Bird 7431 Antennenswitch

High-quality 4-way switch with an exceptional principle. The central connection is located on a movable rail and is permanently connected to another connection. Switching is done by pulling out the gear knob (the rail with the two connections is pulled out of the socket). The knob can then be turned to the desired position. Finally the knob is pushed in again and the rail with the contacts is pushed into the socket and the connected plug have contact. Compared to the connections that are not switched, the blocking is 75 dB!

2x PL 89.00
2x N 105.00
4x PL 115.00
4x N 129.00
Spare cartridge 16.60


Order No.
BIRD-7431 BIRD 7431 Antennaswitch 149.00


SwissUnit Antenna Splitter and Relay use of an SDR with a traditional HF receive is a nice enhancement of any amateur radio station. With suitable software the transceiver can be controlled by the SDR interface. This brings new life to any older radios by adding an up-to-date waterfall feature. But often you face the question, where to get the antenna signal from. Not every transceiver offers an antenna monitor output. What to do?

This is exactly the issue the Swiss made "SwissUnit" addresses. This is the combination of an antenna splitter with an antenna relay and the required controller electronics. When receiving the antenna signal is split up to bith - the transceiver and the SDR receiver. You can use the received signal on both systems, on the radio and on the computer. When switching to transmit mode the relay cuts off the SDR branch of the splitter and the antenna is directly connected to the transceiver. This protects the receiver input of the SDR. As a result you get a very comfortable system with up-to-date SDR reception and waterfall, and your trusted transmitter from the existing radio. the same time as switching the HF signal, the SwissUnit also switches an audio signal. This is used to cut off the audio signal coming from the SDR via the computer soundcard to the speaker system, to prevent audio feedback when transmitting. The supplied switching electronics box takes the PTT signal and supply voltage from the transceiver and switches the relays when going to transmit. The signaling is very simple, a cable can be homemade within a few minutes. Practically any transceiver can be used.

The HF relay and splitter is a qualit product with excellent specifications, which can switch up to 100W power. The splitter is specified up to 400 MHz, but can be used up to the 70cm band without too much losses. The antenna connectors are N sockets, the radio side uses BNC sockets. The control cable from the transceiver uses a 4 pin rund Foster type connector, as it is found on microphones as well.

A control cable radio to use with the FT-991/A is offered as well, other transceiver cables are planned. But it is very easy to make a cable on your own, the required connector is supplied.

Order No.
SWISSUNIT SwissUnit Antenna Relay Not in stock, back on: 26. Jun. 2017 599.00


MFJ-1707: Automatic Antenna Switch it is necessary to use separate antennas for receive and transmit. For example you want to use an efficient vertical on 80m for transmit, but a directional beverage antenna for receive. The MFJ-1707 automatic antenna switch serves exactly this purpose. Just connect your transceiver, receive and transmit antenna as well as power - and off you go! The built-in HF sensor (HF vox) immediately switches from receive to transmit antenna. Instead of the HF vox a cable can be used for PTT keying. After releasig the PTT the switch reverts to the receive antenna after an adjustable delay time (hold time). This delay protects for example a very sensitive receive amplifier. An additional switching contact signals the state of the switch, useful for blocking other devices or. The MFJ-1707 automatic antenna switch can be used with any mode. Max. power is 200W SSB PEP. A 12V DC supply is required, you can use the normal power supply from your transceiver. Size of the switch: 101 × 66 × 38mm.

Order No.
MFJ-1707 Autom. Rx/Tx Antenna Switch 102.40


TRSWITCH: Automatic Transmit/Receive Switch up to 160MHz

In case you use a scanner or a software defined receiver (SDR) for reception, and you want to transmit with your normal transceiver, you need an antenna switch. Such a device must switch the antenna immediately on transmission.

TRSWITCH does just that. The switch has a connection for the antenna, and two connectors for the receiver and the transmitter. The switching is actuated automatically (RF Vox, from 10mW on) or with a PTT line.

TRSWITCH has an additional AF switch built in: when using an external speaker the receiver is muted, instead the CW sidetone is audible through the speaker. The receiver connector is grounded during treansmission, further it is secured with a lightning protector. Without operating voltage the antenna is always switched to the transmitter (or transceiver).

TRSWITCH wotk from DC to 160MHz, the insertion loss at 160 MHz is 0.2 dB. Max. transmit power is 100W, the device requires 13.8V at 200mA.

Download: Manual TRSWITCH (PDF, EN, 600KB)

Order No.


Automatic Antenna Disconnect'Antenna Disconnect', manufactured by Paradan (USA) is a security relay for coaxial antenna cables. As soon as the station is powered down, the antenna is completely insulated from the radio. No more unscrewing of the coax connectors when a thunderstorm comes up.

Especially for remote operated stations this is a critical feature, which can save the entire radio station.

The Antenna Disconnect not only cuts the center conductor of the coax line, but also the outer shield. The antenna side of the relay is permanently connected to an over voltage protection, which cuts voltage surges all thetime, even when operating. The relay is activated from a switched auxiliary power output of theradio. As soon as the transceiver is switched on, the antenna becomes conencted to the radio. Or, if no such aux ouitput is available, the relay is using the same power supply as the radio. As soon as the commnon power supply is turned off, the entire station is powered down and tne antenna is disconnected.

The insertion loss of the Antenna Disconnect relay is just 0.05 dB at 29 MHz. Even on 144 MHz it's just 1 dB. The max. power rating is 1500 W. A green LED shows the operating state of the relay. The switching voltage is supplied by a two wire DC able with Cinch connector.

Technical Data Paradan Relais
Operating Voltage 10 – 18 V
Current consumption 60 mA
Max. Power 1500 W
Insertion loss @29 MHz 0.05 dB
@54 MHz 0.4 dB
@ 144 MHz 1 dB
Dimensions 122 x 66 x 41 mm
Weight 390 g


Order No.
26150 Paradan Antenna Disconnect Relay 125.00

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