I just got my QCX-20 assembled and i'm having an issue I haven't seen talked about (though I could just be blind) - without plugging in headphones, I started trying to align the BPF, and couldn't get a peak (it always stayed around 4-5).? ?I looked over all the parts and solder joints and such and everything looks good.? So, I plugged in headphones to hear this loud tone when aligning - but I actually get a loud clicking as soon as the unit is powered on, which leads me to believe the problem might be elsewhere?? The sound seems to vibrate at a few Hz, and the volume is definitely affected by the volume control.? ?Plugged into my bench supply, it draws 140mA at 13.8V, and the display and menus work fine.

I'm still investigating (I have a DMM and oscilloscope, and I'm normally very good at assembly), but does this sound familiar to anyone???

Thanks!

he problem is that I have +12V on gates of BS170

As Alison says, either The BS170s or source resistors are going to be burnt out.
BEFORE replacing them find out why Q201 is not conducting to reduce the bias voltage. What is it's base and collector voltage? Is the emitter grounded? Is R201 220R and soldered correctly?

in TX after the bias schema and I can`t find a reason of it. Seems that everything in this part is working,
BIAS+ signal is ok (5V),Q205 is switching, Q202 is also switching, for Q201 – I don`t know as it is getting
+0.4V on TX after Q202. Just in case I ??replaced Q202 and Q201 – no effect. +12 V on TX – as I see it
overloads the Q203/Q204 pair and it doesn`t work at all.

What is the proper bias voltage on Q203/Q204 – as I remember from SoftRock similar schema, it should be about 2.5V, right?

2-3 volts depending on the BS170s

2.Is 0V on RX and +0.4V on TX on base of Q201 correct?

0.4 is low, should be 0.6-0.7V Is R206 33R and soldered correctly? What is Q202 source voltage?

73 Alan G4ZFQ

As I was having me breakfast, ( Man ! That pink grapefruit was yummy ! ), it occurred to me that, based on my low output power on 80m from the QCX-17 comment, someone might think that I had destroyed the poor thing !
So, I told the -17 that it is a -30, switched the external output filter back to the 30m model, and presto ! I'm happy to report that output power sprang right back to 4 watts !...
?n.o.t.b. ( nature of the beast )

Now, having said all of that...and, risking sounding like my dear departed grandmother, whenever I planned to play with my BB gun:
"Be careful or you'll put your eye out !"

Caveat:
Do not attempt doing that which I have been successfully doing with my QCX-17 or any other rig unless you are willing to accept total responsibility for the outcome !

In any event, have fun!
72 / 73,
Bill, N4QA

HI,
I'm really trying to keep all question here on the group and not in private email.

I was trying to bring linear PA back to life – as I see, the problem is that I have +12V on gates of BS170
in TX after the bias schema and I can`t find a reason of it. Seems that everything in this part is working,
BIAS+ signal is ok (5V),Q205 is switching, Q202 is also switching, for Q201 – I don`t know as it is getting
+0.4V on TX after Q202. Just in case I ??replaced Q202 and Q201 – no effect. +12 V on TX – as I see it
overloads the Q203/Q204 pair and it doesn`t work at all.

So, the questions that could help me:

1.??
Having 12V on the gates tells me you have miswired something, inserted it backward
or plugged a part into the wrong holes.? Also with 12V on the gates if the source
resistors are not burnt out that would be a surprise either that or you have destroyed
the BS170s.? FYI 12V applied to the gates basically turn the mosfets full on (saturated)
and the operating current for that stage should be quite high (greater than 1A) which
would be destructive.

>>>What is the proper bias voltage on Q203/Q204 – as I remember from SoftRock similar schema, it should be about 2.5V, right?

2.?????? Is 0V on RX and +0.4V on TX on base of Q201 correct?

3.????
Those sounds reasonable. Its the same circuit.??

>>>Maybe you do have a bias circuits schema with proper voltages on RX and TX? Or maybe you remember anybody posted it in the group?

No I do not, best I remember its not been asked before.

Allison

Hans,
does this mean that if a prototype is shown at Friedrichshafen, the QSX will be released after the fair? ;-)
That would mean release in july.

No worry :-)

Regards,
Stefan

Forgot to mention.
CHU 3330 kHz is also roaring in on the QCX-17 tonight.

72 / 73,
Bill, N4QA

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Tonight, I'm running the QCX-17 on EIGHTY METERS !
While transmit power is down near zip point zilch, the attached screen shot shows what I'm seeing ( and hearing, quite loudly ) on 80m FT8 on the stock QCX-17.

72 / 73,
Bill, N4QA

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Thanks for the info.

Recently discussed at length here:?/g/QRPLabs/message/30865

Kinda off topic but, has anyone had any experience with QRPGUYS? I placed an order, it's paid for but I have heard nothing in over a week.

That's pretty much it, Dave !
I'm keeping a couple of fingers on Q1, Q2, Q3...so far, so good.
Supply voltage = 13.8 VDC
Power output level somewhat different for each band.
FB on Forest
We might try a Q on 60m sometime.

Tnx & 72 / 73,
Bill, N4QA

Well, well, well !
Just told my QCX-17 that it's a QCX-60 and, WHAMMO ! It just received its first RBN spot on 5331 kHz from KM3T in New Hampshire, I think it is.
Don't worry, keeping a watchful eye on the spectrum analyzer...
That 60m Cauer filter is doing a great job !


And, just listen to WWV on 5000 kHz and all those AM SWBC stns !

72,
Bill, N4QA
ps
let's see, 15m, 17m, 20m, 30m, 40m, 60m...a six band rig so far !

OOPS!

There's also stuff in firmware that tells each QCX how to act !
?So, I need to add 3) because?I just discovered that, by fibbing to the QCX-17 by telling it that it's a QCX-40, CHU 7850 kHz is now coming in like gangbusters !
therefore...
3) If all else fails, see if by telling your QCX-XX that it's, instead, a QCX-YY, as it were,? it gives you the wanted results !
Works for me !

72 / 73,
Bill, N4QA

The easiest way to give a listen for CHU 7850 kHz on a QCX-40 would be to store 7850 in one of the rig's Frequency Presets, and then transfer that to, say, VFO A.
Don't forget to add your cw offset for USB reception, so store 7850.7 etc, since CHU heavily attenuates its LSB. Also ensure you're set up for CW, as opposed to CW-R.
Hw nw ?

Tnx es 72 / 73,
Bill, N4QA

Hans

Register 03 is set to 0.? It does jump frequency every second when it is zeroing in on the right frequency.

73,
Steve VE3SMA

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Hello all,

As a U3S WSPR user, I 'am looking for the possibility to use the VFO/Signal Generator kit + 12M LPF for use as a sinus wave +/- 25 MHz. generator to act as a LO-signal of a satellite LNB for use with the Qatar-Oscar-100 (QO-100) AMSAT satellite.

Does anyone has experience using this setup for use as a affordable 'GPSDO' (using the VFO/Signal Generator + the QLG1 (which I also own already ;-))? ?

73 de Frank PH2M