QCX 80 Transceiver - Connection for a Straight Key
After 30 years of no activity, I am still learning CW with a straight key which I shall continue to use for the time being.
I recently completed the building of the 80m of the QCX and it is functioning reasonably well except for a few tweaks such as?possibly adding a few turns to T1 transformer.
?
After completing the assembly, I connected 50R dummy load, headphones, and straight key (Kent) with mono jack and was ready for alignment.
When I powered up with a LiFe battery (9.5V) I was rewarded with a loud tone in headphones and after some agonising?time I established that the transmitter was in fact being keyed (measured power at RF BNC output with DVM)?even though I was not keying.
Removal of key jack stopped the keying and I was able to proceed with the alignment.
I also have a Palm Radio PPK straight key which has a stereo jack but this also caused the transmitter to turn on without keying and I removed this.
The microswitch keyed the transmitter normally as did shorting the two offboard connections at the front of the PCB.
My first thought was that there was a fault with the key stereo socket but on closer inspection of this and the circuit diagram it seem that the transmitter is keyed when the
either a mono jack or a "standard stereo jack" is inserted in the socket causing a connecting between the ground and either (or both of the contacts in the socket).
In fact partially inserting either jack into the socket did not key the transmitter until I started using the key. This is obviously unsatisfactory and I wonder whether there is a "suitable" jack which should be used (unfortunately, and embarrassingly so, I am not yet?up to speed with Iambic keys etc).
In fact, I have a short?extension lead with tip, 2 intermediate sections plus the bore which did not set off the transmitter when inserted.Apart from using the microswitch, obviously a quick fix would be to connect a suitable mono (?)?socket to the front 2 key pins?on the PCB?but this is?also not an ideal as the wires could easily break.
Have I made a basic mistake or is this to be expected ?
If it is to be expected, then I believe a caution is required in the assembly manual stating that "..mono jacks (and simple stereo jacks??)?cannot be used in the key socket or should be of a specific length otherwise the transmitter will be keyed".
This would be extremely useful for the inexperienced operator to make it "idiot proof".
I have had a lot of pleasure building this kit so please allow this old man a little indulgence as I can't wait to order the 17m version (I have a MTR-3B for 20/30/40m).
Comments are invited.
Best 73s
Robin
G4DNP
|
Hi all
?
Finished the complete build of QCX 30. Hopefully a pic will accompany this
message.
?
The enclosure is an RS Pt No 411-6632 TS1 sloping front panel, 58 mm rear
height and 35 mm front height.
Have added facilities to select the test options from the front panel and
fitted a 3A variable voltage regulator to adjust the power output.
Also fitted the VU2ESE AGC design in series with C21. The AGC is a very
useful addition.
?
I have a small milling machine to machine the enclosure and the engraving
was carried out courtesey of my brother (cost me a few beers).
?
It’s working very well with best QRB VK3AXF @ 16897km.
?
Thanks Hans for your very generous help to get this one working!!
?
72/73
?
Ian G4GIR
?
?
|
No changes planned, Vernon
73 Hans G0UPL? ?
On Dec 6, 2017 20:52, "Vernon Matheson" < vmath@...> wrote: ?Hi Hans, ? Just wondering if there are any changes coming to the QCX assembly and operating manual version 1.08 in the next short while. My kit should be here in a day or two so will be printing it off soon. ? Thanks ? Vernon ?
|
Re: QCX 20m - Almost done... can't wait
Hi Kurt,
I built the mWattmeter II (kit) from MultusSDR :
I found it does all I need for QRP operation and was quite
accurate when compared to my other test kit .? Now recently
superceded by a new version,
73
Dave
G3WUN
On 06/12/2017 17:29, Kurt Zimmerman
wrote:
toggle quoted message
Show quoted text
Greetings all again;
? ? I would like to add the following on my build.? When it
comes to test equipment my resources are quite limited.? I
don't even have a QRP Watt/SWR meter.??
? Since I'm using an 80m doublet antenna what I'll do is
adjust my tuner with my primary radio (Yaesu FT 920) to set
the tuner correctly.? Then I'll take the antenna connection
and move it over to the QCX operating on or about the
frequency I tuned up for.??
? ? I do have a QRP antenna tuner but only plan on using it
in the field.
If anyone could suggest a good reliable Watt/SWR meter that
will not break the bank I'm all ears..
Other than that I wrapped my toroids I wound them in
accordance to Han's directions.??
I am now curious to see how well a stock built QCX-20 is
going to play.
