What is the gain of a Slim Jim antenna?
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).
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.
What do I need to make a slim jim?
What you’ll need to make a Slim Jim: Some balanced ladder line feeder – either 300 or 450 ohm will do – If making an antenna for 145MHz, then you’ll need a length of 1.5 metres. For other frequencies, use the calculator later in this article. Some co-ax long enough to reach from the base of the slim jim to your radio.
How do you make a Slim Jim antenna?
The project was simple – let some of the youngsters make a 2m Slim Jim antenna out of 300 Ohm ribbon cable. We had made plenty of these before and they work well. You cut a piece of white, translucent ribbon cable of about 60 inches long and bare the wires at both ends by about half an inch.
How do I find out the frequency of a slim jim?
The dimensions are crucial, and here I’d highly recommend M0UKD’s Slim Jim Calculator. You put in the frequency you’re after, e.g. 145.500MHz, and the calculator gives you all of the values you need. Go to www.m0ukd.com/Calculators/Slim_Jim and print out the dimensions you’re after.
What is the difference between A J-pole and a slim jim?
The difference between a J-Pole and a Slim Jim is simple: while both share the same design, the Slim Jim folds another 1/2 wave element over onto itself, turning the single half wave concept of the J-Pole into a double half wave, or ed fed folded dipole antenna.
