Date   

Re: QCX new controller IC Si5153 Error

@CurtisM
 

Ron

I am thinking that I may have plugged the connection from the 50 watt PA TR control into the key jack while troubleshooting.  I am thinking there should not be high voltage on this interface, but may there was and that could have been the issue.  If and when I get another QCX, I think I will install a different connector for this interface.  (but there isn't a warning the manual not to plug this into the wrong spot ....)

I was in the process of troubleshooting the PA that would not transmit, although the gate bias was operating and adjusting just fine.  So when my QCX was damaged I ordered a new controller chip, that took nearly 2 months to arrive.  So now I have two unworking units and new fresh controller IC. 

73 Curt


Re: Problem with BPF

ajparent1/KB1GMX
 

BAsed on your first post on june 29 you have gone backward for loss as you
started at 4db and now its far worse.

Is it possible its inserted in the jig backwards and ground and signal are as a
result reversed?

Allison
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Re: Problem with BPF

ajparent1/KB1GMX
 

To get 30db of loss you either reverse the winding or one transformer
is not even close.

Other possible errors is a shorted input or output, wrong part wrong hole
or improperly cal'd nanoVNA.

At that level of loss I'd question the coax used.  You sure your ground and
signal leads on the jig have the correct connections?

The unit should have for 30m: 
2 trimmers
2x coils would on yellow cores (t37-6)
   2.11uh specified.  5t and  25T  
   The link winding 5t should be at the cold (grounded) end of the larger winding.
2x 101 (100pf cap) at C1 and C6
1 C3  8pf

Mine shows peaked not overcoupled, sorta rounded at the top a tiny bit.
Measured band width exceeds the 30M band easily.

Allison
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Re: QCX new controller IC Si5153 Error

Ronald Taylor
 

No that’s about where it should be. I was just verifying there aren’t any obvious shorts on the 5 volt line. The Si5351a error means that chip isn’t talking to the microcontroller for some reason. It could Also be bad. If you somehow got 12 volts on the 5 volt line then it probably is. I didn’t see the history on why the controller chip was bad in the first place but 12 v on it would hurt it as well. If you can provide some details on what all happened in sequence it would be helpful for diagnosing the problem. Thanks 

Ron

On Sun, Jul 5, 2020 at 14:22 wb8yyy via groups.io <wb8yyy=yahoo.com@groups.io> wrote:
Ron

thanks for reply -- ouch this thing is drawing 112 mA on receive so I image this is not a great sign. 

73 Curt


Re: QCX new controller IC Si5153 Error

@CurtisM
 

Ron

thanks for reply -- ouch this thing is drawing 112 mA on receive so I image this is not a great sign. 

73 Curt


Re: Problem with BPF

GM7
 

I'm struggling to see how this is a tuning issue?

I was towards the fully engaged end of the trimmers so I removed one turn.  I was then at the minimum of the trimmer so I had to compress the turns to get back to mid range on the trimmers.  This just put me back where I started.

Modifying the trimmers and the turns just moves the center frequency up and down and doesn't really change the loss.  No combination of trimmers and inductors puts the loss in a sensible place even when I try different frequencies.

Another example response after removing turns and lots of tweaking.  Again on the design frequency and a good looking curve?  Possibly too narrow?  Loss is over 30dB.

I also removed the inductors completely and re-measured them.  They are 2.1uH as per the manual.






Re: QCX+ alive!

David Fine
 

Hans,

The drilling of the spacers used on the LCD PCB would definitely make it easier to assemble.  I did that on mine after trying to assemble it per the instructions.  That took the pain out of assembly.

Dave, W0DF


Re: Si5351A'Synth & QCX+TCXO

Mike Besemer - WM4B
 

I buy from Mouser.

 

Mike

WM4B

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of dl2arl@...
Sent: Sunday, July 5, 2020 4:47 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Si5351A'Synth & QCX+TCXO

 

Mike, WM4B

yes, I read the manual of the Rev4 Synth where Hans gives hints on usalbe and available TCXOs to fit the pads provided on the PCB.

BUT

ordering one single TCXO from the usual providers will cost more on postage than the TCXO is worth. Do you know a good source?

