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Re: U3S No output.

wes377@...
 

Going to set up now for current draw
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wes377@...


Re: U3S No output.

wes377@...
 

James I think it might be a switching power supply
12 to 5v converter have a look.

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wes377@...


Re: QCX 1485 is alive!

Kirby Cave WB3BBC
 

 Alan,

Thanks for the reply!  I went ahead and removed 5 turns from secondary 3 of T1 as you suggested and that seems to have done the trick!  Now the trimmer cap is about half meshed when the BPF is peaked.  In my impatience in unsoldering the wire of T1 I lifted the pad off the board!   But once I verified I had removed enough turns I was able to scrape the mask off the adjoining trace, bend the T1 wire over to make contact with the tinned trace, and resolder.  Must have worked because once I fired it up again I promptly made my first QCX QSO with a station in this weekends SKCC Sprint!  He gave me RST 529, but hey, I’m running 4 watts!  Thanks again...

73 - Kirby  WB3BBC


Re: QCX 5W CW Transceiver Troubles Part III

Glen Leinweber
 

Andy Brilleaux has a very good idea regarding the speaker/headphone problem.
In direct-conversion receivers like this, there is a very large audio gain.
I'm greatly impressed that Hans has managed to keep this huge gain well-tamed.

But we users can cause problems with wiring the radio up. This involves ground
currents, and how they return to the +12V power source.

Your speaker ground line should likely return to the +12V power source ground,
rather than connect to the QCX circuit board ground.
You can wire the audio "hot" terminal from headphone jack to a speaker, but the
ground return should not be wired to the headphone jack, but return straight
back to the DC power source...awkward, but it may help reduce the disturbing
growl, or kill it entirely.


Re: U3S No output.

James Anderson
 

The PSU seems meaty enough.
Please tell me its not a Switch Mode Power Supply though.?

You would have to put the DVM test leads in series with the positive stub of your PSU and the positive lead supplying the U3S.
Switch the DVM to current scale.
There is usually two scales for the DVM. A socket for the red test lead that will measure milliamps and depending on the DVM, 10 amp isn't unusual for the other socket.
Unless its an auto ranging meter and that would cure that problem. 

James.


Re: JS8mode heartbeat beacon...

Ron VE8RT
 

One more JS8 feature taken from APRS I'd like to see, and it was not my idea.

Smart beaconing, for lightweight pedestrian, bicycle, .... mobile, as an alternative to heartbeat.

Ron VE8RT

On Sat, 7 Dec 2019 03:22:53 -0500 (EST)
jmh6@nhfn.net wrote:


Hi All,

Another way might be to get the API polished enough that the JS8/FT8
code is done by a 2nd off board CPU and connected to the QCX via serial
connection.

Now that 9600 baud serial is known to work and both frequency and
transmitter on/off are remotely controllable, except for timing issues, it
should 'just work'.

There is already code for the Arduino that does the JS8/FT8 coding
needed!

Lots of fun :).


On Fri, 6 Dec 2019, Andy Brilleaux via Groups.Io wrote:

I quite like the idea of the js-8 Beacon mode on a U3S.

Can the reports go to pskreporter or similar ?

I guess if needed dropping PI4,ISCAT to make space would be OK for most normal users.

The rest of JS8 does actually look very good now that I have explored a few more websites about our it.

Let's hope that it won't take years to get our of beta stage.

It's slowly winning an old stick in the mud like me over. That takes some doing :-)








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Ron VE8RT <ve8rt@yknwt.ca>


Re: U3S No output.

wes377@...
 

My PSU is rated for 5volts 3amps output 
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wes377@...


Re: U3S No output.

wes377@...
 

Where do I probe to get current draw when I press PTT?

Wes
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wes377@...


Re: U3S No output.

James Anderson
 

Whats the current drawn on PTT key down.
Have you PSU that will show current in milliamps.
If not, you can use your DVM.


Re: U3S No output.

James Anderson
 

What is the power rating in amps that your power supply can supply.
Is it well regulated.
The current drawn on TX should be about 300ma. Maybe a bit less and maybe a bit more depending on band selection and what components you use in the PA stage. Voltage etc.
With a single BS170 in at 5v I wouldn't anticipate much more than 200ma. 

The U3S will or should only go into reset when you power up the unit whilst holding the PTT button.
It should ask you do you want to reset with the prompt, "are you sure press the left button" and if you press the left button it will do exactly what it says HiHi.

So, it might suggest that your power supply is to small in current supply and or the PTT button is sticky, stuck down, an intermittent short on it.
Or your power supply can't supply the current when you TX. It would have to be some really small cable or a lot of it to create such a volt drop on a good PSU though.

James.


Re: U3S No output.

wes377@...
 

James I just noticed that when I push PTT button
after a few seconds it’s asks me if I want to reset.
    Maybe my input wiring is too small and it can’t supply the amperage???? I’m using tiny test lead type wiring. What do you think?

Wes
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wes377@...


Re: QCX 5W CW Transceiver Troubles Part III

Martin DK3UW
 

what kind of antenna did you use for the first test ?

Martin


Re: JS8mode heartbeat beacon...

Dean Smith
 

QCX.. NEVER interested me until now.....
Yet i can imagine Guido PE1NNZ's setup in a nicely CNC'd box, with two displays,a power and an antenna socket.
Real qrp noise floor comms for outdoor activities. QSX on the horizon...yyeess, just gets better and better.


Re: U3S No output.

James Anderson
 

Anything at this stage would help you Wes.

I think many on here have some form of magnifying glass. I'm never without it now.

Check everything again in detail, break it down into small areas and confirm everything is Ok.

It really is a solid design and can take some abuse but shorts on pins, that's a different ball game.

Crossing my fingers for you.


Re: WSPR, what am I doing wrong?

Don DeGregori
 

Brent,
I found a very small black heat sink with fins. It fits across all 3 BS170's. I used a piece of double backed tape.
It is meant for passing heat to the sink. I'll find the name of it. I'm running about 5 watts and now just a bit warm.

Don


Re: JS8mode heartbeat beacon...

Dean Smith
 

Suddenly a QCX seems attractive to me :)


Re: U3S No output.

wes377@...
 

James I hope your able to understand what I’m saying in the pic. It’s very hard to see but in my magnifier it looks sloppy.
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wes377@...


Re: U3S No output.

wes377@...
 

I think I’ve finally found it.
Ive been looking at PIN 1 and 2 of the Si5351A and it looks like there is a solder bridge there.
 It’s super tiny. I confirmed this because Vout of the 
LM317LZ (center pin) is shorted to PIN2 Which is one leg of the crystal.

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wes377@...


Re: U3S No output.

James Anderson
 

The only other thing that i can think of is check the solder joints on pins 11 and 15 of the Atmega328 and the pins 13 and 14 of the Si5351A.

I'm thinking that if these pins aren't communicating with each other then you won't get anything out of the Si5351A. Clutching at straws again.

I'm still not giving up on it HiHi


Re: JS8mode heartbeat beacon...

Guido PE1NNZ
 

Hi Andy,

That is exactly what I did, it is a nice tiny JS8 setup, JTDX works also great but a bit laggy on a rpi3b :-).