开云体育

I've been looking at building the ubitx v6 as a transmitter only. After looking at the schematics, I am left with a couple of questions. I was hoping someone could help me out with these

1. There is a 11.059 MHz IF and crystal filter that is wired T5 and T6. Why is X7 a 12 mhz crystal? I have seen lots of crystal filters that use a series connected?set of identical crystals. But never with an odd one thrown in. What does this do?

2. I see USB / LSB is achieved by adjusting CLK#1 between 33 mhz and 57 mhz in the 2nd IF on the block diagram. This makes sense to me. The block diagram labels "CLK #0 11.059 MHz LSB". I'm trying to understand why CLK 0 would even mention LSB / USB. If my understanding is correct, the mixing of the mic. signal and the 11.059 MHZ should generate a full AM signal. Later this is suppressed to just LSB / USB by the 2nd RF mixer and 45 Mhz BPF. Or do I have?this all wrong?

3. There are lots of flags labeled "TX". Should this all be tied to 12 volts when transmitting ? It looks like the relay K1 is supposed to be switching this, under control of an Arduino normally.

4. What are M1 / M2 used for? It looks like it part of the RX stage at an audio level, I just can't figure out what they would be doing at all.

5. I'm assuming the trifilar transformers like T8/T9, what AWG magnet wire are people using to build them?

6. All the misc coils like L7, L5 etc indicate "720n". I'm guessing this is 720 nanoHenries. This is listed on the website as being on a T30-6 core. Unless my math is wrong, couldn't these just be air core? Or is there a shielding advantage from using a toroid core?

7. Can I omit the power stage using IRF510? Obviously I'll have less TX power. But I am thinking that I just change the number of turns on the output of T10 to get a 50 ohms output impedance.

I really appreciate anyone taking the time to read this and answer my questions,

Eric?

KK4KYE?