Date   

Re: BPF trimmer sensitive to screwdrivier touch?

Alan G3XAQ
 

Yes, John, that's what I did. One side of the trimmer is grounded but it looks like the PCB layout has it the wrong way round? No big deal. I just wanted to be sure I didn't have a fault.

I have a dreadful thump on the sidetone and on semi-QSK there is a low level RF output during the "hang" time. I seem to remember seeing both these faults discussed on here so it's time to try out the groups.io search function...

73, Alan G3XAQ

On Sat, Mar 17, 2018 at 02:18 pm, John Pagett wrote:


Alan,

You should use an trimming tool which is either fully insulated (hard plastic)
or where the small blade is the only metallic part. In emergencies I've filed
up a plastic knitting needle to make a trimming tool (don't tell the XYL!)

73
John
G4YTJ
On 17 Mar 2018, at 20:39, g3xaq <alan@g3xaq.net> wrote:

I did notice one thing during alignment: when peaking the receiver BPF
trimmer the level changes (and I get noise on the audio) when I apply a metal
screwdriver to the trimmer. Is this expected? I've checked and I do have the
trimmer inserted the right way round: it is aligned with the silk screened
component overlay.

Before I go in gung-ho with a soldering iron and risk damaging the trimmer
and/or PCB, is this expected behaviour or not?

73, Alan G3XAQ



Re: BPF trimmer sensitive to screwdrivier touch?

Denis F6GKQ
 

As John wrote above, use a special trimmer tool.
Never trim an RF circuit using a metallic screwdriver.
Use alignment tools, see attached picture.

--
73 from Denis, F6GKQ
QCX 40m nr 3082


Re: BPF trimmer sensitive to screwdrivier touch?

John Pagett G4YTJ
 

Alan,

You should use an trimming tool which is either fully insulated (hard plastic) or where the small blade is the only metallic part. In emergencies I've filed up a plastic knitting needle to make a trimming tool (don't tell the XYL!)

73
John
G4YTJ

On 17 Mar 2018, at 20:39, g3xaq <alan@g3xaq.net> wrote:

I did notice one thing during alignment: when peaking the receiver BPF trimmer the level changes (and I get noise on the audio) when I apply a metal screwdriver to the trimmer. Is this expected? I've checked and I do have the trimmer inserted the right way round: it is aligned with the silk screened component overlay.

Before I go in gung-ho with a soldering iron and risk damaging the trimmer and/or PCB, is this expected behaviour or not?

73, Alan G3XAQ



Re: QCX CW Beaconing #qcx

John Kirby
 


More info...

QRSS and WSPR freqs
http://www.g6nhu.co.uk/frequencies.html

John
N3AAZ


Re: A word about QRP Labs capacitors and toroids

Steve
 

On Wed, Mar 14, 2018 at 04:18 am, Adrian Scripcă wrote:
I just replaced C25 and C26 with some polystyrene capacitors (I didn't have NPOs for these values) and the output power went up nicely, in accordance with the specified numbers.

I think Adrian may be on to something.  I had already removed windings on L1, L2 & L3 to get maximum power out on my 30m QCX, but after replacing C25 & C26 with polystyrene caps (same value), my power went from 2W to 3W on 12v, for a nice 50% increase.

 

It appears that the stock caps are a bottleneck on 30m, and likely the other higher bands. 

 

Steve, N4IAG


Re: BPF trimmer sensitive to screwdrivier touch?

Roger Hill
 

I get the same thing with the standalone receiver module.

Roger
G3YTN

---
***************************
Roger Hill
***************************

On 2018-03-17 20:39, g3xaq wrote:
I did notice one thing during alignment: when peaking the receiver BPF
trimmer the level changes (and I get noise on the audio) when I apply
a metal screwdriver to the trimmer. Is this expected? I've checked and
I do have the trimmer inserted the right way round: it is aligned with
the silk screened component overlay.
Before I go in gung-ho with a soldering iron and risk damaging the
trimmer and/or PCB, is this expected behaviour or not?
73, Alan G3XAQ


BPF trimmer sensitive to screwdrivier touch?

