Alabama Inter-City Network

What is the AICN?

The Alabama Inter-City Network is a linked system of Remote Bases in Alabama and SE Mississippi that allow users to converse over long distances via 2 meters. For example, a station in Ellisville, MS can talk with one in Opelika, AL., or someone in Mobile could talk with someone in Florence. This systems is on line 24 hours a day and requires no special codes to turn it on.

How Do I access the system?

First you need to determine your local frequency (see separate listing for the frequencies used). You will notice that the sites are on standard, coordinated, repeater pairs, with the standard +/- 600 Khz offset. That means that you can treat a site as you would a normal repeater, with a few exceptions that we'll cover shortly. Once you've set your frequency and offset, you will need to program your radio's subaudible tone encoder. This might be new to you, since most repeaters do not require this tone to operate. Most current 2M radios have this feature, but it seems like they all activate it a little differently, so consult your user's manual. Just remember that it's really just a two-step process... Select the desired tone frequency and then turn on the encoder. My FT-5100 uses the FN + TONE buttons and the main dial to select the tone and the TONE button to turn the encoder on or off. Deciding which tone to use is easy. Most Alabama sites use 203.5 Hz and all Mississippi sites use 136.5 Hz (check the listing above). Now that you have your RF and tone frequencies set, you're ready to go.

Well, I finally figured out how to turn on my subaudible tone encoder.
What is the purpose of requiring this tone? Is the AICN a closed system?

Congratulations; you can now be considered an advanced user of your radio, especially if you programmed this into a memory channel! No, the AICN is not a closed system. The reason the tone is used is to keep out the intermod and other noise present at so many tower sites these days. Such noise at one site would be rebroadcast over the whole system, tying it up. The AICN sites are half duplex, meaning that although split frequencies are used, a site can only transmit or receive at one time.

Is that why I sometimes hear only one side of a conversation?

Yes. When you hear a one sided QSO, it's possible that the side you don't hear is on the same site that your are. This is one of the differences between AICN sites and standard repeaters. Signals received at a site are not repeated out of that same site, but only out on all of the other sites. This was done for several reasons, not the least of which is system cost (no duplexer or special full duplex radio). Another reason is that the system is intended for wide area coverage. Users are encouraged to use local repeaters or simplex to chat when they are close enough to do so. If they are not, then the AICN is there to use. If you wish to hear a local user to you, one trick is to use the radio's reverse button to monitor the input frequency. Another possibility is to try hearing another site.

I've heard that this system is for weather emergencies only, yet the other day I heard a QSO concerning fishing. Is this allowed?

Yes. The original and most important reason for the system is to provide wide area communications support for the Mobile office of the National Weather Service (and others as well). The system has been used to both report wx conditions and to verify conditions shown on their new doppler radar. While this type of traffic takes priority over all others, there is another purpose for the system and this is to have fun. Use the AICN to make new friends, keep in touch while traveling, or to visit old friends who have moved. Using the system helps ensure that everything is working and also allows users (potential weather spotters) to exercise their skill at both using their own equipment and the system's.

Why do people sometimes ask me to repeat the first part of my transmission?

Due to the way the UHF links work, there is some delay from when you first key your mic to the time the last 2M site keys-up. This is especially true when you are conversing across the whole system. Let's use a worse case example. Say that you are in Phenix City and make a call to a station that is on the Hattiesburg, MS site. First, you key your radio which keys the UHF radio at the Phenix City site. Phenix City keys the Clayton hub repeater which keys the Dozier relay which keys the Mexia Hub which keys the Isney relay which keys the Ellisville Hub which keys the Hattiesburg 2M transmitter. That's eight transmitters and eight receivers (including the two users's) that have to come up in a chain reaction on every transmission which takes a second or two to happen. What it boils down to is that you need to pause a moment after keying before speaking, or your first word will be missed.

I hear a lot of CW on the system. What's that all about?

Besides the regular ID for the system, several of the new sites have a single letter ID tagged on to the tail of any transmission from that site. This helps isolate trouble spots as well as give a general area where a station is located. I've included a list with the site listing.

Can I use the UHF backbone for communications?

It is recommended that you don't, as it is preferred to limit access to the backbone for linked sites only. It is frustrating to have the whole system tied up with a one sided QSO because a station is going backwards into a site to carry on what is really a local QSO. Monitoring the UHFoutput from a site, however, might give you a way to hear local stations using your local site assuming you are in the patter of the UHF link antenna.

My dual band mobile rig has a crossband repeat function. Can I use it to link the local site here to another frequency for use around my home?

Yes, but please use caution. Be sure that the squelch will not open on noise, intermod, or such. Use CTCSS to prevent this. Another potential source of embarrassment is with your rig's scan. What if the rig was inadvertently placed in scan or on the wrong channel? Police calls have no place on the ham bands! It's even worse if your rig has been "MARS/CAP" modified and AICN traffic goes out on non-amateur frequencies. Don't laugh, it's been known to happen.

What can I do to help?

Use the system! 99.9% of the traffic on the system has been carried out in a courteous manner. We ask that you help by continuing in this manner. The system is not intended to be for any one person or group, so greet newcomer and old-timer alike... Friendliness and consideration will ensure an enjoyable, effective system for all. As with any amateur communications, allow time between transmissions for other stations to enter the QSO. Remember that this system takes a second or so to come up, so allow at least that amount of time for others. Another way to help is by supporting any effort by your club in sponsoring part of this system. Hope to hear you soon!

73, Don, WD4EGF