Posted in: DMR, People, Projects, Repeater

DMR Microwave Update

Today 25-Nov-2019 Jerry W4BFL, Lew W4LEW, Jerry’s son Anthony KM4MFX and Grant W4KEK teamed up to address improving the existing setup at  the site which were:

  1. Remotely control the repeater settings and controls
  2. Improve data transfer rate between the repeater site and FAU

The following are some picture of the repeater site closet

This is the current state front look of the DMR repeater

These are some of the controls that help enable access remotely

Another view of the repeater and power supply

The 2m duplexer cans that are now used as band pass filters given we have split antennas. This arrangement resolves the intermod and desensig issues.

This is the 2m analog repeater with various pieces of gear on top.

Jerry W4BFL, Anthony KM4MFX, and Grant W4KEK discussing and accessing the repeater

Father and son debating next steps.

The front panel with various ethernet connections to one of the control devices

In maintenance and equipment room of the SS building where Anthony and Grant are working.

Another picture of our DMR machine.

After the team was ready, they split up into two groups

  1. At the repeater, finish DMR configuration to remotely control machine
  2. On the roof, swap out current microwave dish for an upgraded version
  3. One the roof, adjust dish for better reception 

Below are some photos of roof work and view.

Facing west toward Parkland. The structure on the right houses an assortment of cell equipment and has warning signs not to wander into that area.

This is the same cell housing area and the antenna is now used for 2m analog transmission. The solution to the intermod was to split the transmission from reception. This antenna was already in place, we were not using it but it was repurposed to solve a problem.

Another view facing north west toward The Shack at the West Delray Park

This view is of the transmission antenna on the left and the reception bow-tie antenna on the right. The pipe in the middle is not currently used.

These are one of our best investments: commercial grade tow-die dipole antennas. The 2m is on the left and the 70cm antenna on the right.

This is the 70cm bow-tie dipole antenna on a day that is just amazing to be on the roof. The elements face west.

Another view on just an amazing day.

This is the 2m transmission repurposed antenna that is used to solve our intermod issue with our gratitude to Erik Rodriguez KF4LZA who worked on the duplexers. He repurposed the 2m duplexers to act as input filters from the bow-tie antenna.

The connectors at the 2m repurposed antenna.

Another view and notice the 2m transmission feed line that was painted probably hardline.

Looking up at the top of the 2m transmission antenna.

The very top. The connectors had to be replaced when Erick was on site.

This is the base of the 70cm antenna feedline.

This is the base of the 2m assembly and pole holding the antenna. The chrome moly pipe is hardened and will sustain hurricane winds.

Looking at the transmission antenna on the left and the reception antenna on the right.

Looking north-north east toward downtown Delray Beach. The green water tower in the distance near the middle of the picture is the Delray maintenance facility.

This north west shot is looking directly at The Shack.

70cm antenna facing west with Boca to east in background.

The current microwave dish facing FAU engineering building roof. RT95 is in background and this is about 10 stories high.

An up close view of the current dish.

This is the white protection unit.

Taken from the microwave dish facing north, another view if the 2m transmission antenna secured to a pipe.

View of the top of that 2m transmission antenna.

2m bow-tie antenna elements.

Middle element

Bottom element

Another view of the base of the 2m reception antenna.

Upclose of that same water tower in Delray.

Getting ready to replace the current dish with an upgrade more sensitive dish.

Doing the disconnect work.

All hands on deck.

It’s off and what no signal. Had fun with Anthony when I had my Tyt380 UV and set it to GCARA PMB parrot and made a call. Yes, it echoed back and Anthony’s look of puzzlement was interesting. I did not get that picture only exists in my mind.

Setting up the right driver heads.

This is the upgraded dish with bracket begin removed because it was too small. Note the adjustments for the 3 axis for the dish.

Looking at downtown Boca.

Getting the new dish up.

Team work of course. Takes many hands

Yes team work.

This is a cell configuration that is about 3 feet from our dish. Notice south bound RT95 ramp traffic

Anthony looking at that naked lady sunbathing.

This is the view he’s looking at.

On the distance is the FAU engineering building and dish on the roof.

The assortment of lines feed that cell near our dish.

Close, very close.

Grant in focus.

Ethernet feed and connector about to be plugged into the horn.

Note the plastic water tight cap the cable passed through.

Now plugged into the horn.

Good image of the horn with ethernet connected.

Finished job. Now to make it work. May adjustments and trials and errors.

What is the end result?

  1. The DMR repeater can be remotely controlled
  2. FAU to SS dish from 39 mbps to 84 mpbs
  3. New dish was replaced with old dish because it did not work as needed

Hope you enjoyed this and our many thanks to:

  • Robert Eng W1ENG for enabling us to acquire this highly sought repeater
  • Jerry Zaza W4BLF for his many hours and time off from work to make this happen. There are so many things he as done for our benefit we’ll never know, all of which enable us to have a better environment and enjoy our hobby
  • Lew  Lehman K4LEW our repeater trustee for enabling us to access the repeater location and ensure the 2m machine is working as needed.
  • Art Lewis WA4VSK for partnering with Lew and Erik to get the 2m issue addressed. Yes Art is one of our key contributors like Jerry and has spent countless hours at the site and resolving HF issues.
  • Erik Rodriguez KF4LZA for providing his technical expertise and analysis equipment to partner with Art and Lew in solving the 2m issues.
  • Anthony Zaza KM3MFX and Grant Baron W4KEK for proving their youth and expertise and helping hands getting the project complete.

And, yes have probably missed some folks. Will add them as i discover their contribution.


John.C N1QFH