[CW] I don't get it?

[wealsowalk at aol.com]

Don, I am on the periphery of our experimental groups on 500 Kc.  there 
are several groups in the US and yes, the use of the band is old, but 
most of the 3/4 century of work is for communication over water where 
ships were heard all over the world.  Over land, the situation is 
different and most of the communication appears to be by groundwave, 
although there have been a number of contacts over several thousand 
miles.  Furthermore, the work is done at fairly low power, not QRP by 
any means, but low compared to previous work and the antennae in use 
are all electrically short, so the radiation resistance is low and the 
effective power out bare hundreths of what a 1/4 wave would put out.  
Further, the technology that there is a great deal of experience with 
is also all old and one of the positive goals is to learn what newer 
technology can do.  Some, of course, are just implementing older 
equipment.  For example I know that at least one of the group members 
was just this week attempting to purchase a TAJ-19 which is a WWII 
transimitter that naval aviation used, but it is not necessarily the 
transmitter that is the experiment.  Receivers also are in the 
experiment as well as receive antennaes.  If you tune your yeacomwood 
to 505-515 kHz (where the original group is at), you probably will not 
hear anything and for several reasons.  First your antenna is wrong.  
Some people are using s
hort electric probes with wideband preamps to 
hear with.  Also, your radio desensitizes between 500 Khz and about 
1800 Khz because the broadcast band is so strong that the manufacturers 
deliberately desensitize the receivers for that region.  But even if 
you have a proper receiver/antenna, depending upon where you are, you 
still might not hear anything, even with very narrow CW filters, 
because the signals you are looking for are well under the noise.  Some 
are attempting to use PSK31 because that is a low signal approach.  
Another is QRSS CW.  QRSS means very slow.  So slow that a computer can 
scan the region of the signal hundreds of times or more during a single 
dit.  Doing that averages the random noise out, but leaves any peak 
that was a signal.  There are many other new technologies that will be 
applied to the experiment.  Of course, there is also now a toe in the 
door that may result in additional band spectra for HAMs everywhere 
depending upon another part of the experiment:  Can just anybody do 
this?  What happens when I live in an apartment and try to send a 
signal out on this band?  Do I get into the neighbors telephones?  
Sure, out on the farm you can put up a big signal and have a big 
antenna, but at your house, with a short antenna that is loosing most 
of its signal, how badly do we get into our neighbors AM radio?  Where 
does the signal go?  There are litera
lly hundreds of questions that 
need to be answered before the FCC will allocate a band down there to 
the HAMs.  Thus it is an experiment to find out.  WARC has given a 500 
KHz allocation, but the FCC has not, except in the case of the 
experimental licenses.
I hope this is a help to your understanding.
Bill Isakson
AC6QV
California

-----Original Message-----
From: D. Chester <k4kyv at charter.net>
To: cw at mailman.qth.net
Sent: Mon, 24 Nov 2008 10:35 pm
Subject: Re: [CW] I don't get it?


> What is "experimental" about the 500kHz neighborhood? It's not like 
this > is some newly discovered spectrum, never used before. Yet the 
FCC issues > "experimental" licenses to operate there, and now I see 
the Canadians are > doing the same. What are hams going to learn that 
isn't already well > known from the nearly-100-years or so of previous 
use? 
> 
> 73, de Hans, K0HB 
 
The previous users for the most part didn't have the kind of antenna 
and financial limitations most amateurs have, and amateur communication 
is different in many ways from commercial. The "experimental" aspect is 
to discover what amateurs can actually do in that frequency range under 
the circumstances with what we have available. 
 
Don k4kyv  
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