----- Original Message -----
Sent: Thursday, March 03, 2011 7:52
PM
Subject: Re: LF: Topband Test
Are three plots of a 4 Watt RF (probably no more than
500mW ERP) 1967kHz signal transmitted to G3PLX at a distance of 393km.
The numbers along the bottom are UTC hours, but I have no record of the
vertical frequency span. Going on distant memory, The
EVM driver / plotting software writen by Peter used 3.125, 6.25, 12.5 Hz
plots, so I guess the width is one of those two lower values.
The signal starts waving about all over the place once it gets
dark!
These plots were made over the period 20 - 23 Jan 1998
according to the date on the original files, so
roughly 'about' the same point in the last sunspot cycle as we
now are in the current one, but a bit earlier in the year.
These plots pre-dated low cost simple GPS stabilised sources,
but I did have a very good ovenned oscillator and an MSF locked
standard, that could maintain 10^-9 over the duration of the
transmission; and a synthesizer. Essential requisites
for this at the time ground-breaking amateur experimentation. Now
anyone can do it :-)
Andy
'JNT
On 3 March 2011 18:55, Chris
<[email protected]>
wrote:
Hi All,
Yesterday evening Pete, M0FMT, transmitted QRSS
on topband for a test. An unexpected effect was noticed with the trace
splitting in two. Nothing new or 'earth shattering' I expect, but new to us
and worthy of further experimentation.
I have never seen this effect on 137, even with
quite strong audible signals, maybe others have.
Vy 73,
Chris, G4AYT, Whitstable,
UK.
