Just to let you folks know, I've not bowed out of this thread, just been busy with some family stuff so while the thread boiled down into a nice thick soup...
One of the many problems I've encountered with "drift" is of course - when the temperature drops - things tend to quit working.
On top of that - there is little that can be provided for the radio - except to take it and put it in a warm room.
Well, that's fine, but another issue crops up and it can be accelerated in the rapidly changing of environment.
As you know, you fill a glass with ice and water on a hot day, the ice melts and the water tastes pretty good after mowing your yard...but there is another event that I'm talking about - Moisture. The Condensate from the air onto the glass that is at a lower temperature - dewpoint. That is a naturally occurring event and adds a measure of instability to the clarifier and it's need to stay constant.
There's more, including the temperature of the external adjustment - the clarifier itself and it's substrate can be affected by two things - the ambient dew point and the temperature. I can't do much about the dewpoint - but what can be done I've seen and it's quite common - you use it every day when you're on SSB so why not apply that to the clarifier as well?
Well, you can, but then, you can't. Why? Because of two things, one it will compensate for thermal - but it can't protect you from humidity - and using the inherent voltage drop affects the amount of voltage the Varactor has to play with - so the reduced slide can annoy some that want to play "Dobie Grey" and "Drift Away" with Uncle Kracker - and literally Drift - Away...
Worse than Playing "Shannon" because Brian Wilsons' Family dog deserves better...
What am I talking about - try Didoes as a means to track thermal across know resistances in the clarifier circuit. But not like you'd think - more like the AB-Biasing scheme to help drop the voltage across the diode sitting out in free air space by the clarifier and watch what happens.
Before I lost my way with CB Tricks - I had added this to the website as a means to help open a discussion about clarifier and tracking...
But, with any clarifier mod, you do have to use something to offset the higher voltage you got from the straight 8 volts - So I put a resistor and a diode in line in series with each other to help them keep "center slot" and found that the Diode not only dropped voltage but helped with tracking the thermal drift issue by allowing the diode to compensate using its voltage drop in ambient temperature versus trying to oven the Xtal and still be unable to keep the radio closer to center slot due to the drift to warmed up extreme range of nearly a half a channel (up to and including 5kHz) which does not help anyone.
So, Larry, you are working a concept I see as - if we can keep things all the same temperature the radio should not drift - or not nearly as bad as --- wait for it --- starting power up and having to wait over 5 minutes to even check to see if the Clarifier is even close to center slot - you can't make too many friends by being a little off - it tends to scare the natives...
I simply did the resistor/diode up as a means to help my XYL and others to continue to use the PC-122 or any radio that I can take the time to do this mod to - and have had some good success with it. I wanted the ex-XYL to be able to - on a moments notice - turn on her radio and be close enough to center slot so that others can work with her in conditions similar to a round table - but we did it for the Sierra Bravo Nets we used to have.
What does this have to do with SSB Bias? Plenty - because the voltage drop you have across the transistor needs to be tracked somehow and modified to keep it from going into Class A or dropping onto Class C - the transition of both classes can be hard on the part as well as the roundtable users ... applying to the clarifier circuit, we are modifying the voltage divider that provides the Varactor with an adjustable voltage to tune-in a range of frequencies. You can use the diode, in several places along the Clarifier circuit in both a Series and Parallel Compensation - both techniques work across a known resistance - say 1K - but that may require the resistor it replaced to be broken into more spots to apply this. So the issue is more of trial and error - you use the diode and resistor is PARALLEL with each other - in series with - old value - changed to new values, to offset insertion losses and keep the balance.
They do this in AGC as well, but they use the "diode voltage drop" as a means to track rapidly changing signal conditions in AM and SSB modes...
View attachment 25069
The above is simply to demonstrate the "parallel" configuration to help describe what I'm talking about.
Using the above method was to track rapidly changing signal conditions yet provide a lag to help the user hear thru the noise before clampling and attenuation occurred by AGC action
In the principle above, we adapt the diode and resistor to provide the drop and the swamping action you apply the mod to offset a known resistance in the divider circuit to provide the voltage drop change that occurs with temperature as a means COMPENSATE the voltage to the varactor as a means to offset the drift.
This process if it can be done at the factory would allow the temperature of the external to be thermally tracked to help keep "center" slot for many users without having to be forced into a re-tuning issue due to extremes in temperature.
The process of conversion for older platforms is not the easy one.
Now the page above in this post, is only a primer I've since gone on with many projects using the concept but also with the AGC tracking as well
So this is where I stand at the moment...
