FT-7900 ZUM Repeater Build - Part 4

 

Now that I have moved into the new house, I thought I would try getting the homebrew repeater back up and running. While going through the hardware and software, I decided to upgrade the software from Pi-Star to WPSD, change the controller-to-transceivers wiring harness, and put the Raspberry Pi and MMDVM in a new HighPi Pro case.

For the wiring harness, I decided to get rid of the RJ-45 ends and have the mini DIN cables come directly out of the HighPi case. I drilled two holes in the end of the case, passed the snug fitting cables in, and connected them to the boards wiring harness as they were previously, as described below.

After connecting all the hardware, a firmware upgrade was done on the ZUM Radio MMDVM board using the tool in the WPSD software. In my case, the ZUM Radio board is the v1.0 with the F4 chip. If you aren't sure what you have, the board version is printed on the board itself, and the chip, the largest one with connections on all four sides, has the model information laser etched on its face. 

The chip number is seen directly under the wire harness as "STM32F446", an ...F4... chip

With all things updated and secured, the repeater fired right up and is working fine. The final process will be working with the Wisconsin Association of Repeaters to get coordination approval for my new location in Sheboygan Falls, Wisconsin.

Conform to His Image

Fathers, look for opportunities to encourage your children regarding things of eternal value, not about physical or mental attributes which can change with a single car accident, but about the decisions they make, the values they espouse, and for the older ones, their parenting skills, etc. Reflect the model of Jesus, because that is the single most important thing to build up your child. Just like Paul said, encourage each other in our faith. And if they are not following Jesus, continue to encourage, regardless. Magnify eternal values and virtues, and because you are their father, your words of affirmation are weighty. Your words make lasting impressions. Live by example, like Jesus' example. Show them what is important and worth pursuing in life. And never forget to tell them, "I love you!".

A New Thing

"For I know the thoughts that I think toward you, says the Lord, thoughts of peace and not of evil, to give you a future and a hope." - Jeremiah 29:11

"And we know that all things work together for good to those who love God, to those who are the called according to His purpose." - Romans 8:28 

"Do not remember the former things, nor consider the things of old. Behold, I will do a new thing, now it shall spring forth; shall you not know it? I will even make a road in the wilderness and rivers in the desert." - Isaiah 43:18-19 

Sunset at Sitgreaves National Forest, Clay Springs, AZ

Wow, what an interesting time it has been over the last five years, since my wife Nancy passed away. I haven't been on the radio very much, especially HF, which I really miss. Spending summers in Wisconsin, winters in the Tucson area, and half of last summer in Clay Springs, Arizona has been a very interesting experience. I've made a number of new friends - some very close - and have spent a lot of time praying, studying the Scriptures, reading, and talking with everyone that stopped by at my corner site where so many interesting stories were shared. 

I ended up leading a Bible study at the RV park in Tucson for the last two years. What a blessed time of encouraging others in the Lord. So many lives were changed by God's hand. Last year, as we were studying the Gospel of John, our perspective was to understand that the Holy Spirit had John write this book to tell us something, so we should listen and read the text carefully, and with an open heart and mind. Our main question was, "Who is Jesus, that is, who does He say He is, who do others say He is, and how does this affect our lives?". 

Many, by the work of the Holy Spirit, gained a much better understanding of who Jesus is, like in Peter's words from John 6:68-69 where he said, "Lord, to whom shall we go? You have the words of eternal life. Also we have come to believe and know that You are the Christ, the Son of the living God." As a result, some came to Jesus in repentance from their sin and started a new life in Christ Jesus. Praise the Lord! What an amazing time.

A New Home

So what's been happening lately? Well, through much prayer and searching, the Lord has led me back to Wisconsin, but not in the way I was planning. I looked at twelve different properties to build my home plan on, but all fell through for the strangest reasons. Here I was praying over each piece of land asking the Lord to work out His will regarding them. That is when the Lord convicted me, saying, "You ask Me about each piece of land and if that is what I want for you, but you never asked Me about building your house plans". Oops. This is true, so I asked for forgiveness and turned it all over to Him.

The next morning, I got my almost-daily email with land for sale that fit my specific search criteria. The first entry was a house, not land, and not two or more acres. In other words, this should not be in this email because it does not fit my specific search parameters. Understanding this, I said, "Okay, Lord, what are you doing? Long story short, this two-owner house was built in 1975 by the grandparents of a dear best friend of mine, who grew up in it and helped build the home. He now lives a block and a half away.

The evening before closing, I met with the realtor to do a walk-through and we started talking about the Lord. As I told her my story, I mentioned Romans 8:28. The following day at closing, the realtor told me to tell the banker and the closer about what we talked about last evening, that is Romans, so I did. Then the realtor asked me, "What day is it today?". I said, "Um, closing day?". She said, "No, it's 8/28, like Romans 8:28!". Ha! God really does work "all things together for the good, for those who love Him, those called according to His purpose"!

This home and yard hasn't been touched for 50 years, except for a new roof in 2019 and a few replacement windows. It has all the original paint, walpaper, flooring, cabinets, fixtures, siding, etc. So as of the time of writing this, the following boxes have been checked off.

• Move a heat register
• Move the clothes washer and dryer from the kitchen to downstairs
• Remove wallpaper from three rooms
• Paint all walls and ceilings
• Installing a new boiler furnace
• Remove all old flooring and install White Oak wood floors
• Furniture and appliances are on the way
• Install a new front exterior door (scheduled)
• Remove a kitchen window and replace with an exterior door to backyard (scheduled)

There's still more to do, but thankfully the list is much shorter now.

