Date   
D4D: 20m version needs more time

Adam Rong
 

Folks,

As I tested building 20m version one more time and I still found a little bit self-oscillation. As I said this is the nature of this architecture to use only one NE602 for both RX and TX. AA7EE also mentioned about this when he was building his DSB radios:

I had thought I found a perfect fix by muting the front end but it seems not working very stable for 20m as the frequency is higher and the self-oscillation gets easier, I suppose.

What I am going to do, is that I will hold the shipment and announcement for 20m version before the actual shipment starts. I will need about one week to find a proper fix. If it does not happen, I will ask if you would like to switch to 40m or accept refund.

The 40m version is stable and I think you will enjoy this tiny radio to make dozens of QSO’s. 

Thanks,
Adam

Re: D4D: Ready to Take Order

Mark KG5SPO
 

Can I buy a few of the blank PC cards from you, if so how much?

Mark Schiff


On Wed, May 8, 2019 at 10:24 AM Adam Rong <rongxh@...> wrote:
Folks,

I start to take email order now. The introductory price is 39 USD for kit including shipping to worldwide. As in the introductory period, you will get audio cable options for free. The earliest possible shipment date is now improved to May 13.

You can directly PayPal to rongxh@... and let me know 40m or 20m (80m not ready yet). I will ship based on the sequence of receiving your payment. I may delay shipment for one week or two due to workload.

This is the spec so far:

Summary: Crystal controlled single frequency DSB transceiver for 20m (14.074MHz), 40m (7.074MHz) or 80m (3.573MHz), other frequencies could be added per request
Power supply: 10-14V DC regulated power supply or battery pack, 12V is recommended, center positive, reverse polarity protection available
Current consumption in RX: about 15mA at 12V
Current consumption in TX: about 300mA at 12V
RF output: about 1W for 40m band at 12V, and a bit less for 20m band
Spurious suppression: no worse than -50dBc
Antenna connector: BNC connector, 50 ohm
Audio in connector: 3.5mm mono, at least 600mV to activate VOX, connects to headphone connector at PC sound card, no dedicated PTT connector is required
Audio out connector: 3.5mm mono, connects to microphone connector at PC sound card
Amber LED: TX status
Green LED: RX status
Frequency accuracy: -600 Hz ~ + 200 Hz
Frequency stability: Okay for FT8 mode per test. If the optional heater resistor R20* is added, after warm up, long term frequency stability in 10 min will be improved at the cost of acceptable short term frequency stability sacrifice in 30 sec.

Thanks,
Adam

Re: D4D: 20m version needs more time

Adam Rong
 

Folks,

I am pleased to announce that the issue was found. I will take time to verify the fix and the shipment will be pushed out for about a week. To play safe, I will check 40m as well. Sorry for the delay.

BTW, I got crystals for 3.573 today and 80m version will be in plan.

Thanks,
Adam

在 2019年5月11日,下午11:40,Adam Rong via Groups.Io <rongxh@...> 写道:

Folks,

As I tested building 20m version one more time and I still found a little bit self-oscillation. As I said this is the nature of this architecture to use only one NE602 for both RX and TX. AA7EE also mentioned about this when he was building his DSB radios:

I had thought I found a perfect fix by muting the front end but it seems not working very stable for 20m as the frequency is higher and the self-oscillation gets easier, I suppose.

What I am going to do, is that I will hold the shipment and announcement for 20m version before the actual shipment starts. I will need about one week to find a proper fix. If it does not happen, I will ask if you would like to switch to 40m or accept refund.

The 40m version is stable and I think you will enjoy this tiny radio to make dozens of QSO’s. 

Thanks,
Adam

Re: D4D: Ready to Take Order

Adam Rong
 

Folks,

As I have promised, I created a button and you can order directly from my web site:
http://crkits.com

Due to the unexpected stability issue, I have to postpone the first shipment date from May 13 to May 20. Thanks for your understanding, and I wish to give you the best first impression.

BTW, I cannot offer blank PCB right now since all the parts are matched with the PCB quantity. I might reconsider later when I make the next lot.

Thanks,
Adam

Re: D4D: Ready to Take Order

Casey
 

How well will these work on Voice (with a proper Freq Xtal)?

Re: D4D: Ready to Take Order

Adam Rong
 

Very well. I have played music when dummy load is connected and it is quite high quality. However, you will need to inject quite high level volume (>600mV Vp) to activate VOX and you will need an external active speaker to be able to make voice QSO. An extra PTT may be required to enable/disable the microphone.

Thanks,
Adam

On Tue, May 14, 2019 at 12:48 AM Casey via Groups.Io <kc9ih=yahoo.com@groups.io> wrote:
How well will these work on Voice (with a proper Freq Xtal)?



--
Thanks,
Adam Rong

IMD performance of D4D

Adam Rong
 

Folks,

One of potential customers asked about the IMD performance and I think it is a good question. I have to clarify here when I wrote spurious suppression of -50dBc. It is actually for harmonics of 2nd and 3rd and other parasitic oscillations. If we check closely near the carrier frequency with a spectrum analyzer, the IMD products of 3rd, 5th are quite strong. The measured IMD 3rd is not good, which will generate strong overtone in waterfall spectrum and cause nearby channel interference. During design phase, I have noticed it but I have to balance the RF output from the design simplicity with this spec. I also noticed that the carrier leakage without audio modulation is strong too, and it is even higher than the 3rd IMD products.

Those are the facts and I hope you can understand and help improve if you can. Thank you.

