Seem to remember reading that LUF is a calculation based on D layer absorbtion. Propagation predictions software giving LUF uses sunspot number / solar flux and time plus lat / long, but unlike MUF,
G3LDO wrote: There is this thing called LUF (Lowest Usable Frequency). Not much in ham literature about it but from Bill Orr's Radio Handbook it depends on transmitter erp and atmospheric noise. Gene
FWIW, we had most problems with Decca skywave interference at sunspot minimum. There is this thing called LUF (Lowest Usable Frequency). Not much in ham literature about it but from Bill Orr's Radio