Long Wire Radio Antenna Info


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In the early days of radio (1920's), stations were often quite distant from the general public and few transmitted with a lot of power. For good reception in rural areas and most small towns, a good external antenna was required. A good antenna would usually be about 100', insulated on both ends, strung up on the roof, tall poles or from house to barn with a down-lead in wire connected to radio's antenna input. Of course a lightning arrester would be part of the installation. The wire's gage is not important except it must be strong enough to support itself. Copper is  best., bare copper wire works  well and the best stuff  was  stranded  around a steel, center support cable which helped keep it from stretching. See: Typical outside antenna installations.

Nearly all US built radio receivers made from the early days to the late 1930's required an external "long wire" antenna. Most sets made after the late 1920s had one or more terminals on the rear of the chassis or a *pair of wires hanging out the rear that was hard wired to the radio's circuitry. The colors were often black & blue, green & black or they could be any color. Black is usually the ground wire. These wires are for connecting an antenna and ground. The antenna is easily identified; if you are not sure which wire is which, the antenna will be one that makes the radio (when turned on and the volume turned up) come alive when you come in contact with the bare end with your fingers. Unless the radio has internal wiring issues or shorts, you don't have to worry about getting shocked by touching the antenna or ground wires (assuming they are in fact the correct wires I'm describing) and the radio has been properly serviced by a competent technician. If you are not sure, don't mess with it.

The ground wire is not always necessary and some radios SHOULD NEVER HAVE A GROUND WIRE CONNECTED!  Such radio's are the AC/DC type and should have a warning sticker on the back of the set. If you are not sure, do not attempt to connect a ground wire. There are a couple of ways to identify a radio that is safe for a ground connection; one are radios with with a power transformer, the other are radios with terminal marked "ground". Again, if not sure, don't connect a ground wire. The radios that are unsafe for ground wires are the low priced, low end sets with series strung tube filaments (more properly called, heaters). Such sets will often have what's called a "Hot Chassis" and a dangerous electrical shock hazard exist with such radios if certain precautions are not observed. Such radios purchased from the author of this article will have a polarized line cord and should never be defeated.

Beginning in the late 1930's, built-in antennas were introduced as part of the latest state of the art equipment for most radio models. At first they appeared on the better quality console models and within a few years were pretty much standard equipment on most all radio sets.

Most radios that require an external antenna have an "antenna" and "ground" post terminal at the chassis rear, some may have a couple of wires coming out of the chassis. A good radio working properly may pick up a station or two without an antenna connected but reception will be weak and likely very noisy. Often a 15 - 20 foot piece of small gauge bell or speaker wire strung along the baseboard will usually allow reception of stations within a 15 - 20 mile range. For better reception, a longer wire, higher in the air is necessary. I have strung an antenna in my attic that serves quite well for good all 'round reception for continental as well as worldwide short-wave reception.

* A few more things of note; if your radio has two loose pigtail wires coming out the back, chances are; they are the antenna & ground wires. The ground wire is seldom needed. If you are not familiar with operating such and ancient radio, here's some tips; you should get local stations with an extension of a 20 -30' piece of additional wire. For long distance reception (more than 25 miles away) a longer and higher wire will be needed. Reception depends on the stations power, distance and the time of day or night. One other thing, unlike modern radios, the early radios did not have what's called "AVC" (automatic volume control). This means weak stations require a high volume setting and strong stations a low setting. So it's not abnormal while tuning from a weak station to have a strong local station to come in with a BLAST!

Other issues with these old dinosaurs is too much signal, if you have a radio station in your back yard or just a mile or two away, they can come in uncontrollable even with no antenna. For such situations, remove any extended antenna wire, if still to strong, connect the loose end of the antenna wire to the ground wire. If that does not help, contact me

Antenna eliminators. Such devises were available in two varieties; 1) an external devise that was  plugged into an electrical wall outlet or a light socket. Few homes were wired with AC power outlets in the late '20s & '30s.  Only the most upscale, most well-to-do folks had such conveniences. If you only had light socket wiring, you had to operate your electrical appliance or radio by means of an adaptor that screwed into the light socket. 2) the well do folks with the up-scale homes would have their homes wire not only with AC power electrical outlets but an additional similar type socket panel could be installed that contained the antenna and ground connections!

There were a number of so called antenna eliminator devises sold and used so as to not have need of a real outdoor “Long Wire” antenna. These devises were connected (many of them by a capacitor) to the power line (for isolation) which by this means, the power line became the antenna. Antenna eliminators actually worked to some degree but not as good as a real “Long Wire” antenna plus a lot of nose (from the power line) was introduced into the radio. Here's the caveat,  as long as these capacitor in the capacitor coupled devises was good all is OK. However, capacitors in those days were not very reliable, they could and would short out creating a real shock hazard by applying raw AC line voltage on the antenna terminal.

UL laws and shock hazard safety was not a big concern back in the early days of electrical operated appliances and radio. Many shock hazards existed with some radios and other electrical appliances.

So beware and be sure you are not connecting your radio to a shack hazard.

Sonny, the Radiola Guy

© C.E. Clutter


Member of:
Northwest Vintage Radio Society

Member of:
Antique Wireless Association