Poor quality CW and noise bursts start and end of xmits

[rdwing]

I am facing an issue with my new 7000 Mk3 running v2.7 Protocol1, that has very poor transmitted CW tone with a lot of distortion on the signal, and keying clicks on both key down and key up. This is observed on all bands. The antenna is a resonant fan dipole, there are common mode chokes and ferrites, and I don't believe there is any RF coming into the shack.

The following is from CW transmitted at 100W and received on a remote receiver, via the CWX built in keyer.

CWX Thetis

Screenshot 2022-07-26 021120.png (40.78 KiB) Viewed 5795 times

CWX RemoteSDR

Screenshot 2022-07-26 021124.png (64.58 KiB) Viewed 5795 times

This phenomenon somewhat occurs using the TUN button and 2TON buttons as well.

Tun+2TON Thetis

Screenshot 2022-07-26 020535.png (110.32 KiB) Viewed 5795 times

Tun+2TON RemoteSDR

Screenshot 2022-07-26 020523.png (1.25 MiB) Viewed 5795 times

Part of the problem seems to be incorrect timing of the relays when stopping a transmission.
A potential clue: I have a dummy load connected to ANT2. A power meter and antenna are connected to ANT1. When transmitting into the dummy load on ANT2 with a 100W carrier, when I stop the transmission by clicking the TUN button my power meter on ANT1 registers a blip of power, which I find very interesting.

Burst at end of xmit

Screenshot 2022-07-26 175238.png (193.24 KiB) Viewed 5795 times

XMIT Options

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[PD3LK]

Hi,

Resonant antenna on 3901 kHz ? What ham band is that?
Can you show us a example on a appropiated HAM band part?
What happens (next) if you reduce power in few steps?

[rdwing]

Resonant antenna on 3901 kHz ? What ham band is that?
Can you show us a example on a appropiated HAM band part?
What happens (next) if you reduce power in few steps?

Hi, it was the 80m/75m amateur band in the US. 3.901 MHz. It is a resonant antenna, a large multi band fan dipole.

Here it is on the 40m band. Antenna SWR is about 1.5 at this freq. There's nothing else in line, the tuner is bypassed for this. Seems pretty much the same.

I've discovered another issue as well. While sending CW into my dummy load, which is attached to ANT2, some blips can be seen coming out of ANT1, which are being transmitted over the air. I was pretty surprised to see that...see image at the bottom.

From 100W to 5W, the same behavior is seen.

100w

100w.png (659.03 KiB) Viewed 5734 times

50w

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25w

25w.png (319.03 KiB) Viewed 5734 times

5w

5w.png (291.32 KiB) Viewed 5734 times

VNA-40m

nanovna-h4_2022-07-28_00-56-36.png (140.3 KiB) Viewed 5730 times

ANT2 transmissions leaking out on ANT1

Screenshot 2022-07-28 012321.png (2.05 MiB) Viewed 5722 times

[dynamicfusion]

Maybe shielding? Grounded?

[rdwing]

It seems this is a firmware problem, and unlikely to get resolved at the moment.

[w-u-2-o]

It seems this is a firmware problem, and unlikely to get resolved at the moment.

How did you come by that assessment? It could just as easily be a software problem. Or perhaps no problem at all, since it does not affect everyone.

[w9ac]

Can you capture the transmitted CW waveform in the time domain with an oscilloscope? That will tell us a lot about the root cause of any excessive keying bandwidth, hot-switching, etc. It may be easiest to sample at the input to your dummy load with a "T" coaxial adapter.

Paul, W9AC

[JJ4SDR]

To "rdwing,":

Curious about the time delays on the Options form. My PTT delay is 0 and the RF delay 30 ms. Not that this necessarily explains what you are experiencing. The difference between the PTT delay and RF delay in your case is very brief compared to mine.

Options 1.jpg (29.74 KiB) Viewed 5318 times

I am not using the same Thetis version as you and also I am on Protocol 2 (radio is ANAN 7000 DLE MKII).
Thetis v2.9.06. x64 Protocol 2 v2.1.18

What W9AC suggests would be good to have.

73 de Juha
NI2M

[JJ4SDR]

Paul,

I am wondering what the numbers are on Options 1 form in your case? Mine may be off for all I know. I have only changed the PTT and RF delays, nothing else if my memory serves.

73 de Juha
NI2M

[w9ac]

Paul,

I am wondering what the numbers are on Options 1 form in your case? Mine may be off for all I know. I have only changed the PTT and RF delays, nothing else if my memory serves.

73 de Juha
NI2M

Juha,

My CW settings won't apply to you for several reasons as I'm using a specialized Channelmaster.dll file, ASIO drivers, and some hardware modifications to optimize QSK. All delays are set very low, some to zero. As you requested, I have attached my Option 1 settings but please do not attempt to use these values.

Paul, W9AC

Options1.jpg (124.71 KiB) Viewed 5311 times