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338Using the N8LP SteppIR tuning relay with the StationPro I or II

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  • Jim Garland
    Jan 18, 2013

      Hi All,

      Many StationPro owners use SteppIR antennas, and a number of builders have asked me whether it is possible to use the N8LP SteppIR tuning relay with their StationPro. The answer is Yes. The N8LP SteppIR tuning relay (http://www.telepostinc.com/SteppIR-Tuning-Relay.pdf) is a clever device that prevents an amplifier from transmitting into a SteppIR antenna while the antenna is tuning. It can be inserted either in the amp relay control line or the PTT line of a transceiver.


      A simple modification to your StationPro will permit the use of one N8LP tuning relay with all three amplifiers (two amplifiers for the SP-I).The StationPro will automatically tranfer the N8LP device to the selected amplifier. Here are step-by-step instructions. Allow about 30-45 minutes to perfom the modification.


      1. Obtain the needed parts: one 1000 ohm 1/2W or 1/W resistor and about 20 inches of 22AWG hookup wire. The resistor is used as a mounting post, so the larger resistor is needed because of its size, not its power rating.


      2.  Remove the main circuit board from the StationPro. To do this, remove the top and bottom covers, the rear panel, and unplug all the cables from the main PCB. Carefully pry off the Controller PCB from the main PCB, taking care not to bend either board.


      3. Remove R106 (1000 ohm, 1/4 W) from the main PCB. R106 is located just to left of the K114, the solid state relay. If you have a solder sucker, or solder wick, clean the solder from the hole in the vacant pad nearest the rear of the PCB.


      4. Solder the new 1000 ohm (1/2W or 1W) resistor into the large empty pad labeled "G" ot Q102 (an usused transistor). Stand the resistor on its end so that its body is flush with the pad. We'll use this resistor as a mounting post.


      5. Cut the 20 in length of hookup wire in half and twist the two pieces together to form a twisted pair. Strip and tin each end of the two wires.


      6. Solder one wire of the twisted pair to the vacant end of the new 1000 ohm resistor, close to the resistor body, and clip off the extra resistor lead length.


      7. Solder the other wire from the same end of the twisted pair to the now-empty pad nearest the rear of the PCB vacated by the removed resistor R106.


      8. Plug the ribbon cable from the rear panel PCB into the main PCB at P103. It is important that you do this now, before you reattach the controller PCB to the main PCB.


      8. Leaving the other end of the twisted pair free (for the moment), carefully plug the controller PCB into the main PCB, and reinstall the StationPro rear panel and bottom cover. Be careful when you plug the controller PCB into the main PCB that you line up the connecting pins carefully.


      9. Once all the PCBs are reinstalled into your StationPro, with the bottom cover attached, then solder the wires from the free end of the twisted pair to the back of the AUX1 and AUX2 RCA  phono jacks on the rear panel circuit board.


      10. Reattach the removed cables, verifying carefully that the pins of ribbon cables are not accidentally offset into their mating connectors.


      11. Now check everything  to make sure the twisted pair is dressed neatly, and that plugs are installed properly, and tnen reattach the top lid of the enclosure. You're done!


      User Instructions: Plug RCA phono cables from the AUX1 and AUX2 into the N8LP tuning relay. (Either cable goes to either input). Now, when you use an amplifier, it will be automatically hooked up to the N8LP unit.


      Final Note: If you are not using an N8LP tuning relay, you'll need to use a phono cable to jumper together AUX1 and AUX2 on the StationPro rear panel.



      Jim W8ZR