W7CPA NCX-5/NCL-2000 Restoration

I'm a retired Navy avionics tech (AT1) and worked on the EA-6B Prowler my entire career. Most of my hands-on time was spent working on the Improved Capability II (ICAP II - Block 82) version of the aircraft which had the ARC-105. My level of maintenance was performing on-aircraft work so I never had an opportunity to actually open the various avionics boxes. If we troubleshot down to a particular unit, it would be removed from the aircraft and sent to the next higher level of maintenance where those techs would remove the covers and troubleshoot to the component level. Meanwhile we would receive a replacement unit to get the aircraft flying again.

One of the inspections performed every seven days involving the ARC-105 was to pressurize the RT with 10 PSI of dry air. The avionics shop had what resembled a ruggedized bicycle tire pump filled with desiccant. You didn't want to add moisture to the RT. The HF antenna coupler was pressurized to 7 PSI. We used a standard tire pressure gauge to check the PSI. It was a low-tech process but worked fine.

When dialing in a freq on the cockpit box, I recall a rather loud tone in the headset when the tuner in the RT was changing freqs. It was best to remove the headset or turn down the volume.

The skin of the aircraft was one half of the antenna with the other half of antenna being contained in a non-metallic "rib" structure on the top of the aircraft, aft, just forward of the tail. If we were on the ship and needed to test the HF we would have to get permission to remove as many tie-down chains as possible otherwise you basically were grounding the antenna. You would also make sure no one was touching or leaning on the aircraft skin otherwise they would get a 400W nasty surprise. I saw that happen once. :-)

Besides the tactical use of the radio while we were overseas, when airborne the flight crew would use the HF for contacting HAM stations back in the states to make phone patches to call their spouses using MARS.