[SFDXA] The Band Edge- How Close is Too Close?

[Bill]

The Band Edge- How Close is Too Close?

By Duane Traver, WV2B

It was a situation heard all too often. In fact, it can be heard almost 
every contest. A DX station calls "CQ Contest" on 14349 KHz. Strings of 
US stations answer and exchange the contest exchange. But in addition 
another voice can be heard.

Besides the stations exchanging contest reports another voice rings out- 
"You're out of band stupid, don't you know the rules." Some contesters 
are bewildered, doesn't the band go to 14350? Others are argumentative- 
I am not out of band, they contend.

Obviously the mystery voice is not handling things in a proper manner. 
After all, if the stations he is condemning are out of band so is he. In 
addition, he is not identifying his transmissions. But why do these 
arguments keep erupting? Does this guy know what he's talking about?

The Rule

If the band goes to 14350 KHz, then contesters can just set their dials 
to that frequency and operate- right? Wrong! The crux of the matter is 
found in FCC rule 97.307, which reads in part: "Emissions resulting from 
modulation must be confined to the band or segment available to the 
control operator."

What must be taken into consideration is the fact that the frequency 
displayed on the radio's digital display is the carrier frequency. A 
suppressed-carrier single-sideband signal is considered to be 3 KHz 
wide. So, for an USB signal to be confined to the 20 Meter Amateur band, 
the frequency displayed on the transceivers digital dial should not be 
higher than 14347. That may even be too close unless the transmitted 
signal is attenuated by at least 40 dB at 3 KHz. Of course, the same 
goes for a LSB signal transmitted near the lower end of a band or 
segment. Please see illustrations A and B below for help visualizing the 
situation.

                USB Signal
             ^^^^^^^^^^^^
I--------I--------I
347   14350   353

   A. USB signal transmitted with dial frequency of 14350 KHz.

LSB Signal
^^^^^^^^^^
I---------I--------I
147      7150       153

B. LSB signal transmitted with dial frequency of 7150 KHz.

So, the fellow telling all the contesters that they were out of band was 
right! But, is it a big problem? Obviously more education is needed on 
this particular rule. In the 2001 ARRL DX phone contest one DX station 
was heard running US stations on 14349 KHz. in excess of 5 hours 
straight with a steady stream of US callers. Most were Extra class 
licensees.

Although certainly the majority of these callers didn't realize they 
were violating an FCC rule, the action could result in an FCC warning, 
ARRL OO notice, or perhaps an argument from a frustrated fellow 
contester as mentioned at the outset of this article. Since all 
contesters who submit a log sign a statement that they have followed 
their country_s Amateur regulations they should be willing to take this 
rule into consideration and modifying their operation as needed.

In addition, contesting ethics are involved. What if a station finds a 
clear running frequency by operating too close to the band edge, while 
his competitor perhaps fails to find a run frequency out of respect for 
this regulation? Or what if a multiplier is counted by working a station 
calling too close, while other stations don_t get the multiplier because 
they want to obey the rules? Perhaps such situations are part of what 
causes our mystery stations to vent their frustrations.

I hope you find this article of help in your contesting efforts. Further 
information about this particular FCC rule can be found on page 4-34 of 
the ARRL_s "FCC Rule Book." See you in the contests.

Full Article With Comments
http://www.contesting.com/articles/148