Date   

Re: QCX #smoked ? #smoked

Shirley Dulcey KE1L
 

Most of the "12V" power supplies sold to hams are really 13.8V supplies out of the box. (Many of them can be adjusted with an internal trimmer.) A lot of ham gear is designed to operate best at that voltage, which is about what you get from a typical automobile while it is running. The power supply is probably working as designed.


On Tue, Sep 8, 2020 at 3:59 PM John Sharman via groups.io <jsharman6=sky.com@groups.io> wrote:
Finals are ok !


On 8 Sep 2020, at 20:45, ajparent1/KB1GMX <kb1gmx@...> wrote:

Define kaput,  and what item?

Likely fried the finals in the morning and during the day repeated tries finished the job.
THe PS I can only guess about.

Allison
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Re: QCX #smoked ? #smoked

John Sharman
 

Finals are ok !


On 8 Sep 2020, at 20:45, ajparent1/KB1GMX <kb1gmx@...> wrote:

Define kaput,  and what item?

Likely fried the finals in the morning and during the day repeated tries finished the job.
THe PS I can only guess about.

Allison
-------------------------------
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Re: Thoughts on Low Power and fewer turns on LP filter toroids

Hans Summers
 

Hi all

This problem has always come up at intervals on this group. 

It used to be that we could blame suspect capacitors for being lossy since several were found on occasion. 

Not any more! All capacitors are now NP0 ceramics manufactured by Vishay and procured from Digikey. All the toroids are from Diz @ kitsandparts.com. I don't think it at all likely that there are any quality issues with these US sourced parts. 

Which leads us just back to variations in component tolerances, winding styles, soldering (check grounded pins of capacitors which are harder to get soldered well to the groundplane!). And variations and errors in power measurement. All these variations are the most likely cause all along on most previous occasions too... but for sure the capacitors and toroids in the LPFs are really always good now. 

73 Hans G0UPL 

On Tue, Sep 8, 2020, 21:44 Michael.2E0IHW via groups.io <blumu=btinternet.com@groups.io> wrote:
Apart from soldering issues, this must be  the most confounding disincentive  for faint-hearted wonnabe QSX+ers ...

There must surely be a concise winding-checklist for genuine radio "amateurs" ?

Michael 2E0IHW
...........................................................

On 08/09/2020 17:57, Phil/K3UT (ex W3HZZ) wrote:
I've completed a 20M QCX+ and have just fixed a friend's 30M QCX+. Both are working nicely, but at 13.1 volts I get about 3watts output on both, using the onboard RF tool to measure (and less on my Elecraft wattmeter). 

To achieve that output, I had to take two turns off L1 and L3 and one turn off of L2 and fiddle around a little with the spacing of the windings. I did that with both radios.

Any thoughts why the number of turns differs so greatly from that specified in the build instructions? Both kits were shipped about the same time. Could it be a quality control issue of the toroids? I measured the toroids on the 20M version before I installed them, and they were spot on before I took the turns off. I didn't measure them after the turns had been removed.

I'm satisfied with the power output of the units.  Just curious why they aren't meeting the specs as stated in the manual?

Phil, K3UT


Re: QCX #smoked ? #smoked

ajparent1/kb1gmx
 

Define kaput,  and what item?

Likely fried the finals in the morning and during the day repeated tries finished the job.
THe PS I can only guess about.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: Thoughts on Low Power and fewer turns on LP filter toroids

Michael.2E0IHW
 

Apart from soldering issues, this must be  the most confounding disincentive  for faint-hearted wonnabe QSX+ers ...

There must surely be a concise winding-checklist for genuine radio "amateurs" ?

Michael 2E0IHW
...........................................................

On 08/09/2020 17:57, Phil/K3UT (ex W3HZZ) wrote:

I've completed a 20M QCX+ and have just fixed a friend's 30M QCX+. Both are working nicely, but at 13.1 volts I get about 3watts output on both, using the onboard RF tool to measure (and less on my Elecraft wattmeter). 

To achieve that output, I had to take two turns off L1 and L3 and one turn off of L2 and fiddle around a little with the spacing of the windings. I did that with both radios.

Any thoughts why the number of turns differs so greatly from that specified in the build instructions? Both kits were shipped about the same time. Could it be a quality control issue of the toroids? I measured the toroids on the 20M version before I installed them, and they were spot on before I took the turns off. I didn't measure them after the turns had been removed.

I'm satisfied with the power output of the units.  Just curious why they aren't meeting the specs as stated in the manual?

