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Re: DSB transceiver for Digital mode
Adam Rong
Folks,
I have decided on all the key parts, and purchased most of them. The relay reliability is very important, so I have chosen Zettler, the same brand used in Elecraft K2 kit I have purchased before. The ferrite FT37-43 is produced by Fair-Rite and purchased from Mouser. All the capacitors under 1uF is produced by Torch, the top brand in China. I will announce the product via my web site in the May 11-12 weekend and start to take order. The first order will be shipped no later than May 20. If you wish to get some assembled kits, please let me know ahead of time. Thanks, Adam
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Re: Can R3500 work on 8.4V?
Adam Rong
Judging from the schematic, I don't see big problem.
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Thanks, Adam
在 2019年5月5日，下午7:01，YT9TP - Pedja via Groups.Io <yt9tp=uzice.net@groups.io> 写道：
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Can R3500 work on 8.4V?
I would like to use LiPo battery with R3500. I suppose I have to use 2S cells which means maximum voltage could be 8.4V.
Is that to much for this rig?
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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: d4dpartlist20190504.xls Uploaded By: Adam Rong Description: You can access this file at the URL: Cheers,
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Stay tuned for more analog kits
Adam Rong
Folks,
I just realized that FT8 is so popular that someone loves it and someone hates it. However I hope in here both digital and analog kits can coexist. D4D actually is an all analog transceiver without MCU, DSP or SDR. It can used for FT8 and FT4 but it can also been used for voice transmission as long as the input is big enough to drive the VOX. Currently we are offering HT-1A CW dual bander which is a cool radio kit. And we also offer R3500D ARDF 80m receiver. Both are analog radios. I discussed with team and we are going to release the successor of KN-Q7A. We don’t have timetable yet but we think it is a good direction to go. I also like to introduce my minimalist NE602 receiver as a kit. It was kitted based on my Choc perf board for Japan and I want to make a PCB and find a case, so it could be used for a club project. Stay tuned although we are discussing a little bit more about FT8 and D4D these days. Thanks, Adam
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Re: DSB transceiver for Digital mode
Adam Rong
Folks,
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Well, it was leaked by qrper.com. Check it out for now, although some data might be modified later.
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Re: FT8 HT
Adam Rong
In case you are following this thread, please see this:
https://groups.io/g/crkits/topic/31005901#2560 Now the idea comes true. Thanks, Adam
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Re: DSB transceiver for Digital mode
Adam Rong
Folks,
I have put together a final version and it worked perfectly. Now I accept order for beta testing. I will ship 3 kits of 7074 by May 6. If you join beta testing, you will need to keep secret before Hamvention debut. You will have time and equipment to build and test the kit and publish a test report. If you have a popular YouTube account or web site, please let me know so you will have priority. Please contact me offline. The MP version will be shipped on May 20. Thanks, Adam
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Re: DSB transceiver for Digital mode
Adam Rong
Folks,
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This is a bit history for D4D: A simple QRP transceiver kit for FT8. D4D stands for DSB transceiver for Digital modes. It is a Double Sided Band transceiver kit designed for digital modes, especially for FT8. If you have chance to try FT8, you will be amazed by the strong decoding capability due to the communication protocol, digital signal processing and software. I still remember clearly a YouTube video by W6LG who communicated with a bulb. I started to think how much the transceiver could be simplified if you have a moderate antenna like a full sized dipole or EFHW instead of a bulb. A DSB transceiver is much simpler than a SSB transceiver, however it was never used for FT8 as far as I know. I did some experiments on my Choc perf board, a specially designed perf board for RF circuit experiments. I started with a direct conversion receiver for FT8 and it worked okay. Then I built a DSB transmitter and the transmitted signal can be decoded. By referring to the DSB designs of AA7EE, VK3YE and ZL2BMI, I combined them using only one NE602 and a PTT switch and it gave me success to make a few FT8 QSO’s. Personally I really enjoyed it because