With the arrival of international amateur communication, the lack of a worldwide system of station identification led to confusion over call signs. Without prefixes as we know them today, there was no way to use a call sign to identify a station’s country. And since each country issued call signs independently, duplicates were inevitable. This hadn’t been a big problem for US hams before the first international QSOs since Canada was the only other country within normal range having a large numbers of active hams. In Europe, where several countries were reachable, they had been considering the problem for some time.

Lloyd Jacquet, French 2KT, wrote that he did not like the method that had been used for some time by US and Canadian amateurs of replacing DE (the Morse code characters called an intermediate, indicating that the preceding call sign is that of the station being called, and the one to follow identifies the station doing the calling) by other letters depending on who was transmitting to whom.  He rightly pointed to the rapidly growing number of combinations that became possible once a few other countries were added; it would require a dictionary. Jacquet and the French radio organization SATSF¹ suggested using one additional letter—the first initial of the country’s name—at the beginning of the call sign, to indicate national identity, as proposed by Leon Deloy, France’s best-known amateur. Thus, the US (America) would use A; France, F; the UK (England), E; Holland, H; and Spain, S. He did not explain how to handle the situation when another country was added that had the same first letter as one already being used. Another suggested method, pooling (prefix-less) call sign blocks around the world, was deemed impractical since it did not automatically eliminate existing duplicates and therefore would require reassigning many thousands of call signs, especially in the US.

ARRL secretary Kenneth Warner, in response, liked the prefix idea better than the proposed system of intermediates (DE and its variants), but suggested that another option might be to use intermediates composed of one letter from each country. He did not seem to like the idea of lengthening call signs. The example he gave was that if the US used U, Canada, C, France, F, etc., then a US-to-US contact would replace DE simply with the single letter U. Two letters would be used when calling between nations with the called country first. Thus, a US station calling France would be “8AB FU 1BHW.” This might not work, he admitted, since international regulation specifically prescribed the use of DE.

The ARRL appealed to the US Department of Commerce for advice on the matter, hoping that they would suggest a solution at the next International Radio Congress.²

But hams needed at least a temporary solution now. In late 1923 international communications was coming about faster than anticipated, triggered by the first successful two-way contact across the Atlantic. Because amateur call signs were not assigned according to the rules governing commercial stations (which, in fact, had been using prefixes for a long time), the confusion on the air continued and compounded.

The League polled as many amateur radio organizations in other countries as possible in an attempt to construct a scheme that might be accepted by the majority of them. There were many suggestions. A list of requirements to eliminate call sign ambiguity was worked out, mostly trying to avoid lengthening exchanges or changing call signs. That was why prefixes were not considered at first and probably why League Director Charles A. Service continued to advocate replacing DE as the intermediate instead of adopting international prefixes.³ Whatever was eventually agreed upon would be used only until the next International Radiotelegraphic Convention, which might not happen for a few years.

Although there was no complete agreement, the most widely adopted scheme built upon the American-Canadian pattern already in limited use. A single letter was assigned to each country and the intermediate was then composed of one letter for each station, first the called, then the calling station, as Warner had earlier described.

With U for the US, and C for Canada, an example calling sequence would be “1AW UC 9AL,” with 1AW, of course, being the US station. When stations of the same country were involved, only one letter would be used. Thus, DE would be done away with completely since neither letter was assigned to any country in the new list. Duplicates were eliminated by using a different letter that was still “phonetically suggestive” of the country.  The initial list had fourteen entries:

A-Australia
C-Canada
F-France
G-Great Britain
I-Italy
M-Mexico
N-Netherlands
O-South Africa (the exception)
P-Portugal
Q-Cuba (phonetic)
R-Argentina (phonetic)
S-Spain
U-United States
Z-New Zealand

Although there were not enough letters for all the countries of the world, only a small number of them had amateurs.  Eventually there would be a problem, but since twelve were left unused, most believed that the supply of letters would last until the next convention.

Official governmental sanctioning of this scheme was not sought, since the agreement was made directly among groups of amateurs and would neither affect other services nor change any call signs. Nevertheless, several countries unofficially indicated approval.

UK officials, however, insisted that instead of using a new intermediate, British amateurs should add the appropriate letter to both call signs. Thus a French amateur would use the agreed upon intermediate, but in reply, the British station would continue using DE, but call, for example, F8AB DE G2SH. UK amateurs, it seems, were ahead of the game since this is exactly the scheme that would eventually be adopted internationally.

There were some other objections, favoring the British plan, but at this early stage it was deemed not to be universally acceptable since some countries specifically prohibited adding a letter to a call sign. In some other countries non-amateur services were already being assigned call signs based on a sequence of one letter followed by a number. Official prefixes would have to wait a few more years.

Faced with the new reality of international QSOs, amateurs also wondered whether the myriad of worldwide languages would pose an obstacle to easy communication. They began to discuss several so-called universal language ideas that were popular at the time.

In Europe, where multiple languages had long existed within a short distance, amateurs were forming “international radio societies” which were attempting to define a simple international language, or I.L. as they called it, for use on the air.⁴ Their language was called Ido and was based on 11,000 word roots taken from eight languages. Together with fourteen “grammatical terminations,” the roots were used to form a variety of words and conjugations that could be recognized, it was claimed, by a large percentage of native speakers of the various constituent languages.

In North America, Henry W. Hetzel, Secretary of the Philadelphia Esperanto Society argued that radio was just one example of increasing interaction across language barriers, and that there was a greater need than ever for an international language, as promoted by the International Auxiliary Language Movement. He was certain that an international language “will be one of the realities of the very near future,” and that his choice, Esperanto, was certainly better than Latin.

The rationale seemed to take hold at the ARRL, at least for a little while. Reasoning that the question of an international language for radio was linked to the use of one for all other purposes, the League decided to endorse Esperanto in September 1924 after studying the matter for two years.⁵ It was considered the most widely adopted worldwide. Realistically, however, hams would not adopt such a language solely to support their radio activities, Warner admitted, and would not “make the necessary slight effort until the whole world takes up the idea.” With the prevalent use of Q-signals and other abbreviations, amateurs would come to understand that they had little need for a new universal language—they already had one.

de W2PA