Date   

Re: QCX not working

Ronald Taylor
 

If the pins on the LCD are moving around inside the sockets on the main board then, no I’ve never heard that one before. BUT one very common issue is the solder joints themselves both on the LCD board and the main board. One of them could be a bit off and cause the same issue. Do a good re-heat job on all the pin contact spots on the LCD board and all the contacts for the corresponding socket on the main board. 

Sounds like you’re making progress. 

Ron

On Tue, Dec 11, 2018 at 07:06 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:
Good news Ron.
I discovered that the pins that go into the bottom of the LCD were not making contact. When I moved the LCD around a little then the display would come up as it should. I am trying to find the best way to keep the pins where they need to be. Have you heard of the problem before.


On Wed, Dec 5, 2018 at 12:12 PM, Ronald Taylor
<wa7gil@...> wrote:
 If the earlier voltage checks I mentioned are now good (5v out of the regulator, then you need to check voltage on pin 3 of the LCD. This is the third pin from the left. It will vary from 0-5 v as you adjust R47. 

If that’s good then there’s a different problem and (with power off) you will need to do continuity checks from each pinnof the LCD to the corresponding pin of the processor, looking for an open circuit. Also use the ohm meter to check for shorts between adjacent pins of the LCD. 

You are in to some basic troubleshooting here and I highly recommend you read Hans’ excellent troubleshooting guide at www.qrp-labs.com/QCX/qcxtrouble.html

Good luck

Ron



On Wed, Dec 5, 2018 at 09:48 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:
Ok I connected the power to the radio this morning. Nothing showed on the display. I adjusted R47 but nothing. Do you have any more ideas. Thanks


On Tue, Dec 4, 2018 at 4:32 PM, Ronald Taylor
<wa7gil@...> wrote:
Outstanding. Hope everything else works out ok on it. 

Ron

On Tue, Dec 4, 2018 at 14:31 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:
Ok got power now I had the power lines reversed. 


On Tue, Dec 4, 2018 at 2:44 PM, Ronald Taylor
<wa7gil@...> wrote:
If you’re seeing 12 volts on all three legs of the regulator it means the center lead (common) isn’t grounded to the rest of the circuit for some reason. Set your meter to ohms (with Radio power turned off) and check for continuity (zero ohms) from the center leg of IC11 to the negative power connector terminal. If this is a high resistance check closely to see why the center pin isn’t grounded. Could be solder joint or that pad isn’t grounded (very unlikely). 

Don’t power the radio back up till you get to the bottom of this. If you really have 12 volts on the output pin of IC11 then it’s possible other stuff got damaged. 

Ron

On Tue, Dec 4, 2018 at 12:34 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:

Thanks for the fast reply. I took the neg lead of my meter and put it on the neg terminal of the power connector. I took the pos lead of my meter and touched each leg of the IC11 I got 12. ? volts on each leg.
Not such if I an touching the wrong thing with the neg lead.
On Tuesday, December 4, 2018, 10:29:11 AM EST, Ronald Taylor <wa7gil@...> wrote:


Norman, the manual says to first check to make sure you installed R48 and then check to see if the connectors between the display and main board are correct. Next you should check for 5 volts from the voltage regulator. That’s the large three terminalndevice to the left of the display and the 5 volt output should be on the right hand leg as viewed from the direction of the display. If no 5 v then check the left hand leg of the regulator to look for your 12 v input. If that isn’t there make sure you oriented the polarity protection diode the right way. If it’s correct then check for 12 v on both sides of that diode. If it’s the right way and only see voltage on one end then it’s bad. If no voltage on either end then check your power connections. Also one thing to check is the polarity of the 12 v supply. If it’s backwards then the diode is doing it’s job protecting the circuits. The positive should be in the lower screw of the input terminal strip. 

Hope that helps. 

Ron 

On Tue, Dec 4, 2018 at 07:57 Alan G4ZFQ <alan4alan@...> wrote:
> I just completed my qcx kit it looks great. I connected the power to it
> but cannot get any light to come on the display. I have checked and I
> have power on the board but don't know what to check next. Need some advice.

