METRO AREA REPEATER ASSOCIATION
WDØHWT REPEATER SYSTEM
146.25/.85 AND 449.800/444.800
MINNEAPOLIS/ST. PAUL, MN
MARA was formed by 6 amateur radio operators who decided that an
amateur radio multiple site 2 meter repeater system was needed to give
complete coverage when using a hand-held type radio in the Twin Cities
Metro area (then defined as a 7 county Metro area). MARA was
formed only as a Repeater System support group and therefore does not
have regular “Club” meetings for you to attend. Our members get
together on-the-air or meet at other Amateur Radio club meetings in the
area. This repeater system started out in 1973 as a one-site repeater
located in White Bear Lake. In 1978, MARA started adding “remote
receive” sites to this repeater to give better receiver coverage.
When the receiver coverage exceeded the transmitter coverage
MARA installed the system transmitter on top of the IDS Building in
Downtown Minneapolis. The transmitter remained at this location until
1990 when the rent for this site was raised to $475 a month, just too
much for an Amateur Radio operation. Seven 146.25 MHz receive sites now
ring the Twin Cities Metro area. The MAIN transmitter site is now on
the Oakdale Water Tower, located just east of St. Paul, MN near the
intersection of Interstate Highways 694, 494 and 94.
MARA Repeater systems 146.25/146.85 449.800/444.800
The first 20 years, by Dan Karg K0TI
This history is
based on my memory of the events and various
newsletters, notes and other papers I have as we built the system.
May 1972 – Early Start
146.25 - 146.85 frequency chosen at May MRC meeting. Originally most systems were using 34/94. When it was agreed to move off of 34/94 in the Twin Cities there was a transition period where some systems went to a different split for a while until everybody got moved around and new crystals installed in their radios. By spring of 1972 everybody had pretty much moved to their new frequencies. 16/76 and 22/82 were the most active systems in town in those first years. Remember everything was crystal controlled in those days, so to move a group of users from one frequency to another took some coordination. The 25/85 repeater went on the air for the first time on July 27, 1972. At that time the repeater was located at Paul Emeotts (K0LAV) house on the east side of St. Paul.
August 1972 – My first involvement
I had been talking to Paul fairly regularly on 146.94 simplex. In fact I first worked Paul on June 23, 1972. I logged all my 2 meter FM contacts in those days. One day he asked if I could help him with some repeater work, little did I know it would become a 35 year long project! Anyway one day he came down and picked me up and we went up to the White Bear Tank. There I helped Paul set up a telephone pole at White Bear Lake to mount equipment on. For the first few years all the equipment at White Bear Lake would be mounted in outdoor cabinets on a couple of plywood sheets bolted to those short telephone poles.
February 1973 – Some early hardware
In 1973’s February/March issue of 73 Magazine, the K2OAW repeater controller plans were published. This design was chosen as the controller to use for the system. One of these controllers remained in service as the main system controller until 1985. We made many changes and additions over the years to enhance its operation. I talked with K2OAW around 2001 and he was very surprised to learn that his design was still being used at that time. This controller design is still being used at 4 of the receiver sites.
February - March 1973 – The seed is planted
A number of the core MARA group met at the White Bear tank for the first time to help Paul remove the equipment so he could get it home to work on. Getting in and out of the water tank site was too difficult during the winter at that time. We used sleds and toboggans to move the equipment from the site down to the parking lot. We talked about some assignments for projects at the time. Paul would continue to work on the transmitter site and overall coordination of the system. Doug Reed (N0NAS) and Rich Palmberg (N0NFO) volunteered to build up one of the K2OAW controller boards. Dan Karg (K0TI) and Tom Woods (WA0RBW) elected to work on an autopatch design.
Spring 73 - Repeater Directory
The 146.25 - 146.85 repeater is listed in the directory for the first time. A total of 12 repeaters were listed for the state of Minnesota.
