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Re: QCX 20 mulit band ???

 

Hi Paul,

I'm planning to multi-band my QCX for 20/30 meters as well (waiting for parts).? I asked about T1 a few weeks ago, though the discussion quickly jumped to protecting the finals.? The varactor diode in the BPF is an interesting idea.? Steve G4EDG used a simple mechanical switch and a ceramic disk, I'll be using a PIN diode and another varactor/ceramic disk to switch in extra capacitance.? In the end I think they should all work out about the same.? In regards to the primary/secondary windings, I've been advised by others to just leave it at the 3/3/3 turns configuration for 20m.? Again, given the performance of the receiver over such a wide range of frequencies I doubt we'll observe much difference.

The low pass filter is something I struggled with for a bit.? The stock LPF that comes with the kit is based on data published by W3NQN a while back.? Since then there's been an updated list of filters (referred to as Chebychev With A Zero, or CWAZ) which gives a steeper attenuation curve above 14mhz.? Looking around there are also a number of transceivers that only use one LPF output filter for 20/30m with fairly accessible schematics (mcHF, KX2/3, etc.), so there are a few different things you can try there.?

Looking forward to seeing your results!

?

Cheers,
John VA7JBE

Other discussion:
/g/QRPLabs/topic/pushing_the_qcx_t1_question/24970629

CWAZ filters + article:
Re: QCX 20 mulit band ???

 

Paul,

I like your idea of using a switched voltage on a varicap diode in the bpf to select different bands.

I have been planning a multi band qcx but have not got around to it yet but have some thoughts.

I was thinking of abandoning the bpf altogether and just relying on the lpf. There is some suggestion this may work in this paper (link below) because the tayloe mixer provides its own bpf with protection only needed from higher multiples of the frequency chosen.



There have been some comments to previous suggestions of a multiband qcx that the phasing circuit adjustment only delivers maximum rejection of the other sideband for a particular frequency meaning opposite sideband rejection can only be optimised for one band leaving us with compromised opposite sideband rejection on the other bands. How much? Who knows.

Are the power measurements you have made with the appropriate lpf in place for that band?

One other matter is how to change bands quickly using the user interface. I was thinking of using saved frequencies to jump around. And a manually switched filter relay board from qrplabs for up to five bands. 80 through to 17m.

Regards


Simon
VK3ELH
Re: OLED screen for QCX

 

A few more details.? It looks like displays of this type use a WS0010 chipset, which is described as mostly compatible with the 4 or 8 bit HD44780 chipset used on most LCD displays.? Adafruit sells one, though they describe them as being "more timing sensitive" than the regular LCD variety and have put out their own Arduino library.? I have no idea if the custom LCD code that's written into the QCX firmware would work with these, so maybe this is a subject for Hans (once he gets some time away from QSX development.)?

Cheers,
John VA7JBE

Adafruit OLED module:


Adafruit OLED Arduino library:


WS0010 datasheet:
OLED screen for QCX

 

I'd like to use my QCX in below-freezing temperatures and, to that end, have been looking for an OLED replacement to the 16x2 LCD screen that comes with the kit.? I've found one on aliexpress (link below) that looks like it might be a drop-in replacement, but I don't know if I should go for serial or parallel communication.? Could anybody shed a bit of light on this?

Cheers,
John VA7JBE

OLED replacement candidate:
Re: Unable to receive anything on my 20m #chat

[email protected]
 

Hi all, I've tried to listen on 14.074 MHz and I was unable to hear anything. So as a first approach to solve a possible hardware issue, I checked the voltages on the critical points pointed out in the manual. All of them seem to be correct except for the ones I attach:

I used 12.98V as the input voltage:
- IC6: Pins 1 to 8 should read: 2.44, 2.44, 1.63, 0, 1.55, 2.44, 2.44, 11.67 and I get: 2.88, 2.88, 2.87, 0, 2.87, 2.88, 2.88, 12.51. Should I assume pins 3 and 5 are wrong??
- IC7: Pins 1 to 8 should read: 2.64, 2.64, 1.99, 0, 1.89, 2.64, 2.64, 1.67 and I get: 2.91, 2.91, 2.90, 0, 2.90, 2.90, 2.91, 12.47. Again pins 3 and 5 are wrong?
- IC8: Pins 1 to 8 should read: 2.46, 2.46, 0.65, 0, 0.67, 2.48, 2.48, 11.67 and I get: 2.86, 2.86, 2.82, 0, 2.86, 2.88, 2.88, 12.50. Same situation?
- IC9: Pins 1 to 8 should read: 4.84, 4.84, 0.65, 0, 0.67, 2.44, 2.44, 11.67 and I get: 4.87, 4.87, 4.40, 0, 2.82, 2.82, 2.85, 12.50. Same weird thing for pins 3 and 5...
-IC10: Pins 1 to 8 should read: 5.83, 5.83, 5.83, 0, 4.21, 3.94, 5.83, 11.67 and I get: 6.26, 6.26, 6.26, 0, 6.20, 6.21, 6.22, 12.50. In this case pins 5 and 6 do not meet at the appropriate values.

Finally, some of the LCD voltages are strange too, but the LCD is working properly so I do not know whether this is related. Namely, LCD pin 4 is 0V when it should be 4.92, 7 to 10 are 4.96V when they should be ~1V and Pin 14 is 4.6V but it should be 0V. However, it is working fine...

I am sorry to ask so many times, but I am really lost with this.? I really appreciate any help or tip for continuing the troubleshooting.
Also, I've uploaded a new video where you can see that only "Phase Lo" alignment parameter seems to oscillate too much, just in case this is of any help.

Thank you very much :)
Re: QSX Enclosure Request

 

Somewhere I have a can of conductive paint. I¡¯ll give it a try if screening
is a problem.
Adhesive backed copper tape sold by garden suppliers as a slug repellent
is a good option.


Steve
Re: QSX Enclosure Request

 

Hans,

I¡¯ll be 3D printing mine, and one for you! What¡¯s your favourite colour? :-).?

Somewhere I have a can of conductive paint. I¡¯ll give it a try if screening is a problem.?

Steve?
Re: QSX Enclosure Request

 

Sorry if this gets posted twice - it seemed to have disappeared the first try.? I wanted to respond regarding color not making much difference in temperature.? Being a retired NASA engineer I have a little knowledge about thermal management on space vehicles and I can say that paint colors definitely make a difference.? At 14:14 local time I did a quick experiment with two enclosures set out in the sun in my yard, on the grass.? One box is white painted aluminum containing a power supply I built.? The other box is a black anodized aluminum case for my RC transmitter.? I left the boxes in the sun for about 20 minutes, and the temps were stable.? Ambient temp was 94F.? Using an infrared thermometer, the white box was 99F and the black box was 126F.? The black box was too hot to keep my hand on.? I could keep my hand on the white box with no trouble, and it felt relatively cool.
--
Al KD4EO
Re: QCX 20 mulit band ???

 

¿ªÔÆÌåÓý

?

Hi all (again)

?

Here are some thoughts about a experiment I am thinking of trying and would like peoples thoughts

I have done some measurements of my current 20m OCX

All using a dummy load and external power meter

All below is at 13.8v dc? rx @130mA

20m 4.5 watts @ 730mA

30m 4.5 watts @620mA

40m 5 watts @ 580mA

?

I was going to try changing L4 from? 10 turns (standard 20m value, to 13 turns, 14 turns is standard for 30m and 16 turns for 40m)

I intend to use addition low pass filters switched for 30/40m , easy since they can be just ?switched inline with the standard 20m filter

I was going to have a play using T1 30m settings (maybe add a couple of extra turns), I see the primary uses the same number of turns for 30/20m so I was going to try the 4 turns for each additional windings (really the standard 30m setup) which is half way for 20-40m settings, I was going to replace VC1 with a Varactor Diode (or even 2 in parallel ) and just switch the dc voltage via multiturn trimers for bandpass selection for each band, I would expect I would get al least 20/30 meters working maybe add 17m and even 40m with luck.

