Re: LF: RE: 503.6kHz Test

[Gary - G4WGT <g4wgt@tiscali.co.uk>]

Hi Jim, LF,

Thank you for the plot & your observations. I have downloaded the plot to study later.

I had not realised until after the PA FET failure on Saturday night that the LPF toroids were very hot & need to be upgraded if I am going to run that level of power again (5 watts ERP about 4 Amps antenna current). I must also check the matching transformer toroids at the base of the antenna if that is getting hot also, I may look into the alternative matching (tapped coil) which you provided documentation & a spreadsheet for a while ago.

Keep up the good work, I am sure that we all appreciate your input, time & efforts devoted to the hobby.

Cheers,

Gary - G4WGT.

2009/10/11 James Moritz <james.moritz@btopenworld.com>

Dear Gary, LF Group,

This is what the signal looks like for about 11/2 hours up to 2200utc. The red signal is G4WGT, the yellow one is G4JNT's WSPR beacon. The blue line is the noise level scaled to about 300Hz bandwidth, to give an idea of the audible strength as a CW signal. The plot settings are not ideal to show variations in signal level - there are actually short periods where the signal fades to inaudibility that don't show up here, but it gives a reasonable idea.

G4WGT I think must be mainly sky wave here so presumably the fading is due to  different sky-wave paths.  G4JNT is a very stable ground wave signal here during the day, so I imagine the fading here is due to the combination of ground wave and sky wave.

Cheers, Jim Moritz
73 de M0BMU