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uBitx CW transmit problem #ubitx-help #ubitxcw #cw

Lou KI5FTY
 

Hi - I have completed a uBitx build with my daughter and wee are trying to get it on the air in CW mode.  I am running CEC 1.2 firmware on a v5 board.  There is a problem with the transmission in the CW mode.  after the keyer is released the radio continues transmitting a tone for about 1 sec.  it is reduced in volume but still very strong.  I have attached a spectrum display from my SDR showing a number of dots transmitted and you will notice a tail after each dot.  Any ideas?  Also is there a trick to get the rig to not transmit.  I have tried the menu option of transmit off but no matter how many times I try - I am still transmitting.

MVS Sarma
 

Did you wire the 4.7K pull up resistor as recommended on the "key" jack. Please check. In its absence as you switch on, the rig is likelybto go to tx mode on cw permanently.

Sarma vu3zmv

On Wed, 30 Oct 2019, 11:13 pm , <lscalpati@...> wrote:
Hi - I have completed a uBitx build with my daughter and wee are trying to get it on the air in CW mode.  I am running CEC 1.2 firmware on a v5 board.  There is a problem with the transmission in the CW mode.  after the keyer is released the radio continues transmitting a tone for about 1 sec.  it is reduced in volume but still very strong.  I have attached a spectrum display from my SDR showing a number of dots transmitted and you will notice a tail after each dot.  Any ideas?  Also is there a trick to get the rig to not transmit.  I have tried the menu option of transmit off but no matter how many times I try - I am still transmitting.

MVS Sarma
 

My reply may not be relevant in this case.


On Wed, 30 Oct 2019, 11:22 pm Mvs Sarma, <mvssarma@...> wrote:
Did you wire the 4.7K pull up resistor as recommended on the "key" jack. Please check. In its absence as you switch on, the rig is likelybto go to tx mode on cw permanently.

Sarma vu3zmv

On Wed, 30 Oct 2019, 11:13 pm , <lscalpati@...> wrote:
Hi - I have completed a uBitx build with my daughter and wee are trying to get it on the air in CW mode.  I am running CEC 1.2 firmware on a v5 board.  There is a problem with the transmission in the CW mode.  after the keyer is released the radio continues transmitting a tone for about 1 sec.  it is reduced in volume but still very strong.  I have attached a spectrum display from my SDR showing a number of dots transmitted and you will notice a tail after each dot.  Any ideas?  Also is there a trick to get the rig to not transmit.  I have tried the menu option of transmit off but no matter how many times I try - I am still transmitting.

Evan Hand
 

There is also a time delay setting to reduce the relay switching that can be changed with the Memory Manager software from CEC.  I am at work so cannot give you the specific value to change.

This will reduce the time the transmitter stays on, however it does not eliminate it.

73
Evan
AC9TU

Lou KI5FTY
 

yes i did - the rig works normally in ssb mode and the rig stops transmitting after 1 second or so after the key is released.

Lou KI5FTY
 

I see why you thought the transmitter was always on.  the second question I asked was overwritten (at least in my view) by my picture.  the second question was:

is there a trick to get the rig to not transmit for cw practice.  I have tried the menu option of transmit off but no matter how many times I try - I am still transmitting.

Lou KI5FTY
 

if you are referring to the cw delay (TX->RX) - i have it set at 600 milliseconds.  I just switched it to 0 and verified the settings took by reloading them into memory manager.  Nothing has changed.

Evan Hand
 

Other than the straight vs Iambic key setting, I do not have any other suggestions.  It might be RF feedback as that as gotten me in the past.  I worked it out by using a dummy load vs an off center fed dipole.  The dummy load did not have the delay issue.

On the not activating the transmitter, the only way that I know of is to install a switch (or separate fuse as I have) on the PA power supply line. That would allow for using the side tone to practice sending.

73
Evan
AC9TU

Lou KI5FTY
 

Evan - for the cw keying issue, I have tried with a dummy load also and same result.  As for the TX off issue the CEC firmware has a setting to turn TX off but it does not seem to work for me

Thanks

Mike Kilpatrick <mike.kilpatrick@...>
 

Very often apparent computer problems can be cured by a simple reboot of the pc.

 

Why not try re-loading the firmware? At best it could cure the problem. Worse case would be that it proves you have a hardware problem.

 

Mike  VK2DJP

 

 

From: Lou KI5FTY
Sent: Thursday, October 31, 2019 09:24
To: BITX20@groups.io
Subject: Re: [BITX20] uBitx CW transmit problem #ubitx-help #cw #ubitxcw

 

Evan - for the cw keying issue, I have tried with a dummy load also and same result.  As for the TX off issue the CEC firmware has a setting to turn TX off but it does not seem to work for me

Thanks

 

Lou KI5FTY
 

Found the problem with the transmit with trailing tone.  In memory manager you can set CW DELAY (TX-RX) and it was set to 0.  One would assume no delay.  Not true, it must use some system default. Changing it to 1 (10ms) shortened the relay hang time to an noticeable amount and the wave form looks ok.  2 Questions: 

1) is that a bug or undocumented feature ;-)
2) why would there be tone output while the relay is closed but no keyup?