Is anyone able to date this US Mic / Mask?

[Allegra]

Good Evening / Morning Ladies and Gentlemen

I'm afraid I'm showing a part of my vast ignorance in US pilot items.

I'm interested in the mask shown in the third photo. Has anyone any idea of the date for this piece? This particular dealer states it is WW1, but I'm not convinced. I certainly think it could be from the USAAS but as this was initiated in May 1918 and renamed in June 1926 there is a rather large window...

As the items immediately below are definitely WW1 Western Electric, it really makes me wonder:

(SCR Interphone)
(Mic allied with Interphone)

I'll be upfront and state I'm not looking to purchase from this dealer.

The final photo is a similar mask, does the uniform assist in any dating?

The helmets in both photos are Western Electric Type 1A

Many thanks for all replies.

Cheers
Tim

[HARRY THE MOLE]

The microphone mask won't be from WW1. Although voice transmissions were first made in 1900 - not from aircraft though, the use of radio in aircraft was limited to artillery spotting. Radio's in those days were quite large and aircraft were limited to using CW (Morse-code) with a trailing antenna dangling from the aircraft. Although the military were experimenting with voice transmissions towards the end of the war the results were not very promising and wholly unreliable.

[Allegra]

Hi Harry

Thank you for your observation - I didn't think so on the mask front!

While the Military did use Morse Code to a large extent between planes and the ground, they did also use the SCR-68 for voice communication with the plane and the ground quite successfully.

I quote from the pages of 'Curtiss Jenny Restoration':

By the late summer of 1918, approximately 3,000 complete type SCR-68 units were manufactured and distributed to the US Army and most were mounted on De Haviland DH-4s. Conversations between airplane crews and ground stations by means of the radio telephone became routine and they were used during the closing months of the war. For the first time it was possible for ground observers to talk to pilots in the air miles away. Furthermore, Commanders of aero squadrons could also voice warnings to all their pilots as to the movements of enemy aircraft. Squadron formations of all sorts could be maintained in the air as easily as infantry units on the ground. It was reported on November 23, 1918 that squadrons of American airplanes fighting in France were maneuvered under vocal orders transmitted by radio telephone and its advantages were proved in actual air combat.

The SCR-57 and the Mic that is shown I own and was used for communication between the Observer and Pilot.

Cheers
Tim

[HARRY THE MOLE]

Hi Tim,

As you will no doubt be aware, the SCR 68 operated on the 750KHZ band. The aircraft which used these radios had to use a trailing long wire as an antenna. The formula used to work out the length of a long wire antenna is 432 divided by the frequency. The answer you will arrive at is in feet at a 1/2 wave antenna. These radio's had a range of roughly 18 miles, and they saw limited use in the closing stages of WW1 around November 1918. The length of the antenna used limited their use to certain types of aircraft such as you have already mentioned. I do have a radio background - being a former signaller in air defence, and a practicing amateur radio operator, and so I have a little knowledge (a dangerous thing to have) of radio usage at that time. The chances of air to air communication between aircraft during 1918 being of sufficient quality to be of much use would be remote - although it most certainly was used. The mask microphone you have shown looks a little too advanced for WW1, and I would have thought it was likely to be 1920's vintage. But I will bow to your greater knowledge on the subject and accept that I was wrong. Radio communications is a fascinating subject in its own right!

Cheers,
Steve.

[Allegra]

Hi Steve

I think you may have misunderstood me - I agree with you about the mask microphone I believe is as you have stated - post 1920 - I just wanted some confirmation - I saw another without the helmet.

I appreciate your knowledge and any input.

Cheers
Tim

[HARRY THE MOLE]

Hi Tim,

All this antenna theory gets very interesting if you apply the mathematics. Take the old CB band for example. a frequency of 27.500 MHz divided by 468 gives you a working antenna length of roughly 17 feet, but there is always some trimming involved to get an exact SWR on the antenna. Now if you take the frequency of the SCR 68 and divide it by 468 you soon see the problems which arise for aircraft use. Because the frequency is in KHz and not MHz, you have to put a decimal point before the frequency, and so it becomes 468 divided by .750 - which is a whopping 624 feet. Even a 1/4 wave antenna would be 312 feet. it wasn't until they got VHF that antenna's became a more manageable length.

By the way, I'm quite sure you know your stuff inside out. Although I used to know a fair bit about the aircraft of WW1, that was as far as it went. I was never a collector of early aviation equipment.

Cheers,
Steve.

[Allegra]

Oh...wow...my Math ability is: Tim always attempts to do his best...(direct quote from my Year 10 Math Report. My father was an Accountant - he was not overly impressed. In fact so much so, he hired a Tutor for me the following year though I wasn't doing it in Year 11)...LOL

Thank you muchly!

Just by-the-by Steve, here's a link that you may find interesting:

Just when you are over the moon, something comes along...

Cheers
Tim