开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. QRPLabs
  2. Messages
Expanded Topics Messages Polls
Date
Re: Simple and very tiny mic for the QMX. #qmx #ssb

 

Thank you Ronan. I could not remember what it was called.? Tinsel wire. YUK!
Even if you do manage to get that stuff soldered,? it will likely not hold up to any strain whatsoever.?
?
--
regards,
Bryan, N0LUF
Re: more WSJT-X touble

 

On 24/03/2025 13:23, Chris via groups.io wrote:
The 'improved' versions are 'authorised' as they are made by one of the developers as a way to trial additional features,
Chris,

"Authorised" in so far as it is open source.
The variations are not promoted on the main WSJT-X page.
Like the RC versions "improved" versions are best used by more experienced users.

The current stable version is covered by the official user manual, the WSJT-X group and probably used by the majority.

I see confusion when features of modified versions are mentioned.

73 Alan G4ZFQ
Re: SSB Calibration blown finals

 

开云体育

10 meters but they give good output on 6.

Tony
AD0Vc

From: [email protected] <[email protected]> on behalf of adam via groups.io <adam@...>
Sent: Monday, March 24, 2025 4:56 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] SSB Calibration blown finals
?
On Sun, Mar 23, 2025 at 11:15 PM, mux_folder2001 wrote:
TN0110
What is the highest frequency you are using the TN0110s on?
Re: SSB Calibration blown finals

 

开云体育

This is a 9 volt build. It is supplied through an LM338 regulator adjusted for 9 volts. The regulator input is from a 12 volt linear bench supply. The BS170s came from Mouser. They were mounted normally.

Tony
AD0VC

From: [email protected] <[email protected]> on behalf of Bruce Akhurst <bruce@...>
Sent: Monday, March 24, 2025 3:43 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] SSB Calibration blown finals
?
Fascinating. ? ?Would be more so with :
supply voltages that blew them?
power outputs that blew them?
where the BS170’s came from?
how they were mounted?
别迟肠…?
?
Re: SSB Calibration blown finals

 

开云体育

In the QMX+ I just mount them face up with the washer as usual. In my QDXs I have experimented extensively with heat sinks and I found that heat was never an issue. I do not run WSPR, mainly FT8.

Tony AD0VC

From:[email protected] <[email protected]> on behalf of Richard Dyer via groups.io <rdyer39@...>
Sent:?Monday, March 24, 2025 1:16 AM
To:[email protected] <[email protected]>
Subject:?Re: [QRPLabs] SSB Calibration blown finals
?
How did you deal with the reverse mounting/heat sink issue? I have purchased a set of those transistors just in case.?
Re: QMX SSB Vertical lines on VARA waterfall?

 

Are you using VOX? I had the same issue until I upgraded to latest firmware and back to cat PTT control.
?
Chris, w0anm?
Interesting thing happened on my 20-10 meter QMX after loading the latest FW 1.01.003

 

I loaded 1.01.003 last night and ran the calibration routine. I thought everything went ok. I cycled power and started tuning around the bands. The first band I tried was 40 meters. I heard a group talking that were pretty loud so I figured I’d see if they would allow me to jump in. Sure enough they heard me and each station gave me a signal report. None of which was very strong. I was being heard from Los Angeles to Las Vegas from my home in San Diego. I was pretty excited it was working. I turned it on this morning to see if the band was open. Something was wrong, I couldn’t change bands to 10, 11 or 12 meters. Then it hit me, when I loaded the new firmware I never selected the proper band for the QMX. It defaulted to 60-15 meters. I was working stations on 40 meters on a QMX I built for 20-10 meters.?
That’s pretty impressive in my book.?
I’ll go back and run the calibration routine again today for the proper bands. Though I’m not sure it needs it.
?
Don.
VARA Rise/Fall Threshold Changes Affect JS8?

 

KJ7RBS (I think) did yeoman's work in getting the QDX to work with VARA.? He suggested setting:
?
Rise Threshold to 65 (default 80)
Fall Threshold to 45 (default 60)
Min. Samples to 120 (default 480)
?
Two questions:
?
1. Has anyone tried these Vara compatible settings with JS8?? ?I will if no one has.
2. Is there a way to change these parameters other than running Putty to make the changes in the QDX Configuration application?? It'd be nice to just run a script that tells the QDX what parameters to change.
?
Best,
?
Jim
K8DDV
?
?
?
Re: QMX SSB Vertical lines on VARA waterfall?

 

Darrell,
?
Did it only happen this one session or does it happen every time you use your QMX in SSB?
?
73,
BrianB
N6CVO
Re: QMX SSB DX!

 

Congratulations!
--
73, de BD8BTE
op: Lun Yang
Re: Receiving AM?