72;
Kurt - W2MW
-------- Original Message --------
Subject: [QRPLabs] QCX 20m - Almost done... can't wait
From: "Kurt Zimmerman" < kurt@...>
Date: Wed, December 06, 2017 10:04 am
To: [email protected]
Greetings all;
? ? Well I completed my QCX 20m last evening.? I have
had my share of boneheaded mishaps which I take full
credit for.? Initially when I was installing the glass
diodes I broke one.? I manage to pillage one from a
failed QRP project.? Last night when I was installing
the volume pot I applied a bit too much pressure on it
and cracked the board in the pot.? Net result I have no
volume out.? I was able to jumper the leads on the pot
to discover I am getting plenty of audio.? I hope to
salvage the pot and to get the rig on-line this
evening.? I may have to wait until the weekend do get to
operate during the day when 20m will do better with
propagation.
Hopefully these pictures come through.??
Just want to thank Hans for the continue support as
well as providing just a great product.? Other than my
missteps it was a great build.? Can't wait to get on the
air.
72/73;
Kurt - W2MW
|
?Hi Hans, ? Just wondering if there are any changes coming to the QCX assembly and operating manual version 1.08 in the next short while. My kit should be here in a day or two so will be printing it off soon. ? Thanks ? Vernon ?
|
Re: Winding Tip for 80 Mtr QCX transformer (T1)
Good comment John. I'm suprised it has'nt been made before - or has it.
toggle quoted message
Show quoted text
On 6 Dec 2017 at 17:36, John Pagett wrote: Robin,
At this stage, rather than add turns, why not add some extra capacitance
across the trimmer? I would imagine the L/C ratio isn't critical in this
instance. As a start, I'd try something a little less than the range of the
trimmer itself. I don't have the information to hand but if the trimmer is
say 5 to 40pF then something around 30pF can't be too much.
Just tack the cappy on the back of the board at this stage.
Of course you might need more capacitance still, but it's an easy experiment
to make.?
Regards,?
John
G4YTJ
Sent from my mobile phone
-------- Original message --------
From: robin.travis@...
Date:
To: [email protected]
Subject: [QRPLabs] Winding Tip for 80 Mtr QCX transformer (T1)
Hi Des (again) and others
I just searched this topic and your name came up again.
I had to have 3 attempts to wind the T1 transformer.
On the first attempt, I ran out of 28swg wire to complete the winding having
obviously?used generous amounts for the other inductances.
(QRP Labs - please note that a little more wire would not go amiss).
I had some 27swg and 30swg wire and decided to try the 27swg?but trying to
wind 83 turns on a T50-2 toroid is no easy task and I abandoned this in
favour of the 30swg.
I managed to wind the transformer with quite a bit of overlap of 30swg wire
and I presume I have wired it up correctly as I am now hearing stations?
reasonably well from continental Europe. Obviously, 30swg wire?is quite
delicate but it?is certainly workable if one is careful.
The issue I have is with the alignment: it is starting to peak but I am only
achieving a scaling factor of 5 with the plates of C1 completely closed and I
now have to add some more turns.
For optimum performance,?is the target value around 9 as indicated in the
manual and I am wondering whether it is easier to remove turns rather than
add.
In other words, would it be better to add 10 turns rather than 5 turns as
suggested in the manual ?
Again input from you or any other would be most welcome.
73s
Robin
G4DNP
|
Re: Winding Tip for 80 Mtr QCX transformer (T1)
Robin, At this stage, rather than add turns, why not add some extra capacitance across the trimmer? I would imagine the L/C ratio isn't critical in this instance. As a start, I'd try something a little less than the range of the trimmer itself. I don't have the information to hand but if the trimmer is say 5 to 40pF then something around 30pF can't be too much. Just tack the cappy on the back of the board at this stage. Of course you might need more capacitance still, but it's an easy experiment to make.? Regards,? John G4YTJ
Sent from my mobile phone
toggle quoted message
Show quoted text
-------- Original message -------- From: robin.travis@... Date: To: [email protected] Subject: [QRPLabs] Winding Tip for 80 Mtr QCX transformer (T1) Hi Des (again) and others I just searched this topic and your name came up again. I had to have 3 attempts to wind the T1 transformer. On the first attempt, I ran out of 28swg wire to complete the winding having obviously?used generous amounts for the other inductances. (QRP Labs - please note that a little more wire would not go amiss). I had some 27swg and 30swg wire and decided to try the 27swg?but trying to wind 83 turns on a T50-2 toroid is no easy task and I abandoned this in favour of the 30swg. I managed to wind the transformer with quite a bit of overlap of 30swg wire and I presume I have wired it up correctly as I am now hearing stations? reasonably well from continental Europe. Obviously, 30swg wire?is quite delicate but it?is certainly workable if one is careful. The issue I have is with the alignment: it is starting to peak but I am only achieving a scaling factor of 5 with the plates of C1 completely closed and I now have to add some more turns. For optimum performance,?is the target value around 9 as indicated in the manual and I am wondering whether it is easier to remove turns rather than add. In other words, would it be better to add 10 turns rather than 5 turns as suggested in the manual ? Again input from you or any other would be most welcome. 73s Robin G4DNP
|
Re: QCX 20m - Almost done... can't wait
Greetings all again; ? ? I would like to add the following on my build.? When it comes to test equipment my resources are quite limited.? I don't even have a QRP Watt/SWR meter.??
