HAM radio tends to operate out of convenience on , which represents the nominal voltage of car batteries as well as consuming a large number of Amperes, on the order of or even more, in order to be able to reach high wattage broadcasts.

For fixed stations that do not benefit from a battery and would like to power the HAM radio from household outlets, the solution is to buy a power regulator or a power supply that will convert mains alternative current down to direct current. However, power supplies that can reach up to and designed for HAM radios are expensive but mainly due to being a niche product with low demand. On the other hand, one very cheap alternative is to convert a server power supply to provide given that server power supplies are typically high wattage and will be able to supply the necessary current to power the HAM radio reliably.

Even though it is common to remember that car batteries are rated at the real nominal voltage is when the battery is fully charged. Typically, the voltage does not drop, except for when the car is being started, such that even though the car battery is advertised at , the battery will be running at . The effect of this is that most of the HAM radio hardware available is designed with the extra in mind and might fail to work if the output voltage is just instead of .

The rating of the HP power supply seems to be irrelevant and pretty much any HP rack server power supply can be modified according to this documentation. Whether one has a high-end power supply or a typical power supply, it does not matter and HP streamlined the design such that there are almost no differences between the HP power supply controller PCB.

Go figure that HP power supplies already have a surface-mounted variable resistor that allows setting the output voltage of the power supply between and about however the variable resistor will not allow setting the voltage higher than enough to reach .

In order to increase the voltage rating of the power supply, a resistor should be added between the two marked pins on the PCB as illustrated by the wire ends in the image depicting the PCB. Out of curiosity, a variable resistor was added between the two pins ranging from to and it seems that the power supply can reach as low as and go up to . For that reason, it was deemed that it would not help much to convert the power supply to a multiple voltage breakout via the potentiometer and that the final design should just be a flat output to be used with the HAM radio.

That being said, using a resistor, and by also setting the existing variable resistor on the HP PCB, the voltage was set to about . Some heat-shrink tube was used in the process to make sure the resistor does not bridge other components on the PCB.

Finally the two pins are bridged with the resistor, a voltmeter is used to measure the voltage output of the power supply and the power supply is ready to be re-assembled.

This part of the modification has been completed and all that remains is to power-on the power supply automatically and to ensure that the power supply is fitted with some sort of connectors from where power can be drawn for the HAM radio.

In order to power on the power supply when the power lead is connected to the outlet, a resistor can be added on the front panel and by bridging the first and fourth pin on the outer exposed HP PCB.

In reality, the power supply can be turned on with a resistor using just a wire, but adding a resistor between and simulates the minor load that is placed on the two pins when the power supply is used together with the server.

Similarly, it is feasible to additionally add a switch in series with the resistor in order to be able to turn the power-supply on and off but just like the design decision to keep things simple due to the power supply not being able to provide a large voltage output range, it was decided to similarly keep this design simple as well and make the power supply power on as soon as it is plugged in. In typical scenarios, the power supply just provide power to a HAM radio that can additionally be turned on or off, such that it does not matter that the power supply is switched on all the time, the standby power consumption without any consumer being negligible.

This completes this part of the modification and all that is left over is to create a nice case to hide the PCB and add some plug connectors to be able to connect the HAM radio (and other equipment) to the power supply.

The HP power supply already has a case that seems robust enough, made out of metal such that it was decided to create just a front-cover for the HP power supply, a cover that will hide the PCB connector that sticks out of the power supply, will hide the connector cables and will also provide two poles from where current will be drawn.

Wood was chosen for its remarkable properties of isolating electrical current, as well as being a material that is malleable and durable enough to be used for any project. Compared to plastic, wood does not bend due to heat and provides a solid isolation.

The design of the front cover was kept simple: it is a simple parallelepiped made out of 5 cut wooden plates that are glued together, first with super glue, then with neoprene glue and then reinforced with magic putty on the edges.

It was chosen to not damage the HP PCB further as other projects do by drilling through the PCB but instead to just solder 12AWG wire between the PCB and two ring connectors around two large exposed screws protruding from the front of the cap that will be used as contacts.

The right-most pole is marked with a small spot denoting the positive pole to which the red cable should be connected. For best results, a butterfly washer can be used to quickly attach and detach wires to the power supply by hand without needing extra tools.

Furthermore, due to careful measurements, the cap seems to slide in tightly around the power supply such that remarkably there is no additional design needed to fasten the cap on securely. Even so, as the design would imply, the front panel will not be used much but will rather stay in a corner and provide power to the HAM radio.