I do have a good peak now on 20m and the rx is very sensitive, seems to match my FTDX-1200.

What do you think of these ideas??

73

Paul

?

.

?

Sent from for Windows 10

?
Re: QSX Enclosure Request

 

As to the plastic vs metal...

I'm a strong advocate for shielding.? It does two things keep bad stuff in and band stuff out.
In the simplest form that is.

In too many cases in the field and even home a RF transparent case seem to be more prone
to RF issues especially with the antenna near by.? ?Adding even a metallic panel or partial
plate behind grounded to the electronics seem to tame those instances suggesting partial
shielding is often good enough.

An aside to this and related.? Most plastic cases that offered decent rigidity were as heavy
or heavier than metal and also required vents or fans to get the heat out where the metal
could be used to transfer heat.? That makes a difference when some level of water resistance
is desired short of a watertight sealed box.

Allison
Re: T1 winding short to core

 

Robert,

Most cores are non-conductive.? However if you see damage to the enamel wire it does not rule
out a turn to turn short.

I see that most often with two hole cores as some tend to have hard edges around the holes.
I attack them with a small Dremel carborundum cone shaped stone by hand to take out the
sharp edges at the entry making scored enamel insulation less likely.

Allison
Re: QSX Enclosure Request

 


--
Al KD4EO
Re: QSX Enclosure Request

 

WRT? heat...

There is no one best color in the unfiltered sun.?

I've had commercial experience, so a grain of salt.? ?A Kiosk project that was to be in the sun
(it was solar powered) painted all black would die often.? Painted all white it was was better
behaved even on 100 degreeF days.? The difference in internal temperature was about 20C
for one of each side by side!? However the white was considered very unattractive.? ?The
solution was black and white patterned front and black rear (shade side) was the considered
best looking of all three and the lowest of the three temperature wise.

Best bet is a shade to keep the direct sun off.? An experiment with my commercial radio in
direct sun the case was 160++F? A light umbrella positioned so the radio was shaded the
case was about 5 degrees higher than ambient (94 degree day).? It proves any small
reduction in incident sun has a huge benefit in reducing heating.

That and the operator found it more comfortable too.? ;)

Allison
Re: QSX Enclosure Request

 

On Thu, Sep 20, 2018 at 10:43 AM, Chris Smith wrote:
Also outdoors, running portable, the reflective display uses only 6-10mW of power without the backlight turned on.? A great battery outcome. The blue LCD in the QCX was rather hungry compared to that and IMHO (sorry Hans!), as it was only effective in transmissive mode ,a criminal choice for outdoor usage. Had to get rid of that right away.? <<<

Funny I took my blue display out in the sun and it was fine.? However I have a high/low switch at high power position
has some resistance? 100 ohms to tame the current and low is 820 ohms to really lower the current (display, arduino,
encoder, and 5351 under 45ma). That seems to work well out doors for me.? I also have trans-reflective and the
yellow green.

Most back lit displays at 5V out of the box are way too bright.? Also it helps to do a minor adjust on the contrast
as in some case it was a night and day thing.

Allison
Re: QSX feature request

 

you guys mentioning USB and IQ stuff reminds me of this now discontinued kit,?

-Justin N2TOH?
Re: 30m QCX working ¨C but not for long....

 

Can you get CW decoded on the LCD while transmitting?
If so, then that leaves one op-amp (and stuff connected to)....IC10A.
If CW doesn't decode (and the menu item is ENABLED), then
everything past the gain pot (Q7, IC10B, IC10A) is suspect. I'm pointing
out the active devices, not to point suspicion to them, but to broadly
point out the stages - all the parts associated with these stages are suspect.

You have an intermittent - a nasty thing to debug.
I might suspect the earphone jack area. If this thing is overheated during
soldering, it can distort and its spring pressure relaxed...the clearances
inside are tiny.
Re: QSX Enclosure Request

Chris Smith
 

Perfect. ?When can you take my money :)

Best regards,

Chris Smith M0XTE


On Thu, 20 Sep 2018, at 18:50, Hans Summers wrote:

Chris

Yes. The QSX has a green/yellow?transflective LCD. The backlight may be switched on or off under firmware control.?

