Aeronautical mobile as PA1JIM/AM

PA1JIM/AMHow cool is it for a ham to temporarily change your call to aeronautical mobile (PA1JIM/AM) during a once in your lifetime experience? Even more so when you can do that from an airliner at 38000 feet up in the air? The other day my good buddy and associate at Pepper IT-solutions VliegPiet made me an offer I could not refuse: to join him as captain in the cockpit of a Boeing 737 on a return flight from Amsterdam Schiphol Airport to Sevilla, Spain.

Preparation

As a ham and aeronautical enthousiast for me it was double fun! A couple of my ham-friends were standby during the flight. Although it was not certain whether the plane had HF on board, we agreed on some frequencies we would try while I was in the air. One on 20m, two others on 40m and 80m. They monitored these frequencies the whole afternoon and evening while tracking our flight on flightradar. A quick look-around in the cockpit learned me this airplane has a Rohde & Schwartz-Honeywell XK516D on board (400 Watt peak with USB/AM). Yeah!

On air conditions

Approximately one hour after taking off, the co-pilot helped me tuning the radio on frequency and I did my first calls as PA1JIM/AM! As expected 20m was closed. Even this altitude didn’t help much. On 80 meters there was way too much static to pick up any signals. So I only had 40 meter left. The agreed frequency was occupied with an Arabic radio station (illegal?). Compared to a typical amateur or SWL station, the aeronautical radio equipment performs to high standards, but does not have much operational flexibility. For example, the oscillators are dead-on accurate and stable, but can only tune in steps of 1 kHz. There is a tiny RF gain control, but AGC timing is pre-set. There are no filters to notch out carriers or remove the dreaded over-the-horizon radars in use by some countries. Also HF-radio signals behave noticeable different at 38000 feet. Bounces work differently and it is even harder to predict your range.

Plan B

Landed in Sevilla, Spain I quickly apped my friends in The Netherlands to report my findings. They also heard the Arabic radio station and did not copy any of my calls. They quickly found another unoccupied frequencies on 40 meters and by the time we departed I was ready to try again. I couldn’t wait to go on air again.
This time after about 45 minutes (flying above northern Spain) with my first call as PA1JIM/AM I immediately got response of Rob, PA1RAB and Gerald, PA9G. They were able to copy my signal and we had a great QSO for about 15 minutes.

I really had the time of my life on this trip! Learned a great deal of flying an airliner, the instruments, using the radio and inspecting the plane. Thank you Piet and crew for being such friendly and welcome hosts! I can remove this one from my bucket-list.

5 Replies to “Aeronautical mobile as PA1JIM/AM”

    1. Klopt Mark. Voorbereiding van mijn kant was niet optimaal omdat überhaupt niet zeker was dat er HF aan boord zou zijn. Tijdens de vlucht merkte ik wel dat hoe lager je gaat op HF, hoe harder de static op 11,5 km hoogte is.

  1. Jim , erg gaaf man! Het verbaast mij dat ze nog HF onboard hebben. Ik dacht dat men alleen in de oudere vliegtuigen HF radio-equiment aanwezig was voor vluchten buiten Europa. Toch een leuke ervaring. Top!!👍
    Ik vlieg regelmatig met Transavia naar Spanje , maar heb geen relatie die piloot is .😄

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