This page describes the ongoing project of the “Ham Radio Bus”. We mentioned the project over a year ago, and we have been busy…
This was initially purchased as a transit bus, and adapted for ham radio. This page details the upgrades and customizations that were done to make it appropriate for ham radio. Much advantage has been taken of the handicap ramp and area, however on my vehicle this ramp doesn’t fully work. So it’s helpful in other ways.
Power
There are now two power systems in the bus – the original engine battery, and a rear lithium battery for stationary power.
Rear battery is charged in two ways:
- A renogy 30 amp DC to DC converter charges the battery when the engine is running, and charges from a side solar plug. (it does this borrowing the home-run to the battery that the handicap lift uses). The MPPT controller couldn’t quite handle the rooftop panel voltage, so this is now just an extra solar port.
- 400 watts of solar panels on the roof connect to a bougerv charge controller, and add power from the rooftop panels.
12V fans and internal LED lighting circuits, and audio/radio speakers, are tied to the rear power source through individual powerpole fuse boxes.
Feedline
The handicap platform itself is cable-management for spools of needed cables – including coax, power pole, and extension cords.
A PVC passthrough is drilled through the floor to allow cables to go in/out and be sealed.
Antenna
For VHF/UHF – there are two options
- There is a hood mount dual band antenna that can be used while the bus is in motion
- When stationary, there is a tram antenna for 2M/70cm that can be hosted on a mast.
For HF – we have two options
- Inside the roof of the bus there is a run of wire making a loop antenna, that could be used with a tuner while in motion. The roof is non-metallic, except for the air conditioning area.
- At the rear of the bus, we have a 2″ receiver that can be used to hold up antennas. There is a multi-band HF antenna that can be installed by one person, as long as you have a “foot” to push the antenna against to walk it up or down.
Mast
For mast material, I use military aluminum tubes, stored on the bottom of the handicap ramp.
Operator position
There are potentially two operating positions – one in the front and one in the back.
In the front there is a bench that also turns into a table.
The rear has a narrow table that is used as an operator station. Again the wheelchair ramp comes in handy, as it has sturdy mounting holes that we can use for our radio mounts. For VHF/UHF, there is a Kenwood TM-V71A. In the middle we have an ICOM 705, and the far right has a Midland GMRS radio. A GLI net device presents a wifi connection, peers with an internet hotspot, and allows computers, phones, and other devices to access wifi to the radio.
Storage
The bed area serves three purposes:
- Storage of radio gear, additional coax/antennas under the bed
- Somewhere to sleep
- When the mattress is flipped up, the whole thing is a bench.
Safety
- Added both a smoke detector and carbon monoxide detector (a fire extinguisher is already present).
Environmental comforts
- Fans for when it’s hot
- 20 amp AC inlet and wiring large enough to run an air conditioner (the built-in AC requires the engine to be on all the time).
- USBc ports capable of quickly charging phones or powering laptops in several places.
- 12V lighting that can dim, be turned on/off individually, and do white or red light.
- Cigarette adapter plugs for CPAP and other accessories
- Bluetooth audio & AUX in for radio audio
Monitoring
- Each charge controller has bluetooth, so charge current and voltages can be monitored
- The rear battery has bluetooth, and can report either charge current or discharge rate and time to empty.
- In the rear we have a WWV digital clock to provide time and temperature for net control or contest reference.
At present everything needed for a quick POTA or deployment is ready to go.
Future ideas:
- More shelving specifically designed around holding long antenna masts.
- Front 2″ receiver to hold a generator without giving up the rear tow hitch
- Window coverings
- External and internal monitors or displays
Things we’ve learned so far:
- When buying shop for low rust. As low as you can get.
- Tons of ideas on bus uses and refurbishing can be found on “schoolie” forums.
- Fiberglass is a choice. School bus formats have aluminum which can be better in some cases.
- You’ll spend about one new HF radio’s worth for each year of auto insurance…
- Lithium batteries in MN need heaters if you want them to charge. And those heaters need specific charging current that an average solar day may not provide. In fact by default all chargers will refuse to charge below lithium damage temperature – just because they don’t anticipate any heater being inline.
- Either have an AGM that you can use in the winter, or you may need to plug in to shore power to get enough amps for the heater to run. AGMs will charge all day long as cold as it is, but of course with less capacity.
What else do you think the bus needs to make a ham radio destination vehicle perfect?