Rf noise

[678 nh]

Noise goes away when i unplug coax but doing that i get no receive an not dure if thats comin from dc or coax

Not sure oops

 

[678 nh]

There's very little you can determine about coax with only a multimeter.

Start the engine and turn the radio on. When you have the noise, disconnect the coax connector at the back of the radio. Does the noise go away? Plug the coax back in and tighten the connector. Does the noise come back (if it went away)?

Noise can get into your radio either through the antenna or through the power leads. There are different fixes, depending on just how the noise is getting in.

So u recommend a inline choke like tvi. ...will this choke power out

 

[678 nh]

So u recommend a inline choke like tvi. ...will this choke power out

Maybe a clipper?

 

[Mudfoot]

I think its the spark plug noise

Likely, I'm sure. My XJ had 7 S-units of pump whine, so I didn't hear much correlated pulses.

 

[222DBFL]

Try some ferrite snap on chokes on your coax at the feedpoint of the antenna. Usually 6 work. Get the right mix as well when choosing the snap on ferrite chokes. The wrong type mix won't achieve anything. Also, add a good in line DC noise filter. And also with an amp in line you may have to ground the chassis of the amp itself. It might help. Also check the coax between the amp and radio. Not with a multimeter, but like Beetle stated, by unplugging. Start with one thing at a tlme and make a list of all the things you did as this will help with trouble shooting and not repeating unnecessary steps. JMHO.

 

[9C1Driver]

Noise goes away when i unplug coax but doing that i get no receive an not dure if thats comin from dc or coax

What Beetle is saying is this, if the noise does not go away when you unplug your coax that means the interference is riding in on your power lead. If the noise does go away then it's comming in through the coax. The coax example is the toughest to cure

 

[Road Squawker]

Noise goes away when i unplug coax but doing that i get no receive an not dure if thats comin from dc or coax

thats the reason to unplug the coax, know you know the noise is not on the DC power line.

does the noise change when the engine speeds up/slows down?

OOPS,......... Didn't see above post

 

[Beetle]

Noise goes away when you unplug the coax. Then that's how the noise is getting into the radio (along with all the signals that you WANT): it's coming in via the antenna. And as 9C1Driver said, that's the hardest thing to cure. What you have to do is (Step 1): determine just what it is (probably under the hood or in the fuel tank) that's making the noise. (Step 2): Bypass the noise to ground, usually with a disc capacitor or two.

 

[678 nh]

Noise goes away when you unplug the coax. Then that's how the noise is getting into the radio (along with all the signals that you WANT): it's coming in via the antenna. And as 9C1Driver said, that's the hardest thing to cure. What you have to do is (Step 1): determine just what it is (probably under the hood or in the fuel tank) that's making the noise. (Step 2): Bypass the noise to ground, usually with a disc capacitor or two.

The fist thing i will try is ground alternater 2 batt. Then ferrite chokes on sparkplug wires an on coax....but why only in ssb is thr more rf noise.

 

[rabbiporkchop]

how do you check characteristic impedance with an ohm meter?

All coax checked with ohm meter

 

[Robb]

how do you check characteristic impedance with an ohm meter?

He could have only checked it for continuity - is all . . .

 

[222DBFL]

Might want to try 6-10 snap on ferrite chokes at the antenna feedpoint. Use ones that fit snugly around the coax or they won't work correctly. There are a couple of eBay sellers that have good ones that do work. These are the ones I have and have used on a mobile install and they did work! Seller on EBay is henryradio. If you need them for larger coax just make sure they are the right mix for the frequency's being used. The ones I posted were ised on lmr240 at the feedpoint of a homemade dipole. Think I used about 12 of them total. Did the same exact thing on my mobile setup. Used 12 of the ones shown below. They worked well in that install as well. They also work well for wrapping around speaker and power wires. And also for mic cables. The smaller round ones sometimes are easier to work with on mic cables though. Ones like this work well for mic cables. It's attached below the mic itself.

 

[678 nh]

how do you check characteristic impedance with an ohm meter?

The first thing i did was check all coax for continuity only to find that my brand new wilson 18'rg8 was bad so i gav a lil tug an pl259 came rite off so i soldered a new end on then checked an it is gd. This was the first bug i worked out an i only found that becase my swr was high on channel 1 but only with amp on...now 1 on channel one an 1 on channel 40 on am dionostics pass an in ssb i pass antt. Check when i whistle. So now just hav rf noise but only with dx wide open an jeep running an only on ssb. Spark plug noise issue we believe. Tx 4 reply

 

[222DBFL]

Just some info. The newer Wilson antennas have had some QC issues. My local pal has 2 brand new ones that won't tune below 1.7:1. And also won't get a good R or X reading anywhere!!
I put an old one (pre Barjan), on and it tuned perfect!!
I also placed my sirio perfume on the same mount and it was well within limits for not being cut for the vehicle. Both of the Wilson antennas had been cut, had brand new whips of various lengths and all trying to diagnose the issue. This isn't the first I had heard of this either. And this is just my experience with the new ones. The old ones were great!! And the connectors they use are POS!! It's a 2 piece sma to PL259 type if memory serves me correct. They seem to go bad just looking at them LOL!! At any rate hope you get it fixed!!

 

[678 nh]

Just some info. The newer Wilson antennas have had some QC issues. My local pal has 2 brand new ones that won't tune below 1.7:1. And also won't get a good R or X reading anywhere!!
I put an old one (pre Barjan), on and it tuned perfect!!
I also placed my sirio perfume on the same mount and it was well within limits for not being cut for the vehicle. Both of the Wilson antennas had been cut, had brand new whips of various lengths and all trying to diagnose the issue. This isn't the first I had heard of this either. And this is just my experience with the new ones. The old ones were great!! And the connectors they use are POS!! It's a 2 piece sma to PL259 type if memory serves me correct. They seem to go bad just looking at them LOL!! At any rate hope you get it fixed!!

I run a 7 'firestik kw pre tuned 1 to 1 an i hav 5'fs tunable an somtimes i throw on the 102 stainless whip. But yea i put my own ends on wilson coax tx 4 reply