The KA1RCI Repeater Network

145.170 / 144.570 with PL 67.0

Lincoln - Rhode Island

Trustee / Sponsor KA1JNP

Established as KA1BQP in 1987

After moving to Rhode Island in 1984 one of the first FM repeaters that I worked on was 145.170 which had been built by Matt KA1BQP. Matt had built the repeater using two older Motorola radios, donated by Joe (K1CR) WA1RBT, and Matt had the repeater on the air for testing in northern RI for a few months before selling it to Bill KA1JNP.

Bill moved the repeater to his home in Cranston and I found myself up on Bill's roof on December 26th 1987 installing a new antenna for the repeater. These video clips taken by Dick K1CVP show the gang assembled as Bill and I secured the mounts to the side of the house and climbed up onto the roof to install the hard-line.

Bill KA1JNP - Steve KA1RCI - Joe WA1RBT (K1CR) - Mike KO1X - Syl N1DKF - Dick K1CVP - Georgia N1NKF - Tim KA1QYK

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This video clip show the gang reassembled in the basement with the repeater as Joe WA1RBT (K1CR) installs the connector on the hard-line.

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In this last clip we see Tim making the first contact on the 145.170 repeater as Joe flipped the Switch.

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Now twenty years later the same 145.170 repeater is back in northern RI being rebuilt as a new northern node on the KA1RCI repeater network. Bill and I worked together to re-coordinate the repeater at my site in Lincoln RI and I started rebuilding... 

Repeater Rebuild Fall 2007 - Steve KA1RCI

The initial project planning / repeater configuration

Bill KA1JNP asked me to repair / upgrade the 145.170 repeater and find a good site in northern Rhode Island where we could move the new system. I picked up the hardware from Bill and brought it back home to Lincoln to get the repeater back on the air and start the planning phase of the rebuild.

While sitting down with Bill over a "Cup" we discussed plans for the rebuild

Bill helped me load everything into the Big Blue Beast and I brought the repeater back to my QTH in Lincoln to disassemble all the hardware and evaluate what could be reused and what needed to be replaced. 

Something to build on ...

These photos were taken just after bringing the repeater into the house showing the Kendecom repeater, add-on external controller, and the duplexer that I picked up from Bill in October 2007.

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On the air in Lincoln for testing...

I had to wait for Sandy to head into the Zoo for the day and then when the coast was clear I dragged all of Bill's hardware into the radio room getting it setup so we could get the repeater back on the air and do some testing.

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How about a UHF link radio?

My brother in law just finished making me three new custom mounts that allow me to rack mount the Kenwood TK-30 series radios and I just picked up a bunch of TK-730 and TK-830 radios that will be perfect for linking repeaters.

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Ok ok... Stop complaining and do it already!

After a few days of testing Bills hardware here in Lincoln, and teasing Bill relentlessly, he finally broke down and told me to start the rebuild. I started off by making sure that I could fit the existing four cavity BP/BR duplexer and two additional band pass cavities into a 30 inch rack. Then I bolted on a second 30 inch rack for the rest of the hardware including a new AC power strip, power supply, Kendecom repeater, link radio, and S-Com 7K controller. 

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Stop man handling my cans...

I had great deal of fun teasing Billy about how Bruce KD1BE and I were beating the crap out of his duplexer cavities but it was all just in fun. I had mocked up the duplexer to make sure that I could squeeze all six cans into the bottom 30 inch rack cabinet then started gathering all the hardware and materials needed to fabricate new custom mounting rails to support all six cans properly in the standard 19 inch rack mounts.

Syl N1DKF had located a dealer online that I could purchase some 1 inch by 1-1/2 square aluminum tubing from and I sent Sandy to the hardware store to purchase a dozen bolts, washers, and nuts the appropriate size to fasten everything together. Once the 6 foot section of aluminum tubing arrive I measured the space inside the rack cabinet and decided that 19-3/4 inches was the correct length for the new duplexer mounting rails.

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After some checking and measurements I realized that I could not get the cavities close enough together so they would all fit into the limited space available because to the external band reject adjustment tubes. I would have to rearrange the position of the cavities, placing the two additional band pass cavities in the middle of the original band-pass / band-reject cavities, with the reject adjustment tubes located on the outside four corners of the new duplexer arrangement. 

