AICN

Alabama Inter-City Network

 

The Alabama Inter-City Network (AICN) is a linked system of Repeaters and Remote Bases in Alabama that allow Amateur radio operators to converse over long distances via 2 meters and 440 MHz. For example, a station in Southern Alabama can directly talk with one into Northern Alabama. Coverage also extends into East Mississippi and Southern Tennessee. This system is on line 24 hours a day and requires no special codes to turn it on. See the FAQ below for information on how to access a node in your local area. AICN welcomes new users and also new potential local node sites.

 

 


Current AICN Network

CITY

FREQ

PL

CWID

Arab

145.55 simplex

203.5

-

Atmore

Potential site

-

-

Birmingham

145.57 simplex

203.5

B

Greenville

145.19-

203.5

-

Greenville 440 hub

N/A

N/A

-

Huntsville

145.23-

186.2

-

Mobile

Down

-

-

Montgomery

444.450+

203.5 Aicn

100.0 Local

Muscle Shoals

145.41-

203.5

-

Thorsby

145.43-

203.5

-

Tuscaloosa Tall Tower 440 hub

N/A

N/A

-

Configuration on 3/26/2002


Alabama Inter-City Network (AICN) FAQ
- Frequently Asked Questions

 

Who are some of the hams behind AICN?

We gratefully acknowledge Dave/KX4I Tuscaloosa North Hub "Tall Tower guy," Jack/K4YVV (Muscle Shoals site), the guys down south who keep on rebuilding the southern area, including Bob/W4MPQ (new chief design orchestrator, Greenville), Stuart/WD4JRB, Wiely/KE4LTT & Reuben/AD4R (all of Montgomery), Bobby/N4AU (Wetumpka), Jack/KS4UN (Dadeville), Ralph/W4XE (Huntsville) and untold others.

 

What has been happening to AICN?

You probably didn't know, but the whole state has been reconfigured and is in reconstruction, based on different site equipment and linking thrust by all of us that have carried it on. We had an older system in the mid 90's. We are in at least the 3rd generation now, with some previous veterans having moved to other things, some of which happened based on main link-site attrition and loss (including tower lease/contract changes as years went by and other changes) which incurred loss of equipment and convenience to old sites. It's a long story, so we're into rebuild mode now.

 

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 system 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 sub audible 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.


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 you 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 Phoenix 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 Phoenix City site. Phoenix 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 userís) that have to come up in a chain reaction on every transmission that 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 older 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 UHF output 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 cross band 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!


Click below for some maps and photos:

Map of AICN Network

A view from the tall tower hub site

Use BACK key to return


Links to Alabama Repeater Related Sites:

North Alabama Repeater Association http://www.qsl.net/nara/

Huntsville Amateur Radio Club http://www.harc.net/

Alabama Repeater Council http://jschool.troyst.edu/~arc/

Birmingham Club http://w4cue.com/

W4VM Repeater http://www.qsl.net/w4vm/

W4XE Repeater http://www.qsl.net/w4xe/

Skywarn http://www.nalsw.net/

Madison Co. ARES http://www.harc.net/documents/ares.htm


Material Acknowledgements to: KE4CAP, Editor Alabama Section News; KE4OLR, Brian andWD4EGF, Don

AICN Webmaster: Ralph W4XE send email comments to: [email protected] [email protected]