Message-ID: <000f01cb88e3$f3a0b360$0401a8c0@xphd97xgq27nyf>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <4CE7FC47.21165.4FBFDFD@mike.dennison.ntlworld.com>
Date: Sat, 20 Nov 2010 18:51:33 -0000
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Subject: LF: Re: 136kHz Eu DX frequency - summary
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I suggest you use 136.320 for unattended  Beacons and use 137.7 for th=
e QSO
attended mode if you must.
Watching yourself on grabbers is not the ultimate goal.
g3kev


----- Original Message -----
From: "Mike Dennison" <mike.dennison@ntlworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, November 20, 2010 4:50 PM
Subject: LF: 136kHz Eu DX frequency - summary


There have been 6 comments on whether the Eu DX slot on 136.320kHz is
still useful.  To summarise:

Grabbers: One more Eu station has provided a grabber on 136.320, and
one active NA station has stated he is unable to add this sub-band.
Only two grabbers are available outside Europe to monitor this
frequency - RW3ADB (which is almost always off), and KL7UK on demand.
It is therefore difficult for a Eu station to offer an occasional
beacon on the Eu sub-band as there=B4s nobody listening.

There have been two practical solutions to avoiding local QRM to DX
stations.

Split-frequency: This was used some years ago when there was lots of
Eu DX activity and east coast W/VE stations were monitoring.  For
instance, Eu transmit on 136.320 and NA transmit on 137.777.

Split timing: This was used successfully this year on the JA-VE
route. For instance, JA transmit on the hour and half hour, and VE
transmit on the quarter and three-quarter hour. A suggested solution
has been to use alternate days for Eu and NA.

Both of the above solutions are fine but they only work for two
locations at a time. If a third location is added to the mix, such as
Russia, or both East and West Coast America, the solution breaks
down. For instance, Eu transmits on 136.320, UA transmits on 137.777,
but NA also transmits on 137.777 and is prevented from receiving the
UA stations. A resolution would require at least three DX slots, with
every grabber equipped to receive them. The split timing solution
would also need additional timing slots which might lead to openings
being missed.

It is possible to devise a complex solution involving both time and
frequency, especially as the hours of darkness move round the world,
but it need all operators to cooperate.

Is there a real problem? I don=B4t think there is a practical problem
at present. Activity is low and most stations are in touch with each
other via this reflector. If/when the USA gets an allocation at
136kHz, I can see a real need for some kind of plan, but that=B4s not
for a while yet.

In the meantime, it is of course important for beacon operators to
make every effort to avoid interfering with each other. Frequency
spacing is an obvious way, as well as making sure that there are
listening gaps between transmissions. It would also help if more
grabber operators could open more receive slots.

To sum up my own position, I have not found any evidence of
propagation research or QSOs being affected by my occasional beacon
on 137.7752kHz, so I will continue to use this frequency. I will also
use 136.3182kHz whenever I can be sure there is a person or machine
available to receive my signals. I will also try to limit beacons in
time.

As always, if anyone has a practical problem, I am happy to switch
off.

Mike, G3XDV
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D