A wandering Clipper.

[Spooky 2]

Okay what ever. I have never heard a Pan Am pilot speak of this DME while flying anywhere in the SPAC. Please keep in mind that the normal proegression at Pan Am was from Navigator/Relief Pilot to F/O to Capt, thus the pilots flying in the very early 60 had a number of years previously as Navigators (3rd Officer) in that part of the world.

[John Hill]

I will be at a funeral tomorrow for someone who was an aeradio officer in Faleolo and there may be someone there who can shed more light.

It seems pretty likely though, long range (300 mile) radar distance measuring was in use from 1941-42, for example the RAF's OBOE system had the ground station send a signal that was repeated back by the aircraft and operators sitting at CRT screens measured the time of response and hence the aircraft's distance from the station.


RAF Oboe controllers WWII.

The 'GH' system had the aircraft sending to two ground stations which responded and the aircraft navigator interpreted these responses to determine the distance to the two stations and hence get an accurate fix.




It seems more than likely that ten years later Pan Am would take advantage of this technology if it was available and the aeradio operators of Western Samoa claim it was. They would know as they were the ones who kept the ground station equipment serviceable.

[alisoncc]

TACAN, the military nav aid, was just getting going in the late '50's. It operated in the "L" band range of frequencies. The distance measuring aspect of TACAN later became DME in the civilian world. By the early '60's RCA Aviation were manufacturing and supplying their AVQ70 DME for airline use. AVQ75 was their GA version.

PS. Did a TACAN course at RAF Yatesbury in 1964. IFF (Identify Friend or Foe) later became civilian transponders. Modes A, B and C were an IFF function. Mode C then took on the role of altitude reporting. Knew IFF X well.

In all honesty thought the AWA 200Mhz DME was a bit rubbishy accuracy-wise in comparison to the L Band DME.

[John Hill]

Do you know how they coded the responses for IFF? I assume the ground operator only had an 'A' scope to view the return?

[John Hill]

I went to a funeral today but unfortunately the 92 year old who was on duty at Faleolo when the Stratocruiser landed was not there. However another who worked in Faleolo in 1958 said they certainly had DME installed then but was unsure if it was the Australian 200Mhz system or something else. He said TEAL were users of the DME.

[Spooky 2]

Interesting thread. I wonder just what the range of this DME was as many of these aircraft mentioned were not pressurized thus limiting them to some pretty short range line of sight situations. Even the first modern DME was typically limited to something around 150NM.

[John Hill]

It appears the technology and frequencies used were similar to that used in WWII for guidance of bombers over Europe with ranges up to 300miles, I think the B337 had a pressurised cabin and could presumably cruise at the altitude the bombers used however the Solent was not pressuried.

[Nin Pattison]

I was quite pleased to come across this page and post, as Bruce Evetts who wrote "A History of Aeradio in New Zealand and the South Pacific" was my grandfather.

[John Hill]

Hi Nin, I started working in Aeradio in 1965 but I never met your grandfather however I very much enjoyed reading his manuscript and it brought back a lot of memories of places and people I will never see again.