SSB Carrier Supression

[Space Varmint]

See, I don't believe it is a problem with the mixer at all. I think rf is getting on the VXO and phase shifting the frequency.

 

[Space Varmint]

By God they got some weird nets. I'm still not sure what they are doing but the answer me sometimes when I give my call. I think I cured some of that whistle. I through a big fat buffer & CE amp in the mix. I now bounce around 5 watts instead of shouting to get 5. I think guru is right. I need some compression on the audio.

 

[Mikebits]

See, I don't believe it is a problem with the mixer at all. I think rf is getting on the VXO and phase shifting the frequency.

A regulator on your Osc. V+ might help.

 

[Mikebits]

By God they got some weird nets. I'm still not sure what they are doing but the answer me sometimes when I give my call. I think I cured some of that whistle. I through a big fat buffer & CE amp in the mix. I now bounce around 5 watts instead of shouting to get 5. I think guru is right. I need some compression on the audio.

Putting a buffer between your Lo and mixer would help as well. As is, your LO and its feedback stage is coupled through a resistor to the mixer. So Z changes from the mixer will couple to your Lo and cause a change in frequency.

 

[Space Varmint]

Putting a buffer between your Lo and mixer would help as well. As is, your LO and its feedback stage is coupled through a resistor to the mixer. So Z changes from the mixer will couple to your Lo and cause a change in frequency.

You got a point. Unfortunately I took that guys advice and did not use a buffer. Now I did increase the resistive couple. But observing the behavior, I would say it is rf. I'm getting ready to choke the hell of that whole circuit and see if it improves.

 

[Mikebits]

It seems as though your taking the "Finger in the dam approach" You put you finger in one hole, but another leak appears. Instead of patching holes, perhaps you might consider stepping back and building an overall stronger dam. Based on all your previous threads and various inputs that you have been given, you could take an RMS value of all input, and use it accordingly to strengthen your dam

Or you might just end up saying damn a lot as you patch each hole. In the end, the amount of effort to add all the patches may equal one big retrofit.

 

[Mikebits]

Mike, we always but heads.

Sorry to hear that you think we butt heads. We may be buttheads, but I do no think of us butting heads.

I gain nothing regardless of how your project turns out, so it is no skin off my nose if your project works or not. I am just sharing with you the things I learned while working in the comm industry. How you choose to use that advice is up to you.

If your prefer, I will refrain from future comments...

 

[Space Varmint]

Originally Posted by Mikebits View Post
Putting a buffer between your Lo and mixer would help as well. As is, your LO and its feedback stage is coupled through a resistor to the mixer. So Z changes from the mixer will couple to your Lo and cause a change in frequency.

Me:

You got a point. Unfortunately I took that guys advice and did not use a buffer. Now I did increase the resistive couple. But observing the behavior, I would say it is rf. I'm getting ready to choke the hell of that whole circuit and see if it improves.

Nope that didn't get it. Putting a buffer in it right now.

 

[Space Varmint]

Sorry to hear that you think we butt heads. We may be buttheads, but I do no think of us butting heads.

I gain nothing regardless of how your project turns out, so it is no skin off my nose if your project works or not. I am just sharing with you the things I learned while working in the comm industry. How you choose to use that advice is up to you.

If your prefer, I will refrain from future comments...

Man don't get so testy. I'm taking your advice right now. I'm gonna start with a buffer.

 

[Mikebits]

Man don't get so testy. I'm taking your advice right now. I'm gonna start with a buffer.

If we were sitting in a room talking together right now, you would see that I am not testy. It is often hard to convey ones thoughts, ideas, and emotions via text, or internet if you will, and have them interpreted in the right context. At any rate I am not testy or being testy. Got it!

Good luck on the project.

P.S. Don't forget to regulate your lo and audio seperately also

 

[Space Varmint]

That wasn't it either. I think I see it. It's rf in on the audio.

 

[Space Varmint]

Man, I think I know what it is...lol. I think my crystal filter is too sharp. It sounds tinny. Not enough band width. I did change it to 4 crystals.

 

[Space Varmint]

Man, I think I know what it is...lol. I think my crystal filter is too sharp. It sounds tiny. Not enough band width. I did change it to 4 crystals.

