Like a broken record I keep saying my time is very limited. This in turn leaves little time for new builds, but instead I have been hitting the "shelf of shame" and actually fixing some radios that are broken or never did work right.
This presents some special problems as there often is a significant time lapse when I last worked with the rig. Thus, what I did previously often is a mystery that has to be unraveled.
A second larger and perhaps more dangerous malady is the case where I did not follow a standard layout. Hookup often follows muscle memory which by wrote is for the standard.
Using an IF Module has worked very well for me. In a recent post I think I shared there were 7 different topologies for this module. Here is one using the Plessey approach (2N3904 & 2N3906) only fully SMD.
Typically, in my IF Modules I have the Band Pass Filter on the right-hand edge and right near that is the Rx Tx Mixer, an ADE-1. On the left side is the Product Detector and Balanced Modulator an ADE-1 also.
The P3ST with the Left Side ADE-1 PD/BM and Right Side ADE-1 Rx/TX Mixer
In the case of the P3ST the left most ADE-1 would have the Carrier Oscillator (CLK2) signal applied and the right most ADE-1 would have the Local Oscillator (CLK0) signal applied. This is more or less the standard committed to muscle memory.
So, along comes the Shelf of Shame rig which was built several years ago and has a reversed layout. But this rig had the Si5351 and Arduino liberated from the circuit along with some other modules. Not a problem as I have many built up modules just awaiting a project. I did a quick bench test of the spare Digital VFO, and the screen lit up and the controls did their thing.
Upon hooking things up. The rig was as dead as a door nail. Luckily, I had to stop as I needed to head out for my shift at the Board and Care. This was indeed luck as it gave my mind a chance to mull over what could be the problem. I didn't come up with much during that three-hour period.
It wasn't until I was just pulling into my driveway that it hit me. Hey, dummy you wired the Carrier Oscillator and LO as in the P3ST (standard) but this one was reversed. So, the LO was connected to where the Carrier Oscillator should be connected and the same for the other ADE-1. A bit of cable reversing, and it came to life.
Then I noted the received signals sounded distorted and that switching between LSB and USB there was a marked difference in the background noise. Typically, they should be about equal -- but now the difference was huge. I looked at the sketch and using a commercial filter the BFO (Carrier Oscillator) frequencies are pretty much stock, so I tried adjusting the BFO frequencies in the sketch. There was some improvement but not enough to cure the issue.
I am now suspecting a bad crystal filter. So that is the next area of investigation. It was on the Shelf of Shame for some reason and that may have been the issue.
The huge takeaway is to keep better documentation and to make some notes on paper and stuff that in the rig before installing on the shelf of shame. I wasted precious time yesterday trouble shooting a problem I created.
Thus, the thrust of this posting trust no one least of all yourself! You think you are merely passing gas but in reality, you should have had the Depends on. It might be OK to have trust in your gut but never your butt!
So, today around 1300 PDST look for N6QW, 1DCA, somewhere between 14.2 to 14.3 MHz yelling CQ FD using my 66-year-old KWM-1. That'll show those IC7300 ops what ham radio is really about. BTW everyone is always 5X9!
73's
Pete N6QW