10 Meter Conversions
I will point out that I am not perfect-Thats why they call it
AMATEUR RADIO- not PROFESSIONAL RADIO.
You didnt pay for this info, so CHECK YOUR WORK.
Nuff said about that subject.
I love 10 meters. And I can convert a CB radio to go there for not a lot of money too.
My current project is a Robyn SB-505D. This one so far has been easy- as in changing a crystal and the logic on the pll address pins. The re-tune was as simple as it gets. The PLL is a MB 8719.
A word about removing TR 32 or TR 24- you don't need to. If you look at the schematic on these chassis, you will see a resistor- either R128 or R102-depending on which xtal is used with this radio. If you remove or cut this resistor, your amc and alc will be WIDE OPEN. I would think that by changing the value of this resistor, you could limit how much feedback is seen from the final. Something to think about when you want full power. If you want to be distorted, cut it. If you want a good sounding and legal radio, change the value of the resistor. If no alc is what you want on ssb, you can cut the YELLOW wire that finds it way from the alc circuit back to the final section. It might be a different color wire, but yellow is the color in most of the 8719 chassis that I have worked on. You could also add some resistance in series with this wire as well to make it sound better.
The original xtal was a 11.1125. Someone had already changed it to 11.3258 and used a switch to open and close pin 10. I am going to change the xtal freq to 11.700 mhz.. That will start the frequency range at 28.075 on ch 1 to 28.515 mhz on ch 40- perfect for the novice / tech phone band.
A three switch conversion consists of :
1. Cut the trace on pin 10 (if grounded) and wire a switch on each side of the trace
2. Wire a switch between pin 11 and ground
3. Cut the trace on pin 13 and wire a switch across the trace ( this will give 4 missing freqs )
The next radio I converted is a Ranger TR 696F. This radio is now discontinued, but I snagged one to work on. It is also the same radio as the Galaxy DX-959 which is still a current model.
The original xtal freq was 15.360mhz. I changed it to 16.010 mhz and the radio starts at 28.425 mhz.
So to take the radio down, you can cut the wire going to P5 and wire a switch in series.
If you have a problem with "warbling" on ssb, Ranger says you need to do a re-alignment of your radio.
My solution is to find where the problem is to begin with.
When you turn up the alc on a ssb radio, the radio is going to draw more current. If the dc line chokes cannot handle the load, you will get a voltage drop. Change the size of the wire on the chokes and the problem is solved. Instead of 10.8 volts at the final, you will probably see closer to 13.2 volts. I have wound my own chokes for these radios and they all sound great.
The radios that I have observed having this problem are:
SS3900, SS360, Galaxy 2, Formac 700
Ranger RCI 2900 (the 2950's had bigger wire installed at the factory thanks to me)
But of course, any ssb radio can benefit from higher voltage to its final, so this is not
a complete list!
Pictures are next--coming soon!!
