[CQ-Contest] 14MHz harmonics in 28MHz band

i4jmy at iol.it i4jmy at iol.it
Tue Jun 6 19:37:54 EDT 2000


It's not impossible that even 50-100 mW into a single feed multiband 
antenna (i.e. a multiband yagi that's efficient and has gain also on 
the harmonic related band) are enough to be heard thousands kilometers 
away if conditions on that band are good.
Really strange, instead, if this happens with sophisticated setups, 
expecially witha a MM station.
A MM station infact, because confined in a small area, can't accept to 
radiate any strong signal in another harmonically (or not) band unless 
seriously disturbing that band or even damaging receivers.
Typical MM arrangements are quite sophisticated and include absorbing 
stubs and monobanders on each transmitting setup. 
Those extra devices introduce an extra filtering effect of some 40-60 
dB to the inherent attenuation of the amplifier with a PI (or PI-L).

73,
Mauri I4JMY


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