? Since I'm using an 80m doublet antenna what I'll do is adjust my tuner with my primary radio (Yaesu FT 920) to set the tuner correctly.? Then I'll take the antenna connection and move it over to the QCX operating on or about the frequency I tuned up for.??
? ? I do have a QRP antenna tuner but only plan on using it in the field.
If anyone could suggest a good reliable Watt/SWR meter that will not break the bank I'm all ears..
Other than that I wrapped my toroids I wound them in accordance to Han's directions.??
I am now curious to see how well a stock built QCX-20 is going to play.
72; Kurt - W2MW
-------- Original Message --------
Subject: [QRPLabs] QCX 20m - Almost done... can't wait
From: "Kurt Zimmerman" < kurt@...>
Date: Wed, December 06, 2017 10:04 am
To: [email protected]
Greetings all; ? ? Well I completed my QCX 20m last evening.? I have had my share of boneheaded mishaps which I take full credit for.? Initially when I was installing the glass diodes I broke one.? I manage to pillage one from a failed QRP project.? Last night when I was installing the volume pot I applied a bit too much pressure on it and cracked the board in the pot.? Net result I have no volume out.? I was able to jumper the leads on the pot to discover I am getting plenty of audio.? I hope to salvage the pot and to get the rig on-line this evening.? I may have to wait until the weekend do get to operate during the day when 20m will do better with propagation.
Hopefully these pictures come through.??
Just want to thank Hans for the continue support as well as providing just a great product.? Other than my missteps it was a great build.? Can't wait to get on the air.
72/73; Kurt - W2MW
|
Re: Low Power fix on QCX 80 and a sugestion for a possible addition to QCX test gear to measure inductance.
Hi Alan
Current consumption charts that I measured are in the manual.
Agreed, only the final measurement means anything, and only into a 50-ohm dummy load. The onboard power measurement is not claimed to be particularly accurate either.?
73 Hans G0UPL? ?
On Dec 6, 2017 8:19 PM, "Alan G4ZFQ" < alan4alan@...> wrote:
In my opinion, I also have a slightly lower power output?than expected.
Using the online power meter, I ?have 5.2 watts on the drains of Q1, Q2 and Q3 (with both 9.5 and 11.3 V power source) and the following measurement across L1:
L1/L2 Junction = 3.3 watts (11.3V)? and?2.3 watts (9.5V)
L1/power output BNC socket = 2.0 watts (11.3V) and 1.5 watts (9.5V)
I understand these power measurements are not necessarily accurate values but serve for the purpose of comparison.
Robin,
The only one that has any chance of giving some sort of accurate indication is the final one.
The others are not into 50 ohms so really mean nothing.
I note the possible removal of turns from the inductances L1, L2, L3 and L4 but before embarking on this I would be interested to know which inductance did you find was the most critical and turns removed.
I think each has a small effect and all may require adjustment to make a significant difference.
Something somebody said off-list makes me wonder what current does the CQX take, RX and TX? Although perhaps that may mean nothing.
73 Alan G4ZFQ
|
Re: Low Power fix on QCX 80 and a sugestion for a possible addition to QCX test gear to measure inductance.
In my opinion, I also have a slightly lower power output?than expected.
Using the online power meter, I ?have 5.2 watts on the drains of Q1, Q2 and Q3 (with both 9.5 and 11.3 V power source) and the following measurement across L1:
L1/L2 Junction = 3.3 watts (11.3V)? and?2.3 watts (9.5V)
L1/power output BNC socket = 2.0 watts (11.3V) and 1.5 watts (9.5V)
I understand these power measurements are not necessarily accurate values but serve for the purpose of comparison.
