[SFDXA] First Band, Top Band

[Bill]

The Story Behind Top Band - 20 March 1923


  First Band, Top Band

Full Article With Photos:
http://w2pa.net/HRH/first-band-top-band/

Posted on 0057z - 24 June 2013 <http://w2pa.net/HRH/first-band-top-band/>

On 20 March 1923 Secretary of Commerce Herbert Hoover convened his 
second national radio conference and, as before, the ARRL was there in 
force. A May /QST/ photo shows Maxim at center flanked by C. F. Jenkins, 
identified as “inventor of radio transmission of photographs,” and Major 
General G. O. Squier, US Army, Chief Signal Officer. Paul Godley of 
transatlantics fame and ARRL Secretary Kenneth Warner can be seen in the 
background. Besides Maxim and crew, other prominent participants from 
the radio research community included inventors Edwin Armstrong, Louis 
Hazeltine, Professor C. M. Jansky—amateurs all—and many others from 
government, academia and industry.^1 
<http://w2pa.net/HRH/first-band-top-band/#fn-2506-1>

QST May 1923 p. 12 (Maxim, et al)

Maxim at the conference, with Godley and Warner behind

The majority of the attendees, however, represented the broadcasting 
industry, as expected. After all, the conference’s main purpose was to 
determine what could be done to ease the industry’s interference 
problems by establishing new regulations deemed permissible under the 
current law, now eleven years old. Since the previous year’s attempt at 
legislation had failed, this was the only path left.

To accomplish any meaningful relief, other services had to give up 
spectrum space to create new wavelengths for the broadcasters. 
Recommendations included reclaiming the 450-meter maritime wavelength 
and the amateur extension at 275 meters to create a continuous broadcast 
band from 222 to 545 meters (approximately 1,351 to 550 kHz, which is 
very close to today’s AM broadcast band limits). The “government 
reserve” allocation above 600 meters was then recast to include the 
maritime service that would be displaced from 450 meters.

The broadcast band was further divided between /Class A/ stations, those 
with high power and continuous service, and /Class B/ stations “of 
restricted range and ability.” Class B would operate below 286 meters 
where wavelength assignments would be made on a geographical basis so as 
to minimize interference.

Assignments for Class A stations above 286 meters would be handled a bit 
differently. One wavelength would be assigned exclusively to each 
geographical region, and stations in that region would further divide up 
the use of the channel into time slices. The conference asserted that 
this would make it possible to assign fifty such regional wavelengths 
spaced 10 kHz apart. With this scheme in place, anyone with a good 
receiving setup could tune in to various other areas of the country and, 
conditions permitting, would have some hope of hearing them without 
interference.

Ten local areas within each of five national zones would have 
allocations separated by 50 kHz, and no areas in adjacent zones would be 
closer than 20 kHz. All broadcasters were required to have measuring 
equipment to ensure that they were operating within 2 kHz of their 
“assigned wave frequency,” as the rule phrased it.

To ease the transition for an existing broadcaster, a temporary 
classification could be assigned to allow it to continue to use its 
present allocation until it could obtain a new one and move there.

The amateurs would get exclusive use of 150 to 200 meters (1.5 to 2 
MHz), which is larger than our current 160-meter band—widely called /top 
band /by hams. Special license holders would be permitted to operate 
between 200 and 222, and “extra special” licensed stations could use 
“some quiet wave below 286 meters for use in the difficult Rocky 
Mountain region for the benefit of trans-continental relay work.” There 
could be at most six of these stations—a severe restriction. Spark 
transmission was /tentatively/ assigned to 175 to 200 meters, with only 
straight CW allowed between 200 and 220, and CW, ICW and phone between 
150 and 176 meters. Further subdivision was possible and the ARRL was 
asked to recommend allocations by transmission type at a later date. 
Significantly, everything below 150 meters was designated as /reserved/ 
but open to special licensing.

The department would also require all radio stations to surpress 
harmonics to a level yet to be specified. And the conference resolved 
that spark transmitters should be replaced “as rapidly as practicable by 
apparatus which will produce a minimum of interference.” It further 
resolved that amateurs should “by mutual arrangement” observe periods of 
silence during religious broadcasts on Sundays. To put some teeth into 
the regulation, it stipulated that the Department of Commerce had the 
power to minimize or eliminate interference by rescinding licenses, 
regulating operation and other means.

Although the major conference benefits went to the broadcast industry as 
intended, nearly all concerned parties were pleased with the outcome and 
some wondered why the government had not done this a year earlier 
instead of expending energy trying to get legislation passed. (The 
answer would become clear a few years later.) The ARRL board was to 
study the proposed regulations in full and make its own recommendations 
before they became final.