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Next I had Sandy take the section of tubing to her brothers shop and he cut them down to the three 19-3/4 inch sections that I needed to make the new mounting rails.

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Let the drilling begin... 

Once I has the three sections of tubing, along with all the other hardware, I packed everything up and dragged it over to Bruce KD1BE's shop so we could measure and drill all the holes for the cavity mounting. We would also have to drill out the holes for mounting in the duplexer into the 19 inch rack cabinet rails. Bruce carefully transferred all of the measurements that I had made, while mocking up the cavity placement in the rack cabinet, to the new aluminum tubing and one by one he started drilling the holes.

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I even sprinkled some of the sawdust from Bruce's workshop onto the cans for good luck!

 

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With the hole drilled in the first of the new mounting rails for the two original cavities placed to the outside we were able to secure those cans to the top mounting rail and then measure for the placement of the two additional cavities in the center. Once we had those measurements we finished the top rail and it was very easy to use that as a template to drill all the holes on the bottom rail.

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The third mounting rail would just hold the bottom of the two new band pass cavities as they are slightly shorter than the original cavities. In these last few photos we had all the cans mounted on the new rails and up on some saw horses making it easier to measure and install the last rail.

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I started rebuilding all the hardware back into the two 30 cabinets that were bolted together. Brian N1BS also donated a GLB PreSelector/PreAmplifier from the 145.350 repeater to use on this project that I would upgrade and re-tune for the 145.170 repeater.

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Update new duplexer cavities and mounting hardware

The VHF band pass cavities that I had added to Bill's four cavity BP/BR duplexer did not tune well down at 145 MHz and they were obviously built for much higher frequencies of 150 -174 MHz which were just not working out.

After an extensive search I was able to find several Wacom cavities made for the 144-148 MHz band split that were an exact match for Bill's original duplexer. I ended up purchasing four more BP/BR cavities like Bill's and four matching Band Pass cavities. This gave me enough matching VHF cavities to build TWO six cavity duplexers.

(Guess I will have to start looking for another VHF site!)

 

 

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The mounting hardware described in the above story line and photos that Bruce KD1BE and I had fabricated in his shop were made to mount the two different size cavities. I could have re-used these brackets however decided to ask for help from Bruce and John to make another NEW set of mounting brackets for these new cavities. A few hours working with John Ash N1WEM in his shop we had a nice set of custom mounting brackets for this new configuration of duplexer cavities.

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"Just drill here" vs. "Lets think about this and measure"...

I will make an assumption that we all know the difference between Bruce's Just drill a hole here or the "Hecker Method" and Jon's Lets think about this and make a few measurements or the "Ash Method"

"Hecker Method" - During my visit to Bruce's shop (first set of brackets)

• I had a lot of fun
• We use a C-Clamp and vintage drill press
• We accomplished exactly what I asked for
• We did not measure anything just clamped and drilled
• It took approximately two hours to complete the brackets (felt like 20 minutes)
• The brackets fit the duplexer cavities exactly as planned
• The brackets mounted flush with the cavities exactly as the originals

"Ash Method" - During my visit to Jon's shop (second set of brackets)

• I had a lot of fun
• We use an array of very exotic measuring devices
• We use an very impressive 30,000.00 some odd thousand $$$ CNC machine
• We measured each hole, from multiple angles, several times - Then we double check the measurements again
• We drew detailed plans with notes from the multiple measurements - Then we triple checked the measurements against the notes
•  It took approximately two hours to complete the brackets (felt like 6 hours)
• The brackets fit the duplexer cavities exactly as planned
• The brackets mounted flush with the cavities exactly as the originals

Update April 2009 New 60 inch Motorola Cabinet

After months of struggling with the two smaller 30 inch cabinets I was just not able to mount all the hardware for the repeater the way I wanted so I purchased a larger 60 inch cabinet and started rebuilding the repeater. I found this used 60 inch cabinet on eBay for $20.00 which is an insane price, the only problem was the seller located in California had it listed with (Local Pickup Only) and would not ship the cabinet. Luckily my friend Justin from work lives in near the seller and he was able to pick the cabinet for me and ship it to Rhode Island.

