Hi everyone, new member here. ?I have a 6 band WSPR kit on the way and I may be interested in buying a clock kit or two. ?I'd like to have the WSPR kit in the metal box that I ordered with it but I also realize tat the GPS signal isn't going to work well or at all with the patch antenna inside of the box. ?What are my other options for an external antenna? ?Is there a small whip that can be attached to a bulkhead connection? ?I see lots of antenna talk on here but I must be missing any threads that talk about actual antenna part numbers.
Thanks,
Curt
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Hi Andy,
I see your point, but I assume you have a single band operation. I have switched LPF/BPF boards in all my kits and you can't set the LPF/BPF position in Park mode. But thinking about it I wonder if it just stays in the last selected position. I have been using repeated two minute RX mode cycles for long receive sessions and only Park mode for during CAL. I'll have to give it a try your way.
73 Ken G4APB
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Re: QCX no transmit after assembly
I have a working TX. Great! That's a good start. Now C1 maximises in a reasonable position. But I have a lot of noise and next to no signal. The noise reacts strongly to tapping on the board. Andre, The calibration signal is applied to the antenna input from IC3 by way of R43. If it calibrates you should receive something. Maybe a bad joint on T1? when I tune to a frequency (RX only!), then my nearby other receiver responds with a strong continous tone (around 650 Hz) on that very frequency. This is to be expected, it is a direct conversion receiver, the local oscillator will appear to be strong on a local receiver. 73 Alan G4ZFQ
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Re: QCX no transmit after assembly
Hi Alan and Jim,
SUCCESS (well, more or less, see below). I have replaced Q1-3, Q4-5, Q6, and IC3. Now RX draws 125 mA (display installed) and shows a whopping 3,4 W TX-output with 12V input. The drains of Q1-3 show on TX the desired big signal on the scope. So many thanks, once again, for your super help. I have a working TX.
Sadly, however, now the RX side is fouling up. During calibration maximum I-Q balance was only obtained with C1 completely open. So I took off 4 windings from the third secondary of T1. Now C1 maximises in a reasonable position. But I have a lot of noise and next to no signal. The noise reacts strongly to tapping on the board. Moreover, when I tune to a frequency (RX only!), then my nearby other receiver responds with a strong continous tone (around 650 Hz) on that very frequency. This is only a preliminary report. I'll have to look at this more closely and will start by measuring the IC3 pins again.
73 de andre
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Re: Ultimate 3S SI5351error
Then this explains the problem.
You have a signal at Clk2. Clk2 is supposed to be connected to pin 11. But you see no signal at pin 11. So for whatever reason, there must be a break in the connection somewhere. Switch off the power and follow the track between Si5351A Clk2 output, and processor Pin 11. Somewhere there must be a break!
The firmware is just correctly reporting this issue.?
73 Hans G0UPL? ?
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Re: Ultimate 3S SI5351error
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Re: Ultimate 3S SI5351error
What is the signal on the 'scope at pin 11 of the AVR chip??
73 Hans G0UPL
On Fri, Sep 28, 2018 at 11:02 AM Chris Smith < me@...> wrote:
That's certainly mysterious. Vdd is in spec. I'd probe the Vdd supply line with a scope now and look for transients. Failing that it's replace the Si5351A and/or a software problem.
Chris M0XTE
On Thu, 27 Sep 2018, at 21:44, tl10200 via Groups.Io wrote:
Also, I have re-flowed every solder joint on both boards, with particular attention to pins 11 & 15 on the Atmega 328 socket and pins 13 & 14 on the Si5351A board. I have a good, clean, well-regulated bench power supply.
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Re: Ultimate 3S SI5351error
That's certainly mysterious. Vdd is in spec. I'd probe the Vdd supply line with a scope now and look for transients. Failing that it's replace the Si5351A and/or a software problem.
Chris M0XTE
On Thu, 27 Sep 2018, at 21:44, tl10200 via Groups.Io wrote:
Also, I have re-flowed every solder joint on both boards, with particular attention to pins 11 & 15 on the Atmega 328 socket and pins 13 & 14 on the Si5351A board. I have a good, clean, well-regulated bench power supply.
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Re: Ultimate 3S SI5351error
Also, I have re-flowed every solder joint on both boards, with particular attention to pins 11 & 15 on the Atmega 328 socket and pins 13 & 14 on the Si5351A board. I have a good, clean, well-regulated bench power supply.
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Re: QCX no transmit after assembly
Hi Jim,
those 140 ohms at Q5 looked fishy to me too. Now I know why -- thank you. The present state of the board is this:
a. Q4 has been replaced.
b. Q1-3 have been taken out.
c. IC3 has been taken out (was a surprisingly easy job with a sidecutters and a combination of desoldering wick and pump).
To do:
- Replace Q5.
B. Put in new Q1-3.
C. Put in new IC3 (this time on a socket).
I? should get the new NAND-gate by the end of the week. With it installed I'll test again.
73 de andre
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Re: Ultimate 3S SI5351error
The voltage on pin 2 of the LM317Z measures 3.43 V.
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Re: Ultimate 3S SI5351error
Yes, I was using poor RF probe technique. Here's with the probe tip ground spring thingy...
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Re: Ultimate 3S SI5351error
Just for you, DC coupled.
