There was a device called an active antenna - there were construction projects for these. Try google.
The other way is a honking big tuneable loop antenna - but that's not too portable.
"Rudge" wrote in news: snipped-for-privacy@brightview.co.uk:
No,Saturns have plastic panels over a steel chassis. Mostly on the sides,I believe the roof is still steel.
You folks are getting way too complicated. You can just strip about a half inch of a 3 foot 12ga solid wire, bend it over at a right angle so you still have about 1/8" of insulation in the bend and shove it in the antenna hole. Hook that up top an old PC supply and rock on. I have a radio in my shop set up that way and it works fine.
The AM aerial I have here in the UK covers LW, MW and SW and is an externally mounted vertical rod about 4 metres long with a type of balun on the end. The cable is a twin screened balanced type - a special for those frequencies. At the other end is a second transformer that does balanced to unbalanced to feed a tuner. The principle is that most interference at these frequencies radiates horizontally, so you put the aerial above it and have a well screened downlead. Not a cheap device but it works well and is a one time purchase.
If you only need the one station, I'd consider mounting the receiver in your attic so the aerial is close and in a good position and radio link it to the other(s) in the house.
The main problem with plastic bodied cars is interference from the car ignition, etc. On others the engine is in a sort of Faraday cage. Hence the earthing straps you often see across the bonnet (hood) hinges. Although this is mainly for the benefit of others to prevent RFI to TVs etc. But it helps the car radio too.
Car stereo works just fine in my fiberglass sailboat. The "antenna" is just a long antenna cable extension with the shielding stripped off of the last 31 inches. It's tucked up inside the headliner inside the cabin.
CWM
How's your AM reception? 8^)
CWM
About like it is in my car. We really only have 2 AM stations here and one is en espanol
huh? there's plenty of holes around the engine so that it's not a faraday cage. most radios have some sort of filter for this. for that matter, my vette doesn't have any of these and the radio works in it.
Corvettes have a layer of wire screen embedded in many body panels, including the hood.
CWM
have you seen the engine compartment of one? my 94 certainly doesn't have a bottom panel under the engine, nor side panels where the wheels are. there are no bonding straps over the hinges, which are on top of the front bumper anyway. it doesn't have a front panel in front of radiator, just the bumper, which does not have wire mesh, nor any mesh behind it. how much of a faraday cage would it be with only the hood having wire screen, if there was actually one there, and which isn't bonded to anything?
A Faraday cage can be made of mesh. Doesn't have to be solid steel.
Some sort of, yes. But it's still better to stop interference getting to the aerial - especially for distant reception.
I didn't say it wouldn't 'work' Only that it won't work as well as in a metal bodied car unless some form of alternative screening is used.
holes, as in multiple square feet. that's pretty loose mesh. faraday cage holes are sized to the wavelength of the frequencies that are to be blocked.
to claim that the surrounding car body panels of a car engine is a faraday cage is just incorrect. faraday cages simply can't have holes or they leak the signals, making the cage be useless. a cage either is complete, and it works, or is incomplete, and doesn't work. in the latter case, if it doesn't work, why would manufacturers pay to engineer and make, and we have to pay to haul around forever, an incomplete cage?
You are incorrect in many of your observations and conclusions. If your hood and other body panels did not have a grounded screen embedded, Your radio would be entirely useless, especially on the A.M. band. All you would hear is ignition noise, and probably your horn, heater motor, and wipers, through the speakers. The fact that there are some openings is of no consequence.
CWM
The 69 Corvvette I had was ordered without a radio and it was missing the radio kit. That was shielding on the plug wires and distributor. I even got noise in my 8 track player. An AM radio was useless
Well, I remember who gave me the ground plane story. It was a friend who works in an ancillary part of communications. Don't know where he got his information, but he could very well have been wrong.
He even offered me a ready-made box that sounded like it was designed to hold a car radio and power supply. He's been trying to clean up so I hope he still has it.
If I had done this earlier it might have been good, convenient and saved me time. Otoh, it's not like I've suffered so bad these past years. One GE AM-FM clock radio from 1972, in my office, gets one of the 2 DC stations well enough all the time, and the other station about welll enough almost a half of the time. It will work for weeks and then not work for weeks. I think they change things at the transmitting station in DC. WAMU. It's this radio I guess that is motivating me to find a better replacment.
The radio in the bedroom gets both, and both well, though lately it has't been getting the local Baltiomre station WYPR so well. That was perfect for 15 or 20 years! Maybe they changed the transmitter too.
The current very cheap looking Admiral clock radio from tthe 1960's or
70's gets both, although WAMU not perfectly.Plus I keep a radio outside in the summer time. I think it got both stations but I haven't listened yet and I forget how well.
But these are the best of about 20 radios I've bought at yard sales, plus two fairly expensive stereo tuners, which don't get WAMU at all.
Thanks to everyone. Maybe I'll be able to give some follow-up some day.
He's right. The best place for a car aerial is on the (steel) roof where it acts as a ground plane, as well as being as high as practicable. However, field strengths are designed for much less efficient aerials - in urban centres at least. So car designers will go for a 'prettier' look - hence the appalling devices built in to rear screens etc which quite simply don't perform as well in poor signal areas. But the other snag is it's not really possible to use the correct length for AM reception as it would be too long in practice.
Ideally, the aerial should be as far away from sources of interference as possible - and in a petrol car this means the engine. But the downlead should be kept as short as possible too which is somewhat of a dichotomy. IMHO, the best compromise is at the rear of the roof, with a head amp to make up for losses caused by the longer lead. In an ideal world you'd also use separate feeder cables for VHF and MF.
Thanks for replying. It's not reception in the car that is a problem. It's getting the same reception in the house.
So that's the thing. The stations I wanted were in DC about 45 miles from my house, so the field strength is not high here. So my friend was saying even the less efficient mounting place for the aerial, on the side of the metal fender, would be a better place than in the house, where it would have had no "fender" at all. The first floor of my house and the parking lot are the same height. So, that the car radio worked in the car wouldn't mean the same radio would work in the house.
So -- unless I ran an aerial to the attic or the roof, which I didn't plan to do when I talked to him -- maybe he was right that the car radio woudln't have worked on the first floor??
I don't think there is much interference in my wood frame house, with a few electrical outlets, and a few ceiling fixtures, all of which could be turned off if it helped, and one aluminum-frame window. Plus two steel I-beams that hold up the second floor. But maybe these things have more effect than I realize.
I'm judging by noting the effect that various steel bridges have on reception when I drive through them, and a bridge that has no more steel than my house's second floor doesn't have much effect if any.
I'm also judging the FM part by the fact that some radios do receive the FM stations I want in the house. I had thought the car radio was BETTER than any of them, but if it is the not as good as it could be but still a lot better than no ground plane that exists when mounted at the car fender, and not the radio, at least my friend will have been right. Which is important in itself to know, even if there were ways around this by mounting an aerial in the attic.
I couldn't find a single AM radio that would get WRC Washington DC in the house, even when I was on the second floor, even though it came in clearly in the car. My friend said that the car radio wouldn't work as well in the house as it did in the car, even with the aerial mounted on the side fender of the car.
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