Anteena TW-72 Duplexer
TW-72 Opening
The Anteena TW-72 Duplexer is cool gadget that will allow you to connect one dual band antenna to two single band transceivers in your ham shack.
An antenna splitter is fine for cable TV coax, but when you want to connect two transceivers, you have to account for the power output when transmitting. A receiver that is designed to recognize signals with a couple of milliwatts of power will self-destruct when hit with 20 or 50 watts of transmitter output intended for the antenna.
Duplexer or Switch?
There are two basic ways to solve this problem.
The first is to use an antenna switch. With this device, you rotate the switch to connect either one or the other radio to the antenna, or one or the other antennas to the radio. The downside to this is that you can’t receive on both radios at the same time. When the switch is pointed away from either the antenna or transceiver, that device is removed from the circuit.
The second way to solve this problem is to use an antenna duplexer. These devices do a couple of handy things.
First, devices like the Anteena TW-72 prevent the high power output from a transmitter from going to the other radio’s receiver. This is its primary job.
Next, in devices like the TW-72, it divides the VHF and UHF signals from an antenna and sends them to the device’s VHF and UHF outputs. The inverse is also true.
For example, handheld antenna’s for ham satellite use often use duplexers. They connect the VHF and UHF elements of yagi antennas to a single output to a dual band, full duplex radio.
TW-72 Connections
In my application, I’ll be connecting my dual band VHF, UHF j-pole antenna to two different radios. I’ve got a single band ICOM 2300H VHF FM radio that I use for local FM repeaters and club nets. If you’ve seen my review of the Radioddity DB20-G, you know I now also have this nice little UHF, GMRS radio that I’d like to simultaneously monitor while in my shack. The duplexer allows me to do that.
In these photos you can see the antenna lead is connected to the duplexer’s single input. The outputs are connected to the VHF and UHF radios as labeled on the device.
Before connecting the second radio, I tested the UHF output through a power meter to ensure the VHF radio’s output wasn’t going to the UHF lead. As expected, it wasn’t.
The overall build quality of the Anteena TW-72 is solid. The cables are stiff so you won’t be coiling them up right behind your radios. The UHF connectors appear to be good quality and connected to my radios’ SO 239 connectors easily.
The published frequency range for the VHF side covers the HF ham bands so you should have some flexibility for a variety of applications. The device is available both with and without cables if you’d prefer to use your own patch cables. The outputs on the non-cable device are PL259’s not the typical SO 239’s so take note.
The Anteena TW-72 has proven to be a good solution to my use case. I like having both the UHF GMRS radio and the VHF FM ham radio on at the same time fed from the same dual band antenna. For about $35 dollars US, the price seemed quite reasonable.
