As a ham radio or swl enthusiast, you may have several antennas or multiple SDR receivers, and sometime, you would like make a comparision on the performance of different antennas, then you have to plug in and out your antennas to your receiver one by one again and again, and make records on each of them. Obviously, it is a time-killing job and not scientifc. So, is there a more efficient way to do this? Yes, an antenna switch will help you out.

An antenna switch is a RF device that could deliver the RF signals from one of the multiple antenna ports to a common RF port at one time. It switches a single coaxial feedline on the common port to feed multiple antennas. When it is in work, only one antenna is active, all the rest antennas on other RF ports are disconnected or grounded at this time. Unlike the RF splitters, which share a common RF port to multiple ports, or the RF combiner, which combines multiple RF ports to a shared single one, an antenna switch does not share or combine RF ports. So for an antenna switch, only one RF path is active at one time.

The antenna switch introduced here is a pocket-sized 4 position RF switch, working from 0.3MHz up to 150MHz. The switch selects 1 of 4 antennas to your radio and all unused ports are grounded. All of the RF ports are in SMA connectors. In RX scenarios, a Bias-T is a must have device to deliver the DC voltage over coaxial cable. So we also integrate a Bias-T into our antenna switch. It is able to deliver a DC voltage out on all the 4 antenna ports. To enable the bias-T on its specific port, just short the jumper of the port, vice versa. The output DC voltage level is set via a potentiometer on the board, and a 7-segment led is used for monitoring the output DC level. Four red leds are bundled to the 4 antenna ports to indicate the switch position. The antenna switch is housed in a black plastic box of palm size. There are five SMA ports for RF, and one DC port. Meanwhile, reverse usage is applicable on all 4 RF ports. That says you can switch one antenna to four receivers.

Note:

• It is an antenna switch designed for RX only, so any RF transmitting scenarios are not applicable.

• The output DC voltage level on all the Ant ports are in same level, please make sure all of your active antennas are able to endure this DC level before use.

• The built-in Bias-T is not applicable in this case: 5V output on all ANT ports, ANT1 is 5V endurable, and ANT2 is only 3.3V endurable. The result is that the ANT2 may be damaged… In order to protect ANT2, please disable the Bias-T on this port and use the antenna’s own Bias-T.

• The input DC level on DC port should be at least 1.5V higher than the Bias-T output on all 4 antenna ports.

• The Bias-T is disabled by default, you need to enable it by short the jumpers on your desired antenna port.

• Before enabling the Bias-T, please trim the potentiometer to adjust the DC output to your desired level.

• The total CURRENT to all of your antenna loads (4 antenna ports) from Bias-T should not EXCEED 700mA.

• Please DO DISABLE THE BIAS-T IN YOUR SDR RECEIVER IF YOU DECIDE TO USE THE BIAS-T IN THIS ANTENNA SWITCH.

Features:

• Antenna Switch in Palm Size, could be Portable or Base Station.

• Up to 4 Antenna Ports to 1 common RF Output.

• Equipped with Bias-T, Enable or Disable with Jumpers.

• 7-Segment Display for the Output DC Level on Bias-T.

• Reversed Usage on All RF Ports.