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#QCX : Keyer issue solved (?) #qcx

Axel
 

Hi all,

just in case someone has the same issue like me: Keyer in iambic mode
sporadically produced errors, even with a dummy load. Errors disappeared
when in practice mode (no RF).

First, I tried two 1-KOhm resistors to +5V, as suggested from someone else
in this forum. This improved the issue, but did not solve the problem
entirely.

Then I added two resistors and four capacitors (see attached image). This
seems to have removed the problem completely.


Kind Regards,
Axel, DF1ET

Daniel Walter
 

Axel,
Out of curiosity, what antenna are you using? are your leads to your paddles shielded and how long are they? What band is it in?
--
73, Dan  NM3A

Andy V. Borisenko
 

I always had a problem of incorrect transmission CW. and no additional resistors and capacitors solve this problem.
there will be errors on the antenna (i use GP, SWR 1:1), and on dummy load.

Axel
 

I add an image...
The leads are not shielded. On the image you can see, that I folded the leads on a short section, in a way where inductance is minimum. The paddles are homemade, 2 halfes of a hacksaw blade, quite long. QCX is for 20 m. Power source is a LiPo battery.

I had the problems:
- with the dummy load, which you can see in the image. It's made of two resistors 100 Ohm/1 Watt
- with my  endfed, which has two good current baluns/chokes
- with my SOTA antenna, 21 m wire + ATU.

With the 4 C's and 2 R's added, problems disappeared with:
- the dummy load
- endfed (only short test)

I didn't test with the SOTA antenna yet.

The audio jack is mounted in the enclosure, not on the PCB. So it was rather easy to add the additional components.
Enclosure is aluminum, similar to how PD7MAA did it.

Axel

Axel
 

I did the test with my SOTA antenna now (endfed wire 21 m, ATU, no rf-choke or balun):

It's better, but still problems :/

Maybe next I'll use screened wire to the paddles.

Axel, DF1ET

Axel
 

Hi,

I apparently solved my RF-interfernce problem into my paddles now, even with my SOTA antenna. What I did:

* replaced the 200Ohm resistors in my previous fix by 2.2KOhm resistors
* added another two 100nF capacitors directly at the inputs of the Atmega
* halved the length of the hacksaw blades of my paddles
* used shielded cable between paddles and keyer input

Unfortunately, I have the non-RF-interference problem described in "Keyer Issue with QCX - missing or short dahs": dahs are quite often shorter than 3 dits.


73
Axel, DF1ET

Axel
 

Just noticed: With the above changes, for updating the Firmware, You cannot ISP-program the Atmega plugged into the QCX. You will have to pull it out of the QCX and use an external programmer. If desired, I can post a schematic here.

73
Axel, DF1ET

Denis DL5SFC
 

Hi Axel,

have you  unpluged  any key, prior flashing?

Best 73

Denis

DL5SFC

 

Von: QRPLabs@groups.io [mailto:QRPLabs@groups.io] Im Auftrag von Axel
Gesendet: Dienstag, 12. November 2019 09:41
An: QRPLabs@groups.io
Betreff: Re: [QRPLabs] #QCX : Keyer issue solved (?)

 

Just noticed: With the above changes, for updating the Firmware, You cannot ISP-program the Atmega plugged into the QCX. You will have to pull it out of the QCX and use an external programmer. If desired, I can post a schematic here.

73
Axel, DF1ET

Axel
 

have you  unpluged  any key, prior flashing?
Yes, but my modification includes 200nF in parallel to the paddle input, and i think, that interferes with ISP-programming.

73
Axel, DF1ET

ajparent1/KB1GMX
 

That suggests a lot of RF, maybe that needs fixing.

Allison
--
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