The manual gives some voltage checks, where does it go wrong?

73 Alan G4ZFQ






Re: FOX TCXO

Graham, VE3GTC
 

Justin,

Sorry, I don't have an answer to that question.

I had found an online posting (something I think to do with the BITX 40
Raduino maybe) where someone had noted cross talk between the three
outputs and someone else did some measuring of the device with the
conclusion that proper termination made a difference. Unfortunately I
cannot find that posting at the moment.

cheers, Graham

On 12/11/2018, "freefuel@gmail.com" <freefuel@gmail.com> wrote:

Hi Graham, what does the termination do for crosstalk between the outputs? 

-Justin N2TOH





Re: FOX TCXO

Graham, VE3GTC
 

Alan,

I would think that load on the synthesizer in a U3S would or at least
should be constant.

When the U3S drifts under transmit we always jump to the conclusion that
it is heat related as the TX warms up a bit but at a stretch - is this
always so?

Does the U3S actually provide a constant load to the synthesizer during
periods of not in TX mode and when in TX mode?

I know that is a bit of stretch and I have nothing more than a few
qualitative observations but this behaviour seems to fit in with some of
the comments I had seen regarding cross talk between output channels and
the effect on termination on that cross talk.

I would think that the si5351a being a digital device that once
programmed to an output frequency then that should be the output. I
don't know enough about the internals of the si5351a but might there be
something inside (a VCO or similar perhaps) that is affected by changes
in load?

Just a WAG on my part of an observation that made me go "hmmmmm ?!?!"

cheers, Graham ve3gtc

On 12/11/2018, "Alan G4ZFQ" <alan4alan@gmail.com> wrote:

Graham,

However, one thing I did notice which seemed to make a big difference in
stability and this is termination of the synthesizer output.
Those shots were taken when the Synth module was installed in the U3S, I
guess unknown load value? But constant.

You may find this document of interest:
https://www.sitime.com/api/gated/AN10028-Probing-Oscillator-Output.pdf
My "probe" was a small length of wire coiled under my custom U3S box
which has the display at the top and back removed. So it was about 25mm
behind the synth module. No measurements apart from frequency.

73 Alan G4ZFQ







QCX a Phenomenal Transceiver

st3v3nd007@...
 

For the record, I am retired going on 75yrs old and not affiliated with any businesses and giving my two cents about the QCX transceiver.
I have built lots of kits but not one as nice as my 40M QCX. I bought this gem a year ago November and decided to build it a few weeks ago.
I took my time only soldering a few parts each day and one torroid a day taking care to ensure all solder connections are correct.  I
also used IC sockets on all the ICs to prevent any possible overheating of the ICs. Soldering iron temperature was set to 750 degrees. Did
the alignment carefully to specifications. Smoke test was good and power into my QRPoMETER dummy load was 4.3 watts at 13.6 volts.
I set the voltage down to put out about 4 watts for the SKCC weekend sprint and worked 61 stations from Maryland including California, Texas,
France, and many Midwest to East coast stations. Today I tested for maximum output. Here are the results:

Configuration: QCX, LDG Z100Plus tuner, OHR QRP wattmeter, and G5RV antenna at 28 Feet. Power from Alinco DM330 Power supply.
9 volts = 2 watts
12 volts = 3.8 watts
13.6 volts = 4.8 watts
14 volts = 5 watts
15.25 volts = 6 watts
The LDG tuner does a wonderful job tuning to a good match. Thinking about building a another one on a different band. Can't wait to
see what the multiband transceiver QRPLabs is working on.

Shortcomings: It would be sinful to complain about a $49 product that offers so much.

St3v3 in Maryland


Re: QSX tcvr built-in Spectrum Analyzer

Nigel Evans M0NDE
 

Hans built in see meter is great for portable working and added value!

Nigel M0NDE

On Tue, 11 Dec 2018, 1:27 pm Hans Summers <hans.summers@... wrote:
It IS a directional coupler. Power and SWR measurement built in.

