... here's a blast from the past... it was somehow lost in the archives prior to 2005. This modification gives you variable power on Galaxy and Galaxy Clone radios without VRF by using the RF Gain control. One of my earliest posts... Enjoy!
"Super Swing" Superstar Grant.
aka Superstar "Gr"
Standard disclaimer: These modifications (and radios and HF linear amplifiers mentioned herein) are not legal nor type accepted for use on the Citizen's Band in the US of A. They are for educational purposes only. One other note: I realize that most, if not all, of the modifications I write about can be performed by alternately drilling a hole somewhere in the radio and putting a switch or pot therein. I'm just not into that sort of thing. I like for my radio to look 'stock', if that is possible for some 'big ole' export radio.
I am going by memory here, so screwdriver expert beware. If you break it, YOU broke it.
(This modification works on just about any Galaxy / Galaxy Manufactured or Korean/Japanese manufactured clone thereof.)
In writing about his modification procedure, I'll be assuming a few things:
1. Your radio is built like just about every Galaxy radio on the planet.
2. It is similar to the SuperStar 3900 GT and
3. It has dual final output transistors. (10w AM Model).
4. It does NOT have variable RF Power accessible from the front panel.
Most folks I talk to and sources I have read do NOT recommend a 'swing kit' in this type of radio because of the good to excellent modulation properties and resultant swing inherent in this type of radio. I agree.
Here is a modification you can do that will give you:
1. QRP ((super) Low Power Mode)
2. Variable RF output adjustable from the front of the radio and
3. A kind of 'super swing' mode, especially when teamed up with a small
linear amplifier in the 200-250 watt range.
Here is what you will LOSE: Adjustable RF Gain control.
All righty, here we go. The short version of this whole exercise is this (for those of you who want to get right at it): Make sure the audio limiter is intact. Turn the Mod pot all the way up. Remove wires from RF Gain control and wire so that RFG control is always wide open. Remove AM POWER Pot from radio and wire the RF Gain control such that it is now the AM Power Pot. That's about it!
Details and commentary of this hack job are as follows.
The first thing you must realize is that you will LOSE the ability to attenuate the INCOMING RF signal to your radio. In other words your RF Gain control will no longer function. So what? most of you ask. I never use that thing anyway!!! (Me, too.)
If TR32 (The audio limiter transistor or 'mod shunt') has been removed/negated in this radio, PUT IT BACK.
Find the Modulation control for AM, which is typically VR14 in this style of radio. Turn it all the way up. You can tell which way to turn the pot by observing a wattmeter or SWR meter whilst turning the pot and saying 'ahhhhhhhhhhdeeeeeeeOOOOOOOOOOOO'. Turn this pot until the needle deflects the maximum amount.
Next, find the RF Gain potentiometer on this radio (it's on the FRONT and has a shaft sticking through the front faceplate and is controlled by the knob marked 'RF Gain') and note the wires attached thereto. Usually they are gray, red and black. Unsolder the wires from this potentiometer. You will now need to determine which two of the three wires you have just unsoldered, when touched together, turn the RF Gain control to its 'always wide open' position. Do this by turning the radio to a busy channel (19?) and observing the meter and listening to the audio through the speaker. When you touch two of the wires together, the needle will deflect to the right with an incoming signal and you'll hear the audio through the speaker. Solder these two wires together and protect with shrink tubing or black electrical tape. Also protect the remaining wire in similar fashion, as we don't want it flopping about inside the radio wreaking potential havoc. (no pun intended.)
The next step is documenting the AM power potentiometer and de-installing same. Locate the AM Power control pot on the main circuit board of the radio. It is usually VR13 in the Galaxy-type radios. Turn the pot to about 50%. Key transmitter, making mental note of Deadkey. Make note of any resistance markings on this potentiometer. (normally 5K). Get Volt-Ohmmeter (VOM). Range of VOM should be set to about 20v DC. Attach black lead to chassis ground. With radio in the ON position, Mode AM and in RX , measure (and take note of) voltages at three connection points of VR13. You should measure something like: 0v, 14v and ~8v. The two points with +DC voltages we will call HOT. The 0v we will call Ground. REMOVE THIS POTENTIOMETER FROM THE RADIO BY CAREFULLY DESOLDERING IT.
Now that the AM power pot has been removed, you will need three wires, ~20ga and ~10" long. Locate the RF Gain control potentiometer you desoldered the wires from a few minutes ago. (I'm now assuming the radio is positioned such that the control shafts on the front of the radio are pointing toward your belly.) Run a wire from either one of the HOT connection points where The AM power potentiometer was on the circuit board the the leftmost connection on the RF Gain potentiometer. Run a wire from the other HOT connection of the previous AM power pot to the middle connection of the RF gain potentiometer. Solder a third wire between the GROUND connection of the previous AM power pot to the remaining (rightmost) connector of the RF gain control potentiometer.
