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Re: QCX+ and QLG1 GPS issue

Michael Greene
 

Mont,
I have several Arduinos available. I was reading the posts on the "Updating QCX+ firmware using Arduino Uno" topic over the weekend, as well as looking around online to see what others are doing. What would you recommend hardware and software wise as the best setup for onesy-twosies?
Thanks,
Michael



Re: QCX+ and QLG1 GPS issue

Mont Pierce KM6WT
 

On Mon, Nov 2, 2020 at 07:20 AM, Michael Greene wrote:
I am still on version 1.05, as I don't have a programmer.
Do you have an Arduino? 

I've been using my Arduino UNO as an ISP programmer lately.  Works great.


73
km6wt


Re: QCX TROUBLESHOOTING

Syd
 

The biases on C43 through C46 should all be very close to each other since that is where the I and Q pulses are integrated/filtered and all the filter circuits are identical.  So compare all 4 of the caps to resistor (R5, R6, R8 & R9) junctions with a DVM. If one these is off make sure there is a ground at the gnd end of the cap and then check the filter resistance value.  You could also ohm out each cap/res junction to ground just in case some is messing up the  paths from the Quad chip. Make sure the caps all have the same code.

Actually looking at the schematic you should be able to pretty accurately measure all the resistors in-circuit in all the OPAMPS! I have found out the hard way that the pots can give some strange problems if any one of them are at the shorted out end of range, so make sure to  measure them to make sure they are not at the end of range.
wt1v


Re: Clock kit firmware version 1.03d released - fixes day of week bug

nwpac6
 

Since the Local Sidereal Time works perfect from release c1.03b, anything new or changed on that front in the latest?


Re: #qcx Firmware 1.06 release #qcx

Hans Summers
 

Hi all

No significant issues were found with 1.06. Today we started programming and shipping 1.06 chips. 

The shortened splash screen message is just an oversight of mine. I uploaded a new 1.06 file where I corrected this:
I didn't even bother to call it 1.06a since it is such a trivial thing. 

I tested and adjusted three different assembled QCX+ kit orders today. Two had 1.05 chips which I upgraded. One had a fresh 1.06 chip. All three worked perfectly. I couldn't even see the long-standing minor issue of needing to rotate the rotary encoder one click if the calibration (menus 8.12 and 8.13) gets stuck, because none of mine got stuck. 

I have updated the website pages with the needed changes, including the firmware history page. 

73 Hans G0UPL 


Re: QCX+ and QLG1 GPS issue

Michael Greene
 

BTW, when I started having the issue and began reading the manual carefully, I noticed the 2 1K resistors in line with the 1PPS and Data signals in place when the GPS is directly connected to the JP1 interface to protect the GPS in case of a paddle press when the GPS is connected. I added 2 1K resistors to the 1PPS and Data lines inside the GPS to provide the same protection, in spite of the fact that when I connect via the 3.5mm cable that the paddle is not going to be connected. Un-necessary, I know, but it seemed harmless enough and does provide a bit of shorting-to-ground protection for the GPS, as intended in Hans' design.


Re: 50W amp and QCX - running "barefoot"?

Hans Summers
 

Hi Peter

Yes, Ron is correct, it doesn't work... the amp switching circuits just weren't designed to work this way to pass 5W power back through the receive bypass path. 

There are two reasons. 

Firstly, the "on" forward current (assuming 20V supply) is something under 10mA per diode in the receive path. In the transmit input switch it's 20mA and in the transmit output switch it's 42mA. Lower forward current means two things: 
a) higher attenuation (power loss).
b) large signals suffer even harmonic distortion.
These don't matter on receive but on transmit are more important. 

Secondly, though the receive path is on, the transmit switches are not properly off in the presence of large signals (5 watts). The rules for a PIN diode being off are that the reverse voltage must exceed the peak signal voltage. In the receive bypass switch there is a voltage doubler circuit that provides high voltage to the receive switch, keeping it OFF even in the presence of 50W. 

However if you are passing 5W through the ON receive switch, nothing is producing any large voltage to keep the transmit diodes switched properly OFF.  So a proportion of the 5W leaks through the transmit path. 

If you look at the situation on an oscilloscope it will convince you it doesn't work :-)

73 Hans G0UPL 



On Mon, Nov 2, 2020, 21:22 Ronald Taylor <wa7gil@...> wrote:
Hi Peter. That was asked some time ago and shown to NOT work. The best way to do it is to add a relay bypass circuit to take the amplifier out of the path and send the QCX directly to the antenna. You could design the relays to go into bypass mode when the 20 volts is removed from the amplifier so that turning on the amp puts it in the circuit and turning it off takes it back out. The PTT signal would not have to be removed in that case either. 

