Home Brew Aircraft Radio

Built this Nov 2007. I picked up the King KX160 Aircraft Radio for two reasons. 1) It was tubes and 2) my nephew is becoming a pilot and I envision him someday flying into the local airport to pick me up and fly me to Florida. So I wanted to be able to monitor aircraft traffic from the local airport. Additionally there is a tie back to the Collins company. The owner of King Radio Company, Edward J. King, started out with a company called Communications Accessories Company (CAC) that produced coils that Art Collins needed. Collins bought CAC in 1955 and Ed King continued to run the company as a Collins subsidiary for many years. Art Collins fired Ed King, who was a pilot, for an incident that occurred while Ed king was flying a group of engineers to a meeting. Ed King hit rough weather and climbed above it to avoid it. However, the plane was not pressurized and there were not enough oxygen masks for all those aboard. The flight arrived safely but as soon as Art Collins heard about it he had Ed King fired. Ed King then started his own avionics company, King Radio Company and was in direct completion with Collins avionics. The company became a top competitor with Collins in the high performance business aircraft field. Ed King considered the firing from Collins as a major turning point in his life and he started King Radio Company.

The KX160 was made to slide into an aircraft dashboard. So I needed to build something to house the radio. Additionally I had the HBR5 aircraft receiver that also was made to slide into an aircraft dashboard and needed some way to mount it as well. I decided that I would build a chassis that would house both of the aircraft radios, thus this project was born.


1965 Ad for the KX160 Note the 1965 price, $1,045.00	Here's the base chassis all drilled and ready to receive parts. I decided that ultimately I wanted this to go into a cabinet I had built so I planned for remote audio wiring as well as local audio. I also made it capable of operating both radios on either 115vac and 12vdc.

Here's all the parts ready to go into the project	Starting to install the parts. The 1.5volt supply for the HBR5 filaments, the directional coupler for the KX160, some of the switches, and some of the back panel connectors are mounted.

Here's the front panel I built. The KX160 slides into the rectangular square and the HBR5 slides into the top square. Since I had all kinds of panel room I decided that I would provide metering and local audio as well. Meter on the left is power supply voltages and meter on the right is fwd and reflected power for the KX160. Local audio can be switched back and forth between the two radios.			Here's a top view of the chassis with all the power supply components mounted.

The KX160 power supply and modulator is located approx the center of the chassis. The power supply needed to be fed with 12vdc so to run it on 115vac I had to install a 12vdc power supply for it. That power supply consists of the big transformer, circuit board and black heat sink at the front of the chassis. The grey transformer and choke at the rear comprise the 90 volt supply I had to build for the HBR5.		Underside view with more components installed. The 90 volt supply components can be seen at the lower left.	Front panel is now installed and some of the wiring is beginning to be run.

Some rear views with the panel installed. The fan is to cool the 12vdc regulator transistors. When the KX160 transmits it draws some major juice from the 12v supply. Both the KX160 pwr supply/modulator and the 12v supply regulators get pretty warm during transmit. Thus the reason for the fan.			Front view ready to receive the KX160 and the HBR5

Underside complete.	Front view with the radios installed.	Rear view with both radios installed. I didn't have the radio to power supply cable for the KX160 so I had to wire my own cable. I have since obtained a proper cable and installed it. From left to right connectors are: HBR5 antenna, KX160 antenna, remote audio connections, and the last long term strip is for external DC power for the radios.


Final assembly rear view ready to go into the cabinet.	And here's the cabinet I mounted it in.	Here's a view from the cabinet rear.