Questions about spotted QRG

8 posts / 0 new
Last post
Last seen: 2 months 1 week ago
Joined: 2010/06/17 - 08:10
Questions about spotted QRG


I'm just starting with WSPR. The reported frequency of my beacon transmissions often vary wildly from what I intended to transmit. It looks like the following:

1. When I first begin, if nobody spots me, my system uploads its anticipated frequency for the Activity screen

2. After I get spotted, it appears that some kind of average among the spotted frequencies is shown on the Activity screen. Any info on how that average is computed?

I am running a Flex-3000 with DDS LFO. I know from prior experiments that the TCXO driven PLL, while perhaps relatively accurate, actually performs a periodic orbit in drift over the course of an hour or so. The size of this drift, once initially calibrated out, seems to be on the order of 1 ppm.

Using a linear estimate of the frequency correction will only work for about 2 instances per hour. I don't know yet if the orbit is deterministic, i.e., if once mapped over many orbits and its starting point on any given day determined, whether or not one could perform open-loop corrections to the frequency? I suspect it is not that simple... and probably follows some kind of chaotic attractor basin.

Finally, while I'm getting spotted all over my hemisphere (from Japan, to Australia, to Alaska, and all the way to the East Coast), I consistently pick up only one other beacon, located somewhere north of Los Angeles... So I have to assume that my receiving antenna is junk... :-( Which is surprising given the number of spotters who report on that they are using a simple whip antenna...)