Item Description:

You are bidding on one (1) bare PCB for a 2:1 remote antenna switch.

The pictures show the front and back of the bare board and an assembled board (assembled board and parts not included). The assembled board does not have the gas discharge tube installed.

The boards are double sided plated through 2oz copper PCBs with and silkscreen and solder mask for easy assembly. Board finish is Tin/Lead HSAL.

The board size is 2.8" by 3.0". This board is updated to use either swaged standoffs or the original M/F threaded standoffs. It also has a larger  connector for the control wires and provision for a gas discharge tube on the antenna line to the radio.

RF data: 
Loss at 30MHz <0.1dBm 
Isolation from radio port to either antenna when OFF at 30MHz <70dB
Both numbers should improve as frequency is lowered.

Deselected antennas are grounded

A 1.5 meg ohm resistor bleeds static from the selected antenna so high voltage static charges do not build up.

Provision for a 20KW gas discharge tube.

This board will work with SO-239 connectors and with type N connectors. The connectors are arranged on the board with the common connector offset from the antenna connectors for ease attaching the cables. This also keeps the traces to the relays short as they are mounted between the connectors. If square flange SO239 or type N connectors are used they should be mounted to the board using Keystone 2261-2 3/16 long swaged standoffs. These standoffs have a 4-40 thread. Keystone 2262-2 1/4 long standoffs will also work. I use a Craftsman 42861 punch to lock the standoffs in place. Note, the swaged standoffs should also be soldered to the board. Use a soldering iron with a large tip and be patient, there is a lot of ground plane to heat up. If using regular threaded standoffs, use 1/4 long male female standoffs and attach the male side of the standoff to the board using nuts. Once the standoffs are in place, the connectors can then be temporarily attached and the center pin soldered to the board. This will allow use of the ground plane on the boards and make for easy attachment to an enclosure. When using the standoffs, the boards may then be mounted in either plastic or metal enclosures. Use the bare board as a hole template for locating the centers of the SO239 connectors and the mounting holes.

If rear mount SO239 connectors are used (no flange) they must be mounted on metal to provide the ground connection between the SO239 connectors. This may also be done using the flanged SO239 connectors without the standoffs. The board is then held in place by the soldered connector center terminals. When mounting this way, a ground wire (braid) must be run from the metal enclosure to one of the ground pads on the PCB for the board's ground plane.

The relays used are DPDT 400V 8A with the contacts wired in parallel (16A) and should have adequate with margin for most modern transceivers. Note: 1KW is only 223Vrms at 4.5A into 50 ohms but a high SWR can increase voltage levels. The deselected antennas are connected to ground. If neither antenna is selected (power OFF) , both are connected to ground.

The relay control lines are connected through a screw terminal block for easy connection and removal of the wires. A three wire cable is needed, two control wires for the relays (+12V) and a common (RTN) return wire. The control wire RTN is connected to the RF ground on the board. R2 and R3 are in series with the relay coils. They can be replaced by any resistor from 1 to 22 ohms or a wire jumper.

Board Parts List (not including SO-239 connectors and screws)

Mouser and DigiKey have an aluminum box for $10 that will fit the board, Hammond 1590Y.

As with anything connected to an antenna, all of the metal parts should be well grounded. A ground rod must be connected to the antenna relay box  (or coax connector ground if plastic box used) as close as possible to the box. This unit does not provide protection from direct lightning strikes, no system with relays can do that. The coax and control lines should be disconnected when not in use if this is a concern.

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Returns: All items are sold as-is unless otherwise stated. Returns are not accepted unless item is grossly misrepresented. Please notify me of any issue within 30 days of receipt of the item.

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Shipping : Shipping is to USA only.