Date   
Re: QCX no BPF signal

Arv Evans
 

Interesting

"One reason why the internal digital meter could be off is the there are
two pins on for RF and the other for DC voltages.  If you use the wrong
one there is a diode for RF and it will read low by .6-.7V (diode drop).
"

That would seem that some future version might have a code change
that adds 0.6 volts to the reading if using the RF testing input.

Using either of the ADC inputs for measuring voltage might be more
accurate if the input was first used to measure a regulated 3.3 or 5.0
signal and the offset percentage then manually applied to subsequent
measurements? 

While the ADC voltmeter capability was originally for just general
troubleshooting (is voltage there of not there) if we can make it 
more accurate that could be seen as an additional plus for the rigs.
AVR ADC inputs seem to vary a bit in sensitivity, with input impedance
running between 500K and 750K ohms (your mileage may vary).  If
the ADC reads too high it might be possible to add series resistance
to lower the reading.  If the ADC reads too low it might be possible to
add a programmable software offset for the readings. 

Arv
_._





On Tue, Jan 7, 2020 at 10:06 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
One reason whay the internal digital meter could be off is the there are
two pins on for RF and the other for DC voltages.  If you use the wrong
one there is a diode for RF and it will read low by .6-.7V (diode drop).

At this point measure carefully and use an external DMM.  The answers
should not differ more than 10%

Other things if D1 and D2 (or either) are inserted backward there will be no RX.

If C17 is shorted then remove it and see if you get audio.

Most likely is soldering.  though with leaded part when inserting them you
can get a sliver of tin off the leads and a topside of board short.  
AS Alan said a good lens is useful.

 Allison
-------------------------------
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Re: QCX no BPF signal

ajparent1/KB1GMX
 


That's the result of the voltage divider R56/57.  It would be 13.3K with the
tolerance of the resistors.  They could be 33k and 100K to lower loading.


Allison
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Re: LCD Bezels

Nik
 

Can I have 5 please.  PayPal to who.....

thanks,
Nik.

LCD Bezels

m0bmn
 

HI Guys
I hope this is ok to post to the group.
A few weeks back I said I was getting some simple bezels for the 1602 2 line 16 char LCD display modules used by many of use for different QRSS/OCX projects in our own cases.
Well I have now received my second batch of boards this afternoon. the second batch, as I made a error with the first batch of 100 and so they got scrapped, the second batch are ok and look fine.
I also had another problem with the mounting of these displays. The display is back lit and on one side the backlight led block sticks out from under the LCD part, if you just bolt the display to a front panel there is a problem with it standing off on the side with the LED block. I have now got some small spacers that are just the right Hight to level up the display when its mounted. I have bought a lot of them so I can supply them with the bezel. I was going to charge 50p per bezel but since I have had to order them (and pay) twice I hope people dont mind me putting the price up a little to cover my costs and I will also include 4 spacers per bezel too for this new price. how much I hear you cry.... I hope 75p is ok for people. I will be selling these elsewhere too but at a higher price so if you see them on ebay or the like dont buy them that way it will cost more. just drop me a email direct and you can have them at 75p each.
I have checked the postage and anything thicker than 5mm  is a large letter cost and thats a £1.06 stamp., so I will be using a small packing box or jiffy bag to send them out, so I will say postage of £1.50 for as many bezels as you like. I think PayPal is the best way to go for the payment (even if they do take 5% :-( )
I can order more if we need them but I have about 60 available now.
paypal to m0bmn@...
any questions drop me a email
73 Paul
PS expect a email later about sub £2 CW Keys!

Re: QCX no BPF signal

Alan G4ZFQ
 

One reason whay the internal digital meter could be off is
Allison,

The main reason is that the internal voltmeter is low impedance. Hans quoted the figure somewhere but must be around 13K so it will heavily load some of the test points.
I guess Hans was so proud of actually incorporating it within the QCX that he did not think of those who would use their DVM when he made his voltage table.

73 Alan G4ZFQ

Re: QCX no BPF signal

ajparent1/KB1GMX
 

It is a dense board and it doesn't take much to cause a short.

It is why most agree if it does not work soldering is a key issue
to inspect.  A whisker, spatter, odd solder ball, and even
shavings of the tin on wires can be a source of those problems
and why a mark 2 visualize (lens or even magnifying camera)
are a resource as well as using light to see reflections or other
oddities where they should not exist.

