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From: "hamilton mal" <g3kev.ham@virgin.net>
To: "rsgb" <rsgb_lf_group@blacksheep.org>
Date: Sun, 29 Oct 2006 16:46:07 -0000
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Subject: LF: 500 khz
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Status: O

Hi All
Nothing hrd or seen last night on 500. From my previous commercial
experience on the band it will be more like 160 metres rather than 136 or 73
khz.
Given a level playing field with say 10w erp on any of the above bands
reliability would be in the order 73, 136, 500 and 1800 khz.
Given the fact that the average radio amateur can only launch a few
milliwatts on 73 or 136 it has been possible to cover great distances,
especially noticeable on ground wave during daytime.
I can  work OH1TN about 1000 miles to the NE and IK5ZPV SE about the same
distance on 136 khz anytime during daylight with good reports each way
typically 579 and only running less than 0.5w erp. This includes summer or
winter. I cannot do this on 160 metres using 400 w erp output during
daytime. This is where LF has the advantage at this distance and there seems
to be no difference between between day and night time.
Night time with enhanced propagation via the E layer makes worldwide
communications possible on LF with their limited power,  although commercial
stations on frequencies as low as 15 khz can communicate 24 hrs per day,
with lots of erp.
On 500 and 1800 khz during the dark hours world wide communications is often
possible especially when dawn and dusk coincide between the countries
concerned. Ground wave daytime on these two frequencies reliabily only
extends to about 200 miles for the average amateur if you are lucky.
I am sure others can relate to the above info.
Its a pity 73 khz was'nt still available, it was just getting interesting
when the plug was pulled.

73 de Mal/G3KEV