Fall 1973 – Remote receivers take shape
By this time we had decided to see if we could put a remote receiver on the air in the south east metro area. We were facing some challenges in getting the receiver at White Bear Lake to be sensitive enough, between receiver issues, duplexer issues and other things. So to help this out we purchased a UHF GE Progress line receiver and transmitter strip from Don Klier (WA0SSN). This pair would be used to link our first site from Inver Grove Heights to the White Bear Lake tank on UHF. Later we would get more UHF receivers and eventually have 3 GE Progress line receivers running at the water tank for the links. These were tube type receivers, and along with the tube type 146.25 receiver at the water tank made for a fairly power hungry (and heat generating) rack of equipment. Paul had found a very robust power supply to run all of that, I don't recall ever having a failure in that power supply.
May 1974 – A new call sign
After many start and stops the FCC finally started issuing repeater call signs. WR0ADY was issued in May of 1974.
January 1974 - Autopatch takes shape
The autopatch control design I decided to use was based on an article published in the June 1972 Ham Radio magazine. The touch tone decoder was built using NE567 phase locked loop chips, one for each tone (7 decoder chips). The decoding and control logic was all 7400 series IC's. The telephone interface and audio amplifier was built around my own design, using surplus parts from a telephone and some other projects. Later the telephone interface was upgraded to one using a Motorola design. This basic autopatch was in service until 1985 when the first computer based controller came on line.
Early spring 1974 - First Remote Receiver
In parallel with building the autopatch we had been building the first incarnation of the south receiver site. It consisted of a receiver board from a Heathkit HW-202 mobile radio, a K2OAW controller-ID board set and the GE UHF transmitter. We first started running this equipment at Tom's (WA0RBW) house in Inver Grove Heights. It was a big day when we were able to turn on the remote receiver and then drive up to White Bear Lake and hook the link receiver into the system. We didn't have any kind of voter that first few months, so we experimented first with mixing the audio's together between the remote link and the on-site receiver (that didn't work to well) and later putting a relay in to just switch between them. As it turned out this was one of the big leaps forward for 25/85. As noted earlier, we had always had problems really getting the on-site receiver to hear the way it should, so with the addition of the remote site we had a receiver on the system that was not degraded by duplexer loss and transmitter noise. 25/85 finally had some great ears. Tom's house turned into our test bed for the remote receiver design and the autopatch design as it was easy to get to and had a phone line. As soon as the autopatch was ready to be brought on line I installed it at Tom's house, yes the autopatch started working first from the remote receiver site. We spent a number of weeks debugging it there and making changes to improve it performance. Due to the coverage we now had and that fact we had a working autopatch system usage started to take off. We moved the autopatch up to White Bear Lake early that year, probably in Feb or March
Spring 1974 - South Site
Also during this time we were having discussions with the City of West St. Paul to allow us to put the south site receiver equipment on what was then a small ski hill that the city ran in the winter time. The ground elevation of this hill is over 1100 feet and has a commanding view of twin cities area. With leg work by Paul and Tom we were granted permission that spring to install the equipment. The equipment was put on the air at the site on July 5, 1974. We thought the coverage was pretty good from Tom's house; it was incredible up on the hill. Mobiles all over the metro area could access it. It continues to prove it worth every day and is one of the prime receivers for the system over 30 years later.
August 1974 - Newsletter
- The newsletter talks about the system having 3 receivers. White Bear Lake, West St. Paul and Western Minneapolis. - Transmitter is a GE Progress Line 50 watt output. - A note about the White Bear receiver says it was using a GE TPL receiver, which was GE's first attempt at a solid state radio. This receiver never did work very well as it could not cope with the on-site transmitter. As I recall we switched it out to a tube type receiver for a while until we finally got Motorola motrac receiver at White Bear.
September 1974 – Autopatch information
An auto patch information sheet that was passed out to the system supporters shows the autopatch codes to be #726 to activate and #7 to deactivate. This same note shows a list 29 call signs that had contributed money to the operation of the repeater.
