21 Oct 2014

472kHz ERPs

Something seems wrong to me in that the difference between reports I give and I get on 472kHz WSPR suggests either my ERP is higher than I think or the ERPs stated by some others is lower than they think.  I am pretty sure my ERP is about right give or take a few dB "experimental error".  I am able to measure antenna current, I know the actual antenna height and can calculate the effective height. If anything, I believe my ERP is over-stated as my losses are pretty high.  I suppose my reports of others may be a few dB down because of the poor-ish sensitivity of my FT817 at 472-479kHz?

UPDATE 1740z:  I have been on 472kHz WSPR for just over 1 hour now. Just the usual early evening reporters with some very decent reports from G3WCB (101km) and G8LCO (58km) amongst others.   As always, PA3ABK/2 (306km) is putting in a big signal again this evening from across the North Sea. 

UPDATE 1752z:  Just been spotted in Wales by GW0EZY (251km) at -25dB S/N.

1 comment:

Anonymous said...

ERP's on 600m are Estimated Radiated Power for some!! Your signal at my end is about 7dB above what you see because you are off my loop axis by that amount. Not allowing for the off axis reception G3XBM came third last night in mW/Km to me, only beaten by LA4ANA and IW4DXW.

Nice that the number of 600m WSPRers is increasing,weekends can be busy. Just had a slot with six decodes out of 8 on screen- getting like 20m!

I had a word with Mike G3XDV -who is local to me- thanks to a few words of wisdom I have been able to increase sensitivity by improving the noise floor. The remote active bandpass loop helps too, as noise fields drop off at 1/d^3 in the near field even a small separation can make a very big improvement.