Rebus scheme #1


RX3DIT
 

Hello everyone!
For fans of circuit design, I want to offer a rebus scheme.
Here is a scheme from the magazine CQ Amateur Radio, July 2022, page 36.
This is a QRPP transceiver for a 40 meter band.
   Find the fundamental typo that will cause this transceiver to not work.
The absence of connection points is not relevant, do not consider it as an answer.
Have a nice reflection to everyone!​​​​​​​
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru


Curt
 

Igor

Thanks for communication, interesting design.  I see two things, neither of which may be proper answer. I do not see a path to ground at the oscillator crystals, so it may be oscillate. Also I wonder about details of the supply voltage, I think I see a voltage doubler, this requires AC power supply to operate. 

I may occasionally listen with a regenerative receiver, but just a diode and one npn, not sure my vintage ears would hear much. 

I am purposely keeping my remarks on Amateur Radio.  Stay safe. 

Curt wb8yyy 


RX3DIT
 

Curt, сongratulations, you have correctly solved this puzzle scheme. Indeed, it's all about the lack of connection of part of the circuit to the ground. The application contains the correct answer in the picture in red.
Indeed, the diode bridge looks somehow strange. But the author used this transceiver in an experiment powered by a potato battery. I think he was just afraid to confuse the polarity of the "green" power supply and reinsured himself. But still, 1 volt of loss is down the drain :-)
Congratulations again and as a prize I sent you a scan of this article :-)
All the best!
 
Воскресенье, 14 августа 2022, 22:26 +03:00 от Curt via groups.io <wb8yyy@...>:
 
Igor

Thanks for communication, interesting design.  I see two things, neither of which may be proper answer. I do not see a path to ground at the oscillator crystals, so it may be oscillate. Also I wonder about details of the supply voltage, I think I see a voltage doubler, this requires AC power supply to operate. 

I may occasionally listen with a regenerative receiver, but just a diode and one npn, not sure my vintage ears would hear much. 

I am purposely keeping my remarks on Amateur Radio.  Stay safe. 

Curt wb8yyy 
 
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru
 


William Franklin
 

This is basically the Pixie II circuit.  The bottom side of the 10K, 0.047uf cap, 470ohm, 100pf cap and anode of the 1n4148 need to go to ground.

73, Bill, K5WB


From: main@4SQRP.groups.io <main@4SQRP.groups.io> on behalf of RX3DIT <rx3dit@...>
Sent: Sunday, August 14, 2022 4:39 PM
To: main@4sqrp.groups.io <main@4sqrp.groups.io>
Subject: Re: [4SQRP] Rebus scheme #1
 
Curt, сongratulations, you have correctly solved this puzzle scheme. Indeed, it's all about the lack of connection of part of the circuit to the ground. The application contains the correct answer in the picture in red.
Indeed, the diode bridge looks somehow strange. But the author used this transceiver in an experiment powered by a potato battery. I think he was just afraid to confuse the polarity of the "green" power supply and reinsured himself. But still, 1 volt of loss is down the drain :-)
Congratulations again and as a prize I sent you a scan of this article :-)
All the best!
 
Воскресенье, 14 августа 2022, 22:26 +03:00 от Curt via groups.io <wb8yyy@...>:
 
Igor

Thanks for communication, interesting design.  I see two things, neither of which may be proper answer. I do not see a path to ground at the oscillator crystals, so it may be oscillate. Also I wonder about details of the supply voltage, I think I see a voltage doubler, this requires AC power supply to operate. 

I may occasionally listen with a regenerative receiver, but just a diode and one npn, not sure my vintage ears would hear much. 

I am purposely keeping my remarks on Amateur Radio.  Stay safe. 

Curt wb8yyy 
 
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru
 


RX3DIT
 

Hi Bill!
   That's right, your answer is correct. The prize is already in your mailbox, though in electronic form :-)
I just can't agree with you and the author of the article that this is a Pixie. Pixie has a distinctive and fundamental feature - this is the LM386 chip. Therefore, if there is an LM386 - it's a Pixie, no LM386- it's not a Pixie.
Then you can ask me - then what does this circuit look like? IMHO it is very similar to the Micro-80 circuit :-) (Micro-80 circuit under the paper clip for comparison). In the same place, for example, I attached a circuit of my SnejOK-20 transceiver, which I built for the Snowman 2019 test. This is a transceiver with an antenna in one unit. It uses the LM386 and it is a Pixie-like transceiver. (The note in Russian can be downloaded on the website www.club72.su , Vestnik 72 info bulletin, # 15 - November 2018)
All the best!

Понедельник, 15 августа 2022, 1:57 +03:00 от William Franklin <wfrank5wb39@...>:
 
This is basically the Pixie II circuit.  The bottom side of the 10K, 0.047uf cap, 470ohm, 100pf cap and anode of the 1n4148 need to go to ground.
 
