Addressing an earlier post about car radio reception, Bill writes:
Why do car radio's pick up stations much better than your typical home radio? I don't know of any home radio that picks up stations better than even a basic inexpensive car radio, here's the answer why this is.
Modern Home radios have an internal antenna; it's constructed of a ferrite rod, wound with ultra fine, multi stranded Litz wire. These Litz wire internal antenna's work fairly well. Years ago, before the litz wire ferrite rod antenna's were invented, all radio's had to have an external antenna, to pick up stations. Those external antenna wires had to be connected to the radio and strung out doors for good reception. The longer the wire and higher off the ground the antenna wire is, the better they work, in fact, a well made long wire antenna work very very well, but they were not very practical. If you wanted to move your radio around the house, you were dragging an antenna wire around with the radio. So, someone invented the Lizt Ferrite rod internal antenna. The litz ferrite eliminated the need for a cumbersome antenna wire connected to your radio. A car radio is much like an old radio, they do not have an internal antenna. The reason car radios do not have an internal antenna is because it would not work well inside the metal body of the car, the metal car body blocks the radio signal, that's why all car radios depend on an external antenna mounted to the out side of the car. In addition to an external antenna, car radios also have a ground connected to the chassis of the car, this helps the radio signals pass though the radio circuitry, greatly improving the radio reception. Modern Home radio's do not have a ground connection either.
Here's the best solution to improving and receiving radio signals at home. Get a CAR radio and hook it up to a Car antenna, the antenna must be situated out side the house. Hook it up to a 12 volt battery, also run a grounding wire from the body of the radio to a grounding rod that planted deep in the ground outside. THEN you can pick up radio stations at home every bit as good as you can in your car!
It's not just the car radio, but the environment. You're outside instead of in a building, and away from r.f.i. causing devices. Out in the driveway or wherever you're not around that touch lamp, light dimmer, switch-mode power supply, computer, and TV set, nor is the signal having to travel though walls and fit into the structure. Ya ever notice how you get static when under a powerline and how the signal fades when you go under and overpass? Same deal.
Yes, a car radio hooked into an outside antenna can work wonders...even better if you can find one of the old types with a loading ("booster") coil built into the whip...
http://i20.photobucket.com/albums/b218/driveinfreak/ant.jpg
Yes, that little coil does make quite a difference on AM.
If you put one on your car you will get more noise from powerlines, and possibly your ignition, but it will also do a better job at pulling signals out of the air. Just make sure you have it fully extended.
Also if it's an older radio you will want to make sure the antenna trim cap is adjusted properly. There should be a hole in the case with "ant trim" marked close to it. Tune into a weak station around 1400 and tune the cap for the loudest signal.
One disadvantage of using a car radio and antenna is that it's non-directional. You won't be able to null anything out as it will receive equally from every direction. Multipath FM can be a bit of a problem too.
Just for the record there where built in antennas before ferrite loopsticks. The ferrite rods didn't really come in until the transistor radio days. Some of the realy early sets used longwires, but it didn't take log for the open air type coil to became common... http://i20.photobucket.com/albums/b218/driveinfreak/ant3.jpg
Unfortunately a lot of them were made out of cardboard so they're often missing.
Posted by: Drive-In-Freak | July 07, 2013 at 06:57 PM