73 Hans G0UPL


On Thu, Sep 20, 2018 at 8:44 PM Chris Smith <me@...> wrote:

Spot on.? Most of the absorption comes from outside the visible spectrum anyway so the point on colour is moot at least from a heating perspective.

From an interface and usability perspective, things are different though. The combination of the enclosure colour and the LCD type used are a major usability decision. The best outcome for a portable or home use device is a dark enclosure with a transflective LCD (green LED backlit ones). That covers all ambient lighting conditions then. Outside, the case doesn't reflect light blinding you and the display works in reflective mode giving amazing contrast. In low lighting (indoors where there is power!) the backlight can be turned on to use the display in transmissive mode. Hence why the FT-817/818 uses this and all radios are mostly black now. It was a design study that came up with a usability sweet spot. Our eyes and planet pretty much specified this design rather than it being an arbitrary choice.

Also outdoors, running portable, the reflective display uses only 6-10mW of power without the backlight turned on.? A great battery outcome. The blue LCD in the QCX was rather hungry compared to that and IMHO (sorry Hans!), as it was only effective in transmissive mode ,a criminal choice for outdoor usage. Had to get rid of that right away.

As always, buyer beware of people selling primarily functional things in weird or trendy colours. Don't differentiate your product by making it horrible to use.

Best regards,

Chris Smith M0XTE



On Thu, 20 Sep 2018, at 10:52, Hans Summers wrote:
Hi Alan

QSX enclosure outside dimension is 145w x 68h x 73d mm. The heatsink protrudes 25mm at the back panel. The knobs protrude 10mm at the front panel.

Even despite not really having an idle moment I googled a bit more about heatsinks (as far as black/white colour etc is concerned, radiation and absorption are equivalent). It seems that colour is a matter of preference, making a nice smooth protected finish, etc. There is not a significant heat absorption/emission benefit.?

What I read reinforces my opinion. I believe it will be the same with the QSX enclosure. Colour isn't going to save it from getting hot in the sun. It will make little, if any, difference. From your perspective colour should come down to personal taste. From my perspective it is a matter of pricing and logistics.?

73 Hans G0UPL


On Thu, Sep 20, 2018 at 12:28 PM Alan de G1FXB via Groups.Io <g1fxb=[email protected]> wrote:
Hi Al,
for trail carry I use army surplus pouches mainly for convenience & bash protection here in the UK rather than thermal reasons.....
though i'm sure that would also provide the required sufficient thermal protection in your situation.
(May have to make a cut out in the bottom of the pouch in the case of the QSX for the heat sink)

It's hard to judge size from the images supplied so far, only a little wider than the U3 case and 1/3rd / 1/2 as deep?
It looks to be able to fit in something similar to a US 100 / 200 Round pouch,
if it proves too small the 300 Round bag will possibly in addition hold batteries, AMU, and simple wire antennas...
or in Europe and NATO countries, the respirator / field bag are more easily sourced?

I believe IO groups already support polling?
I would vote for black to match the previous high quality anodized finished QRP Labs cases.....

Alan


On 20/09/2018 00:20, Al Clark wrote:
I'm sure Hans is getting overwhelmed with QSX requests, but I had to throw this one in before the QSX gets too far along.? My request is please don't make the enclosure black.? When you have a xcvr outside in the hot Alabama sun, a black case gets really hot - too hot to touch in fact.? And the high enclosure temperature probably doesn't do the electronics and display much good either.? A light color is preferable, like white or yellow.? I suppose red or blue might be useable, but I imagine those would get fairly warm also.? Actually, a gold or yellow anodized enclosure would be nice, but I suppose anodizing would increase the cost.
--
Al KD4EO
Re: QSX Enclosure Request

 

Chris

Yes. The QSX has a green/yellow?transflective LCD. The backlight may be switched on or off under firmware control.?

73 Hans G0UPL


On Thu, Sep 20, 2018 at 8:44 PM Chris Smith <me@...> wrote:
Spot on.? Most of the absorption comes from outside the visible spectrum anyway so the point on colour is moot at least from a heating perspective.