Good luck ... Ron

On Mon, Nov 2, 2020 at 9:49 AM <leepd60@...> wrote:
Can someone enlighten me please?  Can you leave the 50W amp connected to the QCX (and with its 20V supply connected) and use the QCX "barefoot" by pulling out the PTT plug?  That is, the QCX is running through the bypass diodes of the 50W amp on receive (as usual) and on transmit?
Looking at the circuit of the 50W amp, I see that the bypass diodes (1N4007 "PIN" diodes) are biased in the same way as the input switch diode, i.e. with 20mA DC or so when the amp is off.  I'm guessing that that is OK to carry the 5W output of the QCX to the antenna without problem.
I don't want to run 50W all the time, and also don't want to swap BNC connectors frequently to put the amp in and out of circuit.
Am I missing something?
--
Peter Lee
G3SPL


Re: QCX+ and QLG1 GPS issue

Michael Greene
 

Hans,
Very nice suggestion! That should also eliminate that issue.
Thank you,
Michael KN6IZE


Re: QCX+ and QLG1 GPS issue

Michael Greene
 

Al,
Thanks for all  the testing. The tip causing the short as it passes the ring contact makes sense. I like the idea of coating the tip, as this is the only purpose I plan for the cable. Of course, plugging in the GPS end last should be the way to operate, but I like bullet-proofing where feasible.
Here are the results of my testing. I have 2 issues : the shorting during live connection of the PTT/+5V pin to the radio and the radio not recognizing the 1PPS/Data/Gnd connection from the GPS.
I powered the GPS with 5V directly from power supply. Red light comes on. Yellow light pulses, a little later the Green light pulses in time with yellow light, so it appears that it's working properly.

Test 1 :
12V to radio, connected - paddle, dummy load, earphones.
Power on radio - audible click with splash screen, another audible click when screen switched to display frequency (are the clicks normal?) Also, audible click when power switched off (using radio pushbutton for on and off).
Put in practice mode, P displays.
Paddle presses give me dit and dah in Iambic A mode.
Remove 3.5mm plug from paddle - one key down tone heard upon removal
Plug the end of same cable in the 1PPS/Data/Gnd connection to GPS (no +5V to GPS). Radio starts outputting repeated dit-dah-dit-dah..... Still shows P (no G)
Turned it off.

Test 2 :
Plug in +5V cable to GPS, then to radio. Audible click, followed by radio reboot - probably the pin shorting as Al mentioned.
GPS does not power on (1PPS/Data/Gnd cable not connected)
Connect the 1PPS/Data/Gnd cable to GPS, then to radio. GPS seems to work (red light on, yellow pulsing, green pulsing), but radio starts making repeated dit-dah-dit-dah sequence with audible sound when data light comes on. Stays on P mode (no G), clock does not update - so I turned it off.

Test 3 :
With radio off, plug in GPS +5V to radio PTT/+5V, plug in 1PPS/Data/Gnd cable to GPS and radio
Turn radio on
Same result. GPS seems to work (lights as before), radio issuing repeated dit-dah-dit-dah sequence with audible sound when data light comes on, clock not updated, stays in P mode (no G) - turn off radio

Test 4 :
With radio off, plug in PPT/+5V connector to radio (to avoid shorting while live)
Turn on radio
Plug PPT/+5V cable to GPS end - no reboot, so the tip theory seems to verify

Test 5 :
with radio off, plug in PPT/+5V connector to radio (leave 1PPS/Data/Gnd cable unplugged)
Turn on radio - starts normally

Test 6  :
with radio off, plug in PTT/+5V to radio
Turn on radio
Plug +5V/PTT to GPS - no reboot, no lights on GPS (Gnd not connected)
Plug 1PPS/Data/Gnd cable to radio - no change
Plug 1PPS/Data/Gnd cable to GPS - GPS lights working normally, P stays on (no G), radio issues repeated dit-dah-dit-dah sequence, audible sound when data light on, no clock update.

So, that's what I see so far. Al, I think your recommendations on the PTT/+5V issue will address that problem nicely. Thoughts on the other problem where the radio doesn't seem to acknowledge the GPS connection and keeps it in paddle mode?

Thank you,
Michael KN6IZE


Re: QCX+ and QLG1 GPS issue

Hans Summers
 

Hi all

Ny suggestion: 

The QCX+ is made for experimenting with a lot of pads in pairs designed so you can cut tracks. Accordingly it is quite easy, and neat, to cut the tracks to the PTT ring and tip; then solder in two jumper wires into the provided pads. What you are aiming to do is swap the +5V and PTT signals, so that 5V is at the tip and PTT is on the ring. 

This would also have the benefit that you don't need a special cable... any cheap stereo cable with 3.5mm plugs at each end suits fine. No need for the tip/ring swap in the cable. 

I should have done it this way to start with, it was an error on my part. 

If +5V is at the tip there won't be any way 5V can short to ground during the plug insertion. 

I believe this is the correct optimal solution because it fixes my design error at source, rather than attempts to treat symptoms...

73 Hans G0UPL 

On Mon, Nov 2, 2020, 21:15 Al Holt <grovekid2@...> wrote:
One possible solution, which I haven't tried, would be to coat the tip of the connector with something like enamel nail polish. It should insulate the tip and keep it from shorting the ring of the connector to ground.

Other ideas, solutions?

--Al


Re: 50W amp and QCX - running "barefoot"?

