I replaced the power antenna on my 2004 XK8. The stock antenna is very noisy at speeds above 45 MPH or so, and as most know, the antenna raises even when listening to CD’s. I considered installing the switch to disable the power to the antenna. Instead, I found a hidden antenna that works. I don’t know if the antenna could be installed inside the trunk and still work, since it would be surrounded by grounded metal, so I decided to install the antenna on the inside of the plastic rear bumper so it is completely hidden. I purchased a Tune Trapper Marine antenna from Amazon item number B002WQTS58. I chose not to use an amplified antenna, as they have not worked well for me in other situations. This antenna is a quality design, and is intended for marine use, so it can withstand the weather. The antenna is a bit unusual in that it is essentially PVC tubing with coiled copper wire inside the tube. Not a typical antenna one would expect to see. Installation was 30 minutes. I disconnected the electrical plug and antenna lead on the base of the antenna in the trunk. At the right rear side of the car there is a rear fender mounted light. Looking underneath the car in this area, up into the rear fender area, the wire harness for this light can be seen coming through a rubber grommet. I pushed the grommet up from the bottom into the trunk. From inside the trunk it can be seen in the area between the amp/hydraulic pump frame and the rear of the car. Once the grommet was pushed through, I used a large screw driver to poke a new hole. Then from underneath the car, I placed the antenna inside the rear bumper. There are metal pieces that attach the car to the lower portion of the plastic bumper and held in place with some plastic rivets through the bottom lip of the bumper. I placed the antenna between these, which cradles the antenna in place. The antenna comes with a piece of double stick tape at the "center block" where the lead come out. I used this to stick it to the inside of the bumper. I then pulled off the tow hook cover and tie wrapped the antenna lead through the opening. I also tie wrapped the pvc of the antenna to the metal straps that hold/stabilize the bumper. This holds the antenna in place. The lead is routed above the tailpipe and over the bumper shock absorber, then up into the hole that the grommet was in. From inside the trunk, I pushed the end of the lead through the hole I made with a screw driver in the rubber grommet, then routed the lead behind the amp up to the area near the factory antenna. I reinstalled the grommet. I connected the lead to the lead that goes to the radio. This is the only difficult part. The ends are different sizes. I suspect there are adapters available, but I adapted it myself. The antenna seems to pick up stations at least as good as the factory antenna. I didn’t uninstall the factory antenna because I don’t want to have to figure out what to do with the hole, and it all looks stock. Total cost was $42.

 

Steve! That's awesome! I've been trying to figure out what to do with my antenna. I thought about installing something in the compartment that the convertible top folds into, but behind the plastic bumper makes good sense.

My biggest concern was the connector at the existing antenna. As you saw, it's a weird connector and I haven't seen anything similar to it. I browsed the RF connectors on mouser.com, but there's about 5,000 of them and I didn't see anything that looked similar as I scanned through. How did you adapt the connector to make it work with the new antenna? I don't want to cut off the existing connector because I want to be able to return everything to factory condition in the future some day (these cars will be collector's items eventually).

 

This is what I did Sam, but I am not sure its necessarily the best solution for everyone. The new antenna lead connector is the standard radio antenna connector we are acustom to seeing. I cut it off. Then I stripped the plastic coating off of the lead to reveal the braided ground shielding. I unbraided it and sort of fanned it open. I then cut the plastic insulator back that covers the copper center conductor to reveal about a half inch of the center conductor. The center conductor is about the same gauge as the mail connector from the factory antenna, so I just pushed this into the female connector lead that goes up to the radio, then wrapped some electrical tape to insulate it. Then I made sure the now unbraided shielding ground made contact with the ground on the cars antenna wire, and wrapped it all up with tape.

 

Ah! I see. That way the factory connector stays in place, and if you ever want to revert back it's just a matter of untaping the joint and reconnecting the old antenna. Smart! I'm going to do this. I have a little twist in mind to make it only cost about $10.

 

If you are thinking about a regular/inexpensive non-telescoping car antenna mounted in the bumber, its not a bad idea and for the money, worth a shot. I was not sure how it would work because in my limited understanding of antenna technology, I think regular car antenna requires a ground plane to work well. Also, you would need to be sure the antenna metal doesn't touch any grounds like the bumper support straps inside. Easily done with CPVC. Hope I didn't steal your thunder.

 

This is very cool. I looked at the specs. They've wound a full 1/2 wave-length (for FM band, so ~ 5 feet) of wire into a helix and so shrunk the total length to 24". As they said, this configuration doesn't count on a ground plane. Very clever.

I think you might have covered this ... reception comparable to the stock antenna, both AM and FM?

 

My reception is at least as good as it is with the stock antenna, on both AM and FM. In fact, AM was probably more important for me, as I like talk radio. If I listen to music, it generally is CD's, but not always. My wife liked a particular FM station that we get at the house fairly well, but if we drive 10 miles north toward the city, is weak even with our other car. With the new antennna, the station comes in as good as before, so I am happy with it.

 

I like this idea---there's got to be a coupler that can be used between the male connectors? If I get a chance this weekend I'll investigate the Jag. antenna connector to the aerial unit in the trunk. Great job Steve!

 

Actually, I was going to buy a cheap, folded dipole FM antenna at Radio Shack. It's really just three pieces of dipole antenna cable connected together at the center so that each half of the horizontal part acts as a quarter wave antenna. I was then going to connect it to a 75 ohm balun and run regular CATV coax up to the antenna connector in the trunk. I'll connect it to the antenna cable the same way you did with no actual connector, just electrical tape.

