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Step 3.3 of uBitx wiring instructons: missing pull-up resistor causes CW transmissions

rdkrco
 

I overlooked the "DANGER:" warning in Step 3.3 of uBitx wiring instructions because of deliberately skipping around wiring the CW key.

To keep people from shooting themselves in the foot when wiring the uBitx, the 4.7K pull up resistor should be wired to the digital connector blue and green wires as a separate step preferably before turning on the power for the first time and measuring the board current. It is never a good idea to have the board trying to transmit CW unexpectedly?before the frequency has been deliberately set and before a suitable antenna ( or dummy load ) has been prepared.
 

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I haven¡¯t tried it yet but I plan to put a 4.7K ohm 0805 SMD resistor between pins 2 and three on the Raduino. ?I¡¯ve done this many times on other boards. ?0805¡¯s will just fit in that space.



Clark Martin
KK6ISP

On Dec 27, 2017, at 2:54 PM, rdkrco <rdkrco@...> wrote:

I overlooked the "DANGER:" warning in Step 3.3 of uBitx wiring instructions because of deliberately skipping around wiring the CW key.

To keep people from shooting themselves in the foot when wiring the uBitx, the 4.7K pull up resistor should be wired to the digital connector blue and green wires as a separate step preferably before turning on the power for the first time and measuring the board current. It is never a good idea to have the board trying to transmit CW unexpectedly?before the frequency has been deliberately set and before a suitable antenna ( or dummy load ) has been prepared.
 

I did this and could not figure out why the heck it was transmitting.. Yep, missed a step. I didn't have an antenna hooked up, so I hope I didn't damage anything. The receive side of things is fairly noisy but it's difficult to tell whether or not it's a lack of proper ground or the bad indoor antenna I have at the moment.
 

?I just soldered the resistor across the blue and green pins. I rolled up the green wire and tied it off.


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On Friday, January 5, 2018 8:48 AM, "stian.eklund@..." <stian.eklund@...> wrote:


I did this and could not figure out why the heck it was transmitting.. Yep, missed a step. I didn't have an antenna hooked up, so I hope I didn't damage anything. The receive side of things is fairly noisy but it's difficult to tell whether or not it's a lack of proper ground or the bad indoor antenna I have at the moment.


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