73 Hans G0UPL

On Tue, Dec 11, 2018, 16:22 gerrykav via Groups.Io <gerrykav=yahoo.co.uk@groups.io wrote:
Yes, that's what it looks like alright. You can see pads for the primaries on each side.
/ Gerry


Re: FOX TCXO

HF
 

Hi Alan,
Yes, very similar to my observations.  Now that I have the Taitien TCXO installed, I get much more reliable decodes and almost always zero drift reports.  Another thing I observed is that the SNR reported in WSJT-X is now more stable.  I've also noticed that the Taitien's centre frequency drifts a little bit as the ambient temperature varies between 3 and 20 C.  I hope to have a chance to quantify that drift later this week.
Cheers
Halden NR7V


Shack clock contrast adjustment

KI7MWA
 

For overly sensitive contrast adjustment the assembly manual suggests either 220k ohms or a jumper at R4.  Strikes me as a pretty wide difference.  Happens I don't have any 220k resistors, are other values functional? What difference (or differences) will different values make?


Re: Error:Si535A - no clk

Mike
 

Duh, I thought I'd checked everything...

I blew an si5351 and fitted a new one, everything seemed to work, but looking
under my dissection microscope I see a solder bridge.. qrx..

Sorted. I looked and looked with a x10 loupe, and could'nt see any short, but
when you pointed me back to the clock I decided to get out the big bouy.

Nice russian dissection microscopes tend to assist sometimes <vbg>
many thanks Alan.
73, Mike

On 11 Dec 2018 at 14:30, Alan G4ZFQ wrote:

I can see no difference between the two when in the progrock, but unable
to
see whats happening in the VFO because it wont boot...
Mike,

I note the VFO uses Clock 2.
Is that the problem?

73 Alan G4ZFQ



Re: FOX TCXO

freefuel@...
 

Hi Graham, what does the termination do for crosstalk between the outputs? 

-Justin N2TOH


Re: FOX TCXO

Alan G4ZFQ
 

Graham,

However, one thing I did notice which seemed to make a big difference in
stability and this is termination of the synthesizer output.
Those shots were taken when the Synth module was installed in the U3S, I guess unknown load value? But constant.

You may find this document of interest:
https://www.sitime.com/api/gated/AN10028-Probing-Oscillator-Output.pdf
My "probe" was a small length of wire coiled under my custom U3S box which has the display at the top and back removed. So it was about 25mm behind the synth module. No measurements apart from frequency.

73 Alan G4ZFQ


Re: FOX TCXO

Alan G4ZFQ
 

I also use the Fox TCXO in all my QRP-Labs and own projects... > What equipment did you use> for this measurements ?
To monitor the 27MHz I used a FCDPro+ SDR and HDSDR. Any reasonably stable RX with Argo, SpecLab or even HDSDR set to mono input will do the same thing.
My GPS reference is simple, cheap, shown here https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7 a u-Blox GPS which has a configurable output up to about 15MHz. For 27MHz I use the 3rd harmonic of 9MHz, maybe +/- a few Hz.

73 Alan G4ZFQ


Re: Error:Si535A - no clk

Alan G4ZFQ
 

I can see no difference between the two when in the progrock, but unable to
see whats happening in the VFO because it wont boot...
Mike,

I note the VFO uses Clock 2.
Is that the problem?

73 Alan G4ZFQ


Re: FOX TCXO

Graham, VE3GTC
 

Yes, I have seen this behaviour too.

I have been messing about with the QRP-Labs si5351a synthesizer board to
see if I could get a precise (i.e. steady, unchanging) signal from it,
actual frequency (accuracy) was less important.

the design works quite well whether GPS disciplined or not. Using a
standard crystal or oscillator it is (of course) subject to
environmental variations.

I tried the FOXX924B-27.000 TCXO as noted by Hans in the documentation
and as tried by others. Works OK but I did notice the "discrete
dithering" as you have observed. Couple that with GPS disciplining and
the actual frequency output jumped around in response. It seemed as
though the occasional discrete jump in the TCXO and the GPS trying to
correct where "fighting" each other for a bit. I can see where at VHF
this would be an issue.