I'm actually still thinking about putting it in the compartment that the convertible top folds into. It would be easier to route the wire there than down to the bumper. But if I route it down to the bumper, I'm just going to hold the antenna to the inside of the bumper with Gorilla Tape (like duct tape but much stronger and stickier. Also, I think duct tape might be conductive with its silvery finish. Gorilla tape is not).

The antenna connector appears to be unique to the Jag. The connector that plugs into the back of the radio is a standard connector, but the one that connects the alien beacon to the cable is some wierd... uh, alien connector. I scanned through all of the RF connectors on mouser.com, but there are literally thousands of them, and a lot of them don't have images. It would be great if someone could identify the actual connector! If anyone can figure out what connector to order from Mouser, I'll by them a beer.

 

I like showing off my shiny antenna...its bigger than anyone else's on the road, i'm considering adding CB to the car since its approaching the size required as evidenced by the po-po and truckers.

 

LOL! That reminds me of something. I have a HUGE deck off of the back of my house. It's on 4 different levels and it's about 2000 square feet. My wife gets mad when I brag about my big deck. I'll say "You should see my deck. It's huge! I have the biggest deck in the neighborhood. All of the other husbands are jealous of my big deck!" My wife thinks I'm being crass, and I tell her to get her mind out of the gutter. It's not my fault if other people read in to what I'm saying, right?

 

Sam, you might be disappointed by the performance of a dipole antenna in a moving automobile. Dipole antennae are bi-directional (and legal in most Southern states now). They are good solutions for fixed locations where they can be set up with their maximum gain direction pointed at the transmitting antenna. In a moving car you'll have problems with varying signal strength as you turn. Not a problem near the transmitting source but will be noticeable in fringe areas. The traditional vertical antenna is omni-directional and doesn't have this problem.

 

On a more serious note, I bought myself TWO antennas this afternoon. One of them is a flexible, folded dipole antenna, and the other is just the regular rabbit ears. I routed a piece of cable up into the space behind the rear seat where the top is stored when it is folded. I initially tried putting the flexible antenna under the liner at the bottom of that compartment. The antenna was right against the metal decking, and even though that flexible antenna is insulated, it wouldn't work right next to the metal.

So then I experimented with it in different places. Up against the convertible top the reception was great. However I'm concerned that if I put in under the headliner, the reception will be lousy when the top is retracted. I put the antenna against the back of the rear seat, and it seemed to have pretty good reception there. That's as far as I got tonight. Tomorrow I'm going to see if there's a way to slide the antenna between the headliner and the canvas. If so, I'll try the reception with the top up and down. My backup will be to fasten the antenna to the back of the seat where it's hidden from view. The antenna is 54 inches long, so it wraps around slightly. Or, I might just end up attaching it to the rear bumper, as Steve did. More tomorrow...

 

Yeah... I'm aware of that, but I figure anything is better than the alien beacon. My next project will be to rig up a way to switch between the dipole and the mast. I wonder how well a radio signal travels through a relay...

 

Has anyone ever found a shorty replacement ...even like the ones VW uses, the whip antennas?

 

Since you're fiddling with coaxial cables anyway, stop by Radio Shack and see what they've got for Coax Switches. I've dabbled in Amateur Radio in the past and you won't get much loss through them.

 

I would be interested in knowing how that would work...just for curiosity sake. I actually began searching for these short flexible antennas when I found the tune trapper. I think it would look ok, but it changes the stock look of the car, so I went with the hidden.

If Sam comes up with something that provides better reception than what I have, which seems as good as stock, I would be interested. Sam, what if there were a couple of antennas installed, all coupled together? Maybe one behind the rear seat or next to the rear speaker and other places. I'm not sure, but I think the lead lengths would have to be the same to avoid collisions of signals?

 

I have a lot of interest here. Hate the singing of the current antenna. Couple of ideas:

Directionality: Seems that's usually worse in theory than in practice with a dipole, what with signal reflections and all, but it can be made better if needed by mounting the dipole at an angle to the horizontal, say at 45 degrees. (Mounted vertically, its "dead spot" is pointing straight up, just like our current antennas.) The Tune Trapper behind the rear seat, mounted at "45" ... that might be optimum, or a strong contender anyway.

On the 2-antennas idea: I hope I'm wrong, but not optimistic here. The lead-length issue gets to be a problem only when the difference in length between the two leads is a significant fraction of a wavelength (about 10 feet or more). So we can handle that one. But the same applies for the received signals ... if the antennas are separated by, say, 3 feet, sometimes they will reinforce, cometimes tend to cancel. Also, the signals should be combined through a directional coupler, and that will entail at least a 3 dB (50%) power loss for each signal. Again, hope I'm wrong ...

SteveJacks: your experience with reception so far please ... urban, rural, both?

 

I don't understand the problem with the antenna connections. I replaced my antenna with an aftermarket universal power unit I got from a Straus auto parts store and it connected with no problems. Jack

 

I just looked on Google to see what the standard RF connector looks like on a few different antennas. They look like the connector that goes into the back of the radio. That one IS standard. But on my car the connector that disconnects the antenna from the cable back behind the CD changer in the trunk is a weird connector that I haven't seen anywhere else. Are you saying that yours is just the normal antenna connector? If so, I bet your antenna has been replaced previously and the person who did it at that time cut off the factory connector and installed a standard antenna connector. Either that, or Jaguar changed the design at some point and started using the weird connector.