Yours friendly, Razvan DL2ARL


Re: Si5351A'Synth & QCX+TCXO

DL2ARL
 

Mike, WM4B

yes, I read the manual of the Rev4 Synth where Hans gives hints on usalbe and available TCXOs to fit the pads provided on the PCB.

BUT

ordering one single TCXO from the usual providers will cost more on postage than the TCXO is worth. Do you know a good source?

Yours friendly, Razvan DL2ARL


Re: QCX+ alive!

Hans Summers
 

Hi Dean

Thanks for the nice feedback, glad you love the QCX+ kit! 

Yes, fitting the bolt in the bottom right corner of the LCD, right next to the rotary encoder, is tricky! But it DOES work with some effort. 

There wasn't really any alternative, to fit the enclosure and the controls in the desired positions, there wasn't another way to do it. No more mm spare in that area. 

The nylon nuts supplied are correct to use. 

The job can perhaps be made a bit easier by drilling the threads out of the 7mm spacers and four of the nylon nuts. Leaving only the thread on the final four nylon nuts intact to secure the assembly together. 

73 Hans G0UPL 

On Sun, Jul 5, 2020, 20:20 Dean Smith <bardezbiker@...> wrote:
Can't say i had any problems with IC/Resistor placement, i agree it is a little cozy as is C39, the nearest resistor to IC3 is R1 with R2 behind it.
Maybe something for a future revision, tbh i didn't notice on assembly.
IF.....,IF i had to have a grumble,, The LCD fitting nuts'n'bolts are more of a pressing concern. The bolt nearest the Encoder has little space for the nut/spacer ,between the back of the lcd and the backplane pcb. I used plastic M3 nuts all round here to avoid any shorts/overtightning ect. the 16 way molex pins plastic spacer provides the correct gap, anyhow. I'm sure if Han's has already assembled one without the air turning blue,then things will be ok. Just a personal preference:). the one good thing about a pluggable front on the radio, is it helps to assemble without half the kit hanging of it. And those of you still waiting for the kit, you'll not be disappointed! The kit IS the mutts nuts!
Dean (G7EOB)


Re: VFO Signal Generator with incorrect fundamental and sinusoidal contamination #vfo

Alan G4ZFQ
 

I know HDSDR is not as robust as other SDR SW for removing images. Recommendations for better SW?
Alan,

No, it is the one I use. Image rejection is not really a problem although a good audio card helps to keep rejection more flat across the spectrum rather than where you set it. (Usually at the LO offset.)
But, I do not understand why the presence of image artifacts is unpredictable; some days/time-of-day they seem nonexistent, other times very noticeable.
The trouble with SDRs is that they show all the minor spurii that are often not noticed on a conventional radio. I guess there are far more these days, much electronic equipment will not pass emission standards but the authorities do their best to ignore that.

73 Alan G4ZFQ


Re: OOPS ! 50 Watt Amp

Hans Summers
 

Hi Paul

This transistor is very non-critical here. 

The only important parameters of the transistor in this application is that it needs to be a P-channel type, and have a Drain Source breakdown rating of at least 160V. Many MOSFETs have 60V or 100V ratings and this is not enough. The current handling capability and power dissipation capability are of no consequence. It only passes microamps and dissipates microwatts. 

I chose this device just because it met the criteria (P type, high voltage) and was easily available and cheap. The large package and power handling are not a requirement. Only the P type and high voltage. 

73 Hans G0UPL 

On Sun, Jul 5, 2020, 20:26 K2DB Paul Mackanos <paul.mackanos@...> wrote:
Found  FQPF2N60C, TO220, MOSFET at DigiKey, $1.16 each + $4.99 shipping, ordered a few extras.
Paul K2DB

On Sun, Jul 5, 2020 at 1:12 PM K2DB Paul Mackanos via groups.io <paul.mackanos=gmail.com@groups.io> wrote:

Update on OOPS ! 50 Watt Amp

Here is a high def picture with a computer microscope showing a burn mark directly above  Q3 FQPF2N60C, TO220, MOSFET.
I hope I can find one, and pray that's all that went poof !
Paul K2DB



Re: Problem with BPF

GM7
 

Hi Allison,

That's interesting.  I was assuming that there was a more fundamental problem but it sounds like that might be wrong?