However, one thing I did notice which seemed to make a big difference in
stability and this is termination of the synthesizer output.

I was testing using a qrp-labs si5351a synthesizer and prog-rock
monitoring the desired frequency on a frequency locked Icom R75
receiver. My "antenna" was just a simple short piece of wire
conveniently soldered to the synthesizer board output. this was all set
up on the workbench at the far end of the basement. I noticed that the
frequency I was measuring on the receiver was varying every time I was
near the workbench. It would change quickly - up, down, whatever, and
return to near normal after I left it alone. It was a bit of a "light
bulb" moment when it occurred to me that there was enough stray
capacitance and inductance in my body that was being coupled into the
short piece of wire antenna and that was effecting the
synthesizer/progrock to the point that it was causing these changes.

A bit of research on the subject and I found some reference to others
experiencing cross talk between the outputs of the si5351a and within
the documentation there are comments regarding the configuration of the
output drive of the si5351a and output impedance.

I am uncertain at what level Hans' software sets the si5351a to but I
would guess likely at 8ma level which (I think) corresponds to an
impedance of about 85 ohms.

In any case, I found that if I terminated the output of the synthesizer
module ( I used 50 ohms as it was handy) then the output become much
more stable and of course current consumed by the modules also increased.

You may find this document of interest:

https://www.sitime.com/api/gated/AN10028-Probing-Oscillator-Output.pdf

A quick search for similar documents on the subject will find others.

Those are simple qualitative observations.

I found a couple of much higher spec'ed TCXO 0.5 PPM which I have yet
to try. I have put the progrock and si5351a's aside for the time being.

cheers, Graham ve3gtc

On 12/11/2018, "Alan G4ZFQ" <alan4alan@gmail.com> wrote:

A couple of shots showing the FOX TCXO looking at the 27MHz output.
One shows the first 2 minutes of warmup from initial switch-on.
The other shows it warm but dithering, up/down a Hz or so, seemingly
having no hysteresis. (This was part of my WSPR on 2m tests, made 2m
WSPR useless.)

Just the one sample, has anyone else seen this?

73 Alan G4ZFQ





Re: FOX TCXO

DC1MAK
 

Hi Alan,
I also use the Fox TCXO in all my QRP-Labs and own projects...
What equipment did you use 
for this measurements ?

This evening i will have a look on the output of my 
synths...

Several times i thought about a 27MHz source disciplined by 10 MHz ( GPS or Rubidium)

I'll post my experiences this evening

73 de micha DC1MAK


Re: QCX not working

Norman Miller
 

Good news Ron.
I discovered that the pins that go into the bottom of the LCD were not making contact. When I moved the LCD around a little then the display would come up as it should. I am trying to find the best way to keep the pins where they need to be. Have you heard of the problem before.


On Wed, Dec 5, 2018 at 12:12 PM, Ronald Taylor
<wa7gil@...> wrote:
 If the earlier voltage checks I mentioned are now good (5v out of the regulator, then you need to check voltage on pin 3 of the LCD. This is the third pin from the left. It will vary from 0-5 v as you adjust R47. 

If that’s good then there’s a different problem and (with power off) you will need to do continuity checks from each pinnof the LCD to the corresponding pin of the processor, looking for an open circuit. Also use the ohm meter to check for shorts between adjacent pins of the LCD. 

You are in to some basic troubleshooting here and I highly recommend you read Hans’ excellent troubleshooting guide at www.qrp-labs.com/QCX/qcxtrouble.html

Good luck

Ron



On Wed, Dec 5, 2018 at 09:48 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:
Ok I connected the power to the radio this morning. Nothing showed on the display. I adjusted R47 but nothing. Do you have any more ideas. Thanks


On Tue, Dec 4, 2018 at 4:32 PM, Ronald Taylor
<wa7gil@...> wrote:
Outstanding. Hope everything else works out ok on it. 

Ron

On Tue, Dec 4, 2018 at 14:31 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:
Ok got power now I had the power lines reversed. 


