Hi all,

I have had a QDX for a few years. I built it and made it for 9 volts. It has done a great job with over 500 grids worked. In the past I might have made 20 contacts in a day but recently that number has diminished. This week I might have 1 contact. The power out put on 40, 30 and 20 is around 3.8 watts into a very good EFHW antenna. I always use a tuner to reduce pressure on the finals. Also, my clock is synced correctly. I use WSJT, Logview and Gridtracker.

So, here is my question and I don't know anything about this. Can there be a problem with the signal that is being sent? I have ruled out all mechanical issue that I can but a station will answer my CQ and then they never complete the exchange. I answer a station and get a reply and then nothing else. Very frustrating and it is getting worse as time goes on.

Any suggestions?

73, Dean
N2TNN

Dean, N2TNN <N2tnn@...> wrote:

I have had a QDX for a few years. I built it and made it for 9 volts. It
has done a great job with over 500 grids worked. In the past I might
have made 20 contacts in a day but recently that number has diminished.
This week I might have 1 contact. The power out put on 40, 30 and 20 is
around 3.8 watts into a very good EFHW antenna. I always use a tuner to
reduce pressure on the finals. Also, my clock is synced correctly. I use
WSJT, Logview and Gridtracker.

Dean,

What about your reception? Do you see the usual traffic on a waterfall, or
is it quieter than usual?

I had a similar issue, but the received signal level was way too low. It
turned out I blew up two FST3243 and two op amps somehow, I don't know if
it was because my PA oscillated or because of a static build-up on my
dipole (open and ungrounded; since then I added a resistor across the
dipole and grounded the shield of the feeder).

With EFHW there should be no static electricity between the feeder's
wires, but maybe something else happened that killed the frontend...

Adam,
No problem with the front end. Perfect waterfall. I have no problem receive but I am questioning the transmit signal. I have to find the post where Hans talked about the transmit audio is not SSB audio but something else which is why the QDX is different. I never thought about it before but now lack of knowledge is my foe. I'm still learning.

73, Dean

Dean, N2TNN <N2tnn@...> wrote:

I have to find the post where Hans talked about the transmit audio is
not SSB audio but something else which is why the QDX is different.

It's a pure sine tone. Microprocessor receives the audio via USB, analyzes
it, and controls a synthesizer to produce the square wave at the needed
frequency. It's then amplified and converted to the sine wave with output
filters.

Do you have your audio level set correctly? It should be set to maximum.

How many blinks does the QDX's LED emit when you transmit?

Can you find your signals on PSK reporter?

Hi Dean,
You don’t mention the computer you are using.?

Because of the lack of reasonable Pi 4s I incorporated a Pi 3 for my V3 QDX. If I try to run anything but my logging program ( CQRLog ) and WSJT I end up missing decodes. ?

The resultant characteristics are the same as yours. Is your computer fast enough? ?Running extra programs that might take needed resources? ?

73
Dick
W4PID

Dean,

Assuming QDX still working as it has...

We depend on propagation and of recent propagation has been allover the map
both good and mostly bad.

Things to check...
The EFHW feed box usually a gray Corlon box are known for collecting water to bad effect.
The coax may have gotten water in, that usually rots the braid and that has a slow
performance reduction.? SWR may not rise but the loss does.


--
Allison
------------------
Post online only, please no email.

Dick,
That is very interesting concerning the computer processor speed. It is a fairly new machine running Windows 11 and does constant computing. I will shut down all processes and only use WSJT and Logview to see if there is improvement.

I also have to get back to Adam to answer his questions but I also like his description of the Microprocessor duties.

I might have to fire up PuTTy and check the settings.......

Thank you!

Allison,

Thanks for the reply. My set up is a 60 something foot wire up about 35 feet. It is connected to a ceramic thru-hull fitting. The 100 watt UNUN is in the building, grounded to a 8 foot ground rod and the coax is inside out of the weather. Now, my old setup was all outdoors which is where the loss in performance started a few months ago. New antenna and same lousy results.

I just built a high band kit yesterday and will get it on the air this morning. I know it's different frequencies but I'll report if there is improvement..

Thanks again,
Dean

Adam,

Concerning the audio question...

In WSJT when setting up the radio under the AUDIO tab I see QDX for input and output. But, when I click the right side drop down menu I can only put the input to "right" and the output to "both".
Why is that and is that correct?

Dean

On 05/09/2023 12:33, Dean, N2TNN wrote:

when I click the right side drop down menu I can only put the input to "right" and the output to "both".