--
Thanks,
Adam Rong

D4D: Documentations

Adam Rong
 

Sorry, but we are not attending Hamvention this year

Adam Rong
 

Folks,

Due to an unexpected reason, the show of D4D in Hamvention is cancelled. However, we believe that D4D is a promising product and you are welcome to introduce to your local clubs, forums or magazines.

The build and test by dozens of Chinese local hams went very well in the last a few days, and we also knew the limitations of this tiny product. I will start shipping from May 20. I hope you will like it.

Thanks,
Adam, BD6CR

Re: D4D: Documentations

Adam Rong
 

Software settings in Chinese. Try Google translation if you cannot fully understand from pictures.
https://mp.weixin.qq.com/s/VSHwEVKzNMG2F2GUVkCcCQ

Thanks,
Adam

在 2019年5月16日,上午8:05,Adam Rong via Groups.Io <rongxh@...> 写道:

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: d4dpartlist20190519forMP.xls

Uploaded By: Adam Rong

Description:
D4d part list 20m/40m for MP.

You can access this file at the URL:
https://groups.io/g/crkits/files/D4D%20Kit%20Documentations/d4dpartlist20190519forMP.xls

Cheers,
The Groups.io Team

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: d4dqgreva.pdf

Uploaded By: Adam Rong

Description:
D4D Quick Guide Rev A - May 19, 2019.

You can access this file at the URL:
https://groups.io/g/crkits/files/D4D%20Kit%20Documentations/d4dqgreva.pdf

Cheers,
The Groups.io Team

Re: IMD performance of D4D

Adam Rong
 

Gang,

Compared with 2nd and 3rd harmonics, the adjacent channel IMD products are higher. I did try to attenuate the input audio and it will improve but the result was not so satisfying. In this way, I have decided to remove C20 and C23 to change the LPF from elliptical to regular filter. It will improve the impedance matching with the antenna at the cost of higher 2nd harmonics. I will add this note into the full manual.

Beta testers, please remove C20 and C23 as well.

For serious builders, please follow this page to try:
https://pa3csg.nl/?page_id=40

Thanks,
Adam

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 manual.pdf

Uploaded By: Adam Rong

Description:
Preview version of D4D full manual. Still lots of work to do, but I am posting here for comments.

You can access this file at the URL:
https://groups.io/g/crkits/files/D4D%20Kit%20Documentations/D4D%20kit%20manual.pdf

Cheers,
The Groups.io Team

Poor boys DSB FT8

Adam Rong
 

Folks,

Anyone has access to this page?

https://qrpguys.com/poor-boys-40-30-20-1-10w-dsb-ft8-transceiver

It seems new but I am curious about the design concept.

Thanks,
Adam

D4D: First Shipment

Adam Rong
 

Folks,

I just shipped three boxes yesterday to my shipping agent and today they will ship to worldwide. The backlog is not cleared so I will ship some more next Monday. After shipping, I will update tracking number in PayPal.

The full manual preview draft is already in the files section. I will take time to improve it this week. You will see a brand new version when you get the kit.

Thanks,
Adam

D4D for 6m band?

Greg DL3GJ
 

Hi Adam, congrats on fantastic product idea!

I checked the archive and did not find the answer so created new topic: did you consider making a 6m version of the D4D TRX? As most of the traffic on the "magic band" is FT8 it would be perfect device to take for travel - combined with Raspberry Pi and small, portable antenna... If possible - one for me please!

73 de DL3GJ Greg

Re: D4D for 6m band?

Adam Rong
 

Greg,

It could be challenging due to thermal drift of the crystal. A TCXO is very expensive to customize. However, we can give it a try to build a sample.

Thanks,
Adam

在 2019年5月21日,下午4:09,Greg DL3GJ <gjacykowski@...> 写道:

Hi Adam, congrats on fantastic product idea!

I checked the archive and did not find the answer so created new topic: did you consider making a 6m version of the D4D TRX? As most of the traffic on the "magic band" is FT8 it would be perfect device to take for travel - combined with Raspberry Pi and small, portable antenna... If possible - one for me please!

73 de DL3GJ Greg

Re: D4D: First Shipment

Adam Rong
 

Folks,

I have updated PayPal with all the tracking numbers. Orders on May 18 and later will be shipped next Monday. I shipped by post office with tracking, so you can track it on your local post office web site in a few days. For instance, US guys can track on USPS tracking site at 

You can also track on EMS web site in China here:

Normally it will take 10-20 days, so give it some patience and you will get it anyway.

Thanks,
Adam


On Tue, May 21, 2019 at 9:19 AM Adam Rong via Groups.Io <rongxh=gmail.com@groups.io> wrote:
Folks,

I just shipped three boxes yesterday to my shipping agent and today they will ship to worldwide. The backlog is not cleared so I will ship some more next Monday. After shipping, I will update tracking number in PayPal.

The full manual preview draft is already in the files section. I will take time to improve it this week. You will see a brand new version when you get the kit.

Thanks,
Adam




--
Thanks,
Adam Rong

Re: IMD performance of D4D

Adam Rong
 

Gang,

Follow up on this IMD topic:

Two domestic customers reported that D4D won't work with automatic tuner very well. One customer fixed it by switching off power supply of the tuner, the other has no fix yet. I guess it is related with IMD products. The automatic tuner will detect signal frequency and tune to the best point, but with strong IMD products, the auto tuner just failed to work.

Thanks,
Adam