From an interface and usability perspective, things are different though. The combination of the enclosure colour and the LCD type used are a major usability decision. The best outcome for a portable or home use device is a dark enclosure with a transflective LCD (green LED backlit ones). That covers all ambient lighting conditions then. Outside, the case doesn't reflect light blinding you and the display works in reflective mode giving amazing contrast. In low lighting (indoors where there is power!) the backlight can be turned on to use the display in transmissive mode. Hence why the FT-817/818 uses this and all radios are mostly black now. It was a design study that came up with a usability sweet spot. Our eyes and planet pretty much specified this design rather than it being an arbitrary choice.

Also outdoors, running portable, the reflective display uses only 6-10mW of power without the backlight turned on.? A great battery outcome. The blue LCD in the QCX was rather hungry compared to that and IMHO (sorry Hans!), as it was only effective in transmissive mode ,a criminal choice for outdoor usage. Had to get rid of that right away.

As always, buyer beware of people selling primarily functional things in weird or trendy colours. Don't differentiate your product by making it horrible to use.

Best regards,

Chris Smith M0XTE



On Thu, 20 Sep 2018, at 10:52, Hans Summers wrote:
Hi Alan

QSX enclosure outside dimension is 145w x 68h x 73d mm. The heatsink protrudes 25mm at the back panel. The knobs protrude 10mm at the front panel.

Even despite not really having an idle moment I googled a bit more about heatsinks (as far as black/white colour etc is concerned, radiation and absorption are equivalent). It seems that colour is a matter of preference, making a nice smooth protected finish, etc. There is not a significant heat absorption/emission benefit.?

What I read reinforces my opinion. I believe it will be the same with the QSX enclosure. Colour isn't going to save it from getting hot in the sun. It will make little, if any, difference. From your perspective colour should come down to personal taste. From my perspective it is a matter of pricing and logistics.?

73 Hans G0UPL


On Thu, Sep 20, 2018 at 12:28 PM Alan de G1FXB via Groups.Io <g1fxb=[email protected]> wrote:
Hi Al,
for trail carry I use army surplus pouches mainly for convenience & bash protection here in the UK rather than thermal reasons.....
though i'm sure that would also provide the required sufficient thermal protection in your situation.
(May have to make a cut out in the bottom of the pouch in the case of the QSX for the heat sink)

It's hard to judge size from the images supplied so far, only a little wider than the U3 case and 1/3rd / 1/2 as deep?
It looks to be able to fit in something similar to a US 100 / 200 Round pouch,
if it proves too small the 300 Round bag will possibly in addition hold batteries, AMU, and simple wire antennas...
or in Europe and NATO countries, the respirator / field bag are more easily sourced?

I believe IO groups already support polling?
I would vote for black to match the previous high quality anodized finished QRP Labs cases.....

Alan


On 20/09/2018 00:20, Al Clark wrote:
I'm sure Hans is getting overwhelmed with QSX requests, but I had to throw this one in before the QSX gets too far along.? My request is please don't make the enclosure black.? When you have a xcvr outside in the hot Alabama sun, a black case gets really hot - too hot to touch in fact.? And the high enclosure temperature probably doesn't do the electronics and display much good either.? A light color is preferable, like white or yellow.? I suppose red or blue might be useable, but I imagine those would get fairly warm also.? Actually, a gold or yellow anodized enclosure would be nice, but I suppose anodizing would increase the cost.
--
Al KD4EO
Re: QSX Enclosure Request

Chris Smith
 

Spot on.? Most of the absorption comes from outside the visible spectrum anyway so the point on colour is moot at least from a heating perspective.

From an interface and usability perspective, things are different though. The combination of the enclosure colour and the LCD type used are a major usability decision. The best outcome for a portable or home use device is a dark enclosure with a transflective LCD (green LED backlit ones). That covers all ambient lighting conditions then. Outside, the case doesn't reflect light blinding you and the display works in reflective mode giving amazing contrast. In low lighting (indoors where there is power!) the backlight can be turned on to use the display in transmissive mode. Hence why the FT-817/818 uses this and all radios are mostly black now. It was a design study that came up with a usability sweet spot. Our eyes and planet pretty much specified this design rather than it being an arbitrary choice.

