Date   

Re: D4D 20m For sale

Adam Rong
 

Well built.

Thanks,
Adam

在 2019年6月18日,上午11:56,N8DAH <Dherron@...> 写道:

Some pics
<20190617_213412.jpg>
<20190617_213320.jpg>


Re: D4D 20m For sale

N8DAH <Dherron@...>
 

Some pics


Re: D4D 20m For sale

N8DAH <Dherron@...>
 

Still for sale 40$ shipped.


New file uploaded to crkits@groups.io

crkits@groups.io Notification <crkits+notification@...>
 

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the crkits@groups.io group.

File: D4D Kit Assembly Manual Rev.B.pdf

Uploaded By: Adam Rong

Description:
This version Rev.B is the update of the full manual in modifications and accessories sections. Also the photo quality is much better in this version. The Rev. A is now obsolete.

You can access this file at the URL:
https://groups.io/g/crkits/files/D4D%20Kit%20Documentations/D4D%20Kit%20Assembly%20Manual%20Rev.B.pdf

Cheers,
The Groups.io Team


Re: Field Day Equipment of D4D and Raspberry Pi

Adam Rong
 

Folks,

I just posted to YouTube with some editing:
https://youtu.be/la6BSmRS0k0

Thanks,
Adam


Field Day Equipment of D4D and Raspberry Pi

Adam Rong
 

Folks,

Hopefully you can view this video. Should you have any questions, please reply to this thread. Enjoy.
https://mp.weixin.qq.com/s/u7VGaNoBkQkuLb68LNZUFg

I hope I can put on YouTube in a few days with some editing.

Thanks,
Adam


Re: Tecsun 2P3 AM radio kit

bleepingbeep
 

The kit may be purchased through Amazon.

Just FYI.

On Fri, Jun 14, 2019, 5:43 PM Adam Rong <rongxh@...> wrote:
John,

Indeed. Tecsun is the number 1 company in China to produce radio receivers. The kit quality is superb.

Thanks,
Adam


Re: Tecsun 2P3 AM radio kit

Adam Rong
 

John,

Indeed. Tecsun is the number 1 company in China to produce radio receivers. The kit quality is superb.

Thanks,
Adam


Re: Tecsun 2P3 AM radio kit

Adam Rong
 

Matthew,

I offered the kit a few years ago but discontinued later. You can purchase from other channels now.

Thanks,
Adam


Re: Tecsun 2P3 AM radio kit

matthew cook
 

I see the manual on the site but not the kit? Will it be available soon? Also some pictures would be cool.  Tks for the info...


D4D 20m For sale

N8DAH <Dherron@...>
 

Built, tested, working with one of the IMD mods.

Built for 20m solid 1w+ out (was getting 1.2w but turned it down for 1w)

asking 45$ shipped conus (will ship over seas but must help with shipping)

73

 David

 N8DAH

contact off site gud on the zed.


Re: Tecsun 2P3 AM radio kit

AA7US
 

Thank you for bringing this to our attention Adam!

It looks like a fun project.

73,

John
AA7US


Re: D4D: Modification for better IMD

Adam Rong
 

Folks,

Please read the deep modifications from BH4DCL. He modified LPF, PA bias, VOX and the power on transient transmission. Again, please use Google translation to read this page in Github:
https://github.com/cnsit/radio/blob/D4D/articles/D4D.md

Also, if you find it is easy to get the VOX mis-triggered in TX after you modified the #1 in the manual to improve IMD, you can add a 103 cap at the Audio In connector.

Thanks,
Adam


Re: D4D: Modification for better IMD

Adam Rong
 

Tom,

We were discussing the way Elecraft K2 adopted in their SSB option board that you can download from here. See page 24 for balanced modulator portion. The 1M pot is connected to pin 1, 2, 3 of the NE602.
https://ftp.elecraft.com/K2/Manuals%20Downloads/ksb2%20manual%20rev%20G.pdf

However, we found that this way is not effective most of the time. The way to add a diode will reduce the power supply voltage and it is kind of design of experiments from BH4DCL.

Thanks,
Adam


Tecsun 2P3 AM radio kit

Adam Rong
 

Folks,

While I was reading a post in SWLing, I think that you might be interested to read my translation of the manual, although the version might be old. The kit is still available from many channels if you are interested to build one.


In the mid 1960's, with the population of transistors, radio amateurs of China were passionate to build their own radio receivers. It was a dream to have a good looking case for their homebrew radio receiver, so 2P3 case appeared.

2P3 was compact and beautiful. Once it hit the street, it was welcomed. Many people saved money for buying one, and built various radios from single transistor to six transistor superheterodyne with it, and the dream of building a transistor radio with a case came true.

Half a century has passed, but those senior radio amateurs still can remember 2P3. Once talking about

page1image3679031360

transistor radios, 2P3 is always a hot topic. People smile if they were lucky to have built one, and regret if they failed. However, 2P3 is seldom found these days, and it becomes a product for collection. So, it becomes a new dream to own 2P3 again!

We reproduced 2P3 case, and designed and produced a superheterodyne radio receiver kit based on the current component characteristics. Hopefully it can fulfill the senior radio amateurs' dream, inspire the interest of the new generation and help improve their hands-on capabilities.

CRKITS is now proudly introducing the kit to the worldwide. The kit manual translation is dedicated for our customers, to match our standard of service. 


Thanks,
Adam


Re: D4D: Modification for better IMD

tom
 

I'm a little late to this group and am not aware where the 1 meg pot was to be connected, or why. Also what does the diode actually do to improve reception or transmission?
Thanks very much Tom.


Re: D4D: Modification for better IMD

Adam Rong
 

Correct. 1M Ohm pot is no need.

Thanks,
Adam

在 2019年6月12日,下午11:39,Mark Sykes <mark@...> 写道:

Adam,

The 1N9148 diode in the cut trace for modification 2 carrier leakage:  That is instead of the 1M Ohm pot?

Thanks,
Mark
KD8RG


Re: D4D: Modification for better IMD

Mark Sykes
 

Adam,

The 1N9148 diode in the cut trace for modification 2 carrier leakage:  That is instead of the 1M Ohm pot?

Thanks,
Mark
KD8RG


Re: D4D: Modification for better IMD

Adam Rong
 

Folks,

For the modification 2 in the full manual, you can try a better solution. Cut a PCB trace and add a 1N4148 diode as the following picture. It will improve the carrier leakage by about 10dB. So far I haven’t seen any significant side effect. This modification is suggested by BH4DCL.

Thanks,
Adam

在 2019年5月25日,下午10:56,Adam Rong via Groups.Io <rongxh@...> 写道:

Folks,

Please refer to the photo to make modification to improve IMD. The RF output will be impacted but it is worthwhile to do so. Replace C5 by 103. Remove C6. Add a 1uF-10uF cap. Add a resistor of 22-27 ohm. Make connection as follows. Connect the positive pin of 1uF to the upper pad of C6. Connect the negative pin to the interconnection of 22-27 ohm and the original 330 ohm. Remember to adjust the audio output to just stably trigger the relay.



Thanks,
Adam



<image1.jpeg>


Not D4D: How simple a FT8 receiver can be?

Adam Rong
 

Folks,

This is my experiment. I just used a NE602 and a few passive components.

Use Google translation to read this:

https://mp.weixin.qq.com/s/-Es5XWPcKTXxAZ8qdjIk4g


Thanks,
Adam

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