RSOC NW HF Station

This is a description of the AARC operating position that is located in the North West corner of the Ops Room in the RSOC.

Our primary operating position. There is one High Frequency (HF) radio, and to the left is a VHF radio for local communications.

Our primary operating position. There is one High Frequency (HF) radio (1), and to the left is a VHF radio (25) for local communications.

Oh my gosh! Are you kidding me! There are over 25 strange boxes, and only two of them are radios!? What the heck is going on here? (NW Corner Detail)

There are a number of reasons:

  • Older equipment working with newer equipment
  • Different brands, different connectors
  • We have a good sized facility with multiple positions sharing antennas
  • PC control of different hardware and software applications
  • Having options available


We have 3 different positions that are sharing antennas. There is a remote antenna switch in the basement. The antenna switch next to the radio helps to prevent connecting two radios to the same antenna at the same time. Transmitting directly into a receiver will burn out the receiver. The Quad Loop antenna has a dedicated tuner. We have a SteppIR Yagi antenna that has moveable metal tapes enclosed within the booms. The tuner causes the metal tapes to extend or retract to the perfect length for the frequency desired. The tuner controls an external relay that prevents the power amplifier from transmitting when the tuner is actively tuning. The Yagi is also mounted on a rotator. So that’s 5 boxes for the antennas.

Old Eyes

The Elecraft has an external panadapter. A panadapter is a computer display that shows signals and noise that is being received across a frequency range. You can see where someone is transmitting, and then tune to it, rather than spinning the tuning dial listening for a signal. The Elecraft panadapter display is about a 4 inch diagonal. We have the display duplicated on a 19 inch monitor. It can be seen across the room.

Different Modes and Connectors

Are you familiar with DB-9 connectors that are set up for an RS-232 interface? For years these were the standard for computer communication. Two wires to send data, two more to receive data. A Request-To-Send wire along with a Clear-To-Send wire. In some respects it was easier, because each wire had a specific purpose.
For computer communications now, throw a microprocessor in to the mix, and USB connections only need four wires. Power on 1 and 4, data on 2 and 3.
The DIN connector is an electrical connector that was originally standardized in the early 1970s by the Deutsches Institut für Normung (DIN), the German national standards organization. This “standard” connector has between 3 and 8 pins. It is commonly used for microphones and other miscellaneous connections on the back of transceivers.
The first types of small modular telephone connectors were created by AT&T in the mid-1960s for the plug-in handset and line cords of the Trimline telephone.
In 1976, these connectors were standardized in the United States by FCC, which designated a series of Registered Jack (RJ) specifications for interconnection of customer-premises equipment to the public switched telephone network.


If you need to update the firmware in the Elecraft K3, the K3 connects to the Elecraft panadapter. The panadapter only has an RS-232 connector, and our PC only has a USB connector. The panadapter connects to the uPort Moxa RS-232 to USB converter box.  The USB connects to the PC. With a really old PC we would have a RS-232 serial connector, so we wouldn’t need the converter box, but hen again the old PC probably wouldn’t run the current software!

Normally the panadapter connects to the Micro Keyer II (which handles audio, morse key and digital data interfacing) via RS-232.

If we want to connect our WinLink PC mailbox over HF, we need to use the SCS P4 Dragon modem. Connecting via RS-232.

That is why we have the Black Box switch (Black Box is a brand name).


We have a PC with two displays running Microsoft Windows. The PC is used to control and configure some of the equipment. It’s got internet access, logging programs, checklists, manuals and other radio related software. It has an external USB Hub because the PC doesn’t have enough USB ports for our use.

NW Corner Schematic Diagram: