15 Aug 2010 22:25:56

Supplemental Report of the experiments on 500 kHz as a followup to the
report submitted 21 November 2009. Submitted to Jim Dean by Joe Craig,
Marconi Radio Club of Newfoundland.

This information is intended to be used at the WRC-2012 technical meetings
held in the ITU, Geneva, in May and is a report of activities at VX9MRC
NL Canada.

The transmitter comprised a 100 watt class E operating with a drain voltage
of 40 volts and a direct digital synthesis exciter.  Further details may be
found on the MRCN web page by searching for VO1MRC on the internet. The
modes used were conventional CW  which is received aurally and QRSS
which uses long integration times and fourier transforms to obtain very low
effective bandwidths at the expense of signalling rate. It is received using
a computer sound card.

Periods of operation which included communication with other stations were
provided in the first experimental report submitted November 2009.
Since this time, 2-way communications were discontinued.  Instead signal
reports were solicited and reception experiments were conducted
over land and sea paths using portable receivers and compared with
signals from regional aeronautical nondirectional beacons in  LF and MF
bands.

In December, special transmissions were made to mark Marconi's receipt of
the Nobel Prize. These took place continuously as a beacon
from 9-24 December.  Reception reports were received domestic and foreign
stations.

Beacon transmissions took place from 04-8, 27,28 and January 2010 and and
from 30 January-4 February.  From 10 Feb-18 Feb the transmitter
sent a beacon as part of over-land reception experiments with a portable
hand held receiver.  Reliable reception was possible in excess of 200km
using CW.

On 4 March the 100 m wire aerial became iced, forcing the transmissions off.
Various experiments were conducted with antenna tuning.  The transmissions
resumed on 11 March with a shorter antenna about 30 m long.

The aerial was repaired and transmissions resumed on 22 April. Various
formats with CW ID and unmodulated carriers up to 30 s long were
used until 6 May.  Additional transmissions were made on 10, 11 22,
24,26,and 27 May.  A special transmission was made for Field Day
from 25 June -01 July.

Regional reception experiments were conducted 14-24 July.  The beacon
signals were 8 WPM CW and could be heard as far away as Northern Labrador
over a mostly land path. Another transmission took place from 29-30 July.


General Observations:  Very gratifying results were had using a hand-held
receiver and  small active antenna.  CW signals could be reliably copied
over several hundred kilometres during the daytime and at night. Night time
distances seemed to be greater (up to 800 km), but with more variability,
consistent with ionospheric propagation. These receptions could be improved
by using a digital encoding and a more substantial receive antenna.

A highly reliable 2-way 500 kHz circuit was had with VX9ZZZ in Nova Scotia.
Reception reports were forwarded by amateurs in NL,EU and the US fow which
we are mist grateful.

Aside from AGC pumping of car radio in the vicinity of the transmit antenna
there were no reports of any interference arising form these transmissions
to MRCN members or the regional Industry Canada office.

The 500 kHz band is very useful for reliable CW communications and therefore
for digital modes as well.  The groundwave coverage appeared better than
that
on 160m even though the transmit antenna was less than optimal, though
practicable for many amateur stations.  Most amateur stations are  already
equipped to receive 500 kHz though fewer can do so on 137 kHz because the
general coverage receivers are limited and special receive antennas are
usually needed for 137 kHz.

Date: Fri, 20 Aug 2010 08:38:54 -0230 (NDT)
To: James G. Dean  et al. 
Cc: jkpulfer@sympatico.ca, ve3qn@sympatico.ca
Subject: Re: VX9MRC report #2

Hi All,

Many reports came from eastern Canada and the States, but they were
1000-1500 miles away and during the night.  This would be by sky wave and
not ground wave.  Reliable ground wave reception appears to be possible up
to 200 to 500 km over land paths with the present set-up.  This distance is
often a challenge on 3.5 MHz during ionospheric storms, and unworkable on 7
MHz and up.

Cheers
Joe