As Amateur Radio stations expand over the years, the wires and cabling can get rather complicated to trace, fault-find or supplement. This becomes all the more important in a contest-oriented station, where a piece of cable or equipment may fail at a critical moment, and need to be replaced with a back-up that may not have the same connectors on it. A bit of pre-planning in your station design can help a lot with all these issues, and whilst a complete re-wire may not be necessary or even relished, a grasp of a few basic ideas can help alot.

The most important points are:

1. Standardization of Connectors
2. Labeling of all Wires
3. Making Errors Impossible

These are discussed below:

1. Standardization of Connectors
   In order to allow different equipments to be connected in and out as the station is setup or re-configured for a particular contest, it is important that the connectors allow for the fullest versatility. Basically, this means deciding on a particular type of connector for a particular job, and sticking to that choice. All AC power plugs should be the same, which in Ireland means the standard fused 13A plug with no adaptors or foreign two-pin types included. Audio cables may have DIN, Jack or Phono plugs on them, and the sockets on your main equipments will probably remain as-is, but if you are making any kind of distribution panel for audio-switching, you can standardize the plugs at that end of the cable so that they are all interchangeable. An RF patch panel is often included, for reasons of versatility as well as the safety of being able to disconnect all incoming aerial cables when the station is not in use.

2. Labeling of all Wires
   When you are crawling behind your equipment stack, it is important to know what all of the wires are used for, where they come from,and where they go to. Assuming that you have adopted a standard range of connectors, you will be able to know what a cable is used for by looking at the connector type; but to identify the routing, we have to rely on adequate labeling. In an ideal world, a cable will be labeled at both ends with the following information:
   • Which equipment this end plugs into
   • Which socket on that equipment
   • Where the other end is connected to

   and depending on your choice of labeling, you might be able to get all or some of the above written down. All labels should be clear, durable and well fixed. Depending on your finances there are various options available, but some of the more popular ones are:

   • Computer-printed labels, held on with a durable plastic cover.
   • Dymo-Tape embossed labels, that can be clipped around the cable with a staple, or attached along the length inside clear heat-shrink tubing, though this must be done before the connectors are put on.
   • Hand written notes on strong plastic labels such as are used for EProms etc.
   • Hand written notes on special label-tie wraps, that have a flat panel for this purpose.
   • Luggage-Tag style labels, made from thick card or plastic sheet, and held in place with elastic bands, twisted wire, or insulation tape.

   The choice of pen is important when writing your own labels. Some inks may blur when wet, or may fade after long exposure to sunlight. There is no point having a label if you can't read what is on it!

   Colour can be used for quick identification of cables that have similar connectors. For instance, all cables connected with 10m, such as aerial, rotator, preamp etc., can be wrapped with blue tape, all 20 m cables can be wrapped with red tape, and so on...

3. Making Errors Impossible
   If a fault occurs in the middle of a contest, and you have to replace of re-configure equipment, it is very important that mistakes are not made. Connecting the output of the Linear into your Beverage Distribution Amplifier, or connecting 230v AC into the 12v input of your favourite receiver can be costly errors, so it is important in planning your station wiring that these kind of mistakes are not just difficult but are impossible to occur. It is no use relying solely on labeling here. Rather, a proper choice of connectors will stop errors like this. Always use different connectors for AC and DC supply lines, for TX and RX coax lines, and for low and high level audio feeds. There are many types of multi-pin connectors available, so that 'families' of control cables can be kept separate too, so the chance of connecting your rotator controller to your computer's parallel port is ruled out. It is probably easiest when choosing connectors to start by listing the ones that can't be changed, such as those already on major items of equipment. If your printer uses 25w D-Types, keep those just for data and printing - don't use it for the transceiver controls as well.

Getting ready for a Multi-Transmitter Setup.

When considering expansion of your station to include SO2R (Single Operator 2 Radio) or a multi-operator contest setup, careful thought should be given to the quite considerable amounts of cabling that can be involved. The following email was sent by Tom, W8JI, to the CQ Contest reflector, and is very informative...

While I don't have a "real" contest station, I have a large 160m station we are using in the contests. I have six separate lines of receiving antenna, a transmitter-signal nulling system that has about one mile(!) of coax in the delay lines, nine wires of BCD data going out to antennas for switching, and so on. Any antenna can be picked at any of three operating locations, and at one location it is stereo on two phase-locked receivers. There are three transmitting antenna systems, and a lockout system for the transmitters to keep the station honest.

When the feedlines and control cables for 80-6 meter arrays are added to the above mess, it is a lot of wiring (but not as bad as some multi-multis I suspect).

What I do is combine and switch everything possible at one point. A single common point has the feed to EVERY receiver. A single common point has every transmitting antenna. One RF cable now leaves each common point to each radio for transmitting, one RF cable for receiving, and one control cable for BCD coded switching and control data.

When you slide each receiver out there are three cables and the power plug. There is an audio buss (that runs audio to and from every other receiver), an antenna input, and a control cable (muting and sidetone, antenna direction and type, etc).

When you slide each transmitter out, there is an interlock/control line, sidetone line, and RF output line.

My view is it is easier to run one control line out for 11 different antennas, than to bring 11 antenna leads up to the receiver and use a local switch. I also use BCD encoded control lines to minimize the number of wires needed (three conductors can select one of eight antennas, four can select one of sixteen antennas).

Since it gets down to three or four cables maximum to each receiver and transmitter (plus local things like keyers and mics) wiring is a non-issue, the rat's nest stops at the hubs which are near the feedline inputs. A side benefit is lightning is contained at that point, since all cables (including power) can be common grounded to one point. There is less to unhook to move things.

I also use color coded tape all the time, and follow the resistor color codes as much as possible. I start out with one black up to white, and then two blacks followed by a black/ brown black/red, etc. Better than numbers!

I use Black for NE (since that is my primary direction of concern), and work my way up for other directions. Keeps all my mess in order, especially when I write down what color code goes where.