The Six and Ten Report   March 1997

Four years of tropospheric propagation data

The morning skeds on 50 MHz between G3CCH (South Humberside) and G4UPS (Devon) over a 350 km path have been in operation for slightly more than 4 years. The records show a gradual improvement over the 4 year period in both monthly average signal strength and reliability, possibly reflecting incremental station improvements. The first graph shows this trend - graph bars and left hand Y-axis for monthly reliability, graph line and right hand y-axis for monthly average signal strength.

Reliability and average signal strength of G3CCH at G4UPS over 4 years

As described by Ray Cracknell G2AHU when he reviewed the results of the first year of the tests (Six and Ten Report, December 1993), the monthly differences are surprisingly small and could be a random effect. However, looking at the monthly data averaged over the last 4 years, one might be able to conclude that summer and autumn provide the best conditions for tropo-scatter over this path.

Monthly average signal strength of G3CCH at G4UPS

September and October are picked by G4ASR in his generalised "Dxers Year Planner" (The VHF/UHF DX Book) as best months for VHF tropo. The 50 MHz test data seem to confirm this. Due to the frequency of settled weather patterns perhaps?

 

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