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Error on TX (code g) #qcx #error


Matthew Pullan
 

I was testing my QCX 80m today and had problems on transmit. After a few characters, a G would appear as the last digit in the frequency and the QCX would lock up and only transmit an E every five seconds. The antenna was a halfwave, the swr was about 1.4:1, the supply voltage was 14V. I don't have any problems when transmitting into a dummy load. I cannot find a list of error codes, so don't know what's going on. Has anyone else had this problem?
         73 de OE6FEG
              Matt


Hans Summers
 

Hi Matt

It means RF is getting into your keying cable. 

You can solve this by winding the keying cable around a ferrite toroid. 

Even better would be to solve the common mode current problem which you probably have that is bringing RF into the shack. 

73 Hans G0UPL 

On Thu, Oct 29, 2020, 19:48 Matthew Pullan <m0feu@...> wrote:
I was testing my QCX 80m today and had problems on transmit. After a few characters, a G would appear as the last digit in the frequency and the QCX would lock up and only transmit an E every five seconds. The antenna was a halfwave, the swr was about 1.4:1, the supply voltage was 14V. I don't have any problems when transmitting into a dummy load. I cannot find a list of error codes, so don't know what's going on. Has anyone else had this problem?
         73 de OE6FEG
              Matt


Dave
 

The common misconception is that the end fed half wave antenna with a 1:49 Voltage transformer does not need a feed point ground or counterpoise. That is false. In order for the transformer to properly voltage feed the end of the antenna wire it should, indeed must have a decent ground reference. A good ground will also reduce the conduction of RF back up the coax to the rig.  Improve radiation efficiently and reduce RF in the shack and on the rig!  No downside!

Dave


On Oct 29, 2020, at 13:01, Hans Summers <hans.summers@...> wrote:


Hi Matt

It means RF is getting into your keying cable. 

You can solve this by winding the keying cable around a ferrite toroid. 

Even better would be to solve the common mode current problem which you probably have that is bringing RF into the shack. 

73 Hans G0UPL 

On Thu, Oct 29, 2020, 19:48 Matthew Pullan <m0feu@...> wrote:
I was testing my QCX 80m today and had problems on transmit. After a few characters, a G would appear as the last digit in the frequency and the QCX would lock up and only transmit an E every five seconds. The antenna was a halfwave, the swr was about 1.4:1, the supply voltage was 14V. I don't have any problems when transmitting into a dummy load. I cannot find a list of error codes, so don't know what's going on. Has anyone else had this problem?
         73 de OE6FEG
              Matt


N3MNT
 

The "G" is the QCXs way of indicating that it thinks a GPS is connected and puts the radio in the GPS mode which locks the TX.  The keying circuit and the GPS share several pins.  As mentioned above, if RF gets into the key cable can trick the QCX into thinking there is a GPS connected.


Matthew Pullan
 

Thanks for the quick answer. I have plenty of ferrites at home, so I can knock up a CMC choke no problem. I was actually outside using a Fuchskreis antenna tuner, which I assumed would not suffer from CMC, although in hindsight, the lack of a counterpoise would suggest otherwise. I already knew that the QCX is quite rf sensitive from experiments at home.
            73 de OE6FEG
                    Matt


Steve in Okinawa
 

I had exactly the same happen on my last SOTA outing. SWR was around 2:1. I couldn't fix it in the field, but set up the same way at home, a few loops of the key lead around a toroid fixed it. Then I added a small choke balun right at the antenna terminal, which was the real solution because it then worked fine without the toroid on the key lead. Just like Hans said, it's a common mode issue, but i hadn't seen it until I updated the firmware.  JS6TMW


@CurtisM
 

Matt

I am using a commercial EFHW with my 80m QCX+ (its from myantennas) - no issues operating with or without the matching PA (at about 20 watts) - but I do have a ground rod near the transmitter location - and other grounded antennas with on-ground radials (my my 2 verticals) -- so you will just have to try some remedies - but there is way to get there.

73 curt