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Re: QRP Labs VFO/Signal generator and Kenwood TS-520 VFO

 

Charles,?
I can see your point now.? Yes, you are right.? The U3S kit has all these parts. But there is a good description of needed parts in the schematics and BOM.

And a comment: I do not know the details of TS520 schematics to know exactly what is needed.? I still recomend to do the VFO as I would do it.?

73 Bojan S53DZ
Re: QDX HOTEL OPS

 

Which telescopic vertical is it? I have a MFJ1899T but this looks different...
Never used indoor however, once I tried at home and got just a lot of QRM...
Re: Should I be worried about my QDX receiver?

 

Coffee money for Hans on the way!




--
Sverre

LA3ZA
http://la3za.blogspot.com
Re: Should I be worried about my QDX receiver?

 

Thanks Hans and Alan!

No I didn't do the cut, but I have now. Audio gain at the default 54 dB is now OK, USB suppression is fine (see plot), but receive current is still a bit high at 175 mA, but I guess that's OK.

Again thanks for the quick response!


--
Sverre

LA3ZA
http://la3za.blogspot.com
Re: Should I be worried about my QDX receiver?

 

On 18/08/2022 06:53, Sverre Holm wrote:
My hardware is the latest PCB rev 3a,
Sverre,

Did you do the PCB track cut?

73 Alan G4ZFQ
Re: Should I be worried about my QDX receiver?

 

Hello Sverre?

Did you remove the via short on the 3a board? See page 13 of the latest QDX Rev 3a manual

73 Hans G0UPL



On Thu, Aug 18, 2022 at 9:53 AM Sverre Holm <svholm54@...> wrote:
Is my QDX receiver OK? On the one hand it receives?well and last night it picked up transmissions from New Zealand to USA as well as the Falkland Islands on 40 m using my 80 m horizontal loop. On the other hand I have three issues that worry me:

1. I need to increase the Audio Gain by 20 dB to 74 dB in order to receive well
2. My rx current is 185 mA with supply voltage 10-11 Volts vs the usual 140-150 mA
3. The LSB suppression is only 20 - 40 dB down from the USB level as shown below

Especially item 1, the need for higher gain, worries me. Any ideas of whether I should be worried and start to debug the receiver or not?

My hardware is the latest PCB rev 3a, and the firmware is the latest 1.04 (20 July 2022).


73
Sverre

--
Sverre

LA3ZA
Should I be worried about my QDX receiver?

 

Is my QDX receiver OK? On the one hand it receives?well and last night it picked up transmissions from New Zealand to USA as well as the Falkland Islands on 40 m using my 80 m horizontal loop. On the other hand I have three issues that worry me:

1. I need to increase the Audio Gain by 20 dB to 74 dB in order to receive well
2. My rx current is 185 mA with supply voltage 10-11 Volts vs the usual 140-150 mA
3. The LSB suppression is only 20 - 40 dB down from the USB level as shown below

Especially item 1, the need for higher gain, worries me. Any ideas of whether I should be worried and start to debug the receiver or not?

My hardware is the latest PCB rev 3a, and the firmware is the latest 1.04 (20 July 2022).


73
Sverre

--
Sverre

LA3ZA
http://la3za.blogspot.com
Re: QRP Labs VFO/Signal generator and Kenwood TS-520 VFO

 

Hej Charles,
No, you bought the right one.? However, this version provides solelly the bare CLK outputs of Si5351A chip.? Perhaps it will work for the TS520 also like this.?

To test that you just have to connect the CLK0 output with C1 to the LPT input.?
?
73 Bojan S53DZ
?
Re: clock power supply

 

John I installed a 5vdc regulator chip and capacitors inside the clock case so I run it off my 12vdc supply.

73,
Skip NC9O
Re: Polyvaricon capacitor knobs

 

Exactly what I was thinking about this week while sourcing parts.

Shipping isn't bad either. Thanks Mark.
Re: QRP Labs VFO/Signal generator and Kenwood TS-520 VFO

 

Bojan,

There is no T1 toroid with the VFO/Signal generator. So there is no PA 5.00 volts to the toroid
or to Q1.
Was I to buy instead the U3S that has all the parts?

