Re: LF: Topband Test

[Andy Talbot <andy.g4jnt@gmail.com>]

http://www.g4jnt.com/Download/1967jnt1.jpg

http://www.g4jnt.com/Download/1967jnt3.jpg

http://www.g4jnt.com/Download/1967jnt4.jpg

 

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 <c.ashby435@btinternet.com> 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.

See the result and conclusion on my website http://qsl.net/g4ayt on the bottom of page 1.

I have never seen this effect on 137, even with quite strong audible signals, maybe others have.

Vy 73,

Chris, G4AYT, Whitstable, UK.