Date   
Re: D4D Audio very low

 

Adam,

 It is decoding, have checked parts. It does work and I am very happy with it for sure! Just wanted to see if I could help the audio out a hint more.

I made a FT8 700+mile  qso today on a indoor magloop and about 11w using the D4D on a WA2EBY amp.

73

 David

Re: D4D Audio very low

Adam Rong
 

David,

Please don’t add amplifier as the output spectrum is not clear due to inter-modulation, so it is a good idea to stay at 1-watt.

Thanks,
Adam

在 2019年6月6日,上午9:08,N8DAH <Dherron@...> 写道:

Adam,

 It is decoding, have checked parts. It does work and I am very happy with it for sure! Just wanted to see if I could help the audio out a hint more.

I made a FT8 700+mile  qso today on a indoor magloop and about 11w using the D4D on a WA2EBY amp.

73

 David


Re: D4D Audio very low

Jim
 

I also have low audio at around 30-40db with the pre-built 40m you sent me. But it seems to work ok...

73

Jim - KH2SR 

Re: D4D Audio very low

Adam Rong
 

Guys,

30dB is recommended. It is not low.

Thanks,
Adam

在 2019年6月7日,上午12:14,Jim <KH2SR@...> 写道:

I also have low audio at around 30-40db with the pre-built 40m you sent me. But it seems to work ok...

73

Jim - KH2SR 

Re: D4D Audio very low

Jim
 

Thanks for clarifying Adam.

Re: D4D: 2nd shipment

F6GWE
 

Hi group

Few days ago D4D was at home!

This evening first receive! It works well, levels about 60 dB with a magnetic loop on 40 m
Sunday Will beTX day!
Thanks Adam for this toy!
73
Patrick
F6GWE

Re: D4D: 2nd shipment

Adam Rong
 

Patrick,

Thanks for reporting the progress. Wish you good luck in your TX day. I am interested to know how many contacts you will make.

Thanks,
Adam

D4D: 4th Shipment and Some Test on Raspberry Pi

Adam Rong
 

Folks,

Just updated the 4th shipment. Now I have a few kits in my shipping agent so you will get shipped shortly if you order exactly same as the stock kits.

Also, I have played with Raspberry Pi last weekend and I have some preliminary result based on my test with my Elecraft K2. I can remote control with TeamViewer and operate my K2 to snag some FT8 QSO with my cell phone on the go.

You can use Google translation to understand my article in Chinese:
https://mp.weixin.qq.com/s/tIqEqXNTAST7DY_DN7SEZw

Thanks,
Adam

D4D on the magazine: CQ Communication Today online magazine in China

Adam Rong
 

Folks,

D4D was introduced by BG2KAJ, the ex-editor for CQ Communication Today magazine in China, equivalent to CQ or QST in USA. The introduction attracted many domestic hams. He wrote, no matter it is for hands-on experience improvement or QRP culture popularization, this kit is a good chance to try.

Use google translation to read this review article in Chinese:
https://mp.weixin.qq.com/s/ugv4J_31FcLtbLpuP7MJtA

Thanks,
Adam

Re: D4D on the magazine: CQ Communication Today online magazine in China

Laurent Piérard <on2vhf@...>
 

Hi all,
Nice info, mike qrp
73 de laurent on2vhf 

Le lun. 10 juin 2019 à 18:23, Adam Rong <rongxh@...> a écrit :
Folks,

D4D was introduced by BG2KAJ, the ex-editor for CQ Communication Today magazine in China, equivalent to CQ or QST in USA. The introduction attracted many domestic hams. He wrote, no matter it is for hands-on experience improvement or QRP culture popularization, this kit is a good chance to try.

Use google translation to read this review article in Chinese:
https://mp.weixin.qq.com/s/ugv4J_31FcLtbLpuP7MJtA

Thanks,
Adam


Re: New file uploaded to crkits@groups.io

Laurent Piérard <on2vhf@...>
 

Hi Adam, 
You are send my tx qrp for 20m ?
73 de laurent on2vhf 

Le dim. 26 mai 2019 à 17:53, Adam Rong <rongxh@...> a écrit :
I have put a JPG version in Photos.

Thanks,
Adam

> 在 2019年5月26日,下午11:21,Faisal Akber (VA3SFA) <faisal@...> 写道:
>
> Hi Adam,
>
> Thank you for uploading the schematic diagrams.  Unfortunately I am unable to read XPS files.  I run Linux and XPS only seems to work on Windows.
>
> Could you kindly please upload a PDF version of the schematic diagrams?  PDF files work everywhere.
>
> Thanks,
> Faisal VA3SFA
>
>> On 2019-05-26 14:53, crkits@groups.io Notification wrote:
>> 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: d4dschematic20190526for80_40_30_20.xps
>> UPLOADED BY: Adam Rong
>> DESCRIPTION:
>> D4D Schematic for 80m, 40m, 30m and 20m band. Use Internet Explorer to
>> open this file.
>> You can access this file at the URL:
>> https://groups.io/g/crkits/files/D4D%20Kit%20Documentations/d4dschematic20190526for80_40_30_20.xps
>> Cheers,
>> The Groups.io Team
>> Links:
>> ------
>> [1] https://groups.io/g/crkits/message/2626
>> [2] https://groups.io/mt/31798857/300062
>> [3] https://groups.io/g/crkits/post
>> [4] https://groups.io/g/crkits/editsub/300062
>> [5] https://groups.io/g/crkits/leave/defanged
>
>
>



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

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>

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
 

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

tommi647@...
 

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.

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

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

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: Tecsun 2P3 AM radio kit

AA7US
 

Thank you for bringing this to our attention Adam!

It looks like a fun project.

73,

John
AA7US