D4D/FT8


Larry Lovell
 

After placing the 470 ohm resistor across the L1, the signal is still at a different frequency than I had expected.  This is the signal at the antenna when TUNE is engaged in the software.
Receives operates properly.
IMG_1693.JPG
Why is the output not 14.074 MHz?
--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729


Adam Rong
 

Larry,

The lower frequency oscillation is dominating. After you remove it, you will see 20m signal I believe.

If you have a D882 or BD139 on hand, please replace the C1162 to check if it changes anything.

Thanks,
Adam

在 2021年1月31日,上午6:46,Larry Lovell <larry.lovell76@...> 写道:


After placing the 470 ohm resistor across the L1, the signal is still at a different frequency than I had expected.  This is the signal at the antenna when TUNE is engaged in the software.
Receives operates properly.
<IMG_1693.JPG>

Why is the output not 14.074 MHz?
--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729


Larry Lovell
 

I do have a BD139 so I will replace it.  I will let you know.
Where is this 620 KHz signal coming from?  I don't see where it could be coming from in the schematic diagram.  Receive works well and the Pin 6 is at 14.074 MHz.  I might change out the NE602 just in case.
So, I should see a 14.074 MHz signal on the output, is that correct?


On Sat, Jan 30, 2021 at 4:18 PM Adam Rong <rongxh@...> wrote:
Larry,

The lower frequency oscillation is dominating. After you remove it, you will see 20m signal I believe.

If you have a D882 or BD139 on hand, please replace the C1162 to check if it changes anything.

Thanks,
Adam

在 2021年1月31日,上午6:46,Larry Lovell <larry.lovell76@...> 写道:


After placing the 470 ohm resistor across the L1, the signal is still at a different frequency than I had expected.  This is the signal at the antenna when TUNE is engaged in the software.
Receives operates properly.
<IMG_1693.JPG>

Why is the output not 14.074 MHz?
--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729



--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729


Larry Lovell
 

I have decided that I don’t know what the signal should really look like and it seems to be working fine. It is probably my scope that has the issue. I will try to gain a better understanding of the FT8 signals and protocol. 

On Sat, Jan 30, 2021 at 5:00 PM Larry Lovell via groups.io <larry.lovell76=gmail.com@groups.io> wrote:
I do have a BD139 so I will replace it.  I will let you know.
Where is this 620 KHz signal coming from?  I don't see where it could be coming from in the schematic diagram.  Receive works well and the Pin 6 is at 14.074 MHz.  I might change out the NE602 just in case.
So, I should see a 14.074 MHz signal on the output, is that correct?

On Sat, Jan 30, 2021 at 4:18 PM Adam Rong <rongxh@...> wrote:
Larry,

The lower frequency oscillation is dominating. After you remove it, you will see 20m signal I believe.

If you have a D882 or BD139 on hand, please replace the C1162 to check if it changes anything.

Thanks,
Adam

在 2021年1月31日,上午6:46,Larry Lovell <larry.lovell76@...> 写道:


After placing the 470 ohm resistor across the L1, the signal is still at a different frequency than I had expected.  This is the signal at the antenna when TUNE is engaged in the software.
Receives operates properly.
<IMG_1693.JPG>

Why is the output not 14.074 MHz?
--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729



--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729

--
Larry Lovell
73's N7RGW
http://QRVTronics.com
Cell: 214-697-1729