[AMRadio] Anti-AM Opinionated Hams


Mike Sawyer w3slk at hughes.net
Thu Nov 22 13:56:48 EST 2007


You are absolutely correct Don. Sometimes we can be our own worse enemies 
(especially when our contemporaries like to belch and be beligerent while 
operating) On a few occasions, where SSBer's were QRMing us, someone would 
go on sideband and let them know. We've had some positive experiences where 
the SSBer would tune his rice box on AM and state something to the fact that 
they haven't been on AM in years. Ultimately, in the end they would sign 
stating they thoroughly enjoyed the QSO and intend to operate AM more often.
Mod-U-Lator,
Mike(y)
W3SLK


I have observed that AM operators can be just as culpable as SSB operators
when it comes to claiming "ownership" of certain frequencies.  I have heard
SSB QSO's start up somewhere within the Ghetto while there was no-one using
the frequency, and AM'ers actually break into the QSO and advise the
offending stations to QSY because they in the "AM Window".  To me,  that's
no different from the 3892 and 3878 groups or the macaroni net claiming
ownership of the frequencies they use.  Also, I have heard AM operators
admit over the air that they knowingly started up only a couple of kc/s away
from an ongoing "slopbucket" QSO.  When we conduct ourselves over the air in
that manner, we are doing exactly the same thing that we complain about the
slopbuckets doing.

But by the same token, I refuse to recognise Dead Air Groups.  If 3892,
3878, the macaroni, AM Window  or any other "owned" frequency happens to be
clear, it becomes fair game for anyone to occupy. If I fire up nearby, then
the frequency is in use - by me!  If you are queued up in front of the
service window inside the bank, and you step away to take care of other
personal business, you don't return to your old spot when you finish.  You
go back to the end of  the line and start waiting for your turn all over
again.

The best way to handle the  frequency issue is to open your receiver to a
comfortable selectivity, considering band conditions at the time.  Then try
to find a spot where you hear minimal QRM with the receiver set at that
selectivity, and settle in on that frequency.  Preferably, you would have
some means of adjusting transmitter frequency response so that you could
adjust your occupied bandwidth to coincide with your receiver selectivity.
No point in transmitting audio out to 8 kc/s (total bandwidth 16 kc/s), when
the band is so crowded that no-one is going be listening on a receiver that
is set for more than 6 kc/s of selectivity.  I have two passive low-pass
audio filters in my transmitter audio chain.  One gives a gradual cutoff
above 5 kc/s, so that everything is gone past 7.5 kc/s.  The other has a
very sharp cutoff at 3400~.  At 3300~ there is less than a dB of
attenuation, but at 3500~ not enough signal gets through for the modulation
to be detectable on the scope.  Those filters are surplus items I picked up
at different times, that had accumulated in my junkbox.  Similar filters can
be found at hamfests and other sources, or even homebuilt.  There is quite a
bit of data available on active filters that are easy to build.  Even a good
graphic equaliser could be made to serve.  When activity on the band is
light, I usually employ the 5 kc/s filter, but when I have to cut the
receiver down to 4 or 6 kc/s bandpass to find a clear spot, I try to
remember to switch in the 3400~ audio filter.  I rarely switch the filter
unit out altogether, since my transmitter's response is flat well past 11
kc/s.

Another thing I find irritating, which discourages me from operating in the
Ghetto, is that AM stations will sometimes fire up within 4 or 5 kc/s of
each other.  It is physically impossible to operate that close together
without some sideband overlap.  Better to spread at least 7 kc/s apart
whenever possible.  When the band is congested, I can usually copy fairly
comfortably when when another AM station with a clean signal is only 5 kc/s
away, using the 6 kc mechanical filter, but at only 4 kc/s away, I have to
use the 4 or even 3.1 filter, and tune slightly to one side.  There is no
reason to have to do that when there are unused frequencies nearby.

When I start up on a clear frequency, and after my QSO is firmly
established, a SSB group knowingly starts up only 2 kc/s away and then
proceeds to gripe about the AM QRM, I am  stubborn enough for that to make
me feel more determined than ever to stay put.  If they can put up with my
splatter, I can tolerate theirs.  Besides, the AM signal I am trying to copy
has two sidebands - sort of a diversity reception situation.  Very rarely
does intentional SSB QRM make it impossible for me to copy the other
station, even on my half-century-old receiver. But I make it a  point never
to mention the QRM over the air and give the offending operators the
satisfaction of knowing that I am even aware of their existence.

Don k4kyv

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