Robin, The only one that has any chance of giving some sort of accurate indication is the final one. The others are not into 50 ohms so really mean nothing. I note the possible removal of turns from the inductances L1, L2, L3 and L4 but before embarking on this I would be interested to know which inductance did you find was the most critical and turns removed. I think each has a small effect and all may require adjustment to make a significant difference. Something somebody said off-list makes me wonder what current does the CQX take, RX and TX? Although perhaps that may mean nothing. 73 Alan G4ZFQ
|
Hmmm.
That's a tricky one.? I wonder if transmitting a beacon using a mode designed for 'rapid' QSOs is something we should even consider doing?
Thanks
David? G0MRF
|
Winding Tip for 80 Mtr QCX transformer (T1)
Hi Des (again) and others
I just searched this topic and your name came up again.
I had to have 3 attempts to wind the T1 transformer.
On the first attempt, I ran out of 28swg wire to complete the winding having obviously?used generous amounts for the other inductances.
(QRP Labs - please note that a little more wire would not go amiss).
I had some 27swg and 30swg wire and decided to try the 27swg?but trying to wind 83 turns on a T50-2 toroid is no easy task and I abandoned this in favour of the 30swg.
I managed to wind the transformer with quite a bit of overlap of 30swg wire and I presume I have wired it up correctly as I am now hearing stations? reasonably well from continental Europe. Obviously, 30swg wire?is quite delicate but it?is certainly workable if one is careful.
The issue I have is with the alignment: it is starting to peak but I am only achieving a scaling factor of 5 with the plates of C1 completely closed and I now have to add some more turns.
For optimum performance,?is the target value around 9 as indicated in the manual and I am wondering whether it is easier to remove turns rather than add.
In other words, would it be better to add 10 turns rather than 5 turns as suggested in the manual ?
Again input from you or any other would be most welcome.
73s
Robin
G4DNP
|
Re: Low Power fix on QCX 80 and a sugestion for a possible addition to QCX test gear to measure inductance.
Des and Alan
I have just subscribed to the group and I wonder?if?either of you can help an old timer who has?only returned to amateur radio in the last couple of years after 30 years of no activity.
In fact, the last transceiver I built was a Heathkit HW8 which still works?- ?Hi Hi.
I have just completed building the QCX 80 and it worked first time thanks to the excellent Assembly Guide Manual.
In my opinion, I also have a slightly lower power output?than expected.
Using the online power meter, I ?have 5.2 watts on the drains of Q1, Q2 and Q3 (with both 9.5 and 11.3 V power source) and the following measurement across L1:
L1/L2 Junction = 3.3 watts (11.3V)? and?2.3 watts (9.5V)
L1/power output BNC socket = 2.0 watts (11.3V) and 1.5 watts (9.5V)
I understand these power measurements are not necessarily accurate values but serve for the purpose of comparison.
I note the possible removal of turns from the inductances L1, L2, L3 and L4 but before embarking on this I would be interested to know which inductance did you find was the most critical and turns removed.
I am fully aware that inductance values?can vary according to core material, tightness of turns, closeness of turns etc but would greatly appreciate your input as a quick fix until I can set myself up with the inductance measuring circuit.
Kind regards and 73s
Robin
G4DNP
|
Re: U3S drift/chirp - again!
Thanks for the replies Bob and Daniel.
I've changed the step time as suggested by Bob and it has significantly reduced the 'tail' on 28MHz QRSS transmissions. You both gave other useful info for me to consider.
Thanks again,
73,
Ian, G4JQT
toggle quoted message
Show quoted text
Hi Ian,
I built a 10m LPF kit for my U3S yesterday and ran it up on 28.000.089 FSKCW QRSS.??? With long calibration parameters, a similar 'power-on tail' and almost the same -20 Hz frequency error occurred, along with slow drift during the whole transmission just as
the grabber screen shot shows on your U3S.??? It seems that a long calibration time (like 20 240 as in your first posting) causes the standard synth module to cool down too much during the calibration period resulting in the calibration inaccuracy and then
frequency drift when it starts up/warms up again.??? Far better results were obtained with short calibration parameters like "Step Time" = 20 020 (along with Park Mode parameters = 2 150.000.000 to keep the Si5351a 'busy and warm' until the start of the next
transmission) ... so, despite what the U3S operating instructions say regarding calibration time, at 28 MHz it seems that "less is more"!??? After a couple of transmissions with those settings my U3S had settled to almost drift free FSKCW at .089 (see below).?????????