In these photos below I had just started mounting the new matching Wacom cavities in the new 60 inch rack cabinet. The next step will be to remove all the other hardware from the smaller 30 inch racks and rebuild everything into this new larger cabinet. 

 

 

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Update March 2010 - New Antenna!

Finally the 17 year old Diamond X500-NHA antenna gets replaced with a new JAG Electromagnetics 150-4-1/2 half-wave 4-bay VHF dipole antenna.

These two photos show the new UHF Link antenna and Jag 50-4-1/2 half-wave 4-bay VHF dipole antenna.

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These photos show the tower crew preparing the new Jag antenna with mounting brackets.

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Installing one of the Andrew Female Type-N connectors on the LDF5 hard-line.

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Hoisting the new antenna to the top of the tower...

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Update April 2010 Another Duplexer Upgrade!

After such great success rebuilding the Wacom cavities for the Exeter 146.985 repeater with new custom JAG Electromagnetics Type-N coupling loops I decided to rip apart the 145.170 Wacom cavities and upgrade them as well.

In these photos you can see the new custom JAG loops being fabricated in the JAG Electromagnetis lab.

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These photos show the new custom Type-N JAG band-pass / band-reject loops and original Type-N Wacom band-pass loops that I will use to rebuild the six Wacom cavities for the 145.170 Lincoln repeater.

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The first step was to take all of the original SO-239 hardware out of the cavities and clean everything.

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In these photos I have removed all of the old coupling loops and eternal reject notch tuning rods.

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Here are some photos of the new custom Jag Type-N coupling loops with the piston caps for reject notch tuning and the plates to cover the holes where the external reject tuning rods had been mounted.

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The first cavity gets upgraded... I cleaned out the hole in the top of the cavity, installed the new custom Jag Type-N coupling loop, installed the cover plate, and put a self tapping machine screw in the hole mid way down the side of the cavity where the clip for the reject tuning rod had been mounted.

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One finished, five more to go... Should be easy right?

Wrong!

More than twenty years of moisture had cause a large amount of aluminum oxide to build up around the openings for the coupling loops and inside the cavities, they were a mess. As I started working on all the other cavities each one seemed worse than the one before. By the time I made it to the last cavity I had lost all my patience and ended up damaging the recessed mounting hole for the coupling loop.

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Then instead of stepping back and taking a break I started taking everything apart while I was angry and ended up causing more damage.

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In the long run, this turned out to be a good thing as I ended up using the spare set of Wacom cavities that I had been saving for another project. These were an exact match to Bill's original cavities and much higher quality so the finished six cavity duplexer turned out even better than I had expected.

In these photos I have the finished six cavity duplexer on the air for testing with just the RF deck to make sure the new configuration was working correctly. All of the jumper cables making up the phasing harness are made from Andrew FSJ2 heliax and are cut to the exact length 1/4 wave, 3.4 wave, 1/2 wave, and full wave.

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Once the upgraded duplexer had been tested for 48 hours with great success I dragged the hardware back to the house and started bolting everything into the rack cabinet. A third set of mounting rails were fabricated to mount the duplexer and all the hardware was reassembled into the cabinet.

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Update May 2010 - More custom JAG Loops!

I had built out the upgraded six cavity duplexer in the photos above in April using the factory Type-N band-pass loops from a larger set of Wacom cavities and the loops had an offset shape that made contact with the mounting screws. After discussing the problem with my friend Jag he fabricated a new set of four band-pass with no offset that will fit better in these smaller cavities.

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These photos show the new set of JAG band-pass loops and the GLB Pre-selector / Pre-amp that Brian N1BS had donated to the project. I am working on these final steps to complete the upgrades and get all the hardware bolted back into the rack cabinet.

Monday May 31st - HAMCOW High Performance tune-up

Jag provided some great documentation on the new band-pass loops along with the sweeps preformed in their shop that showed us what we should expect for isolation and insertion loss.

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I spent the long 3 day holiday weekend ripping all the hardware out of the rack cabinet and pulling the Wacom offset band-pass coupling loops from the larger cavities and replacing them with the new custom JAG band-pass cavities. I reached out to my good friend Roland N1JOY for help verifying that I had re-tuned the cavities correctly with all the new custom JAG loops and I soon found myself sitting in the HAMCOW going thru another high performance tune-up session.

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More Project Fun to follow soon.