Description

Item Description: You are bidding on one (1) bare PCB board set for a 4:1 remote antenna switch. This board set consists of a relay board (remote) and control board (in the shack). They can be snapped apart at the V-Cut between the boards. The antenna selection control is through the COAX. This is a similar to the old Heathkit HD1481 four to one coaxial switch. The control uses 60Hz AC and pulsed DC (+ and -) up the coax. The RF is isolated using PI wound inductors and high voltage capacitors at each end. The first three pictures show the bare board, the schematics and the BOM. The last two pictures are the front and back of an assembled board set (assembled boards not included). The board's SWR (measured with NANO VNA on ANT-1) is similar to or slightly better than the original HD-1481 except under about 10MHz. The difference there is <0.08. The new board set is about 0.10 better at 29.5MHz. Once a long length of cable is attached, the differences should be irrelevant. ANT-1 has the longest traces on the new board. The boards are double sided plated through 2oz copper PCBs with and silkscreen and solder mask for easy assembly. Board finish is ENIG for RoHS Compliance. The board uses 1/4 Inch 4-40 thread M/F threaded standoffs to mount the SO-239 connectors. Note: Deselected antennas are not grounded and one antenna is always connected to the radio. Antenna 1 is connected even with the switch de-powered. You can short the Antenna 1 SO-239 to ground at the remote end. This will result in a 3 way switch and will ground the antenna path with power OFF. 1.5 meg ohm resistors bleed static from all antennas so high voltage static charges do not build up. This board will work with SO-239 connectors and with type N connectors. Use the bare board as a hole template for locating the centers of the SO239 connectors and the mounting holes. Some heavy duty SO239 connectors have a larger center pin than the holes on the board. The pad is large enough (300 mil) so that the hole may be drilled to fit and still have enough pad left for soldering. 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. I do not recommend using this switch with a KW class amplifier even though the relays used are DPDT 400V 8A with the contacts wired in parallel (16A) and should have adequate with margin. Note: 1KW is only 223Vrms at 4.5A into 50 ohms but a high SWR can increase voltage levels. 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 from the antenna to the control box should be disconnected and grounded when not in use. PayPal Confirmed Address: PayPal address must be confirmed and must be the same as the shipping address. 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. Feedback: Feedback is important to me, please email or contact me with any concerns, issues or problems before leaving feedback and give me the opportunity to work things out if needed. I always leave positive feedback after receiving feedback from the buyer, that way I know the buyer is happy and the transaction is complete. Shipping : Shipping is to USA only.