Spring 1975 - First Building at White Bear Lake
The city of White Bear Lake agreed to let us build a building to house our equipment at the water tank site. Having the equipment in outdoor cabinets severely limited what we could do, and made working on it almost impossible in the winter. I can remember one cold windy day trying to get the NE567 decoder chips in the autopatch set on frequency. They would drift so much with temperature I couldn't just leave the cabinet open and make the adjustments. So I setup my frequency counter on the chip I wanted to adjust and closed the cabinet door and went and sat in the car for 5 minutes to let the autopatch (and me) come back to normal temperature (there was a heater in the box). Then I would quickly open the cabinet, try and set the adjustment before the temperature changed too much. I had to do that process 7 times in order to get all the chips set on frequency properly. The new building was wonderful by comparison; it was about 8x8 feet and allowed room for 3 full sized cabinets along with some smaller cabinets mounted on the wall. In fact the autopatch cabinet was just moved from the outdoor mount to being mounted on the wall in the new building.
April 1975 - Minnesota Repeater Council List
Repeater list has 25/85 listed using the WR0ADY call sign. There are a total of 24 out state and 20 metro area repeaters listed on this list. This includes all bands, 146, 220 and 440.
April 1975 – Autopatch update
I added a time out timer on the autopatch, I don't recall that it was being abused but it was put in to prevent it from tying up the whole system if there would be some autopatch related failure.
Summer 1975 – Beep Beep
Don't have a good date for this but sometime in here we added the courtesy beep to the system. We had heard courtesy beeps on repeaters in other busy parts of the country, most notably the 16/76 system in Chicago and wanted to give it a try. 85 was the first system in MN to have a courtesy beep.
Summer of 1975 – South Site Upgrade
While we could cope with tube type link receivers at the White Bear tank, having tube type link transmitters at the remote sites was something we really wanted to eliminate. VHF engineering had a line of 1 watt transmitter kits that seemed like they would do the job so one was purchased and built up to test with. After some issues with transmitter stability we finally felt like we had something that could go on line. So the south site was pulled out and brought back to where it was born (my work shop) and given an overhaul, new power supply (we didn't need 300 volt B+ and filament voltage any more), some new mounting hardware and other upgrades. I think we still ran the Heathkit receiver at this time. I don't have a good date as to when the receiver was upgraded but sometime around here it was changed out for a Motorola Motrac receiver. This was to become the model for the receiver site equipment we standardized on for the system. The south site as most of the remote sites consist of pretty much this same equipment today. Yes we've had to change out a few dried out capacitor here and there but over 30 years later it still works.
Summer of 1975 – The system can vote
Doug and Rich came up with our first voter. This was a logic based circuit that would lock the receiver audio to the receiver that came up first. So it was called the first-in voter. This worked pretty well. Of course if the receiver to get in first was noisy the whole transmission would be noisy, which would bother fixed stations, but for mobiles it worked pretty well as they would tend to drop out of the noisy receiver due to mobile flutter and then the better receiver would get selected and hold on. This characteristic of the way the voter worked led to fixed stations sometimes being told to reduce power to make their signal better. Somewhat opposite of what you would expect! Of course what the effect was of reducing power was to get the voter to make a different choice.
October 1975 – Newsletter
- Building of the new building at the White Bear Lake tank. - Installation of 3kw generator for standby power - Voting-select system is capable of controlling 4 receivers. And 8 port version is now being built. - Auto patch codes get changed to #618 to bring up the autopatch and #6 to drop it. - A new tube type power amplifier is being installed on the transmitter. - Assignment of 444.8 - 449.8 for a UHF repeater - Linking to Waseca is in the plans - Use of 25/85 for the WINDS weather spotting network during the 1975 severe weather season. - MARA is introduced as the official name for the repeater group.
December 1975 – A little bit of AI
I added what I called the automatic control operator board to the controller. Users today might be familiar with its operation as it is available on most of today’s computer controlled repeater controllers. It was put in on 85 to cut down on kerchunkers and also cut down on some of the extra beeps caused by noise bursts. Basically it counted the number of receiver keyups that occurred without having a repeater beep (courtesy tone) and if there were more that 3 it would force a delay in the receiver COR line, so it would take a few seconds of receiver COR before it would key up the repeater. Once the repeater came up it would reset everything and the cycle would start over. Remember this was all done in hardware, so the little add on board to do this had something like 6 IC's on it.