Phil, K3UT


Re: #u3s QCXPTXCO install #u3s

Dean Smith
 

just been playing with the 25mhz tcxo for q"C"x+ in a U3s.
QRSS is good to 2 meters! a little drift to start due to other components, BS170's ect, then it settles down nicely!
Much better than the fox type tcxo i tried in the past.
Something strange happens to the height of FSK at around 6M it seems to double in height?? maybe me...
Been playing WSPR on 30m with it, and all seems ok. No drift and consistant frequency reports.
i wonder if this TCXO will fit on the Pads on the later revision Si5351a board? would look a lot tidier.
Be nice if you could buy the TCXO on it's own and solder up, or ready tacked to the board?
Certainly a lot less scary than the OXCO option, for those with less experience.
impressed with the results.
Got 10m decoding with my own system on wspr. just wonder how far we can go :)
Dean (G7EOB)


Re: Thoughts on Low Power and fewer turns on LP filter toroids

Arv Evans <arvid.evans@...>
 

In addition to Allison's comments, the filters are designed 
to work with 50 ohms input impedance and 50 ohms output 
impedance.  If either of those impedances are not 50 ohms 
the filter cutoff frequency will be impacted.

Arv
_._


On Tue, Sep 8, 2020 at 11:29 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
Phil,

THe AL used for winding of toroids has a variation of 10-15% so depending on
how tightly wound  plus individual batches you get variation.

The Iron powder material is really like many high volume materials to get it
as close as they tend to be takes a significant bit of effort.  I strongly point
to the spec.


Add to that the caps used are 10% maybe 5% so when you plug in the variation 
it does get to be significant.  That said I'se used those very same table and
many over a 25 filters then tested them ( 5 bands * 5 per) and then tested
them and they were remarkably consistent.  Parts used were not the same
batches but were drawn from my own stocks some quite old.

Also did you adjust L4?

All 4 of those inductors interact and due to reflected impedances and determine
power and harmonic content.

Allison
------------------------------
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QCX #smoked ? #smoked

John Sharman
 

All working well on WSPR for weeks
This morning the display is acting weird and the buttons are sometimes not responsive
This afternoon the display stats flashing on and off with smell of burins from transceiver!!
Hope its just the 5Reg thats blown!
The power supply i'm using is 12v from RS Components ad is giving out 13.8v
Is the consensus that the item is Kaput!!!!
Regards
John


Re: QRP-LABS Low Pass Filter upgrade

ajparent1/kb1gmx
 

Also PCB conductor size and spacing are a factor as well.

For example 100W is 1.4A into 50 ohms so heavier and larger
relays become a factor.

20W is easy 50W takes care, more is significant revision.

Allison
-------------------------------
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Re: Thoughts on Low Power and fewer turns on LP filter toroids

ajparent1/kb1gmx
 

Phil,

THe AL used for winding of toroids has a variation of 10-15% so depending on
how tightly wound  plus individual batches you get variation.

The Iron powder material is really like many high volume materials to get it
as close as they tend to be takes a significant bit of effort.  I strongly point
to the spec.


Add to that the caps used are 10% maybe 5% so when you plug in the variation 
it does get to be significant.  That said I'se used those very same table and
many over a 25 filters then tested them ( 5 bands * 5 per) and then tested
them and they were remarkably consistent.  Parts used were not the same
batches but were drawn from my own stocks some quite old.

Also did you adjust L4?

All 4 of those inductors interact and due to reflected impedances and determine
power and harmonic content.

Allison
------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: QCX+ T1 Toroid Wire Length? #20m #qcx+ #20m #toroid

Bob Ballard
 

Len,

 

Attached above is my input regarding an “antenna tuner” question asked last week.

 

73,

Bob – KG5SQJ

 

From: QRPLabs@groups.io <QRPLabs@groups.io> On Behalf Of Len W1LEN
Sent: Tuesday, September 8, 2020 10:46 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QCX+ T1 Toroid Wire Length? #20m #qcx+ #toroid

 

Hi, what is the gauge of the magnet wire supplied with the QCX+ kit for the toroids and transformer?  Also, is there a particular antenna tuner or tuners that have been found to be most useful with the 50 watt linear amplifier?  
Thanks very much, 
Len W1LEN


Thoughts on Low Power and fewer turns on LP filter toroids

Phil/K3UT
 

I've completed a 20M QCX+ and have just fixed a friend's 30M QCX+. Both are working nicely, but at 13.1 volts I get about 3watts output on both, using the onboard RF tool to measure (and less on my Elecraft wattmeter). 

To achieve that output, I had to take two turns off L1 and L3 and one turn off of L2 and fiddle around a little with the spacing of the windings. I did that with both radios.