Dean,

What version of WSJT-X? Windows? Any VAC?
My Windows/WSJT-X v 2.6.1 shows all 4 of my QDXs as Mono/Left/Right input. Mono/Left/Right/Both output.
I have presumed that is set by what the OS tells WSJT-X and what WSJT-X needs.

The default is Mono, I see no reason to change.

73 Alan G4ZFQ

On 05/09/2023 13:30, Alan G4ZFQ via groups.io wrote:

WSJT-X v 2.6.1 shows all 4 of my QDXs as Mono/Left/Right input.

Your audio device looks like a Mono only input?

Adam,

The audio level is set correctly.
Transmit shows S???? 3 blinks then pause
PSK reporter shows reception reports up to 6000 miles on 3 bands. 80 is closed now.

Also, I opened PuTTy and checked all sub-headings. Everything looks good to me with the filters, transmit and audio levels. I did a factory reset while I was there.

Dean

Alan and the group,

My WSJT-X v 2.5.4 gives my the same options. I changed the input to MONO and no reception. I changed it to RIGHT and instant contact.

I took all the input from the group and popped the hood on the QDX. I tweeked the toroid windings and moved things around. Now I get 4.1 watts out on all bands with 9v. I did the firmware reset...

So, in the last hour I picked up 4 new grids out in the west, 1 POTA and 6 other stations. Just like old times.
I know that's really not how you should trouble shoot but one of your suggestions got things straightened out.

Thank you all, I really appreciate the help.

73, Dean
N2TNN

开云体育

Regarding the use of a Pi 3 that is not a good idea.

One of the WSJT-X developers posted a note in the last year or so stating that a Pi 4 does not have enough compute power for FT8.? Does it work?? Yes it does but only to a certain point.

Last year I started off using a Pi 4 and I found that when the band gets busy with a lot of weak signals the Pi 4 cannot keep up.? I had "Deep" decode set as well.? When I was trying to work a DX station the Pi 4 could not decode the response within 15 seconds.?? The Pi 4 would decode the DX's response after 15 seconds.? And of course the Pi 4 had already started transmitting again but not the correct sequence for the QSO.??? I missed some DX this way :-)

To help you can change the decode to normal or fast.? But you may wind up missing some QSO's that way.

So the issue will be worse with a Pi 3.

You don't need a top of the line computer to run WSJT-X but you need something reasonable.?? I helped another ham setup WSJT-X on his Windows computer and I saw the same issue when the band got busy.?? He was running a low end PC.

FYI I am a retired software engineer who specializes in Linux and in performance.??

Marc

WA6HBR

Hi Dean,
You don’t mention the computer you are using.?

Because of the lack of reasonable Pi 4s I incorporated a Pi 3 for my V3 QDX. If I try to run anything but my logging program ( CQRLog ) and WSJT I end up missing decodes. ?

The resultant characteristics are the same as yours. Is your computer fast enough? ?Running extra programs that might take needed resources? ?

73
Dick
W4PID

-- 
Yes, that really is my last name.

Marc,

Sorry I missed that question. I am using a Windows 11 Op system on a i5 laptop. I also keep the decode on normal.

Now to see how I can get more power on the high band rig I just completed.

Dean

Dick,

PI4 is a fair compute engine but Rasbian is very generalized and ther eis a lot of stuff
going on eating CPU.? SDRs do it by using a real time core (or linux RT) to unload all
excess tasks.

It been my experience that WSJT is not that efficient as there lots of code.
It works best with PI-4s with 4gig or 8 gigabyte parts.

But usually the general rule prevails...? Good, Fast, Cheap; Pick any two.

--
Allison
------------------
Post online only,?
direct email will go to a bit bucket.

开云体育

Dean,

off the top of my head an I5 should be sufficient.? (I'm not a Windows person :-) ) When the issue occurs how busy is the FT8 frequency you are on?

I would use the performance monitor tool and see if the CPU's are being used a lot.?? If so I would find out which apps are using them and close them if you can.? Another possibility is that you are using all of your memory and Windows is having to move the applications data between RAM and disk.?

Hope this helps.? If you want we can try to talk over the phone about this.

Marc

WA6HBR

Marc,

Sorry I missed that question. I am using a Windows 11 Op system on a i5 laptop. I also keep the decode on normal.

Now to see how I can get more power on the high band rig I just completed.

Dean

-- 
Yes, that really is my last name.