The conference also asked the ARRL to recommend how the 200–150-meter 
amateur allocation might be subdivided.^2 
<http://w2pa.net/HRH/first-band-top-band/#fn-2506-2> The League’s board 
then canvassed the membership across the country to come up with a 
unified set of recommendations about allocations and other issues that 
might arise. Although the membership opposed any sort of elaborate 
subdivision plan based upon signal type, there was widespread support 
for something that would protect the shorter wavelengths from QRM. So, 
in a proposal similar to but simpler than the one made by the 
Conference, the board recommended that all modulated forms of 
transmission be limited to the band from 176 to 200 meters, and that 
straight CW be permitted anywhere in the amateur allocation, thus 
protecting the shorter wavelengths which were increasingly viewed as 
important by amateurs. (This reversed the previous scheme where, like 
today, broader modes were confined to shorter wavelengths, that is, 
higher in each frequency band.)

In a worrisome surprise the Commerce Department began to recall amateur 
licenses in order to add a stipulation that no transmitting could occur 
between 7:30 and 10:00 p.m.—an official mandate for the Rochester Plan. 
Knowing about the ARRL’s voluntary program and realizing that not all 
amateurs were League members, the Department was trying to “help” but 
only ended up alarming most amateurs. After the League explained the 
difference between how amateurs viewed a voluntary program as opposed to 
a required one, the Department agreed to suspend further action and only 
apply the new regulation to new licenses until the ARRL Board could 
consider it. With unanimous objection the Board concluded that such a 
mandatory regulation was undesirable and, in particular, would obviously 
prohibit operation during emergencies. The Department’s action would 
remain pending.

The League also suggested that the amateur allocation be expanded to 220 
meters in a more formal manner and establish an “Extra First Grade 
Amateur Operators License” which would conform to the 1912 law 
permitting special licenses. Action on this was also still pending. 
Meanwhile all of the old 375-meter special licenses were being recalled 
since that wavelength was now part of the broadcast band.

On 28 June the Commerce Department signed approval of the new 
regulations, designated General Letter No. 252.^3 
<http://w2pa.net/HRH/first-band-top-band/#fn-2506-3> General and 
Restricted Amateur Radio Station Licenses would permit the use of pure 
CW anywhere between 150 and 200 meters, with spark, modulated CW and 
unfiltered CW being restricted to wavelengths of 176 to 200 
meters—basically adopting the League’s suggestion. Special Amateur Radio 
Licenses could extend the use of pure CW to 220 meters. /Pure/ CW was 
defined as oscillations produced using a power supply of “substantially 
direct current” such as a battery, generator, or rectified, filtered AC 
with less than 5% “supply modulation,” the term used to describe any 
remaining non-DC component. Input power for all three classes was 
limited to 1,000 watts. Each station license would specify the equipment 
in use and the restrictions that applied to a specific transmitter (more 
than one was possible).

/Special/ stations had to be operated by amateurs holding an Extra First 
Grade Amateur operator’s license,^4 
<http://w2pa.net/HRH/first-band-top-band/#fn-2506-4> a newly established 
class, or a First Class or Extra First Class commercial license. The new 
Extra First Grade Amateur license required passing (with a 75% grade) an 
examination containing a new set of questions, sending and receiving 
code at twenty words per minute, and two years of experience as an 
amateur operator, as the League had recommended. General and Restricted 
licenses were again being recalled for modification, this time to 
specify wavelength and quiet hours, whereas special licenses were being 
replaced with newly issued ones to reflect the new allocation.

All licenses would specify that transmitting was not permitted between 
8:00 and 10:30 p.m. local time “nor Sunday mornings during local church 
services.” On one hand, this was recognition of the effectiveness of the 
voluntary quiet hours in the Rochester Plan, and on the other, 
observation that it was not being uniformly observed. The later 8:00 
p.m. start time was a welcome change.

For the first time, amateurs officially had a /band/ assigned to them 
rather than a single specific wavelength (200 meters). Although the 
League did not get the desired access to wavelengths shorter than 150 
meters, the Commerce Department assured amateurs that it would grant 
special licenses to operate there for all applicants who were “seriously 
interested” in experimenting.