At this point, your RF gain control should now act like a variable RF POWER control on the front of your radio. COOL! Turn radio on, turn linear off, Mode should be 'AM'. If you've done everything right, turn 'RF Gain' control clockwise and the wattage should increase accordingly on your wattmeter. If turning the RF Gain control clockwise results in DECREASING power output, you have the leftmost and rightmost leads on your RF Gain pot reversed. Desolder these connections, reverse and re-solder.
If you hear popping noises or get NO power output whilst testing, something is wrong. Check your connections. Pray.
You should notice, as a byproduct of this exercise, that you may now turn your AM/FM power WAY down into the milliwatt range when you dial the RF Gain control counterclockwise. Why does this work? Typically because the RF gain pot can inject about 10Kohms resistance whereas the AM power pot could only muster about 5Kohms resistance. As you increase the resistance by turning your RF Gain control counterclockwise past the 5K resistance limit of the old AM power pot, the wattage drops EVEN FURTHER than possible with the internal adjustment. I love this country.
FYI, to control 'swing' on SSB, your Mic Control should effectively do that, as it always has in the past. By limiting the amount of audio input, you will limit the RF output on SSB.
Now for the fun part: The 'Channel 6 Super-Swing Mode'!!!
Hook up radio into your system as Normal.
Mode: AM, Channel: 6 (or channel of your choice)
Linear: (~225 watt) in whatever power mode (L/M/H/WFO) you like and in the ON position.
Wattmeter installed between the linear and the antenna. Range: low position (~20w)
Your new RF 'Gain' control in the minimum (fully counterclockwise) position.
Key Radio. (linear relay will probably NOT engage. That's OK)
Turn RF Gain control SLOWLY clockwise until linear relay engages and reading on Wattmeter is about 2-3 watts.
Increase range of Wattmeter to ~200.
Speak into microphone: AaaaaaaaaaadeeeeeeeeeOOOOOOOooooooooooo.
Notice huge swing, from about 2 to 150 or so watts. Now that's a swing!!!
Now you've got that patented 'Channel 6 Sound (TM)'...
Other cool things to do with this mod:
1. Talk to the guy across the neighborhood without the linear in super low power mode. People will think his CB has some kind of super-duper-ears kit in it.
2. Whilst using an Antron 99 and low power, tell the receiving station you are going to 'turn the beams around and point 'em at them...', then SLOWLY rotate the RF Gain control clockwise. (do NOT overdrive the linear). Your signal will seem to come out of nowhere as you increase your carrier power from 1 watt to 100 watts or more (measured post-linear).
(Please, no lectures on S-units here...the object is a slow increase in signal strength, which you will achieve. If you've got a much bigger linear and can make their S meter go from 1 to 30+, good for you.)
"Super Swing" Superstar Grant.
aka Superstar "Gr"
Standard disclaimer: These modifications (and radios and HF linear amplifiers mentioned herein) are not legal nor type accepted for use on the Citizen's Band in the US of A. They are for educational purposes only. One other note: I realize that most, if not all, of the modifications I write about can be performed by alternately drilling a hole somewhere in the radio and putting a switch or pot therein. I'm just not into that sort of thing. I like for my radio to look 'stock', if that is possible for some 'big ole' export radio.
I am going by memory here, so screwdriver expert beware. If you break it, YOU broke it.
(This modification works on just about any Galaxy / Galaxy Manufactured or Korean/Japanese manufactured clone thereof.)
In writing about his modification procedure, I'll be assuming a few things:
1. Your radio is built like just about every Galaxy radio on the planet.
2. It is similar to the SuperStar 3900 GT and
3. It has dual final output transistors. (10w AM Model).
4. It does NOT have variable RF Power accessible from the front panel.
Most folks I talk to and sources I have read do NOT recommend a 'swing kit' in this type of radio because of the good to excellent modulation properties and resultant swing inherent in this type of radio. I agree.
Here is a modification you can do that will give you:
1. QRP ((super) Low Power Mode)
2. Variable RF output adjustable from the front of the radio and
3. A kind of 'super swing' mode, especially when teamed up with a small
linear amplifier in the 200-250 watt range.
Here is what you will LOSE: Adjustable RF Gain control.
All righty, here we go. The short version of this whole exercise is this (for those of you who want to get right at it): Make sure the audio limiter is intact. Turn the Mod pot all the way up. Remove wires from RF Gain control and wire so that RFG control is always wide open. Remove AM POWER Pot from radio and wire the RF Gain control such that it is now the AM Power Pot. That's about it!
Details and commentary of this hack job are as follows.
The first thing you must realize is that you will LOSE the ability to attenuate the INCOMING RF signal to your radio. In other words your RF Gain control will no longer function. So what? most of you ask. I never use that thing anyway!!! (Me, too.)
If TR32 (The audio limiter transistor or 'mod shunt') has been removed/negated in this radio, PUT IT BACK.
Find the Modulation control for AM, which is typically VR14 in this style of radio. Turn it all the way up. You can tell which way to turn the pot by observing a wattmeter or SWR meter whilst turning the pot and saying 'ahhhhhhhhhhdeeeeeeeOOOOOOOOOOOO'. Turn this pot until the needle deflects the maximum amount.
