How good is a Slim Jim antenna?
The Slim Jim is probably one of the cheapest and easiest antennas to make, and it’s a very handy one too. You can typically make one of these for under £10, they roll up easily for storage and travel, and are great for use at home, or when travelling, for accessing local repeaters.
What is the gain of a Slim Jim antenna?
Slim Jim antennas have no performance advantage over the conventional J-pole antenna. The approximate gain in the H-plane of the Slim Jim is from 1.5 to 2.6 dBi (-0.6 dBd to 0.5 dBd).
How long is a Slim Jim antenna?
The Slim is an end-fed folded dipole antenna that has a gain of 6 dbi and a nice low RF take off angle….Additional information.
|Length||58 Inches tall|
|Gain||5 db, 7 degree take-off angle|
|Design||End-fed 1/2 wave folded dipole|
|Bandwidth||5+ Mhz from center frequency (146 MHz)|
How does a Slim Jim antenna work?
SLIM JIM ANTENNA PROJECT. The Slim Jim is a vertically polarized omnidirectional end-fed antenna having considerable “gain” and this is concentrated almost parallel to ground toward the horizon rather than skyward making it more efficient than a ground plane type antenna by about 50 percent better.
Is a Slim Jim antenna directional?
Do you need to ground J-pole antenna?
J-Pole antennas are half wave antennas by design. But instead of an RF ground, the antenna should have an electrical ground to protect it in case of a lightning strike. An electrical ground doesn’t enhance the RF radiation of the antenna, but it is an important safety feature on any installation.
Do you need to ground a dipole antenna?
Therefore, a dipole antenna requires two parts in order to radiate and the amount of radiation will be proportional to the dipole current. Note also from Figure 2 that, a dipole does not require a “ground” to work. A good analogy is to consider what happens when we clap our hands.
How do you build a Slim Jim antenna?
1. Measure out and cut about 59 or 60 inches of ladder line. 2. Strip both ends (top and bottom) about an 1/2 to 3/4 inch and bend each toward the center so they will overlap each other. 3. After you overlap the wire, measure the entire length of the antenna.
What kind of feeder to use for Slim Jim aerial?
The most common way to make this aerial is to use a length (155cm) of 300-ohm slotted feeder or 450-ohm ladder-line. Other (and more robust) versions can be built using aluminium or brass rod – perhaps as an outdoor solution.
Can a 70 cm antenna be used at 435 MHz?
At 70 cm it’s useable from 435 MHz to 449 MHz which is the portion of the band I’m interested in. The final installation has the 10′ PVC antenna assembly attached to a 10′ stick of 1″ EMT conduit mounted to the chimney.
What should my SWR be on my Slim Jim?
If you are only able to use your radio’s built-in SWR meter, you’ll be pleased to know that the Slim-Jim is quite a wide-band aerial so doesn’t have to be tuned perfectly, but aim for around 145.200 ish which will ensure you get good results in the FM section of the 2m band.