Alan G3XAQ
 

I did notice one thing during alignment: when peaking the receiver BPF trimmer the level changes (and I get noise on the audio) when I apply a metal screwdriver to the trimmer. Is this expected? I've checked and I do have the trimmer inserted the right way round: it is aligned with the silk screened component overlay.

Before I go in gung-ho with a soldering iron and risk damaging the trimmer and/or PCB, is this expected behaviour or not?

73, Alan G3XAQ


QCX 20M serial 3647 is alive!

Alan G3XAQ
 

I just finished assembling my QCX. I've had it the best part of a week so I'll not be winning any prizes for speed of construction. I did replace the suspect 390pF capacitors in the LPF with Murata SMD types. Anyway, big sigh of relief, it worked on power up with no obvious faults. It hears down to about -125dBm and produces 3W output from a 13.8V DC supply. The second harmonic is -54dBc. I believe some builders see 3.5W and hear -130dBm but I am happy enough with my results.

Thanks for a great kit, Hans.

73, Alan G3XAQ


Re: Sudden failure in early life

Glen Leinweber
 

Steve,
Your I2C transaction looks to be corrupted.
I have transformed your 'scope image (below).
SDA should rise between transactions. It doesn't.
"ACK" looks to come in the middle of a transaction (should come at the end.

Am guessing a power-up problem. Perhaps a slow rise in the DC supply?
In any case, looks like SI5351A sees a I2C framing error.


Re: Sudden failure in early life

George Privett
 

My QCX-20 worked well when completed. However, when I took the LED off and put it back on several times when looking at options for a case, it started to display random characters.  Upon close examination, I found that one of the pins in the header had a cold solder connection. A bit of resin and solder fixed it quickly and I have not had a problem since. This is an amazing radio kit. Kudos to Hans. The instructions are some of the best and I felt like Hans was right there as an elmer looking over my shoulder, while I assembled the radio.

George VY1GP


Re: QCX CW Beaconing #qcx

John Kirby
 

p.s.
QRSS can be CW at various speed or other modes such as FSK
JOHN


Re: QCX CW Beaconing #qcx

John Kirby
 

AL,

The QCX 5 is a big time fun radio, lots of options (TNX G0UPL)

Definitely read regs with respect to 24/7  unattended operation

QRSS freqs, there is a qrss group here on 'groups.lo'
WSPR freqs, spots and chat group, ceck out wsprnet.org

wspr decode download (TNX K1JT)
 http://www.physics.princeton.edu/pulsar/k1jt/wsjtx.html

re wspr and the qcx, WWV and menu 8.6 must be within +/- three seconds or better

check out ARGO, down a copy free big time fun (TNX I2PHD)

re CW done be shy...why?
QCX will decode CW for QSO helper :>)

72 73
John
N3AAZ


QCX CW Beaconing #qcx

Al Holt
 

I'm interested in this mode of operation with my QCX. I like the idea on not having the 'key down' on the QCX for two solid minutes and I don't necessarily need/want to worry about attaching the GPS.

It's very easy to set up the beacon, but I have a couple of questions. What's a good message to transmit, callsign, maybe grid and 73?. How about frequency? My QCX is a 40m version and I haven't seen any band plan for it other than the usual grade-of-license CW portions.

My intended use wouldn't be any kind of unattended 24/7 operation, but just some periodic use. Since there's no organized tracking network other than maybe RBN (which I don't quite understand), I thought I'd just manually utilize the network of KiwiSDR's or other online receivers to gauge reception.

BTW, I'm still working on my code proficiency and too shy for a QSO. 

Tnx & 73,

Al
WD4AH


Re: Ultimate 3S and separete receiver #chat

Stuart Cameron Vk5ade
 

Good evening Ken, thank you for responding to my email i was under the impression that the U3S kit was tx only so i am pleased that it can be set up for rx as well i actually have only just ordered the kit yesterday so i can't wait to receive it and start construction.
I could not find any reference to this.
Kind regards.
Stuart  VK5ADE 




Sent from my Samsung Mobile on the Telstra Mobile Network


-------- Original message --------
From: "KEN G4APB via Groups.Io" <lfoofui.nbz42@...>
Date: 17/3/18 6:24 pm (GMT+09:30)
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Ultimate 3S and separete receiver #chat

Hi Stuart,
to switch the single antenna I use an external changeover relay driven from the Tx pin on the U3 Tx, via a driver transistor.
I then set the U3 Rx sequence to follow whatever WSPR Rx slots I want. Say for example 160m, then 80m, then 60m.
Then follows a CAL period. I set the length to suit what I am doing with the U3 TX. Explain later.

Now I set the U3 TX sequence to ‘RX’ mode slots to cover the time i am receiving above, slots 0,1,2. = RX mode any freq, does not matter.
Then for slots 3,4,5 etc, I set the U3 TX to my WSPR bands, say for example 160m, 80m, 60m, setting freq and LPF settings if multiband operation.
Then follows a CAL period for this Tx, set as long as the U3 Rx slots last. 

So for both Tx and Rx U3s, we have a total of 2+2+2+CAL for the FRAME time.
I set CAL on both for 10 240 (4 minutes) and FRAME to 2+2+2+4=10. (10 00).

To start both off, manually set the TIME on both and start them at the same time (right button press).

This works well for me in a Tx and Rx WSPR bandhopping sequence. If you are doing it on one band only just repeat put more ‘RX’ slots into your Tx to pad it out.

Hope this is what you want.

73 Ken G4APB


Re: Sudden failure in early life

Alan G4ZFQ
 

I am still puzzled by whether all the discrepancies in measured voltages at about half the test points listed in the Manual could be a result of a microprocessor failure - lack of signal or weak signal, etc.
Steve,

If the Si5351 has not been initialised then it will not be working.
If the mixer is not clocked then I'm not sure whether the voltages around it which are DC coupled to the audio ICs will be correct. It must depend on what state the switches in the mixer are in.
If IC4 pins 9, 11 are 2.5V, they should be, then the switches might all be open.

73 Alan G4ZFQ


Re: Sudden failure in early life

Hans Summers
 

Hi Alan

I will clarify that in the troubleshooting. 

If there is an Si5351A fault, on boot up no text is shown on the display. This is because in the initialization steps, talking to the Si5351A happens BEFORE talking to the LCD. 

The specific reason it was done this way, is to make sure the Si5351A Clk2 output is off... So that the BS170 PA gates will definitely be low, regardless of the lack of definitive Rx/Tx control signal state until the rest of the boot-up is completed.

Note that the specific Si5351A fault which causes this, is a failure to communicate with the processor via the I2C bus. Other Si5351A faults could occur (such as problems with the output signals) but NOT cause the boot-up sequence to halt... because as long as the Si5351A doesn't refuse to communicate, the processor is happy.

It would be nicer to initialize the LCD screen first and write "Si5351A comms error" for example, To help provide diagnostic information to the hapless constructor. 

Steve's problem could therefore logically be due to the Si5351A but I think it is a less likely cause. More likely, some short, or spike (on power supply or SWR perhaps), could have fatally annoyed the processor.

73 Hans G0UPL 


On Mar 17, 2018 11:29 AM, "Alan G4ZFQ" <alan4alan@...> wrote:

That paragraph In the troubleshooting is completely consistent and correct. It says firmware up to and including 1.00e. And 1.00e is the latest version. So everything is consistent and there is no ambiguity. And this behaviour is still present, yes...


OK Hans,

Sorry for using the B.. word.
Of course am I missing something? If the micro works there will be the initial boot-up then it goes blank if there is a Si5351 problem?

I do not think Steve has seen this.