Any thoughts why the number of turns differs so greatly from that specified in the build instructions? Both kits were shipped about the same time. Could it be a quality control issue of the toroids? I measured the toroids on the 20M version before I installed them, and they were spot on before I took the turns off. I didn't measure them after the turns had been removed.

I'm satisfied with the power output of the units.  Just curious why they aren't meeting the specs as stated in the manual?

Phil, K3UT


Re: QCX+ T1 Toroid Wire Length? #20m #qcx+ #20m #toroid

Len W1LEN
 

Hi, what is the gauge of the magnet wire supplied with the QCX+ kit for the toroids and transformer?  Also, is there a particular antenna tuner or tuners that have been found to be most useful with the 50 watt linear amplifier?  
Thanks very much, 
Len W1LEN


Re: Select Button on Alignment QCX+ 20m

Arv Evans <arvid.evans@...>
 



The left button (S2) completes a series circuit between 
R44 (3.3K) and R46(10K), with R44 going to +5V and 
R46 going to ground.  If the right button (S3) works 
properly then R46 is probably not the problem.  This 
leaves the value of R44 (3.3K) not being proper...or 
something miss-wired, shorted, or open someplace.  
It is just 2 resistors and a switch, so not a lot of parts 
involved.  

Current through S2, R44,  and R46 (total resistance 
of 13300 ohms) should be 5V / 13300 = 0.376 ma.
Voltage across R46 should be 13300 * 0.000376 = 
3.759V

Arv  K7HKL
_._


Arv
_._



On Tue, Sep 8, 2020 at 4:07 AM Richard M0AUW <cotswoldgent@...> wrote:
Hi Alan,

With the front of the kit facing me, powered up if I press R44 I get 1.14v on the left side and 4.95v on the right.

Richard M0AUW


From: QRPLabs@groups.io <QRPLabs@groups.io> on behalf of Alan G4ZFQ <alan4alan@...>
Sent: 08 September 2020 10:48
To: QRPLabs@groups.io <QRPLabs@groups.io>
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m
 
> When pressing the left button I get 1.14v so I'm presuming I have a cold
> solder joint somewhere on that switch?

  Richard,

Did you measure R44?

73 Alan G4ZFQ




Re: QCX+ Display #20m

Michael N6MST
 

On Tue, Sep 8, 2020 at 07:32 AM, Dave wrote:
Give it a bit of a tap.  That might change things.
That fixed 90% of the problems I ever had with my original Nintendo!


Re: QCX+ Display #20m

Mike Besemer - WM4B <mwbesemer@...>
 

Just hit them all with a soldering iron. You'll know it when you find it.

Mike
WM4B

On Sep 8, 2020 10:53 AM, David Griffiths <davidmgriffiths42@...> wrote:
Thanks Dave, a few taps on the back of the display and all was bright again. Finding the dodgy joint may take longer!

David
G4DMG


Re: QCX+ Display #20m

Dave VE3GSO
 

Great.

Last week at our LARC Kit Building session I examined a members soldering, by looking closely at the component side of the board.

When a joint has had the right amount of heat, flux and solder there is a tiny ring of solder around the component lead, filling the gap between lead and top pad. His were uniform and perfect.

Dave


On Sep 8, 2020, at 10:53, David Griffiths <davidmgriffiths42@...> wrote:

Thanks Dave, a few taps on the back of the display and all was bright again.  Finding the dodgy joint may take longer!

David
G4DMG


Re: QCX+ Display #20m

David Griffiths <davidmgriffiths42@...>
 

Thanks Dave, a few taps on the back of the display and all was bright again.  Finding the dodgy joint may take longer!

David
G4DMG


Re: Help with strange audio fault #qcx

Ted 2E0THH
 

Blimey Justin!

Really pleased that it sorted your problem. My QCX has been powered up virtually every minute since and works like a charm.
I've gone up a license class since and just waiting to sit my advanced.
However I would never have solved the problem without all the help and guidance from the kind souls on this forum.

73s Ted
2E0THH  


Re: QCX+ Display #20m

Dave VE3GSO
 

Give it a bit of a tap.  That might change things.  Number one problem with kits is always poor soldering, cold joints, or even an overlooked joint with no solder at all.

Dave


On Sep 8, 2020, at 10:28, David Griffiths <davidmgriffiths42@...> wrote:

Finished my 20m QCX+.  Powered on and adjusted R47 to get a nice display, went through the alignment process, all OK, put top half of case on, all still OK
Powered off, went for lunch, came back, powered on and found a very dim display, barely readable, and adjusting R47 does not make it any better.
Any suggestions gratefully received.

David
G4DMG