 
 
 
73, Bill, K5WB
 

From: main@4SQRP.groups.io <main@4SQRP.groups.io> on behalf of RX3DIT <rx3dit@...>
Sent: Sunday, August 14, 2022 4:39 PM
To: main@4sqrp.groups.io <main@4sqrp.groups.io>
Subject: Re: [4SQRP] Rebus scheme #1
 
Curt, сongratulations, you have correctly solved this puzzle scheme. Indeed, it's all about the lack of connection of part of the circuit to the ground. The application contains the correct answer in the picture in red.
Indeed, the diode bridge looks somehow strange. But the author used this transceiver in an experiment powered by a potato battery. I think he was just afraid to confuse the polarity of the "green" power supply and reinsured himself. But still, 1 volt of loss is down the drain :-)
Congratulations again and as a prize I sent you a scan of this article :-)
All the best!
 
Воскресенье, 14 августа 2022, 22:26 +03:00 от Curt via groups.io <wb8yyy@...>:
 
Igor

Thanks for communication, interesting design.  I see two things, neither of which may be proper answer. I do not see a path to ground at the oscillator crystals, so it may be oscillate. Also I wonder about details of the supply voltage, I think I see a voltage doubler, this requires AC power supply to operate. 

I may occasionally listen with a regenerative receiver, but just a diode and one npn, not sure my vintage ears would hear much. 

I am purposely keeping my remarks on Amateur Radio.  Stay safe. 

Curt wb8yyy 
 
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru
 
 
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru
 


William Franklin
 

I didn't even notice, until you sent me the article, that a caption under the schematic likened it to the Pixie.  It just looked like the basic Pixie.  When I got my Bayou Jumper and was looking at different regen receiver schematics, I was surprised at how many circuits I found that had components around the oscillating detector with the same values and in quite a few instances even had the same R and C number designators.  Guess there's only so many ways one can arrange components for a particular application.  Thanks for the brain teaser, and it sure did spark some debate about ways to draw circuit diagrams.  Good for the mind to get a workout sometimes!  Thanks again and good luck.

73, Bill, K5WB


From: main@4SQRP.groups.io <main@4SQRP.groups.io> on behalf of RX3DIT <rx3dit@...>
Sent: Tuesday, August 16, 2022 7:25 PM
To: main@4sqrp.groups.io <main@4sqrp.groups.io>
Subject: Re: [4SQRP] Rebus scheme #1
 
Hi Bill!
   That's right, your answer is correct. The prize is already in your mailbox, though in electronic form :-)
I just can't agree with you and the author of the article that this is a Pixie. Pixie has a distinctive and fundamental feature - this is the LM386 chip. Therefore, if there is an LM386 - it's a Pixie, no LM386- it's not a Pixie.
Then you can ask me - then what does this circuit look like? IMHO it is very similar to the Micro-80 circuit :-) (Micro-80 circuit under the paper clip for comparison). In the same place, for example, I attached a circuit of my SnejOK-20 transceiver, which I built for the Snowman 2019 test. This is a transceiver with an antenna in one unit. It uses the LM386 and it is a Pixie-like transceiver. (The note in Russian can be downloaded on the website www.club72.su , Vestnik 72 info bulletin, # 15 - November 2018)
All the best!

Понедельник, 15 августа 2022, 1:57 +03:00 от William Franklin <wfrank5wb39@...>:
 
This is basically the Pixie II circuit.  The bottom side of the 10K, 0.047uf cap, 470ohm, 100pf cap and anode of the 1n4148 need to go to ground.
 
 
 
 
73, Bill, K5WB
 

From: main@4SQRP.groups.io <main@4SQRP.groups.io> on behalf of RX3DIT <rx3dit@...>
Sent: Sunday, August 14, 2022 4:39 PM
To: main@4sqrp.groups.io <main@4sqrp.groups.io>
Subject: Re: [4SQRP] Rebus scheme #1
 
Curt, сongratulations, you have correctly solved this puzzle scheme. Indeed, it's all about the lack of connection of part of the circuit to the ground. The application contains the correct answer in the picture in red.
Indeed, the diode bridge looks somehow strange. But the author used this transceiver in an experiment powered by a potato battery. I think he was just afraid to confuse the polarity of the "green" power supply and reinsured himself. But still, 1 volt of loss is down the drain :-)
Congratulations again and as a prize I sent you a scan of this article :-)
All the best!
 
Воскресенье, 14 августа 2022, 22:26 +03:00 от Curt via groups.io <wb8yyy@...>:
 
Igor

Thanks for communication, interesting design.  I see two things, neither of which may be proper answer. I do not see a path to ground at the oscillator crystals, so it may be oscillate. Also I wonder about details of the supply voltage, I think I see a voltage doubler, this requires AC power supply to operate. 

I may occasionally listen with a regenerative receiver, but just a diode and one npn, not sure my vintage ears would hear much. 

I am purposely keeping my remarks on Amateur Radio.  Stay safe. 

Curt wb8yyy 
 
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru
 
 
 
--
Igor RX3DIT
Отправлено из Почты Mail.ru