Next, find the RF Gain potentiometer on this radio (it's on the FRONT and has a shaft sticking through the front faceplate and is controlled by the knob marked 'RF Gain') and note the wires attached thereto. Usually they are gray, red and black. Unsolder the wires from this potentiometer. You will now need to determine which two of the three wires you have just unsoldered, when touched together, turn the RF Gain control to its 'always wide open' position. Do this by turning the radio to a busy channel (19?) and observing the meter and listening to the audio through the speaker. When you touch two of the wires together, the needle will deflect to the right with an incoming signal and you'll hear the audio through the speaker. Solder these two wires together and protect with shrink tubing or black electrical tape. Also protect the remaining wire in similar fashion, as we don't want it flopping about inside the radio wreaking potential havoc. (no pun intended.)
The next step is documenting the AM power potentiometer and de-installing same. Locate the AM Power control pot on the main circuit board of the radio. It is usually VR13 in the Galaxy-type radios. Turn the pot to about 50%. Key transmitter, making mental note of Deadkey. Make note of any resistance markings on this potentiometer. (normally 5K). Get Volt-Ohmmeter (VOM). Range of VOM should be set to about 20v DC. Attach black lead to chassis ground. With radio in the ON position, Mode AM and in RX , measure (and take note of) voltages at three connection points of VR13. You should measure something like: 0v, 14v and ~8v. The two points with +DC voltages we will call HOT. The 0v we will call Ground. REMOVE THIS POTENTIOMETER FROM THE RADIO BY CAREFULLY DESOLDERING IT.
Now that the AM power pot has been removed, you will need three wires, ~20ga and ~10" long. Locate the RF Gain control potentiometer you desoldered the wires from a few minutes ago. (I'm now assuming the radio is positioned such that the control shafts on the front of the radio are pointing toward your belly.) Run a wire from either one of the HOT connection points where The AM power potentiometer was on the circuit board the the leftmost connection on the RF Gain potentiometer. Run a wire from the other HOT connection of the previous AM power pot to the middle connection of the RF gain potentiometer. Solder a third wire between the GROUND connection of the previous AM power pot to the remaining (rightmost) connector of the RF gain control potentiometer.
At this point, your RF gain control should now act like a variable RF POWER control on the front of your radio. COOL! Turn radio on, turn linear off, Mode should be 'AM'. If you've done everything right, turn 'RF Gain' control clockwise and the wattage should increase accordingly on your wattmeter. If turning the RF Gain control clockwise results in DECREASING power output, you have the leftmost and rightmost leads on your RF Gain pot reversed. Desolder these connections, reverse and re-solder.
If you hear popping noises or get NO power output whilst testing, something is wrong. Check your connections. Pray.
You should notice, as a byproduct of this exercise, that you may now turn your AM/FM power WAY down into the milliwatt range when you dial the RF Gain control counterclockwise. Why does this work? Typically because the RF gain pot can inject about 10Kohms resistance whereas the AM power pot could only muster about 5Kohms resistance. As you increase the resistance by turning your RF Gain control counterclockwise past the 5K resistance limit of the old AM power pot, the wattage drops EVEN FURTHER than possible with the internal adjustment. I love this country.
FYI, to control 'swing' on SSB, your Mic Control should effectively do that, as it always has in the past. By limiting the amount of audio input, you will limit the RF output on SSB.
Now for the fun part: The 'Channel 6 Super-Swing Mode'!!!
Hook up radio into your system as Normal.
Mode: AM, Channel: 6 (or channel of your choice)
Linear: (~225 watt) in whatever power mode (L/M/H/WFO) you like and in the ON position.
Wattmeter installed between the linear and the antenna. Range: low position (~20w)
Your new RF 'Gain' control in the minimum (fully counterclockwise) position.
Key Radio. (linear relay will probably NOT engage. That's OK)
Turn RF Gain control SLOWLY clockwise until linear relay engages and reading on Wattmeter is about 2-3 watts.
Increase range of Wattmeter to ~200.
Speak into microphone: AaaaaaaaaaadeeeeeeeeeOOOOOOOooooooooooo.
Notice huge swing, from about 2 to 150 or so watts. Now that's a swing!!!
Now you've got that patented 'Channel 6 Sound (TM)'...
Other cool things to do with this mod:
1. Talk to the guy across the neighborhood without the linear in super low power mode. People will think his CB has some kind of super-duper-ears kit in it.
2. Whilst using an Antron 99 and low power, tell the receiving station you are going to 'turn the beams around and point 'em at them...', then SLOWLY rotate the RF Gain control clockwise. (do NOT overdrive the linear). Your signal will seem to come out of nowhere as you increase your carrier power from 1 watt to 100 watts or more (measured post-linear).
(Please, no lectures on S-units here...the object is a slow increase in signal strength, which you will achieve. If you've got a much bigger linear and can make their S meter go from 1 to 30+, good for you.)