On Tue, Dec 4, 2018 at 2:44 PM, Ronald Taylor
<wa7gil@...> wrote:
If you’re seeing 12 volts on all three legs of the regulator it means the center lead (common) isn’t grounded to the rest of the circuit for some reason. Set your meter to ohms (with Radio power turned off) and check for continuity (zero ohms) from the center leg of IC11 to the negative power connector terminal. If this is a high resistance check closely to see why the center pin isn’t grounded. Could be solder joint or that pad isn’t grounded (very unlikely). 

Don’t power the radio back up till you get to the bottom of this. If you really have 12 volts on the output pin of IC11 then it’s possible other stuff got damaged. 

Ron

On Tue, Dec 4, 2018 at 12:34 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:

Thanks for the fast reply. I took the neg lead of my meter and put it on the neg terminal of the power connector. I took the pos lead of my meter and touched each leg of the IC11 I got 12. ? volts on each leg.
Not such if I an touching the wrong thing with the neg lead.
On Tuesday, December 4, 2018, 10:29:11 AM EST, Ronald Taylor <wa7gil@...> wrote:


Norman, the manual says to first check to make sure you installed R48 and then check to see if the connectors between the display and main board are correct. Next you should check for 5 volts from the voltage regulator. That’s the large three terminalndevice to the left of the display and the 5 volt output should be on the right hand leg as viewed from the direction of the display. If no 5 v then check the left hand leg of the regulator to look for your 12 v input. If that isn’t there make sure you oriented the polarity protection diode the right way. If it’s correct then check for 12 v on both sides of that diode. If it’s the right way and only see voltage on one end then it’s bad. If no voltage on either end then check your power connections. Also one thing to check is the polarity of the 12 v supply. If it’s backwards then the diode is doing it’s job protecting the circuits. The positive should be in the lower screw of the input terminal strip. 

Hope that helps. 

Ron 

On Tue, Dec 4, 2018 at 07:57 Alan G4ZFQ <alan4alan@...> wrote:
> I just completed my qcx kit it looks great. I connected the power to it
> but cannot get any light to come on the display. I have checked and I
> have power on the board but don't know what to check next. Need some advice.

The manual gives some voltage checks, where does it go wrong?

73 Alan G4ZFQ






Re: OCXO

freefuel@...
 

Hi Jer, will do the kit is still sitting on my bench untouched. however the plan is simple, I'm going to omit the original crystal and everything between it and the Si5351a. I will most likely stand the part up on it's side against the heater transistors. from that point on after I verify it works, I'll snap some photos and box it up. 

-Justin N2TOH


Re: QSX tcvr built-in Spectrum Analyzer

Hans Summers
 

It IS a directional coupler. Power and SWR measurement built in.

73 Hans G0UPL

On Tue, Dec 11, 2018, 16:22 gerrykav via Groups.Io <gerrykav=yahoo.co.uk@groups.io wrote:
Yes, that's what it looks like alright. You can see pads for the primaries on each side.
/ Gerry


Re: QSX tcvr built-in Spectrum Analyzer

gerrykav <gerrykav@...>
 

Yes, that's what it looks like alright. You can see pads for the primaries on each side.
/ Gerry


Re: QSX tcvr built-in Spectrum Analyzer

Ben Bangerter, K0IKR
 

I think I spot the makings of a directional coupler in one of the photos of the main QSX board that Hans has put out - the binocular core transformer highlighted here.  Perhaps it is part of a power-leveling circuit as well?  Fun to speculate!


Error:Si535A - no clk

Mike
 

Confused...
I'm getting Error:Si535A - no clk displayed on a QRPlabs VFO version s1.03

What is confusing me is this...

I have two Synth boards, both of them work correctly in a Progrock,
the I2C levels appear correct, clk0 and clk1 are outputting a signal at about
the right level and frequency.

When I swap each of the synth boards into the VFO board, one boots correctly
and functions, the other gives the Error:Si535A - no clk report.

I can see no difference between the two when in the progrock, but unable to
see whats happening in the VFO because it wont boot...

Any ideas appreciated...
73 Mike