T-5G

T-5G

Current

50 ohms in and out

1.8 - 150 MHz

Nil

Yes

50 Ohms

Ferrite, multiple types

> 1500 watts SWR < 3:1, SSB/CW duty cycles only. Not rated for AM, RTTY and other high duty-cycle modes.

6.2 degrees @ 3.5 MHz

Excellent

SO-239

SO-239

2.3" x 8"

Amazingly, we have combined the T-4G and the T-6G into a single package. The result is "full-spectrum" isolation. At last, you have a weapon to use in the fight against keeping HF RF out of your VHF gear.

Added isolations at VHF frequencies -

The incredible T-4G has been further upgraded through the use of special ferrites and winding techniques which extend the T-5G's isolation into the VHF spectrum. This is important with today's solid state transmitter which use broadband output amplifiers. Wideband power amplifiers often produce energy from the low HF frequencies to well into the VHF region. Filters are used in the output stages of the transmitter to reduce this RF energy to a tolerable level, but the filters in the HF transmitter are only so good and problems are exacerbated when ground loops develop around the communications system. The T-5G solves this problem by helping break up ground loops and keeping RF off the coax's shield not only at HF but also well into the VHF spectrum. The result is a cleaner communications system and less interaction between HF and VHF equipment. The T-5G is used with HF equipment. The T-6 and T-6G are used with VHF equipment.

Why two ground straps?

In communications equipment, signals travel in two directions. During receive operation, the receiver can pick up trash collected by a coax cable's shield acting as a random length antenna. The ground strap nearest the antenna provides a direct path to ground for RF impressed on the shield from sources outside of the operating position. This also helps eliminate RF conducted back into the operating position when transmitting, eliminating one source of RFI.

When transmitting, if the transmitter is not well grounded, unwanted RF can appear on the station's ground system and can be conducted and radiated by the coax's shield. Thus, for maximum isolation, two ground straps are used. One for signals traveling to the antenna, and another for signals traveling back to the radio equipment.

If the T-5G is used in conjunction with earth ground systems, it is best to provide each ground strap with its own ground rod. In vehicular systems, it is best to ground the strap at the antenna end of the T-5G to the base or ground connection of the antenna. The other ground strap will be grounded to the vehicle. If the antenna is grounded to the vehicle directly, the second strap provides a second, low impedance path to ground.

If the T-5G is used at the transmitter end of the coax, ground the copper strap at the transmitter end of the T-5G directly to the transmitter's ground and the other end to your earth ground system. (i.e., one strap is grounded to the linear amplifier and the other to your tuner. The antenna tuner should be "ground central" for all of the station's component grounds.

What we are doing here is to provide a direct path to ground, eliminating the condition where one end of the Line Isolator is looking at a very high inductive reactance before going to ground. The two ground straps could have been connected internally, but at VHF frequencies, an internal ground loop could be developed by the Line Isolator itself. This method provides the most flexible installation and maximum isolation in both receive and transmit operation.

Use the T-4 when a direct ground path is not possible.

The T-4G and the T-5G are perfect for use with Vertical Antenna systems. Install at the antenna's feedpoint.

How does the Line Line Isolator system work?