"The RFI Quick Fix™"
"The Ground Loop Solution™"
T4G Plus is shown; the T4 Plus does not have the ground strap.

T4500 
T4 Plus & T4G Plus 

Type 
Current 
Current 
Design Impedance 
50 ohms in and out 
50 ohms in and out 
Operating Bandwidth 
160  6 m 
160  6 m 
Power Loss, dB 
Nil 
Nil 
Saturation Resistant 
Yes 
Yes 
Internal Transmission Line Z 
50 Ohms 
50 Ohms 
Core Type 
Ferrite 
Ferrite 
Power Rating @ 3.5 MHz 
500 PEP watts PEP if SWR < 2:1, SSB/CW duty cycles * 
> 1500 watts if SWR < 3:1, SSB/CW duty cycles * 
Phase Delay  Unspecified 
6.2 degrees @ 3.5 MHz 
Load Variation Tolerance 
Excellent 
Excellent 
Input connector 
SO239 
SO239 
Output Connector 
SO239 
SO239 
Size  1.75" x 4.75" 
2.3" x 8" 
The T4 Plus and the T4G Plus are identical to the former T4 and T4G respectively but now have increased bandwidth. The T4500 has an isolation factor that is higher than the standard models. They are far smaller in size and weight, too. the power rating is 500 watts PEP SSB/CW service. This makes them perfect for interconnecting a transceiver and a linear amplifier. In low power installations, considerable space can be saved using the T4500. 
Applications: Topoftheline, maximum isolation Line Isolators. Replaces 4KRFLI, 4KVLI and T3 with specifications exceeding those it replaces. Use in all RFI applications and as a retrofit device following standard baluns used in antenna already fitted with a balun. 
The RFI Quick Fix™
For really tough RFI and RF feedback problems, you can't beat the new T4 Plus and T4G Plus Line Isolators™. The T4G Plus shunts stray RF directly to ground with its builtin ground strap. Stray RF hasn't got a chance, yet signal attenuation is zero! Use the T4 Plus when a direct ground path is not possible. The T4 Plus is perfect for use with Vertical Antenna system. Install at the antenna's feedpoint. If you can install a T4G Plus you have the ultimate in Vertical antenna feedline isolation. If you have one of the new rigs which covers HF + 6 meters, then the T4 Plus or T4G Plus are the ideal choices. Install the T4 Plus between transmitter and linear. If you have ground loop problems, there is no more effective way to break them up than with the incredible isolation of the T4 Plus. Install the T4 Plus between the transmitter or linear amplifier and your tuner. Use singlepoint ground at the tuner (all equipment ground go to the tuner ground as does the ground wire to your ground system) in combination with the T4 Plus and you're tuner works like it's supposed to and so does your linear. Using a T4 Plus following the balun supplied with your beam and produce a measurable improvement in F/B and F/S ratios. There is no better way to eliminate feedline radiation. If you are using a coil of coax as a choke balun, the T4 Plus or any of our Line Isolators™ will be far more effective. 
IMPORTANT T4 Plus and T4G Plus Line Isolators are no longer available. I ran out of parts. A few new Line Isolators using toroidal cores and 3" x 4" cases are being made, but the quantity will be limited. The part numbers will be T4 Plus R and T4G Plus R. The "R" means replacement since I didn't change the product number otherwise. The performance of the "R" (replacement) models is the same or better than the old type. When the parts run out, Line Isolators will not be available any longer. See my web store's home page for more information. Ignore the drawings on the description page. The new case is identical to the Remote Balun in size but will have a Silver/Teflon SO239 connector on each end. When your order one of the new Line Isolators, the part number on your order will be the same as the older version. It won't have the "R". This saves me a lot programming time. You'll get the new "R" models. There are none of the older T4 series left. 

For more information 
More detailed graphic on the operation of Line Isolators 







