TCRC -- Twin Cities Repeater Club
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147.210 is the primary
repeater for South Metro
Skywarn!



 



TCRC History
Printable Version   Printable Version
 
Taken from TCRC Handbook, 5th edition.

The Twin Cities Repeater Club was started back in the mid 1970's just as many two-meter repeater systems were emerging in the Twin Cities area. The core was made up of a group of Amateurs with a common interest in Apple IIE computers (a highly advanced system in its day). These enthusiasts were meeting every Saturday morning in a mad exchange of computer software and radio talk. Luckily, that breakfast tradition is still alive today.

The original repeater equipment was on 146.91 MHz and was nothing more than some Hamtronic receiver boards, a Johnson transmitter, and a couple of transistors that controlled the COR function. This hacked together system was housed in a cardboard shoebox and ran in this fashion for several years. The TCRC machine was second in metro area coverage only to the 146.85 MHz system that in 1978 was housed on top of the IDS building in the center of downtown Minneapolis. The key to having a premiere repeater system back then, as it is today, was location, location, location. The TCRC Burnsville site was the best single site, metro wide location available.

Around 1981, the club members were faced with an interference problem. It became painfully clear that we were interfering with the Wilmar repeater on the same 146.91 MHz frequency, which they were coordinated for and we were not. Frequency coordination was somewhat loose in those days. At first, we tried a corner reflector antenna in an effort to shield our transmit signal to the West, but depending on the weather conditions, interference was still present when the band was up to any degree. It was decided that a system upgrade and a frequency re-coordination were needed. The contribution hat was passed around at several of the Saturday morning get-togethers until enough funds were donated for a proper repeater system. The Tech Team was formed and given the responsibility for the project. A new frequency was coordinated on 145.49 MHz and a new commercially-built, $600 repeater was purchased. This new system was rack mounted, had a phone patch, and was remote controllable via CTCSS touch-tones. Quite a step up from our original shoebox machine.

In 1984 (the year the Macintosh was born) there was a drive to change the club repeater frequency to the high side of the 2 meter band. Many of the radios of the day were not able to transmit below 146.00 MHz. There was only one coordinated frequency left in the 2-meter band plan and the club wanted to advance the state of the art in metro repeaters. So a new Mark IV repeater was ordered for the 147.21mhz frequency. Back in the mid-eighties, repeaters had single tone courtesy beeps, CW ID'ing, a phone patch if you were lucky, and that was about it. The new TCRC Mark IV system introduced voice ID's, auto-dial numbers for all club members, real voice mailboxes for all club members, touch-tone tests and much more. We had achieved our goal and were the most advanced repeater system in the metro area.

In 1985, we added the remote receiver sites - one at each point of the compass from the main site in Burnsville. The North site was placed at a club member's house in Fridley one block away from the highest spot in the county. The West site was placed at a club member's house on the west side of Lake Minnetonka. The South site was placed at a third club member's house in Lonsdale. The East site placement was driven by several of the club member that used the river for summer enjoyment so the water tower at the Hastings Old Soldiers home was utilized. A First-In voter was built by one of the Tech Team members and worked pretty well considering its low-tech design. About a year later the club purchased a "signal to noise ratio" voting system which did a much better job at dynamic voting for the repeater users.

On September 2, 1986 the Twin Cities Repeater Club received final approval from the Burnsville City Council to build a new radio communications building to house the clubs two-meter repeater equipment. The project was built entirely with voluntary contributions from TCRC members.

Our agreement with the city called for the club to construct the new building at club expense according to the approved building plan. Upon completion, the club donated the building to the city and signed a 20-year lease, with an additional 20-year renewal option. The lease allows the club to occupy, install, operate, and maintain its amateur radio equipment from the new facility.
Club members completed every detail of the shack.
Club members completed every detail of the shack

Around 1988 discussions about linking to other 2 meter repeater systems could be heard on the air. The TCRC Tech Team went to work on making a connection to the North Dakota "SuperLink" system. This was a series of 12 VHF two-meter repeaters all linked together via a touch-tone accessible UHF link. TCRC members could touch a three digit code on their keypads that would turn on the local UHF link, they than could talk to anyone in any of the other 11 SuperLink cities by touching that citys three digit code. The SuperLink system worked well, however there were those in the club that thought the TCRC system was too busy a repeater system to host the extra chatter that the SuperLink system generated.

In 1991 the SuperLink system was removed from the TCRC machine and was transferred to a small group of metro hams interested in continuing its service in the Twin Cities. The TCRC is proud to have been involved in bringing the SuperLink system to the Twin Cities area.

1993 was the year we started talking about adding additional voice capabilities to the repeater system. The Mark IV had a limited vocabulary and only 5 voice ID strings. We wanted more variety so the Tech Team again went to work designing and then developing a Unix based computer system that we interfaced to the repeater. With this new system, that we named "OLE" (Onsite Language Enhancer), we had unlimited real voice capabilities, report & monitoring capabilities that we never had before, and much more. We could now monitor and control anything we wanted from the door alarm to dynamically monitoring which receiver was voted in at any one moment. Talk about advancing the state of the art, the new TCRC Tech Team mantra was "Whatever the mind of man can conceive, the Tech Team could achieve."

Over the next several years, many RF refinements were made to the system in an effort to squeeze the last little bit of sensitivity out of the receivers and the cleanest RF signal out of the transmitter.

