How to make a j pole antenna for 2 and 440?
J pole antenna generally consists of two elements having different wavelengths of about ¾ and ¼. A coaxial cable is attached with the two elements of the antenna. The conductor of one element is connected to the other element through a coaxial cable, usually copper in nature. The visible range of the antenna is best for the conduction of signals. At the lower angles of the antenna, the signal reception and transmission are best.
The grounding of a j pole antenna is done in a circular pattern. It is done in order to obtain the frequency of maximum wavelength. Constructing a simple j pole antenna is an easy process and can be done by yourself by following these simple steps.
All you need are some simple tools and equipment, and you are good. These include an EMT conduit, a rod that is threaded, an L-shaped bracket, clamps, nuts for locking, and an antenna mount. You can use any type of antenna mount that you have.
Tuning the j pole antenna
The j pole antenna is now ready; we need to tune it for frequency by using an SWR meter. Now we would tune the smaller range of frequency first. For example, in our case, the two-meter frequency is tested first. For a standard 2-meter antenna, the impedance is about 45 ohms, and the frequency is about 147 megahertz. So, you need to tune your antenna according to the desired frequency.
For adjusting the antenna, you can try moving the brackets to reach your frequency. Now we need to tune the antenna for the larger value, 440. The length of the antenna, in this case, is 70 cm. With the longer and of the rod, we need to tune the antenna. The nuts used for locking are required to move the bracket.
Mounting the j pole antenna
The tuning process of the antenna is now done; we need to select a perfect location for mounting it. A rooftop is better for an antenna because the higher you mount your antenna, the more signals you would be able to receive.
Performance of j pole antenna
As far as the performance of this antenna is concerned, the two-meter segment of the antenna is able to cover almost 50 miles range using minimum power. For the longest segment of the antenna, the range is about 70 Miles with more power and about 30 miles with less power. This type is antenna is best for receiving the signals for home use and connecting them to devices like TV or radio.
How to make a cactus j pole antenna?
You can easily make a j pole antenna is most probably copper cactus j pole antenna. It has a transformation range of about 85 miles. It is cheap and most easy to make. A simple dual-band is used to make the cactus j pole antenna. The distance between the smaller and longer length of the antenna is most important and should be kept in consideration.
For making this type of antenna, we need to solder the larger and smaller copper component of the antenna and then make a connection between them using a coaxial cable and some batteries. You can easily drill the holes in the copper pipes yourself and run a coaxial cable through them.
The battery is mostly used for these antennas is about 5-volt power. You can add two or three j pole antennas in a single line connected with a common base ground for increased and better signal reception.
The spacing between the two elements of the antenna should be at least one inch each or half an inch. There should be a connection solder in the center of both. The spacing between two elements should be different from each other, and the rotation can also vary. The mostly vertical position is suitable for attaching the two poles of antennas.
Precautions with j pole antenna
If you make a small-sized j pole antenna, it will become quite difficult to maintain the distance between the two elements of the antenna, and they tend to get bent or distort the signals of the other antenna. For this purpose, you can attach a plastic spacer between both the pipes of the antenna.
It would ensure that there is proper distance between the two legs of the antenna and they are not causing resistance in each other signals. Spacing the two copper rods of the antenna properly makes it more durable.
It is suggested that you use a choke or resistor near the feed point of the j pole antenna. Because while we take readings with the SWR meter, the signals from RF make it difficult to get the signal frequency near the feed line. For a two-meter antenna, we use a coil of 5 turns and a coaxial cable of about 6 inches in diameter. So if we use a resistor of about 4 inches with the feeding point of the antenna, it would be much better and easier to take the SWR reading.
Creating a j pole antenna is easy if you have some metallic rods, an l-shaped breaker, some clamps and nuts, and an antenna mount. The signal range of a j pole antenna is impressive with the two legs of the antenna.