a manual PTT switch will save power consumption and circuit complexity, but you will need to well sync with computer, although it was not really a problem for me. Per request from a few hams, I found a VOX control circuit and modify the hold time to be compatible with FT8, and I put them together and made a few improvements on the signal purity and frequency stability, and it finally became our D4D. Do we have to worry about the unwanted Lower Side Band? Maybe, but for a transmitter of 1-watt, it is not really a big problem. Is it just a toy for a transmitter of 1-watt and only half of the power will be effective? Not really, as I can easily make a few QSO’s as far as 1500 miles range for 40-meter band. Thanks, Adam
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Re: DSB transceiver for Digital mode
Adam Rong
Ron,
I use 14.070MHz HC-49U crystals and pull them high about 4kHz. The crystals were customized before and I have enough stock. They work perfectly for 14.074MHz. Thanks, Adam
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Re: DSB transceiver for Digital mode
Ron Stone
Adam,
Glad to see that you're going forward with 20 meter version sooner rather than later. Are you getting customized crystals for 14.074 Mhz or is it anothet frequency crystal that has to be pulled a bit? If so what frequency is it for 20 mtrs? Thanks. Ron (ka3j)
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Re: DSB transceiver for Digital mode
Adam Rong
80-meter 3.573MHz will be added. Crystals are being customized. Think of a 80-m radio of 1-watt to make a few QSO's? Great fun!
Thanks, Adam
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Re: DSB transceiver for Digital mode
Furtuna Mircea
Hello. Cut the crystal around 1mm around the crystal, scratch the crystal very carefully, just a little, and measure it frequently. It will be a slight increase of 30 maximum 100kz. Verified method, step by step.Mircea-YO9IOF
On Wednesday, April 24, 2019, 7:46:13 PM GMT+3, Adam Rong <rongxh@...> wrote:
Folks, I have placed order for PCB two days ago. The first batch is 350 pcs. I have finalized the parts value and will place order for parts tomorrow. The RF output is 1-watt at 12V for 14.074MHz, and a bit bigger for 7.074MHz. The spurious suppression is better than -50dBc. I hope to start kitting for the first 5 pcs on May 4. If it goes smoothly, I might take order to ship these kits early, so you can send a few test reports ahead of time than the usual customers. Stay tuned and I hope you will like it. Thanks, Adam
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Re: DSB transceiver for Digital mode
Adam Rong
Folks,
I have placed order for PCB two days ago. The first batch is 350 pcs. I have finalized the parts value and will place order for parts tomorrow. The RF output is 1-watt at 12V for 14.074MHz, and a bit bigger for 7.074MHz. The spurious suppression is better than -50dBc. I hope to start kitting for the first 5 pcs on May 4. If it goes smoothly, I might take order to ship these kits early, so you can send a few test reports ahead of time than the usual customers. Stay tuned and I hope you will like it. Thanks, Adam
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Re: FT8 DSB VOX
John Kirby
Adam, I understand and thanks for the reply 72 73 John N3AAZ
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Re: FT8 DSB VOX
Adam Rong
John,
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No. I will keep the schematic paper based only for customers for a period of time. Thanks, Adam
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Re: DSB transceiver for Digital mode
Adam Rong
Jim,
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I would leave it for customers’ modification. We have added a crystal in the front end as the filter. We will have to switch both. Thanks, Adam
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Re: FT8 DSB VOX
John Kirby
Adam,
Sounds good ! Will you release the schematic even if preliminary ? 72 73 John N3AAZ
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Re: DSB transceiver for Digital mode
What about having both crystals and then adding a switch to go between the FT8 and JS8 frequencies?
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Re: DSB transceiver for Digital mode
Adam Rong
Technically it is possible. Just change the crystal and I might be able to customize it. However, we will need to consider the unwanted LSB signal will go into FT8 spectrum and it might cause interference although the power is still QRPp level.
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If we want to experiment, just pull high the crystal a bit to see how high it can go, maybe 7075 or 7076 but not easy to get 7078 for a HC49S holder crystal. Thanks, Adam
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