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Re: Ultimate 3S SI5351error
The ringing there is likely the inductance of your probe ground strap. See LT AN47-8: High Speed Amplifier Techniques:
Worth checking the voltage on pin 2 of the LM317Z to make sure it's actually reasonably close to 3.3V. As I've mentioned before, the regulator implementation on the Si5351A boards is suspect if powered from a 5V source (like piggy-backing the U3S 5V line) as the drop-out voltage range of the LM317Z is exceeded and the resistor ratio is slightly off. This can lead to regulation failing and random problems including crashes because the regulator can't catch up with a power demand from the Si5351A. If you power it from some power supplies, like USB charger type things they aren't even guaranteed to deliver 5V which makes this even worse.
I had to replace the regulator with an MCP1700 on mine before it was stable. Made a world of difference.? Holtek HT75XX if you want something cheaper.
Chris M0XTE
On Thu, 27 Sep 2018, at 19:13, tl10200 via Groups.Io wrote:
Ok Hans, here's a screenshot of clock 2 on the synth module. I guess I should have said 'ringy' rather than 'lumpy' :). At first I could not get it to repeat the problem. The U3S and the SI5351 synth module sat overnight, connected to each other. When first I energized the U3S I got just the "Error: SI5351" without the "No Clk", just like it comes up without the SI5351 synth module attached. There was no output from any of the three clocks. I removed the SI5351 synth module from it's socket, waited a half hour, plugged it back in, turned it on, and this time I got "Error: SI5351a No Clk". This time the 9 MHz signal was present on clock 2 (nothing on the other two). This is the condition where I took the screenshot.
Of course, the U3S module is still non-functional, with or without the synth module connected. Just stops at the error message and doesn't respond to buttons.
Hope this helps,
Tom N7JX
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Re: QCX no transmit after assembly
Hi, Andre
I would expect Q5 source to be just about 0 (zero) ohms to
ground, and the drain should be just about infinite. 140 ohms
would send whatever is coming out of the transmitter into the
receiver. Not a good thing. So Q5 appears to be bad. The purpose
of Q5 is? to connect the receiver to the antenna when receiving,
and to disconnect the receiver front end on transmit.
Install the transistors, leave R42 dangling, connect a voltmeter
to one of the output transistor drains, connect a dummy load, and
apply power. If the drain voltage remains at 0, reconnect R42 and
try again. Still no volts? You've got a radio. 12 volts? You're
still transmitting and receiving at the same time. The dummy load
is to keep the voltage on the drains from spiking and blowing the
new transistors.
73
Jim
On 09/26/2018 03:50 PM, atfu wrote:
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Hi Jim,
tnx, once again. I removed Q6, and also Q1-3. Voltage at Q4 gate
is 0, as it should.
Next I checked resistance from G4 drain to GND (R42 disconnected):
140 ohms. So I replaced Q4.
(I also checked Q5 to GND: 140 ohms. Is that OK?)
So the microcontroller looks ok. Can I now put back Q6, Q1-3, and
R42 without first calling the fire brigade?
As Alan said, pity that we don't sleep at the same time.
73 de andre
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Re: Ultimate 3S SI5351error
I had the same problem on my first u3s, I resoldered a pin on the main chip socket, IIRC, pin 11. This solved mine, check the joints it may help.?
?Andy
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True, but only for 2 minutes. By setting to park it means that the receiver can be on for a long time, until the next tx frame which may enable more spots to be heard, I tx 3 times an hour and receive for the rest bar calibration.?
More than one way to skin a cat depending on which operating instructions are read.
Andy
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Re: Ultimate 3S SI5351error
AC Coupling
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Show quoted text
On 27/09/2018 19:13, tl10200 via Groups.Io wrote: Ok Hans, here's a screenshot of clock 2 on the synth module. I guess I should have said 'ringy' rather than 'lumpy' :). At first I could not get it to repeat the problem. The U3S and the SI5351 synth module sat overnight, connected to each other. When first I energized the U3S I got just the "Error: SI5351" without the "No Clk", just like it comes up without the SI5351 synth module attached. There was no output from any of the three clocks. I removed the SI5351 synth module from it's socket, waited a half hour, plugged it back in, turned it on, and this time I got "Error: SI5351a No Clk". This time the 9 MHz signal was present on clock 2 (nothing on the other two). This is the condition where I took the screenshot.
Of course, the U3S module is still non-functional, with or without the synth module connected. Just stops at the error message and doesn't respond to buttons.
Hope this helps,
Tom N7JX
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But there is a specific RX mode, you don¡¯t have to use PARK mode to receive, i.e;
This mode is new in firmware version v3.11. It is specifically designed for when you wish to use the Ultimate 3S kit with the QRP Labs Receiver kit. It is a mode configuration like all the others in the kit. This mode is designed with standard WSPR reception in mind. Accordingly the ¡°RX¡± mode starts on an even minute, and is active for 2 minutes. The mode sets the Ultimate 3S ¡°Clk1¡± output to 4x the displayed frequency, suitable for driving the quadrature Local Oscillator (LO) in the QRP Labs Receiver kit.
73 Ken G4apb?
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Re: Still digging... looking for a low audio issue
#problem
#qcx
Well thanks to the help form Ron Taylor - wa7gil who pointed out a possible issue that he encountered in diagnosing a similar issue with his QCX.? He had asked me to look at R21? 7.5k & R35 750k resistors.? Ron asked me to look to see if those 2 resistors were switched.? Well guess what?? Those are indeed are switched.? I was able to verify this however didn't have the time to switch them.? I do believe we have found the smoking gun.? Ron had the same issue and experienced the same problem as I.? I will report back after I've correct my assembly error with my final results.
73;
Kurt - W2MW
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James Daldry W4JED
M0RON
Kurt Zimmerman