Also outdoors, running portable, the reflective display uses only 6-10mW of power without the backlight turned on.? A great battery outcome. The blue LCD in the QCX was rather hungry compared to that and IMHO (sorry Hans!), as it was only effective in transmissive mode ,a criminal choice for outdoor usage. Had to get rid of that right away.

As always, buyer beware of people selling primarily functional things in weird or trendy colours. Don't differentiate your product by making it horrible to use.

Best regards,

Chris Smith M0XTE



On Thu, 20 Sep 2018, at 10:52, Hans Summers wrote:

Hi Alan

QSX enclosure outside dimension is 145w x 68h x 73d mm. The heatsink protrudes 25mm at the back panel. The knobs protrude 10mm at the front panel.

Even despite not really having an idle moment I googled a bit more about heatsinks (as far as black/white colour etc is concerned, radiation and absorption are equivalent). It seems that colour is a matter of preference, making a nice smooth protected finish, etc. There is not a significant heat absorption/emission benefit.?

What I read reinforces my opinion. I believe it will be the same with the QSX enclosure. Colour isn't going to save it from getting hot in the sun. It will make little, if any, difference. From your perspective colour should come down to personal taste. From my perspective it is a matter of pricing and logistics.?

73 Hans G0UPL


On Thu, Sep 20, 2018 at 12:28 PM Alan de G1FXB via Groups.Io <g1fxb=[email protected]> wrote:
Hi Al,
for trail carry I use army surplus pouches mainly for convenience & bash protection here in the UK rather than thermal reasons.....
though i'm sure that would also provide the required sufficient thermal protection in your situation.
(May have to make a cut out in the bottom of the pouch in the case of the QSX for the heat sink)

It's hard to judge size from the images supplied so far, only a little wider than the U3 case and 1/3rd / 1/2 as deep?
It looks to be able to fit in something similar to a US 100 / 200 Round pouch,
if it proves too small the 300 Round bag will possibly in addition hold batteries, AMU, and simple wire antennas...
or in Europe and NATO countries, the respirator / field bag are more easily sourced?

I believe IO groups already support polling?
I would vote for black to match the previous high quality anodized finished QRP Labs cases.....

Alan


On 20/09/2018 00:20, Al Clark wrote:
I'm sure Hans is getting overwhelmed with QSX requests, but I had to throw this one in before the QSX gets too far along.? My request is please don't make the enclosure black.? When you have a xcvr outside in the hot Alabama sun, a black case gets really hot - too hot to touch in fact.? And the high enclosure temperature probably doesn't do the electronics and display much good either.? A light color is preferable, like white or yellow.? I suppose red or blue might be useable, but I imagine those would get fairly warm also.? Actually, a gold or yellow anodized enclosure would be nice, but I suppose anodizing would increase the cost.
--
Al KD4EO
QCX on 20m,30m,40m

 

Hi All
recently got my QCX working just right on 20m, i can get nearly 5 watts at 13.8v and more if i increase the voltage so very happy with it, but i was just playing around with the presets and managed to store a 30m freq, much to my surprise it burst into life and i was listening to a cw signal near the dig mode freqs, i connect it to a dummy load and found i was getting just over 5 watts out too, i tried 40m and yes that too was working at a reasonable rx sensitivity. i thought oh well lets see if it tx's and was amazed to see 5 watts again, it didnt want to go down any further to 60m but seems ok on 40m . my question, if it receives ok then? the only real difference on a 40/30/20m QCX is the lowpass filter? is that right? if so could i not simply use the QRPLabs 30/40m lowpass filters in a separate enclosure to use it on the other bands??
anyone tried this?? i am not going to use it as it stands on any other bands , i know the harmonic conent would be high , but that said shouldn't the 20m lowpass filter kill harmonics from 30 anyway?
any thoughts.
73
Paul M0BMN

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