Connex CX 4400 HP

[MindenJoe]

Hi everyone, I picked up an old Connex CX 4400 HP with an external frequency counter. I want it for only 10 meters but somewhere in it's history it was converted to include 11 meters. Going through the frequencies, I noticed that it's missing all of the upper frequencies on ten meters and also has frequencies below the 10 meter band. Looking on the Web, I see that the original mod had you remove a resistor and change the jumpers on J29 and I believe J27. I'm looking for which resistor to solder back on the board, and the original configurations of the jumpers. It does transmit and receive but with massive feed back on TX when I listen with a radio on the other end of the house. You hear very little voice and a lot of feedback. It was putting out close to 30 watts, so I turned it back down to the the factory setting of 10 watts max. I also noticed that the AM modulation pot was turned all the way up, so I turned it way down. It appears to be on frequency but looks like someone went at the pots with a screwdriver. I guess they thought more watts on the meter meant more power. Any help or suggestions would be appreciated.

 

[AK9R]

I moved your thread to the Amateur Radio Equipment forum. However, I think you are more likely to get answers about this radio in the CB Forum. If you don't get any responses here in a few days, let me know and I'll move the thread to the CB Forum. Please do not simply start a new thread in the CB Forum.

 

[MindenJoe]

Thank you for moving to the correct forum! I looked at the instructions for the cb mod and saw that one of the jumpers was in the wrong position. I moved it to the correct position and the factory 10 meter frequencies came back! I also tried a different microphone and turned down the mic gain and the radio transmitted much better. It still sounds a little over modulated so I might try turning down the AM modulation pot a little more.

 

[MindenJoe]

Thank you for moving to the correct forum! I looked at the instructions for the cb mod and saw that one of the jumpers was in the wrong position. I moved it to the correct position and the factory 10 meter frequencies came back! I also tried a different microphone and turned down the mic gain and the radio transmitted much better. It still sounds a little over modulated so I might try turning down the AM modulation pot a little more.

I replaced the capacitors and found that removing the external frequency counter fixed the over modulation issue ( short perhaps). Radio works great now, while testing the radio today I made a skip contact in Hawaii on 11 meters. I was not expecting that, I thought it was someone local. I have also heard what I’m assuming is CW (beacon) on the lower 10 meter band at around 28.2 MHz.