Date   

Re: QCX not working

Ronald Taylor
 

Did you adjust the contrast potentiometer? 

On Tue, Dec 11, 2018 at 12:54 Norman Miller via Groups.Io <kn4gsl=yahoo.com@groups.io> wrote:
Ok I worked the LCD and now when I plug in the power it lights up and stays on. The only problem is I can't get any words to come up. Just a blank screen. I pushed the left button but nothing.


On Tue, Dec 11, 2018 at 12:55 PM, Ronald Taylor
<wa7gil@...> wrote:
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: QCX not working

Norman Miller
 

Ok I worked the LCD and now when I plug in the power it lights up and stays on. The only problem is I can't get any words to come up. Just a blank screen. I pushed the left button but nothing.


On Tue, Dec 11, 2018 at 12:55 PM, Ronald Taylor
<wa7gil@...> wrote:
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: #wspr U3S for 2m WSPR: How to remove the frequency-swing at start of transmission #wspr

mrdynalink <server@...>
 

Today the OCXO arrived. I hope I can assemble it next weekend :-)

73 to the 2m WSPR club !


Re: FOX TCXO

KEN G4APB
 

Hi Hans,
can you provide some actual real life examples of say Tx freq and recommended Park freq?
I have never found this very effective but maybe I just never found an "ideal" park frequency. What is the highest freq I can set Park to in the U3S?

73 ken G4APB


Re: Shack clock contrast adjustment

KI7MWA
 

Ken, thanks.  You answered your own question at the same time I was answering it.


Re: Shack clock contrast adjustment

KI7MWA
 

Hey, Ken!  In the file www.qrp-labs.com/images/clockkit/clock_assembly3.pdf , at the top of page 6, under the heading "LCD Contrast Adjustment" is the following text (along with an illustration of the position of R4 on the Clock circuit board): "Resistor R4 is an optional resistor, which is in series with the top of the contrast adjustment potentiometer R1 and +5V. Typically the contrast voltage required is less than 1V and the adjustment is rather sensitive. If you wish, you can fit a 220K resistor in this position, which will make the contrast potentiometer less sensitive to adjust. Install one of the two choices: a) A 220K resistor at R4 (this resistor is not supplied in the kit, OR b) A jumper wire in the position shown, and NO R4."


Re: FOX TCXO

HF
 

Hi all

To summarize: Since the Si5351a's load changes at TX startup, its own power dissipation changes substantially as others have noted.  In other words, it warms up.  So, when the internal oscillator's load capacitance changes in response to the increased temperature, it pulls the crystal's resonance frequency.  When using an external oscillator instead of the original crystal, that changing capacitance is isolated from the oscillating circuit, eliminating the effect. 

I would like to offer an alternative theory that I think also fits the data:  The changing temperature of the Si5351a at TX onset puts some heat into the copper PCB traces that go over to the crystal.  The crystal then warms up a little bit and generates the observed chirp.  The PCB itself also moves some of this heat to the crystal, causing it to drift frequency a little bit during the entire TX.  Additionally, heat from the PA transistor could find its way over to the crystal, also contributing to drift during the TX.

Regardless of whether the internal capacitances are changing in response to the temperature rise, or the heat actually reaches the crystal, the solution is to use Park Mode to reduce the Si5351a's temperature changes.  I added a capacitor load to Clk1 on my U3S to mimic the load of the PA in an attempt to make Park Mode's dissipation more closely mimic that of TX mode.

If the latter theory is contributing part of the drift or chirp, thermally isolating the crystal could reduce the effect.  Once can lift the crystal off the PCB adding very thin wires to connect it.  Those wires would reduce heat transmission from the Si5351a.  One could glue a chip of metal to the crystal to slow down the heat gain from the PA.  One could wrap the crystal with foam to reduce the heat it receives from the PA.

If the former theory is dominant, maybe the effect could be reduced by programmatically minimizing the Si5351a's internal load capacitance and adding external NP0 capacitors on the PCB to give the crystal the load it expects.

Any thoughts on this?

Halden NR7V


Re: Shack clock contrast adjustment

KEN G4APB
 

Answered my own question!! That comment was for display brightness. 

The contrast pot R1 is 100k so any value of R4 that reduces its effective travel is helpful in making the pot easier to adjust but the same policy can be applied, i.e starting at 100-Kohms. 180-Kohms should work well. 220-Kohms or 270-ohms may also suit your taste. 


Re: Shack clock contrast adjustment

KEN G4APB
 

Where oh where does it say 220K ????????

b) Reduced brightness: You may find the LED backlight of the LCD module too bright for your liking, or if you wish to operate from battery power, perhaps you consider that it consumes too much current. In that case, fit a wire jumper between A1 and A2, and use a suitable valued resistor at the R2 position: experiment, e.g. starting at 100-ohms. 180-ohms has been reported to work well. 220-ohms or 270-ohms may also suit your taste. 


Re: FOX TCXO

Hans Summers
 

Hi Graham

I believe it's as I've said a few times. The U3S load on the Si5351A in TX and non-TX is not the same. 

During TX the Si5351A must drive the PA. It must drive the BS170 gate impedance. Which itself is lower as the frequency gets higher. The Si5351A also needs more power as the frequency increases, as CMOS takes power when it switches. 

During non-TX the Si5351A does (by default) operate Clk1 at the operating frequency. But that doesn't drive anything. So the Si5351A is consuming less power. 

More power during TX than non-TX. Means the Si5351A, as it is dissipating more heat during TX, increases its temperature. That effects the parameters of the oscillator section of the Si5351A, which pulls the frequency.

Hence the "park mode" which operates the Si5351A Clk1 at your chosen "park frequency" during non-TX. That keeps the Si5351A working hard in non-TX; because you can set the park frequency much higher than the operating frequency. So the Si5351A consumes more power due to the CMOS parts switching more often (higher frequency). Though Clk1 isn't driving any load. 

So the trick is to find a frequency, higher than the operating frequency, at which the higher current due to the higher frequency, is EQUAL to the Clk0 current consumption when it is driving the BS170 PA gate impedance. Then being no change in current consumption between TX and non-TX, there is no temperature change of the Si5351A silicon. Therefore no change in oscillator component characteristics, and hence no drift of the reference crystal frequency.

This is my understanding of the situation after all my observations of the U3S and Si5351A.

73 Hans G0UPL 

On Tue, Dec 11, 2018, 20:44 Graham <planophore@... wrote:
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@...> 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
>
>
>
>
>
>
>




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