A New Station

Desk and breakfast bar area on the east end of the kitchen.

Cardboard mockup of the desk (lower left) and the breakfast bar (higher right) area.

On the east end of the galley kitchen, I'm building in a small desk and breakfast bar where the clothes washer and dryer were located. The desk is where I'll be setting up the new station with a Yaesu FT-710 AESS HF radio and a Yaesu FTM-7250D 144/440 radio. 

Funny enough, this house already had a small tower set up, so I mounted a Diamond X-200 vertical on a 10 foot mast atop the tower at 42 feet, and a Diamond X-50 on a stand-off arm at 29 feet. The FTM-7250 is up and running, as well as a YSF mode, WPSD hotspot. 

For an HF antenna, I found a fair deal on a Hustler vertical that I'll try out, since there's no way to set the Barker and Williamson BWD-90 folded dipole up here.

Final Thoughts

I am very grateful to the Lord for bringing me back to Wisconsin. Since coming back, God has been reconciling several relationships that were broken for a number of different reasons. While going through these processes, it is clear that God's hand is in it all, and I thank Him for this. I am very thankful to have a home again, and pray this home serves the Lord's purposes.

Airstream Ham Radio

In May of 2023, I began living full-time in my 2023 Airstream Flying Cloud 23FBT. As my interest in amateur radio continues, finding good information on setting up an amateur radio station in an RV, with all the issues surrounding mobility and power, doesn't come easy. I hope this explanation of my station setup will be helpful to those who operate out of an RV, and to my fellow Airstream owners who don't want to poke new holes in their trailer.

The two radios sit atop the table I made for Nancy before she passed away. Linux Mint runs CQRlog software.

Your station itself will probably be as individual as we are from each other, but the behind-the-radio setup has some specific rules to follow in order for the station to work properly. I won't get into all of that, as, since you are reading this, you are likely an operator and have at least a basic understanding of things. The real issue for many RV'ers is finding unobtrusive routes for cables, providing sufficient ground plane for antennas mounted to the RV, and protecting everything from the extended "earthquake" from moving your RV down the road, or off-road.

One of my main goals in building a setup is to not do something that cannot be undone and appear as if it never was. In other words, no new holes or modifications that can be detected by the casual observer's view; everything must be out of view and reversible. With this in mind, I found a way to route coax without creating any possible leaks. 

The 2023 Airstream FC23FBT, like many other RV's, has a roof-mounted snorkel-like refrigerator vent that has a very nice cover over it. This makes a perfect place to run coax up to the roof that no one will ever notice. For those with non-metal RV roofs, a roof-mounted antenna may not work, but this location may provide a top-side entry location for whatever setup you have. Be sure a sufficient grommet and cable holds are made to prevent damage to the coax while your RV is moving.

The coax passes through the front end of the refrigerator vent snorkel, behind the large cover.

In my case, I ran the coax from the vent, down behind the refrigerator and forward to a floor port where the plumbing comes up from the fresh water tank. From there, I fished the line on top of the water tank to another floor port on the curb-side of the trailer where the water heater is located. The coax comes up into the trailer there and to the radios sitting on a little table I made for Nancy. 

A Yaesu ATAS-120A screwdriver antenna is mounted with a UHF connector antenna bracket to the lower half side of the metal AC chassis. This is electrically grounded to the trailer body/skin which also acts as a ground plane for the antenna. I can also swap out the HF antenna for a 2m/440 antenna and flip the antenna switch to the Yeasu FTM-7250D. 

The antenna bracket is standing off the side of the AC chassis with extended bolts to allow for the AC's composite top cover to clear the antenna. Of course, antennas are removed and the radios are safely stowed while travelling.

The UHF connector antenna bracket with stand-off bolts is on the curb-side of the metal AC chassis.

Power is supplied directly off the batteries via a RIGrunner 4004U fuse block.

Internet connectivity is supplied via Starlink, which is now powered by a 12v to 48v step-up booster and PoE setup I made. A Nest router is also running on 12v so no shore power or inverter is needed for internet to operate. When Starlink isn't available due to overhead obstructions, such as tree cover, a PEPwave 4G/WiFi repeater router (also 12v) provides internet when 4G cellular or public WiFi is available.

Outcome

So far, I've accomplished my goal of operating from the Airstream without making irreversible changes.

There are no wires or cables detectable except where they are connected to devices. Perfect!

To date, I have had nothing but good signal reports. Awesome!

I have not run the AC while transmitting, but testing will show if there are issues with interference.

There seems to be no issues regarding receiving signals with the AC on.

After removing the curb-side bed and adding a Stressless recliner, there's plenty of room to relax and operate from anywhere.

Operating out of my winter get-away near Tucson, Arizona in grid DM42ke (Nov 2023)

Operating out of Hartman Creek State Park near Waupaca, Wisconsin in grid EN54jh (July 2024)

Taste and See...

1 John 3:1 Behold what manner of love the Father has bestowed on us, that we should be called children of God! Therefore the world does not know us, because it did not know Him. 2 Beloved, now we are children of God; and it has not yet been revealed what we shall be, but we know that when He is revealed, we shall be like Him, for we shall see Him as He is. 3 And everyone who has this hope in Him purifies himself, just as He is pure.