February 1976 – Planning Letter
Paul sent out a planning letter discussing current and future plans. It talks about the plans for 85 and how many receivers sites we were thinking of putting on line. It also discusses plans for an even larger coverage system, with the receiver sites spaced out even further. This larger coverage system was nicknamed WARP for wide area coverage repeater. Paul included hand drawn maps showing the current and planned 85 coverage. He also talked about linking 85 to other systems around the state. The letter also included the new WR0ADY logo decal that was available.
February 1976 - Central Site
With the success of the south site and usage growing quickly we started thinking about more receiver sites. Rollie Paulson (K0OSS) was helping us some during this time, testing a receiver site near the St. Paul/Minneapolis border just east of the U campus, but that never really got moving along to far. Soon afterwards a group of U of M students stepped forward and started helping out and what was to become the central site. The equipment was built by Mark Johns (WA0RGV, now K0MDJ). This site used what was now the standard platform, a Motorola motrac receiver, VHF Engineering transmitter and the K2OAW controller.
March 1976 – Early Linking Plans
A planning document is written up by Tom (WA0RBW) that describes in detail the southern Minnesota linking project that shows the hardware required at White Bear, Northfield and Waseca to accomplish the link.
March 1976 - Newsletter
- A note discussing the courtesy beep on the system and how it should be used. As noted above, I don't have the exact date the beep it was installed, I do have my original schematic of the circuit, but it is not dated. - Discussion of the receiver sites that were on line at the time. o White Bear Lake o West St. Paul o Central (U of M) o Columbia Heights o South West (not on line yet) - Information how the repeater will be used this season for weather spotting. The spotting system was called WINDS (Weather Information Notification Dissemination System). 3912 khz was also still being used for spotting. It was brutal to try and use 80 meters with thunder storms in the area. The static crashes were most times stronger than the people you were trying to talk to.
June 1976 - The first designs for a real voter
In the background Bruce (WA0FQY, now K0SON) was working on how to do real audio quality voting and had a design on the bench during this time period. This particular design did not ever make it to the on-line system but it was a test bed for later designs.
Summer 1976 - Central Site
Again with lots of legwork by Paul and assistance from Mark and others we were able to get permission to put the new central site on the Moos tower on the U campus. I think it was just called Health Sciences Unit A at the time. MARA was the first amateur equipment to go up on the building. Having the central receiver on-line we pushed the mobile and portable coverage even further west.
Summer 1976 - UHF repeater
Always wanting to try new things I was working on putting a UHF repeater together. The first system to go live at White Bear Lake consisted of a GE Progress line stations (tubes again). We had found a surplus base station that was in really clean shape so figured it would make a good repeater platform. It worked quite well but of course had the maintenance issues you get with tubes. This I believe was the first ham radio UHF repeater system on in MN. This version was carrier squelch.
Summer 1976 - West Site
Since Tom (WA0RBW) worked out on the west suburbs, so he was interested in getting a receiver online out that way. We built up another receiver site and got permission to put in on one of the City of Minnetonka water tanks. The original install was in an outside cabinet. Later the City asked us to move to a different water tank where the equipment is housed inside. The original west site used a surplus WABCO railroad radio receiver. It was upgraded to the standard motrac platform in September 1977
Fall 1976 – Forest Lake Site
I’m not sure of the dates for this, but around this time we added the Forest Lake site. This is located on Lee Dugdale’s (K0HPY) tower and is collocated with the 146.13 receiver. MARA crew help Lee install a 100 feet of Rohn 25 tower and antennae’s This site consists of the same hardware as the others. Motrac RX, VHF Engineering TX and K2OAW controller. Bob Helwig (K0IKV) built up most of the hardware for this site. Getting the link down to WBL was a challenge at first. Up to this point we have been using an antenna located on a telephone pole at the water tank site (up about 30 feet). This worked fine for all the existing receivers as they are all south and west of the water tank. Forest Lake however was northwest, right thru the water tank structure. As we didn’t have another UHF antenna on top of the tank to use we put a short pole in the ground on the north side of the tank and installed a yagi pointed up towards Forest Lake. The 7/8 in line was just lying on the ground going around the take. I think it was just that way over the winter and the next spring we installed another UHF Omni antenna on top of the water tank to use as a link receive antenna.
Fall 1976 – A real voter
The long time dream of a real signal quality voter was to be finally realized. Using an updated design based on the highly successful GE commercial voting system and a selector design that Bruce (WA0FQY) found in 'Electronic Design' magazine we build up a voter capable of handling 8 receivers and actually picking the best sounding receiver (least amount of background noise). The build and testing took a number of months before we had something we could put online. When it was installed in the system we learned a lot about the existing system audio, we found all kinds of hum and noise that we didn't realize was there and spent considerable time fixing all of those issues. We quickly learned that anything that induced any extra noise on received signal, even if you could not hear it would be detected by the new voter. We were still running the tube type link receivers at the time so getting them cleaned up was a bit of a challenge.
October 1976 - Outlink linking project.
As noted above we had been working with a number of groups to the south, mainly Waseca and Northfield on methods to link 85 with the 34/94 system in Waseca, mainly to support severe weather spotting. This was before it was called Skywarn. To that end we did get the equipment installed at White Bear Lake and in Northfield to make the hop down to Waseca. This system was online from time to time over the next few years but never really got used all that much.
November 1976 - A new voter design (this date conflicts)
We now had 4 receivers on-line in the system and the 4 port voter was full so a design was laid out for and 8 input first in voter. I think the build was done over the winter and we started testing in the spring of 1977.
December 1976 - Improve the autopatch
To improve the NE567 DTMF decoder Doug and Rich built up some LC based band pass filters for the DTMF decoder in order to help it decode better. The filters were very good and helped the decoder work better and false less.
Winter 1976-1977 – Newsletter
- Discussion of the linking system between White Bear and Waseca. - A list of sites shows the following setup o White Bear Lake – Main TX and RX. GE Progress Line (tube type) link RX o South Receiver – Motrac RX, VHF Eng TX, 6db ant o Central Receiver – Motrac RX, VHF Eng TX, 6db ant o NE Receiver – Heath HW202 RX, VHF Eng TX, 3 ele beam facing North o West Receiver – WABCO RX, VHF Eng TX, 6 db ant. o NW Receiver – Future - A questionnaire was included to get some feedback from the users about current and future system plans. - A listing of key people involved with operation of the 85 system as published in the winter newsletter shows the following assignments: o Paul Emmeott - K0LAV: Overall system coordination, transmitter site maintenance o Dan Karg - WB0GDB (K0TI): Autopatch, South Site, Linking Project, Special Systems o Tom Woods - WA0RBW: West Site, Central Site, Linking o Lee DougDale - K0HPY: Northeast site o Bruce Jungwirth WA0FQY (K0SON): Receiver voting, transmitter site. o Bob Helwig (K0IKV): Receiver voting system o John Rooks WA0YCZ: Northfield linking relay point.
Late 1976, Early 1977 - Voice IDer.
Again, wanting to constantly be innovative and try new things I decided that a voice IDer would be a neat project. Using 2 8 track tape drives and a bunch of home brew hardware (voice detectors, timers and audio amps) a voice IDer was built up and installed on the system. The primary tape drive held the repeater voice ID audio and the other drive held the informational audio. This informational audio could be brought up on demand and gave a brief description of the system or other news of interest at the time. Sort of an early attempt at the ham radio news programs that go on today. With the help of Wayne Selly (K0UBL) the audio tracks for the ID's were laid down in a broadcast production studio, and Bob (K0IKV) spent much time splicing audio tape together to get it all to work smoothly. We were able to get many of the local TV news anchors of the time and other local TV and radio people to read IDs for us. None of those computer generated ID’s we have now. These were ID's with some warmth to them. Later we remixed the tape and set it up so it would be trigger on the top of the hour (yet another add on board) Voice ID the system. If and when the time got off some one would have to go to the water tank and reset it. Once again 85 led the way and was the first system in MN with voice identification.
February 1977 - 5 receivers sites on the air.
- Now we had receivers sites in White Bear, West Saint Paul, Central (U of M), Forest Lake and Minnetonka. - Plans were being laid for a northwest receiver site. - Work was being done to bring a 6 meter repeater on line. This meant we could out hear the White Bear transmitter in a lot of directions so we started dreaming of a better transmitter site.
May 1977 – 3 Repeaters Linked
The 3 repeater interface was installed. This allowed us to cross link any of the 3 systems at the water tank. VHF, UHF and the UHF linking hub. The linking hub is what tied use to the link to Northfield and Waseca.
May 1977 - IDS survey
I have a hand drawn layout of the IDS center roof showing the location of all of the antennas at the time on the roof. This was done to try and figure out where the best place to locate our antenna and to understand the site. My notes on the drawing say 32 antennas, 8 micro wave mounts and 2 open mounts.
June-July 1977 - 'High in the Sky with ADY'
When it started to look like getting on the IDS building, the tallest structure in downtown Minneapolis, we launched a project to build up a suitable transmitter for the site. Bits and pieces of a Motorola 110 watt continuous duty base station were put together, along with a UHF Motorola motrac receiver for a link receiver. Bob, K0IKV would build up a super 13.8 volt power supply to run it all. All of that was racked up in an old Motorola base station cabinet and we had a transmitter that we felt was up to the task.
The July/August issues of 'The FM Scanner' (the TCFMC newsletter) had a story about the 85 transmitter being on the IDS building. We were testing from the site by then, but this was probably the first time news of being on IDS was in printed in any newsletter. With the help of a grant for the first year of rent on the building we were able to get the installation completed. At that time the cost to be on IDS was $160 per month.
July 1977 – First MARA Picnic
MARA sponsors a picnic and annual membership meeting at Mounds Park. About 50 people where in attendance.
July 1977 – MARA incorporated
The organizers of 25/85 formed a non-profit corporation to oversee the repeater system operation. The initial board of directors consists of K0LAV, K0IKV, WB0GDB, WA0RBW, and WA0FQY
November 1977 - Repeater List
A list published by TCFMC in November 1977 showed a total of 22 repeater systems having Twin Cities metro coverage, 19 on 2 meters, 1 on 220, 1 on 440 and 1 on 6 meters.
Fall 1977 – Newsletter
- Discussion of the installation of the transmitter on IDS. Including costs involved. - Discussion of the incorporation process. And a list of the current board of directors. Two types of membership are provided for. The operating member and the supporting member. - New logos are available that have the new IDS building in the logo - Looking into building a micro-processor controller for the system.
Summer 1978 – Newsletter
- Discussion of a Northwest RX site and a RX site on IDS. While we experimented with a RX on IDS it was never brought on line. - Special Thanks to WA0CTZ for helping to procure solid state UHF receivers to be used for the remote site links. These will replace the aging GE Progress tube type receivers. - FCC will not be renewing WR repeater call signs, so a club call for MARA was applied for and received. During the spring of 1979 we will change everything over to use WD0HWT as the repeater call, retiring WR0ADY. - MARA T shirts were available. MARA started taking orders in July 1978. There were 3 colors available, Blue on White, Dark Blue on Light Blue and a special Black on Orange. These shirts had the MARA/IDS logo on them - We were still investigating building a micro processor controlled controller for the system.
July 23 1978 – Second MARA Picnic
MARA sponsors a picnic and annual membership meeting at Mounds Park.
Fall 1978 – UHF gets new life
UHF repeater (444.800/449.800) is upgraded to solid state Motorola motrac equipment from the tube type GE equipment that had been running. The repeater is still located at the White Bear Lake tank site. At this time we put 114.8 PL on the repeater and it’s been that way ever since. The selection of 114.8 was influenced by the repeater systems in the Chicago area. As a group we traveled there quite a bit and we wanted a PL that was the same as there. The radios at that time pretty much only allowed 1 PL tone, none of this programmable stuff we have now.