The initial curve I had looked like a good BPF response and was on the center frequency it was designed for.  Is it still possible to achieve that and be badly tuned?  I had assumed it wasn't but it is just an assumption.

I measured the inductors when I wound them and removed turns to get them to the correct values.  They have quite a bit of adjustment available by squeezing or compressing the turns.


Re: Problem with BPF

GM7
 

Ron, Geoff

I agree with you but I just can't see it.  I've attached some photos of the BPF.  It's tricky to photograph so I'm not sure how useful they will be.


Re: Problem with BPF

ajparent1/KB1GMX
 

Its just not tuned.

Double tuned band pass filter tend to be hard to get right as tuning one side does interact with the other.
Often I shows as a hump well off to one side is badly tuned and if close but not quite, high loss in
the desired band and maybe a badly shaped skirts.

Note the trimmers are relatively small value so if far off (inductor or padding cap) you will not have
enough range of variable cap to correctly tune.

Allison
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Re: Problem with BPF

GM7
 

The BPF doesn't look so good.  

The BPF Out in particular is completely wrong with an impedance of 0.  

I'm not sure if the BPF In looks reasonable?


Re: OOPS ! 50 Watt Amp

K2DB Paul Mackanos
 

Found  FQPF2N60C, TO220, MOSFET at DigiKey, $1.16 each + $4.99 shipping, ordered a few extras.
Paul K2DB

On Sun, Jul 5, 2020 at 1:12 PM K2DB Paul Mackanos via groups.io <paul.mackanos=gmail.com@groups.io> wrote:

Update on OOPS ! 50 Watt Amp

Here is a high def picture with a computer microscope showing a burn mark directly above  Q3 FQPF2N60C, TO220, MOSFET.
I hope I can find one, and pray that's all that went poof !
Paul K2DB



Re: QCX+ alive!

Dean Smith
 

Can't say i had any problems with IC/Resistor placement, i agree it is a little cozy as is C39, the nearest resistor to IC3 is R1 with R2 behind it.
Maybe something for a future revision, tbh i didn't notice on assembly.
IF.....,IF i had to have a grumble,, The LCD fitting nuts'n'bolts are more of a pressing concern. The bolt nearest the Encoder has little space for the nut/spacer ,between the back of the lcd and the backplane pcb. I used plastic M3 nuts all round here to avoid any shorts/overtightning ect. the 16 way molex pins plastic spacer provides the correct gap, anyhow. I'm sure if Han's has already assembled one without the air turning blue,then things will be ok. Just a personal preference:). the one good thing about a pluggable front on the radio, is it helps to assemble without half the kit hanging of it. And those of you still waiting for the kit, you'll not be disappointed! The kit IS the mutts nuts!
Dean (G7EOB)


OOPS ! 50 Watt Amp

K2DB Paul Mackanos
 


Update on OOPS ! 50 Watt Amp

Here is a high def picture with a computer microscope showing a burn mark directly above  Q3 FQPF2N60C, TO220, MOSFET.
I hope I can find one, and pray that's all that went poof !
Paul K2DB


_._,_._,_


Re: Problem with BPF

geoff M0ORE
 

Looks like Ron beat me to it, I was about to suggest that one or both transformers were wired back to front.i.e. the primary and secondary windings were reversed. This could give a good frequency response but high loss.

On 05/07/2020 17:12, Ronald Taylor wrote:
Is it possible that on one end or the other you got the transformer primary wire in the secondary hole and vice versa? 

Ron

On Sun, Jul 5, 2020 at 08:52 HB9FIH <erich.rieder@...> wrote:
I also had issues with low pwr.
Now have a VNA and will soon check the BPF and fix them.
Own 2*20m and 2*40m.
I am enthusiastic operating with them, asap I moved to SV8 / TA3 and plan to partcipate by challenges again.
--
---
73 de Erich

HB9FIH

HS0ZLS