Dear LF Group,
I'm pleased to see PA0SE's FS measurements agree well with my own - it
looks like we are getting quite good at this now!. I measured my ERP a
couple of weeks ago, after making some slight improvements to my antenna;
it is still an inverted L, but it now has an average height of around 9.5m,
and the same 40m length as before. The 400mW figure was derived from an
average of 11 field strength measurements at distances between about 1.5
and 3km. Comparing these to measurements I did last year at the same
locations, it is interesting to see that the variations in calculated ERP
between different locations are very consistent - ie. if one location gave
a measurement 1dB above the average last year, it was also 1dB above the
average this year, so whatever causes the variation is stable over quite
long periods of time. All the ERPs were within about 1.5dB of the average ERP.
The antenna current of 4.6A is well down on what I get on a cold winter's
day, so I think this antenna should give 500-600mW ERP under good conditions
I used a "Jason" mode test signal when performing the measurements - this
is ideal for FS measurement, because it is practically a continuous
carrier, and makes it easy to measure the amplitude.
Cheers, Jim Moritz
73 de M0BMU
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