Yep that was it. So when I held a note and got the power up over 5 watts and sorta stable, it sounded like a whistle. I finally started noticing that the voice sounded tinny all the time which is what tipped me off.

 

[Space Varmint]

On that note I will explain a few things. I forgot that the filter was not a straight ladder network like the schematic shows. The I even added a forth crystal and man, I had no carrier at all. I thought I was doin' something!!!

I'm saving this filter. I still have to figure out how I made it It will make a nice CW filter for later. I'm redoing my filter now. I went back to feeding two crystals 180 deg. out of phase. It sounds great but got to work on the grounding.

 

[Space Varmint]

Hey Mike. I had to put that buffer back in. After I fixed that crystal filter problem I did some CQs and got two people who said my audio was a little distorted. Now if I shout in the mic I can see the double sideband bubbled flat top right in line with the clipping in the audio, but I really couldn't hear it on my receiver. But if I give a good shout in the mic I can hear the tone shift a little. I think that's what he was talking about. We didn't talk much. He is in Springfield IL and I'm in Atlanta and only putting out about 7 watts. He was putting out 150 watts and I had trouble copying him as well as he, me. Sometimes he came in solid but allot of QSB.

 

[Space Varmint]

Ground Loops!!! The Humanity!

 

[Mikebits]

Hey Mike. I had to put that buffer back in. After I fixed that crystal filter problem I did some CQs and got two people who said my audio was a little distorted. Now if I shout in the mic I can see the double sideband bubbled flat top right in line with the clipping in the audio, but I really couldn't hear it on my receiver. But if I give a good shout in the mic I can hear the tone shift a little. I think that's what he was talking about. We didn't talk much. He is in Springfield IL and I'm in Atlanta and only putting out about 7 watts. He was putting out 150 watts and I had trouble copying him as well as he, me. Sometimes he came in solid but allot of QSB.

I am not familiar with HAM acronyms. From google QSB has the following meanings.

QSB Fading QSB Qualified Small Business (IRS category) QSB Queen Street Backpackers (Auckland, New Zealand) QSB Quality System Basics QSB Qualified Supplemental Benefit QSB Quantum Singleton Bound

So can I assume you are talking about fading?

 

[Space Varmint]

I am not familiar with HAM acronyms. From google QSB has the following meanings.

QSB Fading QSB Qualified Small Business (IRS category) QSB Queen Street Backpackers (Auckland, New Zealand) QSB Quality System Basics QSB Qualified Supplemental Benefit QSB Quantum Singleton Bound

So can I assume you are talking about fading?

Fading in and out. Next time Google "Q signals" , there are a few of them. Anyway I think I'm straight now. I tell ya Mike, this thing needs to be on PC board. Other than the 7 to 10 watt amp...3 stages, the whole rest of the thing is on proto-board. So, what I have to do is twist wires around until all of the carrier is gone. There are about 3 key areas, one of them being the modulator section itself. You wanna talk mini circuits....lol. That first can has a few home made mini-circuits. But after I got the buffer installed and fought with new ground loop, I went through and bent wires to were there is no carrier. Not readable on my power meter anyway.

 

[Space Varmint]

Wooo Hooo! Just got a guy about 10 miles from me. He said my audio was real clear but a little tinny, but perfectly readable. See? I only got two crystals in my filter and it's still a little too sharp.

 

[Mikebits]

Fading in and out. Next time Google "Q signals" , there are a few of them. Anyway I think I'm straight now. I tell ya Mike, this thing needs to be on PC board. Other than the 7 to 10 watt amp...3 stages, the whole rest of the thing is on proto-board. So, what I have to do is twist wires around until all of the carrier is gone. There are about 3 key areas, one of them being the modulator section itself. You wanna talk mini circuits....lol. That first can has a few home made mini-circuits. But after I got the buffer installed and fought with new ground loop, I went through and bent wires to were there is no carrier. Not readable on my power meter anyway.

By proto board, I assume you are talking about double sided copper clad perf board. Keep the leads short, and adjoining boards should be via coax or RF connector. An old saying a friend of mine use to say. A ferrite bead on every lead Non RF leads of course. We made prototypes this way, so it can be done, just take care on layout and such.