Mobile Need help with antenna setup.

[Peter Buckles Fondi]

I checking on AM Mode. I installed Wilson 2000 center load. I checked the ground to antenna with the Ohms meter and no reading. I disconnected both ends of the coax and tested ground to center post and no reading.
I connected coax to radio and the other end of coax to the antenna and checked the ground to antenna and set the Ohms meter to 20K Ohms and got a reading of 9.82.
Transmission and receive sound terrible like squelch overlapping voice. SWR is strange. channels 1,40 and 20 are at zero when I key the mice and when I release the mice the needle chumps up and settles to zero again. See attached photo

 

[Crawdad]

If I'm reading your post correctly it appears your coax tests OK.

receive sound terrible like squelch

I not sure I understand what you mean about "squelch sound". A properly operating squelch is little or no audio. Not splitting hairs just trying to understand your issue.

Safe to say that Tx and Rx audio issues are unlikely to be related to your antenna system. More likely to be RFI from your vehicle and surrounding sources. How are you supplying the 13.8 Vdc to your radio? Have you tried operating in different locations? Away from buildings, powerlines, street lights, transformers, solar power installations, etc.? Have you made certain your antenna mount has good contact with bare sheet metal, i.e. grounded?

The real experts here should be along to help. I (and others) would also recommend a visit to www.k0bg.com. Great website with loads of good info on mobile installations. Especially on antenna mounting pros and cons.

73 & good luck

 

[Peter Buckles Fondi]

If I'm reading your post correctly it appears your coax tests OK.



I not sure I understand what you mean about "squelch sound". A properly operating squelch is little or no audio. Not splitting hairs just trying to understand your issue.

Safe to say that Tx and Rx audio issues are unlikely to be related to your antenna system. More likely to be RFI from your vehicle and surrounding sources. How are you supplying the 13.8 Vdc to your radio? Have you tried operating in different locations? Away from buildings, powerlines, street lights, transformers, solar power installations, etc.? Have you made certain your antenna mount has good contact with bare sheet metal, i.e. grounded?

The real experts here should be along to help. I (and others) would also recommend a visit to www.k0bg.com. Great website with loads of good info on mobile installations. Especially on antenna mounting pros and cons.
noise, that's the noise I hear along with the voice

If I'm reading your post correctly it appears your coax tests OK.



I not sure I understand what you mean about "squelch sound". A properly operating squelch is little or no audio. Not splitting hairs just trying to understand your issue.

Safe to say that Tx and Rx audio issues are unlikely to be related to your antenna system. More likely to be RFI from your vehicle and surrounding sources. How are you supplying the 13.8 Vdc to your radio? Have you tried operating in different locations? Away from buildings, powerlines, street lights, transformers, solar power installations, etc.? Have you made certain your antenna mount has good contact with bare sheet metal, i.e. grounded?

The real experts here should be along to help. I (and others) would also recommend a visit to www.k0bg.com. Great website with loads of good info on mobile installations. Especially on antenna mounting pros and cons.

73 & good luck

 

[Peter Buckles Fondi]

Okay. I checked out the link. Thanks. It was very helpful. Obviously the noise I experience on receive is loud static. I get it with another CB transmitting 1/2 a block away and with the squelch turned all the way to the right. I assume I have a bad ground or I'm close to close to electrical equipment interference.
I have the antenna mounted on the side of the vehicle (which I now know makes a bad ground plane), because the top of the car is not grounded to the rest of the body. My dilemma is this: I can solve my antenna problem with a good magnetic mount, WHICH I DON'T WANT or I can find another way to attach the antenna. I'm asking, would it work if I attach the antenna to the roof rack and then connect a ground wire from the antenna bracket to the roof.

 

[Slowmover]

Okay. I checked out the link. Thanks. It was very helpful. Obviously the noise I experience on receive is loud static. I get it with another CB transmitting 1/2 a block away and with the squelch turned all the way to the right. I assume I have a bad ground or I'm close to close to electrical equipment interference.
I have the antenna mounted on the side of the vehicle (which I now know makes a bad ground plane), because the top of the car is not grounded to the rest of the body. My dilemma is this: I can solve my antenna problem with a good magnetic mount, WHICH I DON'T WANT or I can find another way to attach the antenna. I'm asking, would it work if I attach the antenna to the roof rack and then connect a ground wire from the antenna bracket to the roof.

There are recent threads where the question about roof rack is asked. I’d suggest a search; contributor Handy Andy gave a recitative thereon in one of those.

Other threads concern pickups and roof-mount antennas.

.

 

[Crawdad]

Peter,
The main reason for mounting a mobile antenna directly in center of the vehicle roof is because it helps to provide what most vertical antennas need to be efficient radiators and receivers; a "ground plane" as close as possible to antenna feedpoint and directly beneath the vertical element. This is why most experts recommend drilling a hole in the roof as the best mounting location. However, most of us aren't too crazy about roof holes so we look for a compromise, some of which also compromise antenna performance to some degree. The roof rack idea is most likely one of those compromises but almost every mobile installation is.

Having said all that, I am by no means an expert but I don't believe that your noise issues are related to your antenna location or lack of "ground".

Speaking of "ground", it can be a confusing term in relation to a transmitting radio system, careful study of k0bg's pages may help to clarify the different meanings of ground, mainly the difference between "DC ground" and "RF ground".

Your noise issues are most likely related to either a nearby source or possibly an issue with your radio or both.

73

 

[NoEyes]

Okay. I checked out the link. Thanks. It was very helpful. Obviously the noise I experience on receive is loud static. I get it with another CB transmitting 1/2 a block away and with the squelch turned all the way to the right. I assume I have a bad ground or I'm close to close to electrical equipment interference.
I have the antenna mounted on the side of the vehicle (which I now know makes a bad ground plane), because the top of the car is not grounded to the rest of the body. My dilemma is this: I can solve my antenna problem with a good magnetic mount, WHICH I DON'T WANT or I can find another way to attach the antenna. I'm asking, would it work if I attach the antenna to the roof rack and then connect a ground wire from the antenna bracket to the roof.

Not an expert but everything is a compromise when doing a mobile install and only you can determine which compromises are worth it and which are not.

Your center loaded coil is below the roof line and too close to the body work which will give you large problems not even encountered as yet plus the ones you are experiencing.

You could try raising the coil above the roof line and see if that helps but it would have to be almost fully above the roof including the bottom of mount to work in some fashion.

As for the roof rack it shouldn't matter since the metal under it will become a tiny bit of ground plane we have with a vehicle which really isn't a ground plane as much as it is distance above earth.

Next you'll want to visit a good site on proper bonding which does in fact prove most useful.

 

[BJ radionut]

Mobile HF and SCB Models (new-tronics.com)


Products (new-tronics.com)

• SCB
  • Description
    • 22" height to coil
    • 46" overall height
  • Approximate Bandwidth:
    • 250-400 kHz.
• SCB-S
  • Description:
    • 9" height to coil
    • 35" overall height
  • Approximate Bandwidth:
    • 150-200 kHz.

 

[BJ radionut]

ALSO: That coax running thru the door jam!!!!! WILL FAIL!!!!
Unless that door NEVER gets used!