-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Galaxy dx2547 clarifier 10 turn pot
- Thread starter KneeBiter
- Start date
The pot in the diagram posted here: https://www.cbtricks.com/radios/galaxy/dx2547_mosfet/index.htm
shows a 1k control marked "Fine" on the diagram.
Other Galaxy radios that have a Coarse clarifier show it connected to the pins "C1, C2 and CG", seen on the socket J9 where the stock clarifier is connected. There is a jumper wire connecting "C1 and C2" that would have to be removed. The Coarse control is 20k.
73
shows a 1k control marked "Fine" on the diagram.
Other Galaxy radios that have a Coarse clarifier show it connected to the pins "C1, C2 and CG", seen on the socket J9 where the stock clarifier is connected. There is a jumper wire connecting "C1 and C2" that would have to be removed. The Coarse control is 20k.
73
That is what confused me. I looked at the schematic and noticed the fine marking and 1k. But the 2547 only has 1 pot. No fine and coarse. Also all the other pots are marked vr# on the schematic but couldn't find a vr in clarifier circuit. Just that r1k. Just trying to get the clarifier to be not so touchy.
Wrong. Single clarifier pot is 20k ohm. Finding a 10 turn pot that will fit in the small space available will be next to impossible.
-399
You can use a typical Coarse pot (20K with 1K Fine)
BUT...
That radio uses a "fixed" VCO meaning it tracks the front panels knob - much like a HR2510 - so the frequency it shows, is supposed to be one it's on.
If you want to use a 10-turn pot...those are 20K value and you'll have to rework that section to avoid the hassles of the VCO (PLL) forcing the clarifier to follow the tuning dial and frequency display.
The process is a lot like just removing this circuit above, and just put in the Galaxy Coarse/Fine knob.
See C1 and C2? These are for the Clarifier section and C1 is the SUPPLY side from the VR7 TX FREQ pot.
C2 runs off to the Clarifier section, but C1 is FED by F1/F2/FG - which is your RX Fine side on a typical Galaxy.
So before you start to cut traces, look for and remember the C1 is the ENTRY point for Fine in the above example.
Best results?
Keep R113 and D38 for linearity of the Clarifier control from your Constant 8V source - but the 20K pot can be easily inserted - just look at how J411 is done, then treat the 20K pot as J903 does - High side to F1 - Variable to F2 and Ground (low) to the FG terminal - note how R114 is - again the choice is yours, but R114 lets the FINE range work linearly and helps to stabilize the drift and load your pot will place across this circuit and expected load...
...you also have another BANE to work with, that is at the Clarifier oscillator itself...
See R153? It's the same as R114 - so the circuit LOADS using both.
- so R114 can be LOWERED - but I strongly urge you not to remove it to keep the Clarifier linear and as you modulate - less drift or warble will occur - the higher R114 is - so best results? Make R114 560~680Ω ohms and remove R153 as you see fit - you can swap the VALUE of R114 and R153 - just get rid of one of them to help stabilize the tracking you're going to need...
BUT...
That radio uses a "fixed" VCO meaning it tracks the front panels knob - much like a HR2510 - so the frequency it shows, is supposed to be one it's on.
If you want to use a 10-turn pot...those are 20K value and you'll have to rework that section to avoid the hassles of the VCO (PLL) forcing the clarifier to follow the tuning dial and frequency display.
The process is a lot like just removing this circuit above, and just put in the Galaxy Coarse/Fine knob.
See C1 and C2? These are for the Clarifier section and C1 is the SUPPLY side from the VR7 TX FREQ pot.
C2 runs off to the Clarifier section, but C1 is FED by F1/F2/FG - which is your RX Fine side on a typical Galaxy.
So before you start to cut traces, look for and remember the C1 is the ENTRY point for Fine in the above example.
Best results?
Keep R113 and D38 for linearity of the Clarifier control from your Constant 8V source - but the 20K pot can be easily inserted - just look at how J411 is done, then treat the 20K pot as J903 does - High side to F1 - Variable to F2 and Ground (low) to the FG terminal - note how R114 is - again the choice is yours, but R114 lets the FINE range work linearly and helps to stabilize the drift and load your pot will place across this circuit and expected load...
...you also have another BANE to work with, that is at the Clarifier oscillator itself...
- so R114 can be LOWERED - but I strongly urge you not to remove it to keep the Clarifier linear and as you modulate - less drift or warble will occur - the higher R114 is - so best results? Make R114 560~680Ω ohms and remove R153 as you see fit - you can swap the VALUE of R114 and R153 - just get rid of one of them to help stabilize the tracking you're going to need...
Last edited: