Operating in the World of Ham Radio Technology — Defining the Personal Journey. Part 3.

Hope you've all been having a nice summer so far. Work's been steady, community events have been popping up, and there's lots of summer refreshes in tech on the horizon.

Chapter guide:

Part 1- Fitting the lab with retro radio equipment.

Part 2- Exploring your local RF scene, learning from the best.

Part 3-From hacking HF to building Critical infrastructure.

Part 4- Hamfests, the meet and greet is worth the trip.

Part 5- Safety first, your local RACES & CERT awareness PSA.

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While searching for project work, I've come across a number of ways to line up my past experience with current project possibilities.

I'd like to announce that I will be rebooting current scheduled content for the next few parts of the blog. We're going to be looking at sifting through the numerous projects I've considered as plans have changed from its initial creation back in April.

This plan will let me do 2 things going forward:

1. Establish a step by step process of how to accomplish some of my exploration into research goals. In short, I'm taking some time to plan intel from information. Some of the upcoming projects are going to cover listening and transmitting well outside my own humble homelab environment. For that, I'll need to wrangle the impulsive stuff to a process and get the right people listening.

2. I'd like to start small and scale up with the projects I'm documenting here. This puts the projects that would be in the line of fire from varying risk into a more controlled setting. It'll also give me time to budget for each project.

So with that said, we're diving into the three RF centered projects that will be commanding my attention for the remainder of 2026. A three part plan and network expansion is in order, so let's get started.

• First, I'm looking to build a cheap HF radio from my existing radio devices. I'd create a, ESP32 web server for listening to this as well.

• Next, I noticed a coverage gap for a radio project on a local map. I'd like to build a 20 mile range Meshtastic network node to remediate this issue.

• Finally, I'd like to volunteer all of my networking, gear and RF knowledge into the AREDN project. AREDN will provide WiFi & VoIP capability to city or rural denizens, depending on where I point a remote-controlled antenna.

All of these plans are subject to change day-to-day. I might make a connection at Hamfest who informs me that a stock antenna may be up to the job in a node for instance. Or I might have financial setbacks or windfalls. Project work is dynamic, ever changing and you need to be ready to adapt with it.

Tinkering with repair kits, Refreshing components on a Realistic DX-100.

The first project I've mentioned before, so I'll go over it with some additional high-level background from early on. One of the first RF devices I repaired was the unlikely Radioshack Tandy Color Computer 2 . The device has a RF signal modulator internal for handling video signals. In fact, any early Video Cassette Recorder (VCR), computer or game console from the 80's tended to have these due to how prolific and available components were. To get a TV broadcast picked up on analog TV, you plug a pair of antenna wires or a coaxial connector into the back of your tv to get a signal over an air-based broadcast frequency. For these set top devices, the purpose of turning your device to channel 3 and plugging in the electronics effectively created a modulated signal over a short cabled RF connection. This is the same technology seen in wireless antennas over decades back. Composite input came to replace that by the late 80's, and internet cable also innovated on coax with the DOCSYS modulation standard. Both are outside the scope of the project.

The takeaway here is that there are common modules used for RF both inside terminal equipment and outside through reception. Just like with digital network computers, wireless connections and wired connections can be sent from point to point with the right knowledge.

All that is to say, the Realistic DX100 should provide a great opportunity to create a HF receiver for living up to its name. I dare to imagine that this could pick up other countries like Mexico or Canada if the propagation conditions align with the possibilities. Of course given the age, it's still a 5W radio on AM & SSB, so there are natural limitations here.With that said, replacing a radio's own HF antenna with a better external wireless antenna is our goal. We know it's possible because another amateur operator has already been documented as such.

With the right resistance feeders and setup with standardized plugs (BNC termination, coaxial cable, etc), one could create an effective HF antenna setup both indoors and outdoors. This does require soldering and inserting new resistors and parts. In doing so, I should seriously consider if re-capping the device itself is worth it. New capacitors would ensure that the radio is ready to go for the next 3 decades of use without issues or risks of potential leaks.

HF antennas are among the oldest types. Though there is a built-in extending antenna with the DX-100, it's rare for this to get any sort of outdoor performance at significant quality. The setup will need to be an HF Dipole split with a 50 ohm coax setup (fun fact, all coax cable is typically 50 ohms by default). The connector itself is bridged and adjusted via any necessary filters. This gets split to two semi-exposed wires going opposite directions. The wires can be anything from ethernet to tape measures as is the case of beginner Yagi antenna design. The length run of the cables is set, but the setup and directionality of the antenna can vary somewhat. The cables are then joined with a resistor to prevent current from flowing between them.

I plan to add this radio to my IoT network. Accomplishing this is possible with the help of an ESP32 paired with a 3.5 mm headset jack & potentiometer. This would put HF on my setup of VHF & UHF with the Radioshack Digital Trunk already configured. With the right parts and setup, this will be the first part of establishing an antenna array outside my own window.

