Drive-In-Freak writes:
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.
An additional advantage a car radio has that it gets its power direct and "clean" from DC 12V battery whereas a home radio first has to transform mains AC to DC low voltage. This is very often the cause of interference esp. with a "modern" switch power supply. Because of this the car stereo also has an "unlimited" amount of power available for peaks whereas a home radio is limited by the transformer specs. On batteries even more so of course.
Posted by: Johan | July 08, 2013 at 02:39 AM
Less RFI noise is a huge advantage in mobile DXing. And vehicle radios with the old traditional whip antenna seem to be more sensitive than the built in windshield wire antenna.
If you have the old style whip, try extending it about 24-30 inches and it will improve the sensitivity quite a bit. Do this by getting 36 inch lengths of steel, flexible music wire in various gauges from the hobby store. Don't add too much length or you will run into overload and desense problems unless you are really out in the boondocks.
My extended whip 2006 Ford Ranger truck radio picks up more than my $400 Eton E1, though the selectivity is much worse, obviously. Mobile DXing is the way to go.
Bill
RADIO-TIMETRAVELLER
Posted by: RADIO-TIMETRAVELLER | July 08, 2013 at 08:07 AM