 (Rx) NP23/17 - 4900 IP6; ungapped (ue1560)
- L2 (Rx) NP23/17 - IP6 400; (ue127)


The original materials are of the type Philips 3H1 (obsolete), and should be replaced by 3H3.
- L1 (Tx) P18/11 pot core Philips, 3H1 - 3400 ungapped (ue1620)
- L1 (Rx) P18/11 pot core Philips, 3H1 - 3400 ungapped (ue1620)
- L2 (Rx) P18/11 pot core Philips, 3H1 - 315. (ue149).
There are other brands, looking for the "ue" similar.

Hello friends, can I use this type of ferrite core instead of the models you provided and is there a problem if all three are ungapped? And if I use this core (GU 16*26), what is the AWG of the wire and how many turns should I wind it? And to achieve the mentioned inductances, do I increase or decrease the number of turns? And I could not find AC128 and 2sb324. Please introduce some other alternatives. Thank you for your help.

[Skippy]

"And I could not find AC128"

The place to look for germanium transistors is eBay.

[Jafar]

"And I could not find AC128"

The place to look for germanium transistors is eBay.

Do you think I can use the T/R LOCATOR transmitter circuit by Charles D. Rakes because the parts are more common and I was able to find them?

[Jafar]

"And I could not find AC128"

The place to look for germanium transistors is eBay.

And can I use this circuit too?

[Skippy]

"can I use this circuit?"

I have no idea. I was merely offering advice on where to purchase vintage parts.

[ZuMi77]

alternatives to AC128:

2SB405

2SB492 which is the best.