September 1978 – Link receiver upgrades
As part of upgrades the tube type link receivers are on the way out. The receiver to voter interface card was designed 9/2/78. Half a dozen GE Master Pro receivers have been donated to the system and are in the process of getting converted, tuned and mounted in equipment racks in preparation to getting them on-line. Making the conversion was a 2-3 day project, getting the old tube receivers out of the cabinets, mounting up the new receivers and then cabling the receivers to the interface card cage and the on to the voter.
May 1979 - Auto Patch Upgrade
The speed-dial only board was added to the autopatch. We then added a timer that changed the autopatch mode at night so only the numbers stored in speed dial could be dial. This was done to provide better control of the autopatch at night when not as many people were around to monitor it. At this time we had certain emergency services programmed into speed dial on the autopatch phone line, so mobiles could dial the hi-way patrol and other agencies easily. Remember this is before the days of 911
May 1979 - Auto Patch Changes
A number of enhancements to the autopatch were done in May, We changed the autopatch codes to the more common * up and # down. Additional commands were added to the autopatch logic to be able to turn the patch on and off and put it into speed dial only mode using DTMF tones. Some further circuitry was added to allow these changes to work properly, including adding some delay in decoding the * digit so the autopatch would not be 'talked' on with a voice. One feature that we don’t even have today was the ability to detect when the called party hung up and automatically knocked down the autopatch.
November - 1979 - The really big show
The highly popular MARA slide show premiered at the St. Paul Radio club. This production was the result of many months of planning and work and the outcome was fully automated 45 minute slide show, using 2 projectors, and studio produced narration using professional voices. The first section of the show talked about the basics of FM and repeaters. It then went into more detailed information about some of the components of the 25/85 system in particular, addressing the remote receiver sites, voter, transmitter and the autopatch. By the winter of 1981 this show had been presented to 53 radio groups around the state. Tragically the audio and slides that were part of this show were lost in a fire in 2000. I have some of the original text that we used when planning the show, but that is about all that remains.
Winter 1980 - Digital Controller
First plans are laid out for our new digital controller for the system. This would provide positive control of the system and provide telemetry back to the control operators of system status. This would replace the antiqued secode control system using rotary dial control heads and stepper motors.
June 1981 - Digital controller goes live
The digital control goes on-line. While this part of the system the users never see or hear, it provides vital control of the repeater and with its telemetry capabilities provides system troubleshooting and status information to the control operators in real time. Remotely we can see which receivers are receiving signals, which one is voted and what touch tones are being sent by users. We can enable or disable any receiver and control all other aspects of the system.
June 1981 - Autopatch Upgrades
We were having some trouble with preventing long distance calls from being made on the autopatch so an improved circuit was installed to detect either 0 or 1 as the first digit in the dialed number and drop that patch if that happened.
Winter 1981 – Newsletter
- Announcement of the 2nd annual 85 Open Forum. Friday Feb 13, 1981. This was to be held at the Har Mar Mall, Roseville, MN - New and updated 85 voice identifiers were added to the system - The UHF link between 85 and the Waseca system is fully operational - A note about the MARA slide show. Recent bookings were Waseca, Austin, Faribault and Duluth. - The weather alert tone has been changed to just a beep alert instead of playing the complete live audio from the weather service.
September 1982 – More autopatch Upgrades
I finally replaced the NE567 tone decoders with a state of the art single chip DTMF decoder. The improved decoding reliability and cut down on maintenance time. The NE567's required continual alignment in order to keep them working properly.
Winter 1983 – Newsletter
- IDS lease is renewed for a 3 year period starting in 1982 - 6 meter linked repeater is partially working - Announcement of the 4th annual MARA open forum, Feb 5, 1983. To be held at the VFW post in Roseville, MN - MARA Sunday night bulletin board, run by Dave Blair WB0YUC (sk). - Summary of the 3rd annual MARA open forum held Feb 6, 1982 - A fundraising raffle was held at the 1982 Amateur Fair hamfest. Over 400 raffle tickets were sold. Prized included an ICOM 2AT handheld, Callbooks and a WX alert radio. - MARA name tags are still available. - A list of 170 supporting members was published in the newsletter. Compare that to the 29 that were listed in 1975.
