Re my QCX 20M tcvr:   I killed the Woodpecker!!  Switched the Schottky (D3) and the 1N4148.  Then went back to checking the IC 9 voltages. They were still out of whack.  As I mentioned before, when I pressed on the IC I got a “chirp”. On very close inspection I could see that one of the pins appeared cold-soldered.  I re-soldered the pin and BINGO…..The tick-tick-tick Woodpecker disappeared and the alignment tone was stronger. I’m not happy with it yet because comparing it to another QCX it should be a lot stronger. I’ll go back through the tuning again and see what evolves. I will also re-check the other ICs.

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of KeithP
Sent: Saturday, February 26, 2022 8:44 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Russian Woodpecker??

 

Russian Woodpecker find:

Given the weird voltages on IC 9 (QCX 20 M CW). I decided to take another look at the components.  Ahahhh! There, I discovered that I had placed D3 (1N5819 Schottky) where D5 was (1N5148 Switching diode) and vice-versa.  I’ll reverse them today and see what that does (with the hope I didn’t damage anything else.  Prior to finding this, all the functions on the LCD were working fine.

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Ronald Taylor
Sent: Thursday, February 24, 2022 4:38 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Russian Woodpecker??

 

Is this a QCX Mini Rev 1 or some earlier model like one of the QCX Classics or QCX+? 1.08 is a very recent firmware version that is backwards compatible with all the older models of QCX. Reason I'm asking is that the Rev 1 Mini had some issues at times with bad op amps that was corrected in later versions with different parts and factory testing of the board. QCX+ and QCX Classics didn't have many problems with op amps ... Thanks .. Ron

 

On Thu, Feb 24, 2022 at 12:54 PM KeithP <salmo@...> wrote:

I should have said the info printed was “Revision 1.08” not Version 1.08.

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Ronald Taylor
Sent: Thursday, February 24, 2022 3:21 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Russian Woodpecker??

 

Keith. You didn't indicate which model of QCX you built. The problem sounds like you are getting a low frequency oscillation somewhere in the audio chain .. .maybe... The best way to start testing is to get out of the alignment menu and do the voltage checks around all the op amps as directed in the troubleshooting procedure. Those will sometimes point to at least the general area of trouble. Let us know what you find... Ron

 

On Thu, Feb 24, 2022 at 11:20 AM KeithP <salmo@...> wrote:

Well….I hope that’s the problem (sort of!). Must check the same frequency on the other QCX. I didn’t hear it there previously.

Still getting a very low tone on the first one despite many attemots.

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of w3buw@...
Sent: Thursday, February 24, 2022 1:57 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Russian Woodpecker??

 

As I recall the old Russian woodpecker (Over the Horizon Radar) was active on or near 20 M. May be the Ukraine conflict has reactivated for some reason?? Here is some info on the infamous woodpecker!!

https://military-history.fandom.com/wiki/Russian_Woodpecker

W3BUW