In 1997 and again in 1998 we added additional repeater systems at the main site in Burnsville. Our fine 224.54 MHz repeater system and our 444.30 MHz UHF repeater system are now supplying great coverage on their respective bands in the Twin Cities metro area. (Thanks to Doug LaBore, NBIS, for providing this history of the TCRC - Ed.) This concludes the history taken from the TCRC Handbook.

The Long Road to 6 Meters
by Phil Lefever, KBNES
(from THE REPEATER, December 2003)

About four years ago,(late 1999, ed.) sombody (it may have been me, but I don't want to take the credit/blame for it) brought up the idea of the club putting a 6 Meter repeater on the air. This was about the time that 6 Meter capability was becoming a major selling point on many new radios, meaning there would be a larger potential group of users. Also, building a 6 Meter system was fairly simple, due to the common availability of surplus, inexpensive low band VHF equipment. The entire system could easily be constructed for well under $1000!

After doing more research, we found that the best way to get on 6 Meters was to build a "split sight" repeater. This means that the receiver and transmitter are located at different locations, to provide the needed isolation between the two radios. On most higher frequency repeaters, cavity duplexers are used to provide enough isolation that the transmitter and receiver can actually share a single antenna! The hitch with a repeater at 50 MHz is that the duplexer is about 5 feet tall and very expensive. Split sight is the way to go, but where would we put the transmitter?

The plan started to move forward, and the General Electric radios were purchased. (You can find anything on Ebay!) Next, we needed to get a frequency pair allocated to us. The coordination of our frequencies dragged on for quite a long time. Finally, witht he help of Jeff, WKF, the Minnesota Repeater Council granted us the pair of 53.37/52.37 MHz, sometime early in 2002. We were also granted a link frequency for the receiver site to send the audio over to the transmit site. Now, we could order the crystals needed to move the GE radios to our new frequencies.

Now the next issue was finding a second site at which we could locate the transmitter. The obvious choice for us was another city-owned water tank, 1.6 miles to the East of our current main site. The distance should provide an adequate amount of isolation, and the other site should provide excellent transmitter coverage. The TCRC has always had an excellent relationship with the city of Burnsville. We had a meeting with Linda from the City, and she started processing our request. Other things that had to be taken care of were a frequency study done with our proposed transmit frequency at the new site, to assure that we won't mix with another transmitter there and cause problems. Also we had to get the City to draw up a lease. This required my attending and speaking at a City Council meeting on behalf of the TCRC. Several revisions later, we were finally granted a lease for the new site! Another issue that had to be worked was our access to the top of the water tanks, which was greatly restricted after the 9/11 terrorist attacks. More hoops for us to jump through, but eventually, we got it all worked out.

The next step involved modifying the GE radios to do what we needed them to do. This involved moving them to our frequencies and tuning. Then the radios were split and the receivers were swapped, so that one radio would listen on 6 Meters and transmit on the link frequency, while the other radio would receive the link and retransmit on 6 Meters. Also, a controller had to be added to provide the ID's, the timing, and courtesy tone, etc. We also installed PL tone boards to protect the 6 Meter input and the link input from accidental interference. Be sure to remember that the repeater requires a 100Hz PL tone for access!

During a Spring 2003 tower climb at the main site, the 6 Meter receive antenna was installed. Both the antennas are a basic 1/2 wavelength vertical antenna about 10 feet tall. We had a leftover run of hardline on the tank from a prior upgrade we did to the 220MHz repeater, so the feedline was already in place. For the transmit site, we were fortunate to find that a paging company was vacating the tank, and was willing to donate an old run of 7/8" hardline that was already on the tank. In fact, they were more than happy to donate it to us, because it saved them the expense of removing it! It was a very lucky break for us, as installing 250 feet of cable on that tank would be a major hassle! The transmit antenna was installed on the new water tank in the middle of October. Also, two link antennas were installed near the ground, one at each site.

With the radios already to go and the antennas all up in the air, all that was left was to plug things in. The system worked well from the second it was turned on! We did develop a minor problem in the transmitter after a few days of activity. It required just a minor amount of tuning to straighten things out. The transmitter is feeding the antenna with a solid 65 watts or so.

It was sure a long road with many folks to slow our progress, but it is great to finally have the repeater on the air for our members and other users in the Twin Cities. There have been precious few 6 Meter repeaters here in the Cities in the past, and virtually none of them are kept in a working state. Hopefully, with all the new 6 Meter-capable radios out there, we will get a decent amount of usage. So far, we have been getting excellent coverage and audio reports on the new system. In some ways the repeater is a bit of an alligator (big mouth, small ears) but this is mostly due to the fact that most users are using small compromise antennas. Users with HT's will have the most trouble getting a solid signal into the repeater. Also you'll find that the long wavelength of 6 Meters makes it harder to get the signal out of a vehicle if you are trying to use your HT in a car. An external antenna is a MUST. With a good 6 Meter mobile antenna and 25 watts of power or more, coverage is very similar to the 147.21 repeater. Give it a try if you have the equipment for 6 Meters.

While "repeater DX'ing" is usually more of a nuisance than a treat, we are fully expecting that from time to time, 6 Meter band openings will cause our newest repeater to have much wider coverage than our users are accustomed to having. That's why the repeater ID gives our location, so that in the event of a band opening event, remote operators will know what system they are getting into("Burnsville, Minnesota, Grid Echo November 34").


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