73 Alan G4ZFQ


Neither is it a bug. It is just the order of how things work in the firmware currently. Architecturally this is the way the firmware is written. If everything is working properly, then there is never any issue. But if the Si5351A has a fault, then the screen stays blank, whereas it would really be more helpful if it wrote something about the problem on the screen. It would be a useful improvement to the firmware.

I did take a look at it last week and I will figure it out. If it was trivial I would have done it already. It isn't just a matter of swapping the ordering of two initialization function calls. There are detailed reasons why the initialization at power-up has to do things in a specific order. Changing that is possible but it's a little complex.

73 Hans G0UPL
http://qrp-labs.com


On Mar 17, 2018 11:06 AM, "Alan G4ZFQ" <alan4alan@... <mailto:alan4alan@...>> wrote:

        I read the while thread again, I don't think I missed anything.
        What bug?
        The troubleshooting was written after 1.00e, and after PCB Rev 3
        and the lateat manual. But the troubleshooting should apply to
        everything, all versions (PCB and firmware).

        So I'm confused about everything. What comment did I make about
        what? And what bug? Please enlighten me gents!


      Hans

    Troubleshooting, LCD blank

    "Check with a DVM that there are no short-circuits between adjacent
    LCD pins, or between any LCD pin and Gnd or Vcc. Check for
    continuity between each LCD pin and the corresponding pin on the
    processor. You can do this with the board upside down, and the LCD
    module plugged in.

    If ALL of that checks out fine, then there is one more possibility
    for a blank screen, in firmware versions up to and including 1.00e.
    In these versions the firmware carries out initialization steps
    which clear the screen. Then it tries to communicate a command to
    the Si5351A Synthesizer chip IC1. The commands to IC1 are sent over
    an I2C serial communication link. If for some reason, the Si5351A
    does not respond to the command to acknowledge it, then the I2C bus
    will hang up while infinitely waiting for the response of the
    Si5351A. The screen will remain blank indefinitely and.."

    So was this altered? can a bad Si5351 or connections to it still
    cause the blank display?

    73 Alan G4ZFQ





Re: Sudden failure in early life

Alan G4ZFQ
 

That paragraph In the troubleshooting is completely consistent and correct. It says firmware up to and including 1.00e. And 1.00e is the latest version. So everything is consistent and there is no ambiguity. And this behaviour is still present, yes...
OK Hans,

Sorry for using the B.. word.
Of course am I missing something? If the micro works there will be the initial boot-up then it goes blank if there is a Si5351 problem?

I do not think Steve has seen this.

73 Alan G4ZFQ


Neither is it a bug. It is just the order of how things work in the firmware currently. Architecturally this is the way the firmware is written. If everything is working properly, then there is never any issue. But if the Si5351A has a fault, then the screen stays blank, whereas it would really be more helpful if it wrote something about the problem on the screen. It would be a useful improvement to the firmware.
I did take a look at it last week and I will figure it out. If it was trivial I would have done it already. It isn't just a matter of swapping the ordering of two initialization function calls. There are detailed reasons why the initialization at power-up has to do things in a specific order. Changing that is possible but it's a little complex.
73 Hans G0UPL
http://qrp-labs.com
On Mar 17, 2018 11:06 AM, "Alan G4ZFQ" <alan4alan@gmail.com <mailto:alan4alan@gmail.com>> wrote:
I read the while thread again, I don't think I missed anything.
What bug?
The troubleshooting was written after 1.00e, and after PCB Rev 3
and the lateat manual. But the troubleshooting should apply to
everything, all versions (PCB and firmware).
So I'm confused about everything. What comment did I make about
what? And what bug? Please enlighten me gents!
 Hans
Troubleshooting, LCD blank
"Check with a DVM that there are no short-circuits between adjacent
LCD pins, or between any LCD pin and Gnd or Vcc. Check for
continuity between each LCD pin and the corresponding pin on the
processor. You can do this with the board upside down, and the LCD
module plugged in.
If ALL of that checks out fine, then there is one more possibility
for a blank screen, in firmware versions up to and including 1.00e.
In these versions the firmware carries out initialization steps
which clear the screen. Then it tries to communicate a command to
the Si5351A Synthesizer chip IC1. The commands to IC1 are sent over
an I2C serial communication link. If for some reason, the Si5351A
does not respond to the command to acknowledge it, then the I2C bus
will hang up while infinitely waiting for the response of the
Si5351A. The screen will remain blank indefinitely and.."
So was this altered? can a bad Si5351 or connections to it still
cause the blank display?
73 Alan G4ZFQ