Allison
-------------------------------
No direct email, it goes to bit bucket account due address harvesting in groups.IO

Re: QCX no BPF signal

Alan G4ZFQ
 

Thank you so much! I found a tiny piece of solder causing a short. I'm now getting a strong 9 on the BPF reading.
Great! Hope all the rest goes OK!

73 Alan G4ZFQ

Re: QCX no BPF signal

Theo
 

Thank you so much! I found a tiny piece of solder causing a short. I'm now getting a strong 9 on the BPF reading. Again thank you so much for you patience I really appreciate it!

Re: QCX no BPF signal

ajparent1/KB1GMX
 

One reason whay the internal digital meter could be off is the there are
two pins on for RF and the other for DC voltages.  If you use the wrong
one there is a diode for RF and it will read low by .6-.7V (diode drop).

At this point measure carefully and use an external DMM.  The answers
should not differ more than 10%

Other things if D1 and D2 (or either) are inserted backward there will be no RX.

If C17 is shorted then remove it and see if you get audio.

Most likely is soldering.  though with leaded part when inserting them you
can get a sliver of tin off the leads and a topside of board short.  
AS Alan said a good lens is useful.

 Allison
-------------------------------
Please reply on list so we can share.
No direct email, it goes to bit bucket due address harvesting in groups.IO

Re: QCX no BPF signal

Alan G4ZFQ
 

I'm now checking what you said and the DVM reading of IC8 Pin 5 is about .72V.
All the soldering looks good on both R28 and R29.
The voltage on the end where the body of the resistor is close to the board is .37v and the other end I'm getting a reading of 0.00v
Without actually looking I'm guessing that the end of R29 that is 0V is the one that connects to R37 and C39 and R59?
IF I'm right look for a short circuit to ground at this point. A whisker of solder, even a badly etched board. This needs a good glass!

73 Alan G4ZFQ

Re: QCX no BPF signal

Theo
 

Okay, I think we need to go back to the beginning to make sure I'm measuring all of this correctly. 
When I measure IC4 pins 7 and 9 with the onboard voltmeter I get 1.7v but when measured with an external one I get 2.4v. Since IC4 isn't in the manual's voltage readings is the external voltmeter reading the correct one I should use?
IC5 Pins 3 and 5 both read 1.6v when using the onboard voltmeter but 2.4v when using the external one, and for all the other pins the onboard and external voltmeter give the same and correct reading. Since this IS in the manual and incorrect according to the onboard voltmeter, the problem then must be before IC5? 

Re: QCX no BPF signal

Theo
 

I'm now checking what you said and the DVM reading of IC8 Pin 5 is about .72V. 
All the soldering looks good on both R28 and R29.

The voltage on the end where the body of the resistor is close to the board is .37v and the other end I'm getting a reading of 0.00v

Re: Progrock and serial programming durability

cct.oei@...
 

I don't know how I missed this message, but yes, I would be interested in a .HEX file for testing the modified ProgRock formware - and yes, I do have means of programming.

Thanks!

Clint

KA7OEI

Re: MSF or DCF clock module instead of GPS

Alan Jones <oalanjones@...>
 

Steve,
I have the same issue here.
I have a GPS usb dongle connected to my Pi 4B.
I still don't understand what you did to get the GPS signal to the shack.
Can you paint a picture for this old Soldier? LOL

Thanks...

Al, N8WQ

On Mon, 06 Jan 2020 18:52:40 -0500, Steve MW0KST <stevedavies77@...> wrote:

To solve the indoors GPS signal problem I use an external active GPS antenna connected to a passive GPS antenna in the shack (5V supply up the GPS antenna coax)  

This gives a decent GPS signal for my U3S GPS and GPS dongle used on my Raspberry Pi.  

I like the idea of the radio clock though...

Steve


Re: 50W PA 0.1uF capacitor markings / manual error

Hans Summers
 

Hi Andrew

Manual writing is a lot of work and some copy and paste makes it easier, but sometimes results in errors where I forgot to change something or in my haste to write 10's or over 100 pages in a reasonable timescale, made a typo etc. Luckily, nothing too serious. 