 

The bandwidth of an AM receiver might be 10khz, the QMX strips out all but 3.2khz of that AM signal.
While it is harder to tune in with the QMX, if there are interfering signals within the 10khz AM signal
then this can often be filtered out using the QMX receiver.? What's more, you can choose to use either
the upper sideband or the lower sideband of that AM signal, whichever has less interference.
?
It should be possible to add normal AM reception to the QMX through a firmware update,?
but that would be a very low priority for a rig meant to be used on the ham bands.
Especially since using the QMX as an SSB receiver often gives better results.
?
Jerry, KE7ER
?
?
On Mon, Mar 24, 2025 at 03:38 AM, Chris wrote:

The current QMX SSB receiver can receive AM because what is transmitted is the two sidebands and a carrier but it's not receiving it as AM, it's receiving as SSB using one sideband of the AM signal and ignoring the other sideband and the carrier.? You don't get the advantages of true AM reception where precise tuning is not required, and you have thrown away half of the data.
?
Try it with a rig that can receive SSB and true AM on a broadcast AM signal.? You will see that the AM signal can be received as SSB but you need precise tuning to get the correct tone, with AN you don't need precise tuning and the signal to noise is a little better.
?
Chris, G5CTH
Re: PA 50W on RD16HHF1 #20m #50w

 

Nate,
?
When Allison says a max of 16 volts, she means the power supply into the rig.
Transmitting on 80m with the QMX from a 12v supply into a 50 ohm dummy load can cause
peak voltages of more than 60 volts from drain to ground at those BS170's.?
And 60v is the absolute max listed in the BS170 datasheet.
?
In addition to reading the datasheet for the FET's, you also need to know how the circuit works.
That is not a trivial task, unless like Allison you have spent a career doing this stuff.
Here's a tutorial on a Voltage Mode Class D push-pull amp such as used on the QMX:
?
?
Why such high voltages?
As described in that tutorial, the action of transformer T501 causes twice the power supply voltage to appear
across each BS170 when it is not conducting.? In addition, the LPF in the QMX blocks
the undesired harmonic currents from going out to the load, which raises voltages further.
?
For those wishing to see what's going on, I'd recommend using
the LTSpice simulator on a model of the QMX final.? Such a model can be found
in the left-most of the four simulations found in this file:
The discussion is in this thread:??
?
Jerry, KE7ER
?
?
?
On Mon, Mar 24, 2025 at 05:20 AM, Nate Reik wrote:

On Sun, Apr 25, 2021 at 10:53 AM, ajparent1/kb1gmx wrote:
There is some magical thinking with regard to RD15hhf parts.
RTFM, in this case, the data sheet.

First its a 16V max part.
Can someone explain this? I'm trying to understand maximum values of RF transistors...and the RD16HHF1 datasheets I see don't say 16v anywhere. I see 20v and 50v ratings...and I see things about rules of thumb elsewhere...but how do I determine from the datasheet of an RF transistor what the maximum DC supply voltage is?
?
Thanks for any help with my learning!?
?
-Nate
N8BTR
Re: QMX+ Mono Audio Output

 

Paul,
?Okay thanks!
?
Dave
W6MQI
Re: PA 50W on RD16HHF1 #20m #50w

 

I'd appreciate some pointers to guidance on RF circuit design, especially power amplifiers.? Some sort of text book maybe.
?
Chris, G5CTH
Re: QMX+ Mono Audio Output

 

Dave,
I have an old set of Radio Shack communications headphones that are mono. I use a mono to stereo adapter plug on it and it works fine. It's similar to this one:
?
--
73, Dan - W2DLC
Re: more WSJT-X touble

 

WSJT-X has moved on to 2.8.0 now.? The 'improved' versions are 'authorised' as they are made by one of the developers as a way to trial additional features, some of which are useful.? That one was sent privately to fix a long standing bug that I'd been pestering about since last October.? There's a lot on the web about them.
?
Chris, G5CTH
QMX SSB DX!

 

Thanks again Hans for the great work on this radio and firmware! in addition to many US and CA contacts from my QTH in Minnesota, I’ve made my first ever QRP DX contacts. Madeira island on the first firmware version the first day and yesterday afternoon to Switzerland! ?Both on 20m using a 1/2 wave dipole in my attic. These were big stations with big ears but they gave good signal reports.?

I haven’t used my main radio all week!?
KF0OUH
?
Re: PA 50W on RD16HHF1 #20m #50w

 

Ahhh, so thus 50v divided by 3 or 4.... Giving 12.5-16.6V. Got it.?
So it would be OK for 20v IF you had a perfect output load matched to the transistor? Makes sense. Thanks, Gary!?
?
-Nate
N8BTR?
Re: more WSJT-X touble

 

On 24/03/2025 11:42, Martin DK3UW via groups.io wrote:
so that is not the original WSJTX ?
Martin,

It is a modified version, (improved in some ways?).
Try it if you wish although I would think it best to use the 2.7.0 version if it does what you want.
Hamlib is here


73 Alan G4ZFQ
Re: SSB Calibration blown finals

 

Richard, I did this in QDXs with a Wakefield heatsink I drilled and tapped.?
?
?
-Nate?
N8BTR
1361 - 1380 of 140795