SSB Carrier Supression

[Space Varmint]

You have been spotted SV

Uh Oh!

Looks like it's the end of line.

 

[xanadunow]

Plese make me feel welcome to feel, it is not the end of the line. You have been on line (active) long enough, since my last posting(to respond)..

Regards,
xanadunow

 

[Space Varmint]

Plese make me feel welcome to feel, it is not the end of the line. You have been on line (active) long enough, since my last posting(to respond)..

Regards,
xanadunow

Huh? Oh sorry Xan the man. I must have been busy. I'm about to try out my new linear. All I had was an MRF477 for the final which is 40 watts and I checked around and found the most anybody got out of one was 25 watts

MFJ has a transmitter that uses one and it's only 5 or 10 watts!

 

[xanadunow]

It does really sound like Xmas - everywhere around

 

[xanadunow]

Please do go on SV , I do apologise.

Regards,
xanadunow

 

[audioguru]

Please post another ducks quacking WAV file for the end of 2008.
I found a good one but I can't attach it here.

I watched a recent TV show about UFO's. They had airline pilots quacking with severely narrow audio bandwidth. Nobody could understand what they were saying and they had to repeat everything many times.

 

[Space Varmint]

Please post another ducks quacking WAV file for the end of 2008.
I found a good one but I can't attach it here.

I watched a recent TV show about UFO's. They had airline pilots quacking with severely narrow audio bandwidth. Nobody could understand what they were saying and they had to repeat everything many times.

Now your getting it. And yes they do use SSB. I did have a quack before I regulated the oscillators. Even now a very strong signal can cause it. It is from loading which might cause the oscillator to shift, either the BFO or even one or both LOs because they must maintain a particular offset to sound perfect. So even if you use PLL and the BFO is free running, excessive loading from say the audio, will cause the "quack"...lol. But hey, you should love it. You would think if anybody could understand it, it would be Scrooge McDuck.

 

[Space Varmint]

It does really sound like Xmas - everywhere around

You like that? That is good. Kinda sad it is over. Hope you have a great New Year though Xan. And to all of you a prosperous & Happy New Year.

 

[Mikebits]

Now your getting it. And yes they do use SSB. I did have a quack before I regulated the oscillators. Even now a very strong signal can cause it. It is from loading which might cause the oscillator to shift, either the BFO or even one or both LOs because they must maintain a particular offset to sound perfect. So even if you use PLL and the BFO is free running, excessive loading from say the audio, will cause the "quack"...lol. But hey, you should love it. You would think if anybody could understand it, it would be Scrooge McDuck.

Your LO's should be isolated from audio. There should not be loading unless your improperly isolated.

 

[audioguru]

I still have 24 hours to enjoy the last of 2008.
Then tomorrow night I celebrate 2009.

 

[Space Varmint]

Your LO's should be isolated from audio. There should not be loading unless your improperly isolated.

Mike Mike...Your not thinking. I will run cover for you here. If the power to drive the audio is excessive, then you might get a slight dip in the voltage at the onset.

 

[Space Varmint]

I still have 24 hours to enjoy the last of 2008.
Then tomorrow night I celebrate 2009.

You might celebrate? Oh boy! I can just see that. I bet your the life of the party

 

[Mikebits]

Mike Mike...Your not thinking. I will run cover for you here. If the power to drive the audio is excessive, then you might get a slight dip in the voltage at the onset.

My thinking is just fine. Your 1N914 unbalanced diode mixer is completely mismatched on every port. You neglected Z-matching in your design. Your IF out to your crystal has no Z matching whatsoever. Your LO port is driven by a 1K resistor with no isolation buffer in between. Has the concept of 50Ω matching completely escaped you? If your audio is sagging your supply, then your supply is underegulated or just lacks regulation altogether. No cover needed on my end.

 

[Mikebits]

One more thing. You might want to consider isolating your LO's from main supply with individual regulators. For example, main supply is +12v, use 7810 regulators for LO's. Any noise on LO supply will modulate you oscillator and propogate out your antenna. Just a suggestion.

 

[xanadunow]

last smile..

..it is, in this year - for me. You are all a great bunch of fellows!

Wishing you The Best,

With Regards,
xanadunow

 

[Space Varmint]

My thinking is just fine. Your 1N914 unbalanced diode mixer is completely mismatched on every port. You neglected Z-matching in your design. Your IF out to your crystal has no Z matching whatsoever. Your LO port is driven by a 1K resistor with no isolation buffer in between. Has the concept of 50Ω matching completely escaped you? If your audio is sagging your supply, then your supply is underegulated or just lacks regulation altogether. No cover needed on my end.

Why do I need 50 ohms? Am I matching it to antenna or something? I look for results with simplicity.

 

[Nigel Goodwin]

Why do I need 50 ohms? Am I matching it to antenna or something? I look for results with simplicity.

It doesn't have to be 50 ohms, but that's the usual standard, you can match at any impedance you like - but finding 145 ohm coax cable can be difficult?

 

[Space Varmint]

It doesn't have to be 50 ohms, but that's the usual standard, you can match at any impedance you like - but finding 145 ohm coax cable can be difficult?

And there you have it. I was gonna mention coax. In that part of the circuit there is no coax. All I want out of the balanced modulator is great carrier suppression and good voice. I got that so what's the problem?

I got some short on my linear I need to find and fix. I just used a drimmel tool to grind out the PC board so after I fix it I will definately let you know what other hams say about it. They jumped me quick when I fired up the CW rig and had some rf getting back to the PLL. Easy fix. Just a ground loop. Now I get top reports.

 

[Nigel Goodwin]

And there you have it. I was gonna mention coax. In that part of the circuit there is no coax. All I want out of the balanced modulator is great carrier suppression and good voice. I got that so what's the problem?

From all reports you've got poor carrier suppression and poor voice

For decent suppression from that simple circuit you need accurately matched diodes, and impedance matching to the transformers as well.

 

[Space Varmint]

Ha Ha. I'm still working on the amp. I got a whole 3 watts so far. I'll let you know.