Cobra 135 Noisy Receive HELP

[digitalwacker]

I have an old 23 channel Cobra 135 that works, but has an extremely noisy receiver. There is a constant 6 S-unit signal of static. I'm assuming it may be an old capacitor? Anyone have any suggestions?

 

[SLUGGO_]

Disconnect the antenna and connect a 50ohm dummy load directly to the radio. If there is still 6 s-units of noise, then there is a problem with the radio. If this is the case, let me know, and I will tell you where to go from here. 73s

- Sluggo

 

[digitalwacker]

No noise on the dummy load

 

[SLUGGO_]

No noise on the dummy load means that the receive on your 135 sucks !!

 

[digitalwacker]

Now thats not much help

 

[sonoma]

if no noise on the dummy load is common. that means the noise is coming in from the antenna. a noisy cap would also be noise with the radio on a dummy load. it may be just the conditions at your place right now. check it at different times and see if the noise changes.

 

[Atlasta]

Look around for external noise sources. I had to unplug the power supply on my laptop because it was causing excessive noise in my 135.

Are you anywhere near some HV power lines? Maybe a leaky power transformer up on a pole? Neighbor have an electric fence? Do you have a wireless router close to the radio? Any of these things could cause noise.

I use a 135 as an everyday radio and for the most part it's a quiet receiver

 

[digitalwacker]

Noise seems to be there regardless of location. It receives fine, just always has 6 s-units of white noise. Also wondering if anyone knows how to center the clarifier. Mine has to be all the way to the right to be on frequency on 19

 

[sonoma]

here is a link to the cobra radio service manuals. scroll down to which one you have. there is a 135 and a 135XLR . so not sure which you have.

CBTricks.com Cobra Electronics (Dynascan) Radio Index