Droidcam offered an android based solution to my mic problem. Unlike WoMic of iVcam it cuts to the chase and provides an http stream of the audio, bypassing the need to feed it into another pc for processing. The demand for this also required setting up more consistent Wifi, so with our powerline setup and an added router from the bargain bin we moved from the basement to the 2nd floor and set our devices up just fine. Finally, I could stream audio and video from the android device over the network and to any devices to play back via VLC. We now had access to RF equipment for HF, VHF & UHF listening.

Can't hoist a new tower? Build the antenna with what you got.

The remaining two projects will also use outdoor antennas for their applications and coexist with the HF setup. This requires careful considerations for where to physically locate these antenna devices. Ideally, antenna arrays with far-reaching requirements are outdoors with line-of-sight capabilities. In lack of that, the higher up the antenna can be, the better any reception and transmissions will be. You might think about building a tower in your own backyard, or perhaps having a local cellular company build one in your stead.

The problem with erecting structures is that not everyone wants to deal with the politics of land development considerations. Towers take up visual and physical space, so new construction might be frowned upon by neighbors, leasees and Home Owners Associations (HoA). To keep everyone happy, you need to consider all the rules involved and strike up a conversation or two with folks. One trick I've determined is to consider coverage from the highest point of a property downward. This means typically from the roof level and lower, whatever level is most feasibly possible to build new construction on.

This brings a quick survey-result of my personal property. For a 2 story 3 floor building, there is roofing outside the bedroom window on the 2nd floor. This makes it effective for both access and installation of RF equipment without being too much of a neighborhood eyesore. It also makes maintenance more streamlined and localized to a window. Finally, the setup keeps antennas away from powerlines as this is the number one thing that new antenna array designers must avoid when creating new construction. For hobbyist construction, public spaces like easements and utility poles aren't exactly up for grabs.

Finally, once you determine an ideal site for an antenna array you're going to want to make sure of 2 things. First you'll want to ensure your setup won't cause interference. The 3 antenna setup I'm aiming for here will use 30 kHz to 15 MHz spectrum space for HF, 893–918 MHz for Meshtastic and 2.4 GhZ for AREDN. AREDN needed special consideration to avoid using the default 900 MHZ band; the 33 CM was already covered by the Meshtastic node. A double-check on current AREDN nodes indicates that NA only has 3 active emergency 900 MHz devices, so this won't be a worry for this project. Once all planning is considered, I'll be checking on the Standing Wave Ratio (SWR) with a borrowed instrument designed to do such.

Mapping a course for effective Meshtastic coverage.

With the HF hobby set sail, I'd want to work on building up and out my Small Board Computing (SBC) knowledge into a viable project to help the RF community. I once built a badge based on ESPNOW and local connectivity protocols & showed these off at maker fairies locally. This idea allowed for writing and exchanging data between ESP32 C3 badge devices. I have long since abandoned the project, but the idea has been recently married to radio frequency technology.

I went through numerous protocol types for project work:

-APRS -Echolink -VOX hands-free -Icecast -QC calling -QRZ logging -VoIP comm -etc

There are hundreds of project possibilities, but what one to go for that makes sense for my experience? By working with existing map models we can determine areas and requirements to cover for establishing and maintaining communications within a handful of projects. I landed on the desired SBC that's closest to my background work with ESP32 based badges and inventions with Meshtastic.

Meshtastic provides an off-grid point to point network. It's used by worldwide enthusiasts over thousands of nodes. Compared to APRS, speeds increase from Kilobits to Megabits allowing for more involved and direct communication over text and networking. This also allows for tracking all sorts of devices. Our local radio club went over the utility and technical details about Meshtastic, so please give it a watch sometime if you get a chance [Meshtastic — An Introduction — YouTube].

Building nodes interests me much more than using them. If you buy a simple kit for this, you might get a few meters of range. If you want to give your Meshtastic node a serious antenna, then you certainly can. Higher gain antennas can allow for greater range on a 5W small board computer. Going back to ESP32 hardware, you can utilize a few services such as the ESPS3FN8 radio devices. There's also nRF52840 from Nord Semiconductor which allows for stable range and reach over long distances. The map says that devices used locally are of the Heltec models. These devices are going to be best used to talk to devices within a 10 mile radius with the included antenna, with promise for further range with better quality antennas.

Where can you buy an ESP32 Meshtastic node? Well If you want to try to get into it right away you have the option of visiting your local Microcenter. At this time it appears this option was taken offline and you'll need to purchase them from sellers on eBay and Amazon. It's important to get legitimate equipment with reliable components, because just like with other radios there are issues with running this type of equipment for long periods of time.

With antenna considerations, mounting these to a high point and material for outdoors is also worth consideration. With our local weather we have warm temps up to 90 degrees as well as freezing winters with snow, ice and below 0F temps. A fiberglass antenna provides the longevity advantage here.

AREDN in Cell format — the most ambitious project of the bunch

Cell design fascinates me. A local water tower now uses its own design to host radio equipment. It's painted blue to blend in with the architecture, which is a design trick used in rural areas to disguise towers as well. I'd like to invite my readers to look for these devices on their next camping trip.

