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FT8 by D4D DSB Transceiver

hisami dejima
 

Hello Friends,

Sorry for my off topics.
Does everybody know the project called "D4D" ?
I knew it recently, and I was astonished.

http://www.crkits.com/
"D4D DSB Transceiver Kit for Digital Mode"
 
This aims for the FT8 operation by the simple transceiver of the DSB method.
Unfortunately this project has an essential defect.
For example, When transmit FT8 at 1,500Hz (AF) on QRG 14.074MHz.
The signal of the indispensability is 14,075,500Hz (RF) at the USB side.
Then an unnecessary signal is transmitted to even 14,072,500Hz (RF) at the LSB side.
Both output is the same.
This frequency is known as  PSK subband.
 
I do not deny the experiment of simple systems.
However, I think that this project should act in AM subband.

How do you think?

73, Hisami 7L4IOU