March 1983 – And even more autopatch Upgrades
An upgraded circuit was added to the autopatch to better interface with the digital controller.
June/July 1985 - Flat audio modifications
In effort to improve the voter selection and improve the overall audio in the repeater all the receiver sites were brought into the shop, one at a time and converted to flat audio. This cuts down on the amount of audio processing done on the signal and delivers a more uniform signal to the voter.
Summer 1985 - SCOM controller
In the fall of 1984 I had seen a pretty nice computer controlled repeater at one of the Chicago hamfests. Over the next months we investigated if it would suit our needs and worked with the manufacturer of the controller to improve it with some features we really needed. We did decide to purchase one and it was installed in the summer of 1985. This replaced the K2OAW controller (ca. 1973) and all the hardware associated with the autopatch (ca. 1974). This controller was made by SCOM (still around today) and was call the big board controller.
Fall 1985 – UHF Gets New Hardware, and a new Site
With the help of a friend of John Desmond (K0TG) that was working at Motorola we were able to procure a complete Motorola MSF5000 repeater station out of the engineering department. Basically this was built out of parts that engineering had used during the design phase of the MSF 5000 hardware and software. The MSF5000 series hardware had only been available to the market for a couple of years when we got this. We might have been the first ham group in the country to run this hardware. Even today some groups are just upgrading to this version of equipment. The MSF 5000 was delivered to us all programmed and tuned on our frequency. With this on the way I thought a better more central site was needed for the repeater. I still had good connections with the owner of Capitol Electronics (now owned by MRE) and asked if we could use the ham band cut antennae that was still on the tower. This antennae had originally been installed by me and some other hams when we all worked at Capital in the late 70’s and had supported various UHF repeaters over the years. With authorization to go on the Capitol tower and a new MSF5000 in place we had a very good coverage centrally located UHF repeater system.
August 1986 - Oakdale Tank
MARA comes to an agreement with the City of Oakdale to install radio equipment on the Oakdale water tank. Initially equipment installed there is a linking repeater for the Superlink system and a 145.01 packet node.
November 1987 - MARAthon
As a precursor to some of the nets that go on 85 these days, and as a fun thing to do the MARAthon net was run November 1. This was sponsored by MARA and the Courage Center Handi-Hams The intent was to go as long as possible and get as many check in's as possible. Certificates were mailed out to everybody that checked in. I don't have information as to how many checked that night. The certificate shows the main net control operator was John (KA0NGO) with the second net control Avery (K0HLA). The recording operator was listed as Eric (N0HQC) It also shows that we had the following repeaters linked up for the net, WB0ZAK (444.450), WB0VAJ (147.105), N0FDY (145.190) and K0USR (147.000)
As one of the operators of this net I can tell you we had 303 check-ins that night. We also sent a copy of the MARAthon net log and write-ups in several local ham newsletters to the Guinnes Book of Records but after several months of waiting we received a very nice letter head letter from them stating that they were very sorry that we would not be in their book because they did NOT have a catagory for what we did....
73 es DX de K0HLA Avery
Summer 1990 - Remove Transmitter from IDS
With the increasing cost of being on IDS, it started out at $160 dollars a month and was now in the $500 dollars a month range it was decide that there was not longer enough funds available to keeps the transmitter at IDS. Of course the White Bear Lake site was always the backup so operations continued from there. Plans were then made to install a good transmitter at the Oakdale site. This would allow 85 to run a bit more power than was possible at the White Bear Lake site, plus it give the advantage of allowing the receiver at White Bear Lake to hear better.
Fall 1990 - Move to new building
Due to the installation of cellular equipment at the White Bear site, the city made arrangement with the cellular company for MARA to move our equipment into a separate section of the new building they would be installing at the site. This actually gave us a bit more room and a somewhat nicer building. The old building which has stood since the early 70's was torn down by the MARA crew after we finished moving everything to the new building. The repeater was only off line for a few hours during the move.