Maps will determine coverage areas and dead zones for certain devices. They won't outright tell you what antenna to use or the DBi value to look for, that's on you to figure out. Ask your local Meshtastic community if you think this project makes sense to help the cause. Here, the goal is to bridge a northern node to the central points closest to the city through hops. By adding a new hop with an outdoor antenna, we join these northern nodes to the city nodes, creating a greater and more effective mesh through smart design principles.

PoE provides up to 45w of power, well beyond the needed limit for transmission. Ranges for this tower also indicate that it would achieve the same result, connecting nodes around the city to each other for emergency situations. The antenna itself will be a Mikrotik mANT box 2 12s directional antenna with 120 degree angle coverage. This will be paired with a rotation system via an Arduino uno and stepper motor for outdoor remote control. Ambitious doesn't begin to describe this plan's complexity level, but I believe I can make it happen.

All of this is possible to hook into my existing FreePBX network for VoIP deployment compatibility. This means I could offload my FreePBX network itself and Cisco managed router onto its own resources. If an area I'm covering, either rural or urban city, needed to reach me they could hook-in to this voice network as an alternative to their radio comms. I'd need to replace the equipment in the rest of my computer lab to make this action plan effective. This turns my network public-facing and provides an ongoing life and essential service utility to the general public.

This area will need the most development attention so I plan to stretch this one into the fall, but just before the winter if possible. This is due to given climate conditions as well. If I'm going to be using a cell outside my own home, I'm going to make some time to ensure the components are long lasting. Options include conformal coating for weather resistance and proper insulation.

Pitching the budget, how much is this gonna cost?

Well upfront costs fall into a simple 3 category alignment here. For the HF tune up it'll take some repair time but cost the lowest at $40. The Meshtastic project will take up double that at $80, spending time in software and setting up an antenna to the roof mast. The longest project will be the AREDN cell coming in at $160–240 depending on the homelab network segmentation plan. You might also consider time, labor and the back and forth to get the harder ideas off the ground.

This doesn't count the long term prospects of energy use and wear & tear, however. Here you have a few options. You could seek a grant from the ARRL among your local RACES or ARES group and argue this is for emergency services. If you're working on RF gear for your Masters or PhD research paper you could also inquire about grants this way. Options are present and numerous for the truly-determined in this space.

Of course all of this sounds crazy at the moment, and that's because it is. Be sure to do as much due diligence here as possible; check with your local town board meetings about rules and regulations, otherwise you could end up with a knock on your door from the FCC or local gov.

Preparing to be logged, the security risks of long range have never been larger:

From my hacker days I've learned how people love sniffing out radio and Wifi communications. Wardriving is still a popular activity to find and map surrounding open Wifi access points. Accidental wardriving might also happen if you don't know what's happening in your Meshtastic node. "Client mute" is the right option here to mitigate. This isn't a foolproof solution however, and security is certainly lacking behind due to all of the complications of newer ideas gone successful. This is how I determined the need for other Meshtastic nodes in the first place.

Data when utilized effectively can create opportunities both good and ill intentioned from map models. Theoretically, a hacker could use a collection of databases such as Shodan or Censys alongside wardriving to determine active and open internet endpoints on a network. This can result in risk to the number one thing for any country to defend: Critical infrastructure. This needs no further explanation to any radio operator who's aware of how EmComm (FEMA, AREA, RACES and emergency off-grid communications networks) are categorized as such. To the rest of us, a quick reminder that Amateur radio is classified under the same utility as fire and ambulatory category separation; it's important to talk to loved ones in the event of a disaster where the grid goes down.

Finally, I landed on the idea of separating this volunteer network and gear away from my homelab. The reasoning is that all of the management tooling and resources are best left air-gapped and away from any of my own personal property. Should an issue arise on my homelab, there is a risk of the AREDN router falling under control of a possible attacker. Should that happen, they could create a complicated client AP attack in which the router is made to imitate a common AP within the city boundaries. This risk shows how dangerous this part of the project plan is, and should be taken very seriously to avoid potentially fatal & consequential actions.

Wrap-up

If you're looking for a cybersecurity tip in all this, you're in the right place. Try to limit the node details and exposure with the name (sometimes called the SSID). Increasing my public presence is more associated with real name information so this may not be possible for everyone. If you're a part of a community, reach out for options in regards to getting a node established.

If you can work with your local town, you can establish concerns and remarks on local laws before planning some of the bigger parts of a long-range Wifi rollout. Visit a public hearing and talk about the project's ideas and what land or locations you would need access to for optimal coverage for your project. Most importantly, go slow. Remember that you're working with good, fast and cheap operating costs vs scope. Most Amateur operators want a good and cheap to be the totem so they can keep doing and keep learning along the way. Slow burn of your projects will also keep your desire to keep on transponding from burning out.

Well speaking of slow burn, I hope my readers avoid getting sunburned this summer. Stay cool and drink plenty of water. Tune in next time for updates on the project & Rochester Hamfest. As always:

Stay safe out there & 73.