Ronald Taylor
 

Hi Peter. That was asked some time ago and shown to NOT work. The best way to do it is to add a relay bypass circuit to take the amplifier out of the path and send the QCX directly to the antenna. You could design the relays to go into bypass mode when the 20 volts is removed from the amplifier so that turning on the amp puts it in the circuit and turning it off takes it back out. The PTT signal would not have to be removed in that case either. 

Good luck ... Ron

On Mon, Nov 2, 2020 at 9:49 AM <leepd60@...> wrote:
Can someone enlighten me please?  Can you leave the 50W amp connected to the QCX (and with its 20V supply connected) and use the QCX "barefoot" by pulling out the PTT plug?  That is, the QCX is running through the bypass diodes of the 50W amp on receive (as usual) and on transmit?
Looking at the circuit of the 50W amp, I see that the bypass diodes (1N4007 "PIN" diodes) are biased in the same way as the input switch diode, i.e. with 20mA DC or so when the amp is off.  I'm guessing that that is OK to carry the 5W output of the QCX to the antenna without problem.
I don't want to run 50W all the time, and also don't want to swap BNC connectors frequently to put the amp in and out of circuit.
Am I missing something?
--
Peter Lee
G3SPL


Re: QCX+ and QLG1 GPS issue

Al Holt
 

One possible solution, which I haven't tried, would be to coat the tip of the connector with something like enamel nail polish. It should insulate the tip and keep it from shorting the ring of the connector to ground.

Other ideas, solutions?

--Al


Re: QCX+ and QLG1 GPS issue

Al Holt
 

I opened the case to do more measurements. It's nice the jacks have the see-thru windows.

What I think is happening is as the plug is inserted, the tip of the plug is touching the sleeve of the jack AND touching the ring of the connector. That shorts the ring of the jack and +5V to ground.

 --Al


Re: Nixie Tube Display for Frequency !!!

Per - LA9XKA
 

Please note that these IV-6 tubes are VFD tubes and not real Nixie tubes.

73 de LA9XKA - Per


Re: QCX+ and QLG1 GPS issue

Al Holt
 

If you measure continuity between the ring connection and chassis ground (common), as the plug is slowly inserted into the jack there's a moment where the two short, connect together. When the plug is fully seated, the short is gone and the ohmmeter shows a higher resistance. 

It might be helpful testing this with a insulated rod, like a wooden dowel to see if the short is coming from mechanical action of the jack. I'll try that later.

--Al


50W amp and QCX - running "barefoot"?

G3SPL
 

Can someone enlighten me please?  Can you leave the 50W amp connected to the QCX (and with its 20V supply connected) and use the QCX "barefoot" by pulling out the PTT plug?  That is, the QCX is running through the bypass diodes of the 50W amp on receive (as usual) and on transmit?
Looking at the circuit of the 50W amp, I see that the bypass diodes (1N4007 "PIN" diodes) are biased in the same way as the input switch diode, i.e. with 20mA DC or so when the amp is off.  I'm guessing that that is OK to carry the 5W output of the QCX to the antenna without problem.
I don't want to run 50W all the time, and also don't want to swap BNC connectors frequently to put the amp in and out of circuit.
Am I missing something?
--
Peter Lee
G3SPL


Re: QCX+ and QLG1 GPS issue

Michael Greene
 

Al,
Interesting! I've done some further testing. I will post it here as soon as I get a ew minutes. I took notes, so my memory shouldn't cause issues.
Michael


Re: No wspr spots with QCX

Arthur Paton <artpaton@...>
 

Hi Curt
My 20M QCX+ has a TXCO and a GPS wired to it.  It is updated immediately, and continuously.  Still no WSPR spots.  My WSJT-X is also linked to an application that updates my computer clock from a national standard and is good to 1uSec.  Don't think its the timing on either device.  Also did WDPR a few weeks ago and all was fine.  Lots of spots.
73
Art N9AEP

On Thu, Oct 29, 2020 at 5:11 PM wb8yyy via groups.io <wb8yyy=yahoo.com@groups.io> wrote:
Indeed get time straight, and within about 1 second of utc on atomic clocks. Two many seconds off, nothing will decode.

The wspr passband is only 200 Hz wide. With U3S it takes several calibration cycles to get there, I am not sure about qcx. Set for middle of band initially to see if you land some spots and what freq is reported. If you have a modern commercial rig with tcxo etc, transmit your qcx into dummy load and see what freq you measure

Curt


Re: QCX+ and QLG1 GPS issue

Al Holt
 

ALERT, Will Robison (as opposed to DANGER) :-)

I made up a PTT-GPS cable, by cutting a spare 3.5mm TRS moulded M to M patch cable in half and Ohm-ing out the wires to get the right color code used.

I tried it in both of my QCX+ units and plugging in and unplugging it caused the QCX+ to reset. And this is both with and without the QLG1 connected. The tip wire of my cable is totally disconnected.

Just inserting the plug gently into the PTT jack blanks the display indicating loss of +5V to processor.

Further investigation is needed!!

--Al


10W linear build video #building #linear

Kevin Polston
 

There is an informative build/test video for the 10W linear at https://www.youtube.com/watch?v=wBiz594O5LA by NA5Y.
He also has a series on the 50W amp too.

Kevin M0XYM