Perhaps try a "Step Time" = 10 020 which should provide a calibration accuracy of 1 Hz with up to 20Hz of frequency correction at 28 MHz which should be enough to keep a U3S on the display frequency in a stable temperature environment.
FWIW, one of my standard Si5351a synth boards had a bad reference xtal which caused 'jittery/wobbly' FSK tones and a calibration error no matter what the cal settings.????????? I also have a QRP-Labs OCXO/Si5351a module which performed extremely well keeping
the U3S right on frequency with no drift regards of the calibration time length.?????? While it can be done manually, the QLG-1 GPS makes initial U3S calibration easier with the OCXO synth, but after the Ref Frq parameters in the U3S are set to match the particular
OCXO, it should stay on frequency.??? In the end, the GPS is useful to keep the U3S clock accurate, but perhaps that is not so important for QRSS?
73, Bob??? ZL1RS
On 5/12/2017 5:43 AM, ian liston-smith wrote:
Right, had my U3S have 6 minutes calibration between transmissions over night. Still the frequency is 20Hz low when frequency display is reading 28.000.890 and still has the 20Hz power-on 'tail'. Chris's grabber in not 20 Hz out.
I'm running out of options here. Do I assume there is something really wrong and chuck in the towel for 10m QRSS? I don't think there's anything left to adjust.
Is it worth getting the???OCXO/Si5351A synthesizer module kit? Is that still frequency stabilised by the
QLG1 GPS receiver module kit or is that not necessary?
Was having a lot of fun with the U3S, but maybe mine is starting to fail...
73,
Ian, G4JQT
|
QCX 20m - Almost done... can't wait
Greetings all; ? ? Well I completed my QCX 20m last evening.? I have had my share of boneheaded mishaps which I take full credit for.? Initially when I was installing the glass diodes I broke one.? I manage to pillage one from a failed QRP project.? Last night when I was installing the volume pot I applied a bit too much pressure on it and cracked the board in the pot.? Net result I have no volume out.? I was able to jumper the leads on the pot to discover I am getting plenty of audio.? I hope to salvage the pot and to get the rig on-line this evening.? I may have to wait until the weekend do get to operate during the day when 20m will do better with propagation.
Hopefully these pictures come through.??
Just want to thank Hans for the continue support as well as providing just a great product.? Other than my missteps it was a great build.? Can't wait to get on the air.
72/73; Kurt - W2MW
|
Hi,
I second Simon's opinion: FT-8 is a highly interactive mode with seconds to interact and was never intended as a beacon mode. Beside that the QSO runs in automatic mode. No chance to implement this in the U3s. And the crocodiles are coming into the FT-8 pond, so no chance for a 200 mW signal.
73 de Hajo
|
Re: U3 V3.03b no power output after connecting QLG1
rule one, remember to take your towel ;-)
db
toggle quoted message
Show quoted text
On Dec 6, 2017, at 2:53 AM, Alan G4ZFQ <alan4alan@...> wrote:
forgotten to add the jumper for the PA, Colin,
Rule 1)
DO NOT PANIC!
73 Alan G4ZFQ
|
Hans,
?Have you looked at going to say an ESP32 device? They would certainly eliminate any constraints for a long time on memory, cpu, I/O, etc.? I don't know what price break you get on the Atmel devices and how much you could get on the ESP32.?
73, Michael
KM4OLT
|
On Wed, Dec 6, 2017 at 06:24 am, James Zelazny jr wrote:
but would like to see FT8 replace JT9 for selfish reasons
Error,I meant replace Opera with FT8. Jim
|
Dean,
PI4 is being used with good results and just my opinion,should replace CW beacons altogether.Not many people are aware of this mode and how useful it is.
Software is almost too simple to use -
Of course GPS is required.FT8 would be interesting if it were to replace modes not so used in the U3S now.I have tried Opera recently and found NO ONE is there anymore.I fear that FT8 will end the same way soon as another mode emerges,but would like to see FT8 replace JT9 for selfish reasons :) JT9 also pushed to the wayside so I see a use for a FT8 beacon just because everyone is there to receive it now.Just check the decrease of modes used/not used,FT8 is winning,for now.
PI4 INFO-
|
Mike
Kurt Zimmerman
Hajo Dezelski
Michael Monteith