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If there is any reactance to the loads on S1 and S1, it will be coupled into the S3 tuned circuit, affecting the resonant frequency.? I assume that these reactances are minimal and fairly stable, and

France, No reason to believe this build is not repairable, and requires the purchase of a new kit. *May I suggest you concentrate in clearing the transmit "fault" first. * Are you sure you have

Alan,? Understood. I read that note in the manual but I didn't expect the values to be that far off. Still waiting on the first QSO but things look good on WSPR.? Thanks for helping a confused

I agree, the varactor scheme would be cranky to work with. We could calibrate out non-linearities and temp dependence in software, operating at VHF so we are in a reasonably linear part of the

Hi OM. I was testing my inoperative QCX and you were right. The device has a bad RX, but it also stops transmitting. So I do not know what to do if I try to fix it or if I want to buy a new device at

Hi OM. I was testing my inoperative QCX and you were right. The device has a bad RX, but it also stops transmitting. So I do not know what to do if I try to fix it or if I want to buy a new device at

I’m in! Alan W3AL

Or let me put it this way: - in traditional FM, you shift the carrier frequency by some amount proportional to the (instantaneous) amplitude of the audio signal - in EER, you have to shift the carrier

If there's anything critical here, it's that S1 and S2 into that FST3253 give symmetric signals. So if you feel inclined to worry about something, make sure the S1 and S2 windings are wound equally

Jerry, I can't see how the varactor FM method might work, as you need precise frequency control. With I2C writes, you control the PLL and thus you have precise control. With varactor, you don't.? The

Hi Rob Interesting, it was essentially a fault at same place in the signal path as?L1 connects directly the the antenna socket. Might be a useful reference for future troubleshooters trawling the

Fully meshed C1 would seem to indicate too low inductance on S3. Removing turns is the wrong way to go.? Are you sure C5 is correct value? I.e. not too small? -- VY 73, Wes AE6ZM Sierra Vista, AZ

Jerry makes a good point. S3 is the reasonant circuit with C1. If the C1 plates are around half mesh when peaked the turn count and inductance are correct. Primary, S1& S2 windings work simply in

Excellent idea!

That's it! I knew I had to be doing something wrong, just a case of knowing what it is. Tnx Bob, Andy, for helping me out. Brian VE7JKZ

Allison, Yup, the si5351 is poorly documented. It takes a little bit of reading between the lines and experimentation to figure out what it really does. On the other hand, it is a $1 part meant mostly

With many thousands of QCX transceivers on the air, should we consider a QCX QSO party?? We can have band specific awards, power maximum awards (not all QCX transceivers have the same output), and

I've completed a 40M QCX (built the 20M last year). Doing the BPF alignment, I could only get max signal with C1 nearly fully meshed (at a power of 10), so I removed 5 turns from T1 (which was easier

I'm very curious how well the i2c writes into the si5351 do. Looking forward to your notes on how clean you can get the signal.<< Jerry, All you need to test the signal generation is a raduino.?

I agree with Bob.? Andy -- The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.