Antenna/Fuel Pump Interference

[David Pendleton]

I just bought a high-power CB antenna (Midland Power-Max 18-258) to mount on my rear window.



In the documentation, is the following notice:



"This antenna may cause interference problem if mounted on Rear Window of cars equipped with Electronic Fuel Pumps. Front or Side Window mounting of this type of vehicle is recommended. "



I'm thinking in my case the lift pump might be affected. Side windows aren't an option for me (they roll down).



Anyone ever experienced this? Any ideas or thoughts?



Thanks all.



Dave

 

[RMachida]

In the documentation, is the following notice:



"This antenna may cause interference problem if mounted on Rear Window of cars equipped with Electronic Fuel Pumps. Front or Side Window mounting of this type of vehicle is recommended. "

I think the keyword here is "Electronic" as opposed to "Electric".

 

[Caveman]

I tried one of those new CB antennas that looks like a cell phone antenna. I mounted it on the passenger side rear window and grounded it properly. I went thru two CBs before I switched to an under the mount with a firestick. I haven't had an issue since.

 

[David Pendleton]

I tried one of those new CB antennas that looks like a cell phone antenna. I mounted it on the passenger side rear window and grounded it properly. I went thru two CBs before I switched to an under the mount with a firestick. I haven't had an issue since.

What happened to the radios?

 

[Caveman]

I think both ended up with fried RF receivers. The symptoms were no sound in and no sound out. The reception died on both after two weeks and no outbound signal. I SWR'd them myself including the latest. Both of the radios were brand new, one Cobra and one Uniden. I now have a Galaxy 959. I bought the antenna mounting bracket for under the front hood and put a 3' firestick on the mount. I get up to 10 miles reception now. Oo.

 

[Graphic man]

if you can stay away from the glass mounts

your SWR will be through the roof

and if it is to high you will fry the CB



a wilson 1000 or 5000 are about the best on the market today

 

[David Pendleton]

What does SWR mean?

 

[Gary - K7GLD]

What does SWR mean?

SWR = Standing Wave Ratio - a measure of antenna performance and proper match to the output impedance required by the transmitter for best transfer of RF power to the antenna. If the SWR is high, both transmit and receive performance is degraded, and the transmitter might suffer damage. Swr is measured by relatively inexpensive meter that attaches to the output of the transmitter where tha antenna lead normall connects - like this:



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These meters are an absolute MUST for proper transmitter setup and operation - and many CB rigs have them already built in to the set. Radio Shack is one inexpensive source for a SWR bridge.

 

[B.G. Smith]

I just bought a high-power CB antenna (Midland Power-Max 18-258) to mount on my rear window.



In the documentation, is the following notice:



"This antenna may cause interference problem if mounted on Rear Window of cars equipped with Electronic Fuel Pumps. Front or Side Window mounting of this type of vehicle is recommended. "



I'm thinking in my case the lift pump might be affected. Side windows aren't an option for me (they roll down).



Anyone ever experienced this? Any ideas or thoughts?"



Is there a chance they are talkingf about interference to the radio from the fuel pump rather than the radio interfering with the fuel pump??? When I installed my ant. (firestick) on the bed rail about 18" behind the cab I ran the ant. wire up under the truck and near the wiring to the VP44, the radio sounded like a chainsaw with the engine running. I got a filter from RS and solved that problem. bg

 

[RMachida]

I think they are referring to the fuel pump interfering with the radio. Initially, I thought the reverse but this makes more sense...

 

[Crunch]

SWR = Standing Wave Ratio - a measure of antenna performance and proper match to the output impedance required by the transmitter for best transfer of RF power to the antenna. If the SWR is high, both transmit and receive performance is degraded, and the transmitter might suffer damage. Swr is measured by relatively inexpensive meter that attaches to the output of the transmitter where tha antenna lead normall connects

When I was looking at CBs several of the radio shops in the area told me that the CB radio has no effect on SWR. They said that you buy an antenna and tune it to the vehicle, which becomes part of the receiver/transmitter setup. Once the SWR is as low as it gets you buy whatever CB you want and hook it up. Was also told to avoid window mounts and magnetic mounts because they don't make good contact with the metal on the vehicle. While some radio shops were ready to sell me any antenna, a few pointed out that because I wanted the antenna mounted in a stake-hole mount in the bed I needed a top-loaded antenna (coil at the top) because the signal in a base-loaded antenna is blocked by the truck cab. Was also told to avoid using more than 18' of antenna coax if possible, and if I had to add coax to do it in 3' increments. My Cobra 148 has an SWR meter built in, but all the radio shop people said that the built-in meters weren't as accurate as the separate units. I have an old Radio Shack SWR meter, but since it only costs about $5-$10 for an SWR tune-up I let them handle it. I was also told that Wilson makes some of the best antennas, but I ended up with the Firestik because it has a 5 year warranty. Trashed my old antenna in a covered parking garage--it was probably OK, but I figured it's a lot cheaper to replace the antenna than the radio.