Poor quality CW and noise bursts start and end of xmits

rdwing
Posts: 92
Joined: Sat May 21, 2022 2:05 am

Poor quality CW and noise bursts start and end of xmits

Postby rdwing » Wed Jul 27, 2022 1:00 am

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.
Screenshot 2022-07-26 021120.png
CWX Thetis
Screenshot 2022-07-26 021120.png (40.78 KiB) Viewed 2183 times
Screenshot 2022-07-26 021124.png
CWX RemoteSDR
Screenshot 2022-07-26 021124.png (64.58 KiB) Viewed 2183 times


This phenomenon somewhat occurs using the TUN button and 2TON buttons as well.
Screenshot 2022-07-26 020535.png
Tun+2TON Thetis
Screenshot 2022-07-26 020535.png (110.32 KiB) Viewed 2183 times
Screenshot 2022-07-26 020523.png
Tun+2TON RemoteSDR
Screenshot 2022-07-26 020523.png (1.25 MiB) Viewed 2183 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.
Screenshot 2022-07-26 175238.png
Burst at end of xmit
Screenshot 2022-07-26 175238.png (193.24 KiB) Viewed 2183 times

Screenshot 2022-07-26 175803.png
XMIT Options
Screenshot 2022-07-26 175803.png (12.76 KiB) Viewed 2183 times
Last edited by rdwing on Fri Jul 29, 2022 1:39 am, edited 1 time in total.
PD3LK
Posts: 194
Joined: Mon Nov 11, 2019 8:45 pm
Location: Apeldoorn, NLD

Re: Poor quality CW and noise bursts

Postby PD3LK » Thu Jul 28, 2022 6:49 am

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?
73 PD3LK Leon
rdwing
Posts: 92
Joined: Sat May 21, 2022 2:05 am

Re: Poor quality CW and noise bursts

Postby rdwing » Thu Jul 28, 2022 7:31 am

PD3LK wrote: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.png
100w
100w.png (659.03 KiB) Viewed 2122 times

50w.png
50w
50w.png (433.08 KiB) Viewed 2122 times

25w.png
25w
25w.png (319.03 KiB) Viewed 2122 times

5w.png
5w
5w.png (291.32 KiB) Viewed 2122 times

nanovna-h4_2022-07-28_00-56-36.png
VNA-40m
nanovna-h4_2022-07-28_00-56-36.png (140.3 KiB) Viewed 2118 times

Screenshot 2022-07-28 012321.png
ANT2 transmissions leaking out on ANT1
Screenshot 2022-07-28 012321.png (2.05 MiB) Viewed 2110 times
dynamicfusion
Posts: 57
Joined: Thu Oct 14, 2021 5:23 am

Re: Poor quality CW and noise bursts

Postby dynamicfusion » Thu Jul 28, 2022 9:23 pm

Maybe shielding? Grounded?
rdwing
Posts: 92
Joined: Sat May 21, 2022 2:05 am

Re: Poor quality CW and noise bursts start and end of xmits

Postby rdwing » Thu Aug 11, 2022 6:39 pm

It seems this is a firmware problem, and unlikely to get resolved at the moment.
User avatar
w-u-2-o
Posts: 5525
Joined: Fri Mar 10, 2017 1:47 pm

Re: Poor quality CW and noise bursts start and end of xmits

Postby w-u-2-o » Thu Aug 11, 2022 7:42 pm

rdwing wrote: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.
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w9ac
Posts: 290
Joined: Sun Apr 09, 2017 4:01 pm

Re: Poor quality CW and noise bursts start and end of xmits

Postby w9ac » Tue Aug 16, 2022 2:45 am

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
Posts: 434
Joined: Fri Jul 30, 2021 10:09 pm
Location: TEXAS, USA

Re: Poor quality CW and noise bursts start and end of xmits

Postby JJ4SDR » Thu Aug 18, 2022 1:06 am

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
Options 1.jpg (29.74 KiB) Viewed 1706 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
Last edited by JJ4SDR on Thu Aug 18, 2022 1:12 am, edited 1 time in total.
PC: 8 Core i7-10700 CPU @ 2.90GHz, NVMe SK Hynix 512 GB SSD, 32GB RAM
Windows 10 Home, Version 22H2
Thetis v2.10.4.3 x64
Protocol 2 v2.1.18
JJ4SDR
Posts: 434
Joined: Fri Jul 30, 2021 10:09 pm
Location: TEXAS, USA

Re: Poor quality CW and noise bursts start and end of xmits

Postby JJ4SDR » Thu Aug 18, 2022 1:11 am

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
PC: 8 Core i7-10700 CPU @ 2.90GHz, NVMe SK Hynix 512 GB SSD, 32GB RAM
Windows 10 Home, Version 22H2
Thetis v2.10.4.3 x64
Protocol 2 v2.1.18
User avatar
w9ac
Posts: 290
Joined: Sun Apr 09, 2017 4:01 pm

Re: Poor quality CW and noise bursts start and end of xmits

Postby w9ac » Thu Aug 18, 2022 1:34 am

JJ4SDR wrote: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
Options1.jpg (124.71 KiB) Viewed 1699 times

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