One of the many problems I've encountered with "drift" is of course - when the temperature drops - things tend to quit working.
On top of that - there is little that can be provided for the radio - except to take it and put it in a warm room.
Well, that's fine, but another issue crops up and it can be accelerated in the rapidly changing of environment.
As you know, you fill a glass with ice and water on a hot day, the ice melts and the water tastes pretty good after mowing your yard...but there is another event that I'm talking about - Moisture. The Condensate from the air onto the glass that is at a lower temperature - dewpoint. That is a naturally occurring event and adds a measure of instability to the clarifier and it's need to stay constant.
There's more, including the temperature of the external adjustment - the clarifier itself and it's substrate can be affected by two things - the ambient dew point and the temperature. I can't do much about the dewpoint - but what can be done I've seen and it's quite common - you use it every day when you're on SSB so why not apply that to the clarifier as well?
Well, you can, but then, you can't. Why? Because of two things, one it will compensate for thermal - but it can't protect you from humidity - and using the inherent voltage drop affects the amount of voltage the Varactor has to play with - so the reduced slide can annoy some that want to play "Dobie Grey" and "Drift Away" with Uncle Kracker - and literally Drift - Away...
Worse than Playing "Shannon" because Brian Wilsons' Family dog deserves better...
What am I talking about - try Didoes as a means to track thermal across know resistances in the clarifier circuit. But not like you'd think - more like the AB-Biasing scheme to help drop the voltage across the diode sitting out in free air space by the clarifier and watch what happens.
Before I lost my way with CB Tricks - I had added this to the website as a means to help open a discussion about clarifier and tracking...
But, with any clarifier mod, you do have to use something to offset the higher voltage you got from the straight 8 volts - So I put a resistor and a diode in line in series with each other to help them keep "center slot" and found that the Diode not only dropped voltage but helped with tracking the thermal drift issue by allowing the diode to compensate using its voltage drop in ambient temperature versus trying to oven the Xtal and still be unable to keep the radio closer to center slot due to the drift to warmed up extreme range of nearly a half a channel (up to and including 5kHz) which does not help anyone.
So, Larry, you are working a concept I see as - if we can keep things all the same temperature the radio should not drift - or not nearly as bad as --- wait for it --- starting power up and having to wait over 5 minutes to even check to see if the Clarifier is even close to center slot - you can't make too many friends by being a little off - it tends to scare the natives...
I simply did the resistor/diode up as a means to help my XYL and others to continue to use the PC-122 or any radio that I can take the time to do this mod to - and have had some good success with it. I wanted the ex-XYL to be able to - on a moments notice - turn on her radio and be close enough to center slot so that others can work with her in conditions similar to a round table - but we did it for the Sierra Bravo Nets we used to have.
What does this have to do with SSB Bias? Plenty - because the voltage drop you have across the transistor needs to be tracked somehow and modified to keep it from going into Class A or dropping onto Class C - the transition of both classes can be hard on the part as well as the roundtable users ... applying to the clarifier circuit, we are modifying the voltage divider that provides the Varactor with an adjustable voltage to tune-in a range of frequencies. You can use the diode, in several places along the Clarifier circuit in both a Series and Parallel Compensation - both techniques work across a known resistance - say 1K - but that may require the resistor it replaced to be broken into more spots to apply this. So the issue is more of trial and error - you use the diode and resistor is PARALLEL with each other - in series with - old value - changed to new values, to offset insertion losses and keep the balance.
They do this in AGC as well, but they use the "diode voltage drop" as a means to track rapidly changing signal conditions in AM and SSB modes...
View attachment 25069
The above is simply to demonstrate the "parallel" configuration to help describe what I'm talking about.
Using the above method was to track rapidly changing signal conditions yet provide a lag to help the user hear thru the noise before clampling and attenuation occurred by AGC action
In the principle above, we adapt the diode and resistor to provide the drop and the swamping action you apply the mod to offset a known resistance in the divider circuit to provide the voltage drop change that occurs with temperature as a means COMPENSATE the voltage to the varactor as a means to offset the drift.
This process if it can be done at the factory would allow the temperature of the external to be thermally tracked to help keep "center" slot for many users without having to be forced into a re-tuning issue due to extremes in temperature.
The process of conversion for older platforms is not the easy one.
Now the page above in this post, is only a primer I've since gone on with many projects using the concept but also with the AGC tracking as well
So this is where I stand at the moment...
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