Having a band of wavelengths opened up new possibilities for reducing 
QRM. Warner optimistically, if unrealistically, suggested that, “we have 
so many cycles in our band that if we distribute ourselves even 
approximately evenly we should have almost no QRM.”^5 
<http://w2pa.net/HRH/first-band-top-band/#fn-2506-5> But to take 
advantage of the space, amateurs needed a technique to make it easier to 
change wavelength, normally a cumbersome procedure. “This is something 
we have never developed because it hasn’t been permitted us before,” he 
noted. A frustrating yet common occurrence was that you would hear a 
station you’d like to work calling on a different wavelength from your 
transmitter, then fail to raise him because he was not tuning around 
with his receiver. The League secretary marveled at “how funny it is to 
call blindly and hope our correspondent will be kind enough to turn his 
knobs to our wave; how much more to the point to call on the wave we 
know he’s listening on!” He cited an example where two stations miss 
each other, one on 200 meters and the other on 215—a difference of about 
105 kHz. And he called for invention by the members, writing that, “We 
don’t believe there is a circuit whereby it can be done efficiently with 
even two controls; the couplings have to be changed and it is likely to 
become a half-hour job” just to QSY!

The second big job was to devise transmitters that produced no spurious 
emissions—or at least fewer of them. The Commerce Department indicated 
that it might consider lifting the quiet hours requirement if amateurs 
could build “a transmitter which is silent on the waves it isn’t 
supposed to be using, even when listened to next door.” This was an 
implied reference to interference to broadcast listeners who would 
likely be using unselective receivers—a broadcaster on 222 meters, for 
example, is only 150 kHz away from 200 meters. This clearly called for 
the use of /pure CW/ with no modulation effects of any kind. “When all 
these things are solved,” predicted Warner, “a /bugproof/ amateur 
transmitter will be the result; we shall be much happier, our work will 
be much more pleasant and more enjoyable.”

Ahead of the ARRL board’s upcoming detailed consideration of the new 
rules, Warner summed up his impressions and suspicions this way:

     From the standpoint of the broadcasters it’s FB but from that of
    the amateur—? It seems somebody else has their eye on the waves
    below 150 meters and we did not succeed in our effort to secure an
    amateur band around 100 meters … The majority sentiment on the
    Conference was to fix up the broadcasting business so it could
    succeed, and tribute was exacted from the government services; the
    amateur, the commercial, and even perhaps the facilities
    safeguarding life at sea, to make that possible.

BT sep smAround this time amateurs began to discuss how band allocations 
were specified and talked about. Echoing an increasingly popular 
opinion, /QST/ correspondent A. N. Goldsmith asked how and why 
wavelength was chosen over frequency to describe radio waves, when 
frequency was much more “natural”^6 
<http://w2pa.net/HRH/first-band-top-band/#fn-2506-6> in his estimation. 
After all, nobody referred to AC power as 5,000,000-meter waves. The 
practice of specifying wavelength probably dated back to Hertz 
(ironically enough, since his name would later be used internationally 
as the standard unit of frequency), who was experimenting with waves of 
only a few meters, and to studies of light waves which had frequencies 
so high as to be “practically impossible” to comprehend, wrote Goldsmith.

But for radio it seemed a big mistake to think in terms of wavelength. 
It was much easier to speak about “space for transmission” in terms of 
frequency, since that amount of space depended directly on the frequency 
of the modulating signal. Thus the frequency at the center of a signal’s 
band of occupied frequencies is the /carrier frequency/. It then becomes 
easy to say, for example, a 200-meter CW signal at a speed of 20 WPM is 
on a carrier frequency of 1,500 kilocycles and occupies a band 10 cycles 
wide. Similarly, a phone signal occupies a band having a width that is 
double the maximum desired audio frequency, which, Goldsmith asserted, 
ranges from roughly 4,400 cycles for speech to 15,000 for “high grade 
music.” The band of wavelengths depends on the wavelength itself, 
whereas the band of frequencies is the same for a given mode of 
transmission regardless of the carrier frequency. Using frequency made 
it much easier to talk about signal occupancy within bands.

This discussion also made clear why spark was on its way out. A spark 
signal extends out indefinitely from its carrier, getting weaker as you 
move further from the center. “A well-behaved modern station must have a 
definite address. It must occupy a certain numbered residence of 
reasonable width on the /Street of Carrier Frequencies/, and it may not 
invade everyone else’s home to some extent. And that is exactly what the 
spark station unfortunately does,” and why it must be eliminated, wrote 
Goldsmith. Having used wavelength for so long, it would be difficult to 
make the change due to “conventional and sentimental objection” to it, 
he added.  But converting was easy, really—dividing 300 by the 
wavelength in meters gives the frequency in megahertz. To get the 
frequency at 200 meters, you divide 300 by 200 which equals 1.5 MHz.

With the arrival of a band and allocations within it, amateurs would 
have to change both how they /produced/ signals and how they /talked/ 
about them.

AR sep sm

de W2PA

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Full Article With Photos:
http://w2pa.net/HRH/first-band-top-band/