Charles Brown
Re: QDX RF Filters

 

Hi Dan,

Looking at your RF Sweeps, it seems to me that your first section of L12 is right on (20m sweep), that the tap between 30 and 36 might be off by one turn, but not enough to warrant removing and rewinding.? Note that 30 meters is low, indicating that there may be a turn too many on the second winding (19 to 30), and 40meters is too high, meaning a turn too soon for the tap.? If the tap were moved, it would most likely move the pass bands correctly.? Again, not something that I would do as you will not notice any difference in the receiver.

I am less sure about the 80 meters sweep.? It does not show enough inductance on L12, though the dip does not indicate an L12 problem.? I would recheck the 80 meters low pass filter (LPF).? ?Count turns on the two inductors and verify the capacitors are correct.??By chance, have you verified the LPF filter selections testing that only D1 and D4 are on?? ?The other 4 should be off.

The above is my interpretation of the information.? It could be wrong, so please verify and get back to me with any errors.
73
Evan
AC9TU
Re: Low signal levels on QDX

 

On 17/08/2022 14:00, chris coleman wrote:
I have had then problem with my QDX of low signal levels and 500Hz lines on the waterfall. As others have found, it initially works and then on subsequent uses gives a low signal level.
Chris,

Is this a v3a? If so have you done the cut track requirement?

73 Alan G4ZFQ
Re: QCX+ exit button issue

 

Ok, got it sorted out. R46 was a dud. Supposed to be 10K, was only 1K (yes, color code indicated it was supposed to be 10K). Swapped it out with a fresh 10K resistor and good to go.?
Special thanks to Ron for his insight into all matters QCX+.
Re: Low signal levels on QDX

 

I found the 500Hz lines on mine in the beginning and isolated it to the center of the BNC connector being of the split variety?- pushing the four pieces inwards to connect better to the outside?world took care of it.

Virus-free.
Low signal levels on QDX

 

I have had then problem with my QDX of low signal levels and 500Hz lines on the waterfall. As others have found, it initially works and then on subsequent uses gives a low signal level. I rewound L12, reworked T2, redid virtually all solder joints and checked all component values. Unfortunately, to no avail. The transmit worked with correct power out on all frequencies, so I am sure the bandpass filters were OK. Unfortunately, by the time all of this was done, the board was a bit of a mess and so I ordered another and built this. This time I only built the receive side and left out the 80m bits. Same problem. I did not delve into the terminal facility and left this side of it as supplied. I have tried 3 different windows computers, on a windows 10 machine I get no output and on a widows 11 machine I low signal output (there may be a clue in this). Before proceeding to hack to new QDX. Has anyone any suggestions. It seems I am not alone with this problem. I was very careful in building both QDXs and so the problem might not be in the hardware. Any thoughts from anyone.
--
G4HCW
QDX RF in Shack

 

Learning that just 5 watts to antenna and bit of RF in shack can cause WSJT-X to
act up and not work right. Was using an unshielded computer motherboard. Went back
to laptop. No problem. Just an FYI.
Re: WAE Contest

 

I'm with you Martin. thank god for the big guns. ;)
Re: QCX+ exit button issue

 

Hi Wayne. One suggestion would be to measure the voltage on pin 26 ("Buttons") of the microcontroller. With no buttons pressed it should read zero volts. The left button press should change it to something like 3.5 volts ish and the right button should make it something higher than that but not all the way up to 5 volts .. . like in the range of 4 volts. The encoder button should make it go to 5 volts.?

Also, with power off, check continuity from the common side of all three buttons to pin 26 of the microcontroller. Look for zero or very low ohms.

If all of that looks good, try swapping the microcontroller out of your 40 meter unit to see if that might be it.

Good luck ... 73 ... Ron

On Wed, Aug 17, 2022 at 1:04 AM kf7rcm@... via <kf7rcm=[email protected]> wrote:
Just completed a 20m unit, I have a 40m one to compare it to.?
Doesn't work like the 40. The select and exit buttons seem to work with the exception that you cannot exit out of different selections. You have to turn it off to reset it. Checked continuity of the buttons and resoldered all the IC2 connections. Resoldered JP3,4 and 5. Issue with programming? Performed a factory reset, didn't help. Unit has the AGC and TCXO installed.
Suggestions on where to go from here?

Re: QDX HOTEL OPS

 

Today was the 20M telescoping vertical.
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