|[AMRadio] Re: AMRadio Digest, Vol 36, Issue 30|
k4kyv at charter.net
Sun Jan 21 10:04:56 EST 2007
I was thumbing through some old QST's and handbooks from the 30's last
night, and reviewed some of the pre-war subband arrangements. Interesting.
Prior to 1932, there were no subbands on 160, just as it is now. On 3.5-4.0
mc/s, there was an 80-metre phone band, 3500-3550. No phone on 40 or 10.
On 20, with a special licence and permission from the Radio Inspector, you
could run phone on 14.1-14.3 mc/s . The entire 20m band went from
In 1932, at ARRL's request, the FRC (Federal Radio Commission) approved
changes to the phone allocations: Phone operation on 160 (1715-2000 kc/s)
would be restricted to 1875-2000. The reasons given were that the sunspot
cycle would be bottoming out within the next couple of years, and much of
the regional cw activity on 80m would have to move to 160, due to the
expected 80m skip zone, so they wanted to reserve the lower end of the band
to cw. Another reason was BCI. At that time, BCI from 160m phone was
almost as much a headache to amateur radio as TVI was in the 50's. So the
thinking was, move 160m phone up to the top end of the band, and that would
increase the frequency space between the broadcast band and 160m phone. The
top end of the BC band ended at 1500 kc/s then. However, less than a year
later, at ARRL's request, the phone subband was extended back to 1800-2000.
1715-1800 remained cw only.
The 80m phone subband was moved from 3500-3550 to 3900-4000. Canada opened
up the 3900-4000 kc/s subband, but Canadian hams could continue to use the
old 80m allocation as well. One of the reasons for moving the US allocation
to the top end of the band, was interference to aircraft communition just
below 3.5 mc/s. That wasn't the hams' fault; aircraft receivers of that era
were simply too non-selective.
No 40m phone operation was allowed before WW2. 40 was eventually opened up
to phone because the foreign broadcast interference was causing amateurs to
vacate the top end of the band, and it was hoped that a phone allocation
would bring amateurs back to the upper frequencies. There was fear that the
US might also reallocate the top end to broadcasting if it wasn't being used
The phone subband on 20m was reduced from 14.1-14.3, to 14.15-14.25. Phone
operation on 20 back then was kept in the middle of the band to reduce the
liklihood of out-of-band spurs from phone stations interfering with other
There was no 15m band before WW2.
At first, 10m was cw only, just like 40. Then a small phone subband at
28.0-28.5 was opened, later to be expanded to 28.0-29.0. The entire band
was 28.0-30.0 mc/s.
The 80m and 20m subbbands were made "class A." Incentive Licensing 1932
style; hams without the class-A ticket had to vacate 80 and 20, even if they
previously had the RI's permission to use those bands. The class-A licence
required no further code test, and the written test was limited to topics
directly related to radiotelephone operation. There was a mandatory
one-year waiting period that an operator had to be licensed before he could
take the class-A exam.
In addition, there was an "Extra First Class" amateur licence, but it
carried few additional privileges, much like the Extra Class before 1968.
This message was typed using the DVORAK keyboard layout.
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