Lotus Elan and Lotus Elan Plus 2 Forums

Hi all,

I have recently fitted a Retrosound radio to my Elan plus 2, Christopher Neil. It sounds excellent and I would recommend one of these. It also blend into the dash of my car perfectly. I've attached a photo.

Ipod playback os excellent. The radio reception is very good unless the car is moving and then there is interference with the motion of the car.

Does anyone have advice on how to get good FM reception in my Elan. I understand that this is a challenge.

Many thanks,

Rob

Salut Rob

Lotus had their interference kit - a plate over the spark plugs and a vertical one between the bulkhead and engine - don't know how effective it was, though.

What king of spark plug leads do you have ? Apparently the modern coiled conductor type were developped to reduce EMI - solid-core types would be the worst for EMI, I think.

I'd like to see more photos of your car, please. I have a soft-top +2 and am always interested in seeing photos of others. Looks like you have a Spyder Zetec with Jag seats ?

Merci

@+

Vernon

Thanks for the information Vernon. I will post some more pics when I take some! It is a CN Spyder conversion indeed. It is a fantastic car to drive and look at.

The interference does not seem to come from the engine as there is nine when stationary even with the engine revved. The signal seems to waiver when the car is driving along.

Any other suggestions anyone?

In my case I have a shielded co-ax aerial cable that goes to the rear of the car and my aerial is mounted on the left side at the back, as far away from the engine as is practical.

No good for AM, but FM works OK.

Monopole antennas like whip car aerials need a ground plane (conductive flat area at the antenna base) to work well. In a 'normal' car, this this is provided by the steel bodywork. Unfortunately for Elan owners, GRP doesn't conduct. Wikipedia has a good article.
The Elise was plagued by poor radio reception, and Lotus fitted an active antenna with a powered amplifier in the aerial base to try to boost the reception. Apparently this was not a great success. Elise forums have threads of owners trying to create ground planes on the underside of their engine cover with self adhesive aluminium tape to improve reception (it didn't help that the Elise aerial is right on top of the engine).
Its been a while, and I am afraid I can't remember enough about how big a ground plane needs to be relative to aerial height to be effective.
Absent changing your radio, I think you should investigate the possibility of creating a ground plane of some sort at the base of the aerial (the dimensions required may make this impossible), or mounting an aerial amplifier near to the antenna.
Good luck.

I am watching this thread with interest as I also have a similar problem. I don't know the solution either. I am fairly certain that the interference does come from the engine however even though like you say is seems worse when the car is diving rather than stationary with the engine on. Mine however is almost as bad stationary with the engine on. I've tried suppressing / filtering the spark (HT leads plugs, and LT coil), the noise from the generator at the control box and the incoming power to the receiver with no real improvement. I don't want to however go putting loads of tin foil or plates over the engine / bay, so if it is this then so be it. A ground plane for the aerial would defo help but I don't know how this can be done in the Elan.
I was wondering if going to DAB would work? Any one know? Would the reception be even worse and completely cut out like it does at home with poor signal, or is DAB in a completely different frequency range that isn't effected by the RFI from the engine?

DAB can be a solution depending on the area where you drive most. I am fortunate because on a 30 (ish) mile radius of home there seems to be a good DAB signal. I have a DAB adapter hidden in my glove box which I listen to through a period radio in standard position in the dash. The downside is you have to open the glove box to change station but I listen to the same station 80+ % of the time so no worries.
There a DAB adapters that work and those that don't. I initially bought an Acoustic Solutions unit which was useless - they are now available on Ebay quite cheap so I think other found them useless and the suppliers are trying to unload them. I then bought one selling under the Goodmans name. This work well and the station selection is something easily done in a moving vehicle - not so for the acoustic solutions product.
When I enter an area where the DAB signal is poor I just change to FM with the odd imperfection.
DAB doesn't work as well in a fibre glass car as it does in s steel car. The DAB signal is basically a data stream that is decoded and turned into the sound you hear. It uses a system (spread spectrum) that uses clever techniques to recover the data even in noisy conditions but the Elan contributes more noise to the system than would happen in a steel car so it will eventually pack up but I've found its worth doing. The other thing against radio reception in an Elan is how low it is - rule 1 when installing any antenna is getting it a high as you can!
In case you wondering I have spent most of my 50ish years professional life involved with radio systems so I do know a bit about it.
Cheers
Baggy

Thanks for all of your help I will try some options. I've also been told that fitting a thick ground cable from the ground point on the aerial down to the chassis works really well. Has anyone tried this?

Also has anyone tried to fit an artificial ground plane?

Appreciate your expertise all,

Rob

In my Elan I ran a shielded coax to the rear near side wing where the aerial is mounted. I made up a ground plane from the lid of a biscuit tin lid cut to shape to fit on the underside of the wing and mounted the aerial through it. On fm it works fine with no interference.

I did buy a good quality aerial as well.

Thanks powellsmail. How big was the tin plate?

Rob, which Retrosound model did you buy? Do any of them have a CD player built-in? Is it mounted simply with the face plate - if not how is it held in place?

Mike

Mike,

It is a model 2. No cd but full ipod connectivity. Fits like a standard two knob radio. Lots of fitting instructions on the web and on YouTube. Are you in the uk? If so I can recommend that guy I bought it from.

The radio is excellent, by the way.

Rob, I am in SW Scotland. Here we have rubbish DAB coverage, so good old FM is what's needed.

Mike

Nice install Rob. Your RetroSound looks great. I see in the owners manual (link below) that the mounting depth is only 4.3", which is great for the Plus 2 with the heater box interference issue.

http://a248.e.akamai.net/pix.crutchfiel ... O2B_DL.PDF

I used a different modern radio in order to get Sirius Sat Radio capability. Mine has the main system mounted in the boot, and a very shallow dash controller.

I tried creating an antenna ground plane as well. I used conductive foil duct tape and aluminum foil to shape around the right rear fender. Didn't have any impact. Have a ali plate I am going to try next. Idea is to clamp the antenna mounting stanchion down on to the ground plane plate, and then run a webbed flat ground strap from the plate to the main rear ground.

For interference issues, I found the greatest improvement by making sure the speaker wires do not run next to the main wiring loom from the boot. Speaker wires should be place left side of car and main loom, including main Positive battery cable, right side of car. Also moved main Plus 2 ground from the bolt at the bottom of the boot floor to the right rear tower body bolt.

I found this article pretty good for determining the noise sources and possible mitigation. Crutchfield also sells the RetroSound line and has pretty good info on their products. The issue I focused on was ground loop, which is caused by the various stereo components (including the antenna) being grounded separately to the frame / battery at points of different potential due to dodgy connections.

http://www.crutchfield.com/S-AJ2rZRBGCQ ... guide.html

I don't use AM or FM much in the Plus 2 any more, as Sirius or iPod works better.

HTH

Stu

Stu,

Thanks for the information, very useful. I'm also going to try a copper sheet ground plane and also connect the aerial ground to ground connection in the boot floor. I'll let you all know whether this cures it.

Rob