Re: Sudden failure in early life

Hans Summers
 

Hi Alan

That paragraph In the troubleshooting is completely consistent and correct. It says firmware up to and including 1.00e. And 1.00e is the latest version. So everything is consistent and there is no ambiguity. And this behaviour is still present, yes... 

Neither is it a bug. It is just the order of how things work in the firmware currently. Architecturally this is the way the firmware is written. If everything is working properly, then there is never any issue. But if the Si5351A has a fault, then the screen stays blank, whereas it would really be more helpful if it wrote something about the problem on the screen. It would be a useful improvement to the firmware.

I did take a look at it last week and I will figure it out. If it was trivial I would have done it already. It isn't just a matter of swapping the ordering of two initialization function calls. There are detailed reasons why the initialization at power-up has to do things in a specific order. Changing that is possible but it's a little complex.

73 Hans G0UPL 


On Mar 17, 2018 11:06 AM, "Alan G4ZFQ" <alan4alan@...> wrote:
I read the while thread again, I don't think I missed anything. What bug?
The troubleshooting was written after 1.00e, and after PCB Rev 3 and the lateat manual. But the troubleshooting should apply to everything, all versions (PCB and firmware).

So I'm confused about everything. What comment did I make about what? And what bug? Please enlighten me gents!


 Hans

Troubleshooting, LCD blank

"Check with a DVM that there are no short-circuits between adjacent LCD pins, or between any LCD pin and Gnd or Vcc. Check for continuity between each LCD pin and the corresponding pin on the processor. You can do this with the board upside down, and the LCD module plugged in.

If ALL of that checks out fine, then there is one more possibility for a blank screen, in firmware versions up to and including 1.00e. In these versions the firmware carries out initialization steps which clear the screen. Then it tries to communicate a command to the Si5351A Synthesizer chip IC1. The commands to IC1 are sent over an I2C serial communication link. If for some reason, the Si5351A does not respond to the command to acknowledge it, then the I2C bus will hang up while infinitely waiting for the response of the Si5351A. The screen will remain blank indefinitely and.."

So was this altered? can a bad Si5351 or connections to it still cause the blank display?

73 Alan G4ZFQ



On Mar 17, 2018 10:34 AM, "Alan G4ZFQ" <alan4alan@... <mailto:alan4alan@...>> wrote:


        Your remark raises the question of which is the most up-to-date,
        the Rev 1.10 assembly manual or the Troubleshooting Guide.


    Steve,

    Assembly 1
    .
    1
    0
    2
    6
    -
    J
    a
    n
    -
    2
    0
    1
    8

    Strange Copy/Paste:-)
    Troubleshooting, I think completed later but I see no date.
    But the firmware question remains.
    If the 5V and ground is on the micro, the 20MHz working and all
    connections to the Si5351 good then it points to the micro. BUT the
    question of the firmware bug is not answered.

    73 Alan G4ZFQ


      I understood

        from both that the processor startup or freezing bug was fixed
        either by
        firmware or some parts changes. My Atmega says 1.00 e, and,
        obviously I
        would not be asking all these dumb questions if my radio had
        kept working.






