Loop antennas may be constructed in many forms including horizontal full wave loops in square, rectangle or triangle (delta) shapes. They can also be in the vertical plane and are most often in the same shapes with the delta being very popular as it has both vertical and horizontal polarization. The impedance at the loop resonant frequency is approximately 100 ohms but will very slightly on harmonics. Loops are “quiet” antennas compared to verticals and dipoles and are omni-directional. The also exhibit gain on harmonic bands. Once you try a loop antenna you will know why they are so popular with old timers but still a secret to newcomers. Shown below are some typical designs:
Full Wave Horizontal Loop Antenna (a.k.a Skyloop)
This antenna is horizontally polarized and should be mounted as high as possible but works well at low heights of 10-30 feet. They are quieter than a dipole or a vertical, have a broader bandwidth and will usually out perform a dipole antenna.To determine the approximate circumference in feet of a full wave loop antenna use the formula:
1005/Freq in Mhz = length in feet.
The feed point impedance of a full wave loop antenna is theoretically in the vicinity of 120 ohms and requires a 2:1 impedance transformer (for single band loops or a 4:1 balun to match on multiple bands) with 50 ohm line. You will also need a feed line choke or better yet, just get the Hybrid 4:1+1:1 in a single box.
Vertical Delta Loops
Vertical delta loops can be oriented several way but the most popular is to have the “pointy” end at the top (usually a single support) and the lower horizontal ends just out of reach of humans and animals. Best feed point is 1/4 wavelength (246/f(mhz)) from the top point down one side. Vertical delta loops use the same 2:1 baluns as the horizontal loops or 4:1 for multi-band operation.
PURPOSE
These kits are designed to choke common mode currents going into or exiting from your Tuner Genius cables. Filters are supplied for the RF Input (s) RF Outputs, DC power and LAN input. The DC power line choke helps keep common mode current out of the power line which could cause interference to other devices connected to the same power line if not suppressed. The LAN cable choke keeps any RFI off the LAN cable input.
USE
RFI-AT-FLEX-TG Standard kit for tuners with SO2R option and RFI-AT-FLEX-TG3 for tuners with 3 antenna outputs option (1X3).
Note if you use other cables into the tuner such as PTT or otherwise, use FSB31-1/2 snap on ferrites for these lines and wind 2 or more turns thru center if possible. These ferrites sold separately.
KIT INCLUDES
|
Filter Type |
Usage |
SO2R Kit |
3 Antenna Kit |
|
Snap On (1/2” ID) |
DC Power |
1 |
1 |
|
Snap On (1/2” ID) |
Ethernet/LAN input |
1 |
1 |
| FSB31-1 |
RF Output |
2 |
3 |
| FSB31-1 |
RF Input |
2 |
1 |
|
Total Filters |
6 |
6 |
INSTALLATION GUIDELINES
SO2R Kit - Part# RFI-AT-FLEX-TG (2 Inputs, 2 Outputs)
RF Output:Snap On Filter (1” ID) – 3 turns (1/2" cable) or 6 turns (1/4" cable) of coax cable through center for each output - Use 1 for channel A and one for channel B Output
RF Input Snap On (1" ID) - 3 turns (1/2" cable) or 6 turns (1/4" cable) of coax cable through center for each input - Use one for channel A and one for channel B Input
Ethernet Cable:Snap On Filter (1/2” ID) – multiple turns through center
DC Power:Snap On Filter (1/2” ID) – 2 or more turns of DC (+ and -) power cord through center
3 Antenna Kit - Part# RFI-AT-FLEX-TG3 (3 Antennas, 1 input)
RF Output:Snap On Filter (1” ID) – 3 turns (1/2" cable) or 6 turns (1/4" cable) of coax cable through center for each output
RF Input Snap On (1" ID) - 3 turns (1/2" cable) or 6 turns (1/4" cable) of coax cable through center for TX input
Ethernet Cable:Snap On Filter (1/2” ID) – multiple turns through center
DC Power:Snap On Filter (1/2” ID) – 2 or more turns of DC (+ and -) power cord through center
Also make sure you connect a good RF ground to the tuner ground post.
