"FIFI" 2012 MidAtlantic Air Museum/Reading PA performance -- K1NSS photo

We thought we understood that Thursday afternoon was supposed to have been a short maintenance flight, with hours afterward on the ramp for RF testing. This was the first opportunity to do so since the plane returned from Florida on April 6. We have been pressing for time on the ramp, but have necessarily been out-prioritized every time. We did take advantage of testing in the hanger with the heavy donated 28 V power supply, and into a dummy load. This was very necessary, but certainly not sufficient.

What really happened was just the reverse of what we thought we understood. We were set up for ground testing with a Heil Gold Line mic and a Behringer speech amp to drive the ART-13. The mic was fine for ground testing, but not appropriate for in flight. I intended to go on the short flight just for listening tests relating to ignition noise. But the critical RF tests into the antenna for the first time were to have been done on the ground after the flight.

Instead of a short maintenance flight, it turned out to be a pilot qualification flight with many touch-and-gos and soft stall recoveries. This went on for three hours. It became pretty apparent that there would be no time for ground testing after we got back.

So Paul and I made the most of the situation, and prioritized matching the antenna in the air on 75, 40 and 20 meters. We were able to do so on all three bands with the Collins 180S-1 manual antenna coupler from the 1950s. There were no surprises, and the element matching values were pretty much as predicted. On 20, there was no change in matching in the air vs on the ground. We didn't have a chance to make this comparison on the other two bands. The flight environment wasn't the best for the testing, but we made it work.

Listening tests indicated considerable activity on 40 and 20 meters above any ignition noise level. This was encouraging. At that time of day, there was no apparent activity on 75, and the ignition noise and atmospherics were noticeably higher. We will need more data to conclude the suitability of this band in the air. I was reminded of the difficulty of tuning SSB with the BC-348, its BFO, and its lack of band spread. I had to switch from AVC to MVC to even come close to doing it.

The very high level of low frequency acoustical noise from the four powerful engines 100% modulated the ART-13 in key-down. Not surprising, but a disappointment, since we could have had our first on-the-air contacts with what we heard. KA5RHK, in Arkansas, with whom I've communicated on AM over the years was loud and clear. But we needed a noise cancelling lip mic in this environment instead of the Heil desk mic. Also, we had something malfunction in our speech amp lash-up at the time that we could have at least tried it.
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Instead of a short maintenance flight, it turned out to be a pilot qualification flight with many touch-and-gos and soft stall recoveries. This went on for three hours. It became pretty apparent that there would be no time for ground testing after we got back.

Loney Duncan
WØGZV
Richardson Team

Hello Test...and Then Some.