Re: Sudden failure in early life

Alan G4ZFQ
 

I read the while thread again, I don't think I missed anything. What bug?
The troubleshooting was written after 1.00e, and after PCB Rev 3 and the lateat manual. But the troubleshooting should apply to everything, all versions (PCB and firmware).
So I'm confused about everything. What comment did I make about what? And what bug? Please enlighten me gents!
Hans

Troubleshooting, LCD blank

"Check with a DVM that there are no short-circuits between adjacent LCD pins, or between any LCD pin and Gnd or Vcc. Check for continuity between each LCD pin and the corresponding pin on the processor. You can do this with the board upside down, and the LCD module plugged in.

If ALL of that checks out fine, then there is one more possibility for a blank screen, in firmware versions up to and including 1.00e. In these versions the firmware carries out initialization steps which clear the screen. Then it tries to communicate a command to the Si5351A Synthesizer chip IC1. The commands to IC1 are sent over an I2C serial communication link. If for some reason, the Si5351A does not respond to the command to acknowledge it, then the I2C bus will hang up while infinitely waiting for the response of the Si5351A. The screen will remain blank indefinitely and.."

So was this altered? can a bad Si5351 or connections to it still cause the blank display?

73 Alan G4ZFQ


On Mar 17, 2018 10:34 AM, "Alan G4ZFQ" <alan4alan@gmail.com <mailto:alan4alan@gmail.com>> wrote:
Your remark raises the question of which is the most up-to-date,
the Rev 1.10 assembly manual or the Troubleshooting Guide.
Steve,
Assembly 1
.
1
0
2
6
-
J
a
n
-
2
0
1
8
Strange Copy/Paste:-)
Troubleshooting, I think completed later but I see no date.
But the firmware question remains.
If the 5V and ground is on the micro, the 20MHz working and all
connections to the Si5351 good then it points to the micro. BUT the
question of the firmware bug is not answered.
73 Alan G4ZFQ
 I understood
from both that the processor startup or freezing bug was fixed
either by
firmware or some parts changes. My Atmega says 1.00 e, and,
obviously I
would not be asking all these dumb questions if my radio had
kept working.


Re: Sudden failure in early life

Hans Summers
 

I read the while thread again, I don't think I missed anything. What bug? 

The troubleshooting was written after 1.00e, and after PCB Rev 3 and the lateat manual. But the troubleshooting should apply to everything, all versions (PCB and firmware).

So I'm confused about everything. What comment did I make about what? And what bug? Please enlighten me gents!

73 Hans G0UPL 


On Mar 17, 2018 10:34 AM, "Alan G4ZFQ" <alan4alan@...> wrote:

Your remark raises the question of which is the most up-to-date,
the Rev 1.10 assembly manual or the Troubleshooting Guide.

Steve,

Assembly 1
.
1
0
2
6
-
J
a
n
-
2
0
1
8

Strange Copy/Paste:-)
Troubleshooting, I think completed later but I see no date.
But the firmware question remains.
If the 5V and ground is on the micro, the 20MHz working and all connections to the Si5351 good then it points to the micro. BUT the question of the firmware bug is not answered.

73 Alan G4ZFQ


 I understood
from both that the processor startup or freezing bug was fixed either by
firmware or some parts changes. My Atmega says 1.00 e, and, obviously I
would not be asking all these dumb questions if my radio had kept working.

Would I learn anything useful if I pulled the Atmega and checked all the
voltages I measured again? I also have a good 'scope and can check
waveforms, but I don't see anything about this in the manual or
troubleshooting guide that is relevant until the unit is somewhat
functional.

73,

Steve


On 3/17/2018 3:57 PM, Alan G4ZFQ wrote:
I am not (yet!) familiar enough with the QCX circuitry to know whether I
have a faulty Atmega or if all the discrepant voltages are due to
something else.  I have the latest board Rev 3, so I assume it has the
latest firmware as well.


Steve

I seem to be RTFM for you:-)

Hans' comment about the firmware is confusing.
The latest is said to be 1.00e (is it on a label on the micro?) which
is also said to have the bug.
You need Hans to confirm.

73 Alan G4ZFQ