Surely you mean 5 bands, not 6 bands? A lot of the QRP Labs kits use 5-banded resistors but not 6! I agree I have been able to read 4-band resistors intuitively and instantly at sight, since before my age got even into double digits. 5-bands, not so. But I am finding that with use, I get more used to 5-band and I can almost recognize them as fast as 4-band now. 

Like it or no, 5-band became the norm these days! 

73 Hans G0UPL

On Tue, Jan 7, 2020 at 12:03 PM Andrew Lenton <a@...> wrote:
On Tue, Jan 7, 2020 at 08:54 AM, Andrew Lenton wrote:

Hi easily done 1 x 10^6 1uF 1 X 10^5 1uF we have all made errors with powers of 10, the worse situation is the 6 banded resistors, as all the multipliers have changed due to the third black band being a zero, so 10K is now Brown Black Black Red which 10.0K (add the voltage band of red and the tolerance band of 1 % another black nearly all resistors now look black and red!)

using old colour scheme, I did not have to work out the value, I could just see the value  instantly, now I have to make sure  which  end to start, to even work out value. It would have been far better, if the third digit was a zero or black then keep the multiplier as is. 50% of construction faults I have repaired are due to the multiplier being a power of 10 out, or if the third band is not used then miss it out.

BR Andrew (spelling  corrected version)


 

Re: QCX no BPF signal

Alan G4ZFQ
 

Pins 1 and 7 are good on IC5, IC6, and IC7
IC8 is the first discrepancy. IC8 pin 1 and 7 both read about 1.3v
And what does IC8 pin 5 read ON YOUR DVM? It will not be the same as in the manual. It should read around 2.5 volts. Please give all voltages, the mixup between the two meters confuses things.
Again:- the on-board meter is used for the manual's figures. Some readings will not be the same if a DVM is used. IC8 pin 5 is one.
Assuming IC8 pin 5 is about 0.65 volts on your DVM check soldering on R28, 29 and their values.
What voltage at each end of R29?

73 Alan G4ZFQ

Re: 50W PA 0.1uF capacitor markings / manual error

Andrew Lenton
 

On Tue, Jan 7, 2020 at 08:54 AM, Andrew Lenton wrote:

Hi easily done 1 x 10^6 1uF 1 X 10^5 1uF we have all made errors with powers of 10, the worse situation is the 6 banded resistors, as all the multipliers have changed due to the third black band being a zero, so 10K is now Brown Black Black Red which 10.0K (add the voltage band of red and the tolerance band of 1 % another black nearly all resistors now look black and red!)

using old colour scheme, I did not have to work out the value, I could just see the value  instantly, now I have to make sure  which  end to start, to even work out value. It would have been far better, if the third digit was a zero or black then keep the multiplier as is. 50% of construction faults I have repaired are due to the multiplier being a power of 10 out, or if the third band is not used then miss it out.

BR Andrew (spelling  corrected version)


 

Re: 50W PA 0.1uF capacitor markings / manual error

Andrew Lenton
 

Hi easily done 1 x 10^6 1uF 1 X 10^5 1uF we have all made errors with powers of 10, the worse situation is the 6 banded resistors, as all the multipliers have changed due to the third black band being a zero, so 10K is now Brown Black Black Red which 10.0K (add the voltage band of red and the tolerance band of 1 % another black nearly all resistors now look black and red!)

using old colour scream, I did not have to work out the vale, I could just see the value  instantly, now I have to make sure  which  end to start, to even work out value. It would have been far better, if the third digit was a zero or black then keep the multiplier as is. 50% of construction faults I have repaired are due to the multiplier being a power of 10 out, or if the third band is not used then miss it out.

73 Andrew

Re: Backordered QCX #20m #qcx

@CurtisM
 

Dan

Enjoy the ride, don't build in haste. I did mine using a laptop next to my workbench area, to match part locations. No worries with when it comes, start reviewing assembly manual while you wait. Takes a little time through customs.

73 curt wb8yyy

Re: QCX no BPF signal

harleyleenuke
 

I had similar readings on one of my qcx.  Just tossing this info out,
built 5 of the qcx transceivers.  Two had low or no receive.
 I traced it down to C17  , 39nF capacitor.  
The capacitors were both bad.  I replaced them and got my receiver working awesome again.  I could hear down to -128 db.
 So maybe you have the same issue, if your lucky.